Can you fill your tires with nitrogen at home instead of car center refills? Yes! It’s easy to give your tires a refill by yourself by using a nitrogen-filled cylinder and following the correct steps. Remove as much air as possible from the tires, then refill them with nitrogen. A 96-percent nitrogen fill is good enough since you cannot get rid of all the air before you start filling.

Fill your tires with nitrogen at home

Filling your tires with nitrogen at tire centers or car dealerships will quickly pile up your car maintenance costs. So, why don’t you invest in a home nitrogen refill setup? Here’s what you will need. Also, check the table below for the analyzed numbers.

1. Nitrogen tank or cylinder

For your home use, you will need a nitrogen cylinder (mid-sized tank) just like the ones you use for welding gases. You can opt for a tank that holds about 300 cubic feet of nitrogen, which will be enough for about 60 refills.

The mid-sized tank is a reasonable investment. Getting the 300 cu/ft size will cost about $400, so can opt for a small-sized one like a 125 cu/ft on Amazon. You’ll pay about $40 to refill 300 cu/ft if you run out of nitrogen.

If you do the calculations, your 300 cubic feet of nitrogen cylinder can refill your car tires about 15 times. You will end up saving lots of money since most nitrogen refills cost between $3 and $10 per tire ($12 – $40 for all tires).

2. Digital tire inflator

Tire inflators let you regulate how much air fills your tires. It connects from the nitrogen tank to the tire valve.

Connecting your digital tire inflator or gauge is a matter of plugging and screwing. You can use Teflon tape for an air-tight connection to the gas cylinder.

Some inflator packs come with standard valve caps, which you won’t use (use the nitrogen valve caps instead).

3. Portable nitrogen analyzer

You don’t want all your effort in setting up a nitrogen filling system to go to waste. Get a portable nitrogen analyzer to check the nitrogen percentage in your tires after each refill.

Besides the cylinder, an N analyzer is the other expensive part of your DIY nitrogen filling station.

4. Nitrogen valve caps

After your tires are rocking at least 96 percent nitrogen, you want people to know you’ve gone green.

Have you ever seen those green tire valve stem caps labeled N2? Those are the ones you need to seal your tires.

5. Lift jack

As a car owner who loves DIYing, a lift jack is part of my toolset. If do not have one, it will another addition to the things you need during your tire filling procedure. I recommend getting a heavy triple lift jack (check the exact price on Amazon).

How much does it cost to fill tires with nitrogen?

With the breakdown of all the things you need to fill your tires at home with nitrogen, we can estimate how much you will spend.

Here’s an interesting comparison table.

Let’s break down the second table. We’re working with a 300 cubic feet cylinder that can roughly fill 60 tires. It means you can fill all the four tires of your car 15 times before buying another supply of nitrogen for your cylinder.

As mentioned, filling your tires at a gas center costs anywhere between $3 and $10. Let’s use $5 per tire fill, which means you’ll spend $20 for all your tires.

Procedure for filling nitrogen in your tires at home

The purpose of filling your tires with N gas is to enjoy the benefits it offers. We’ll discuss the benefits later in this post, but first here are the correct steps you need to follow.

• Remove the valve core to let out as much existing air as possible from the tire. If you don’t have a special tool for removing valve cores, use a pair of needle-nose pliers. Lift your car using a lift jack before removing the valve core.
• Connect the digital tire inflator to the nitrogen cylinder and fill up the tire with about five pounds of pressure. Then, let it blow out again to eliminate the remaining oxygen.
• Before all the air blows out, screw back the valve core.
• Now, fill up the tire with pure nitrogen to full pressure.
• The next step is to find out how much N is inside your refilled tire. Use the nitrogen analyzer gauge by connecting its nozzle to the tire valve. Let it analyze the air coming out of the tire for about 25 seconds.
• Repeat the steps if the N reading is less than 96 percent.

Can I put nitrogen in my tires myself? Where can I fill my tires with nitrogen? These are some of the questions I saw people asking online during my research.

If you follow the steps I have listed above you can clearly fill your tires yourself, and do it at home.

How do you check nitrogen-filled tires?

Plug the nozzle of your N analyzer onto the tire valve. As air escapes from inside the tire, the analyzer will display the percentage of N.

Tires filled with nitrogen will generally show a percentage higher than 92.

You won’t have to worry much about your tires losing pressure if you go the ‘green way’. However, you can still use the digital tire inflator to check the tire pressure when it’s cold, before driving, or after 3 hours of driving. When using the inflator to check your tire psi, do not connect it to the cylinder.

Compare the psi you’ve measured with what the car manufacturer recommends. You can find those details on the doorjamb sticker usually found on the driver’s side. Both readings should be roughly the same. The inflator has a deflation button in case of excess pressure.

Does cold weather affect nitrogen-filled tires?

Yes, a drop in temperature affects tires filled with nitrogen. During the cold season, a 10-degree Fahrenheit drop will cause a two percent pressure loss in N-filled tires.

The solution for this issue is to fill your tires 10 percent higher than the manufacturer recommended psi. However, do not go beyond the tire’s recommended psi. It might blow up.

Benefits of filling tires with nitrogen

By nature, compressed nitrogen is more homogenous and has large molecules. Its large molecules minimize tire leak-outs. However, there are other benefits of using N to fill your car tires.

1. Minimal tire temperature changes

N does not heat up as quickly as compressed air does. Because of that, your tire temperature will remain consistent hence minimizing the chances of tire blowouts associated with overheated tires.

2. Its effect on tire life

A tire operating temperature plays a part in how it wears out. If you opt for nitrogen, your temperatures will remain almost constant even after long drives hence causing minimal wear and tire associated with heated tires.

3. How it holds-up your tire pressure

You’re guaranteed consistent tire pressure for the most part of using your car. Nitrogen maintains its temperature in a hot environment hence your tires won’t have an increased pressure like in air-filled tires.

Nitrogen particles are large compared to normal air so pressure loss will be slow even in cold weather.

4. Its reaction with your tires

N is inert and dry. It is way less reactive compared to normal compressed air that can react with moisture and cause rust on the metal rim.

5. Is it a real ‘green’ option?

Nitrogen is considered a green alternative since tire pressure is constant and consistently at the right level. I turn, your car tires will run smoothly with less rolling resistance hence fuel-efficient and save on fuel expenses.

Because N can lengthen the life of your tires there will be no need to replace them often hence help in slashing your tire maintenance costs.

Besides the advantages I have listed, vehicles that operate in hazardous areas like mines should use nitrogen in their tires to reduce fire risk since it is an inert gas.

Also, you can consider using nitrogen instead of normal air tire filling because of the following reasons.

• If you drive a high-performance vehicle
• Frequent travels to areas with cold weather (pressure loss in air-filled tires)
• Live in cold or warm areas since extreme temperatures can affect air-filled tires
• If you use high-quality tires and hope to extend their lifespan

What are the disadvantages of nitrogen?

Ditching compressed air tire filling comes at a cost.

For instance, here is a valid question.

1. How much does it cost to fill tires with nitrogen?

You’ll need to think about the cost. The standard cost to fill a tire can vary from $3 to $10 per tire. The price depends on variables like tire size and pressure.

On the other hand, standard air is mostly free or $1 at many gas centers. Some dealerships, tire centers, and service stations offer free refills on-site if you buy their tires or a car from them.

2. Less available compared to normal gas

Nitrogen can be challenging to find since it’s less popular as a tire refill gas and you’re more likely to find it in select service stations.

3. Tire manufacturer warranty issues

Some tire manufacturers have policies regarding filling up their tires with nitrogen. Not all tire brands appreciate nitrogen use and may not cover it in their warranties.

I advise that you check with the tire manufacturer to see if a particular tire model you have will still be covered by their guarantee or not.

Conclusion

Filling your tires with nitrogen at home is simple. The huddle you’ll have to cross is the initial investment cost of buying the cylinder, digital tire inflator, nitrogen analyzer (you don’t have to buy it), and the valve caps. In the long run, you’ll save money while enjoying better performing tires than when using normal compressed air in your tires.

How Long Does It Take to Change a Tire?

When one has the rights tools and skills, it may take 15-30 minutes to change a tire. This time depends on one speed and way of doing it. But for a beginner, it may take up to an hour to finish. Tire centers take more time because of the specific process involved.

Additionally, the time taken to change a tire depends on the vehicle model, the locations and conditions of where you are changing it. For instance, changing a tire under a scorching sun may be unbearable and may take more time or even under the rain. One may take up to 45 minutes to change the tire in a tire center, depending on how busy the shop is.

If you are an expert, doing it yourself may take less than 15 minutes. Therefore, you can change and replace all four wheels in less than an hour. But for a professional car racer, it’s even faster. Their mechanics have to be quick because they are in the race. The mechanics can change all four wheels in 15 minutes.

How Long Does It Take to Change Four Tires and Do Alignment?

A standard car alignment takes an average of one hour for a two-wheel or four wheels, excluding the waiting time. Based on how busy the center is, you may take around 3 hours. If there is too much play on any ball joint, track rod, suspension, it could even take longer as various components need replacement.

Read more: How Far Can You Drive on a Spare Tire?

The time taken depends on the age, condition, and style of the car. An older vehicle using shims will take more time for alignment than a brand-new one. Again, it will take more time if the car’s internal components are rusty or too exposed to humidity.

What Involves Alignment?

• The mechanic does a test drive to see how far the wheels are from their natural angle.
• Clips wheel sensors to check the pressure
• Adjusts rear wheel first, then the front wheel if necessary
• Ensures the steering wheel is at the center
• confirms all issues addressed by another driving test

How Long Does It Take to Change a Tire Pressure Sensor for TPMS?

TPMS is an integral part of the valve stem. So, replacing a TPMS is the same as replacing a valve stem. First, you need to dismount the tire and remove the old sensor. Then install a new sensor, remount, inflate the tire, and reprogram the sensor. The whole process takes around 15 minutes for one wheel.

Can I Replace TPMS Myself?

It’s not advisable to replace TPMS by yourself. Though the process is easy and only takes a few seconds, it requires a lot of caution. It may result in unbalanced tires, which deteriorates the stability of your car.

Can I Fix the TPMS Sensor Without Replacing It?

It’s almost impossible to fix TPMS without replacing it. Most of them die when the battery fails. Though it’s easy to cut the module, remove the old battery, and replace it with a new one, you may not seal the module correctly. There is also the likelihood of failure in the future if you fix the TPMS. The module’s design is also meant for replacement once the sensor fails.

Generally, your tire changing time depends on how you regularly maintain your car tires. If you expose the tire parts to humid, they rust, which will call for more changing time. Therefore, always keep your car and replace any component when necessary.

Reset Procedure

1. Push down the lock and unlock button on your car keys fob at the same time. The horn will chirp twice.
2. Unscrew the front left valve stem cap.
3. Press the valve stem for some seconds to let the air out of the tire until the horn chirps. Replace the valve stem cap.
4. Repeat the third procedure in the right-front, right-rear, left-rear wheels in that order. The system will reset, and TPMS lights will shut off.

This procedure applies to the GMC Sierra 2004- 2020. Resetting helps solve GMC tire pressure sensor problems. Examine the pressure in all four tires to ensure TPMS functions correctly, and tires have the recommended pressure.

2020 GMC Sierra TPMS Relearn

• OBDII dongle is not required
• Confirm TPMS sensors are properly installed
• Adjust tire pressures to placard value
• Apply parking brake
• Turn vehicle to ON/RUN
• Push the trip odometer reset stem until Tire Pressure is displayed
• Push and hold trip reset stem to begin the sensor matching process
• Push trip reset again to confirm
• Horn chirps 2x DIC displays TIRE LEARNING ACTIVE
• Use tool to activate LF sensor
• Single horn sounds
• Repeat for RF/RR/LR
• Horn chirps 2x for relearn complete

Where is the TPMS Reset Button?

It is the normal trip reset trim on your dash cluster (on the odometer). You will find the TPMS button located beneath the steering wheel. If you can’t trace it, refer to the vehicle owner’s manual.

Can You Reset TMPS Without a Tool?

Yes you can. First, spin the ignition to the off-position press, and release the brake pedal. Cycle the ignition off to the run position three more times ending in the run position. You will hear the horn one time, and TPMS flash message. Do the sequence for all tires until you get a completion message.

Check this too: Which Tire is Better for Fuel Efficiency?

How Do You Turn Off the Tire Pressure Sensor on a GMC?

• Start the GM vehicle.
• Find the lowercase “i” button on the driver’s information panel. You will find it to the right of the steering wheel. Push down the button multiple times to access the TPMS system, and identify the specific tire activating the dashboard signal luminescence
• Press the reset key on the driver’s information panel. The button features a checkmark and is at the lower end of the board; if this fails, press and hold down the “I” button and press the reset button.

Conclusion

Follow the above steps to reset the tire pressure sensor in the GMC Sierra. If it doesn’t work out, consult the experts.

Check this too: Bad Key Fob Symptoms

While it is not common knowledge, you can make your car fuel efficient by using tires that do not make your car work extra hard on the road. This may entail some trial and error, but having a few fuel-efficient tire options certainly takes the guesswork out of the equation. Here are the best car tires for fuel-efficiency.

Top 5 Best Tires for Fuel Efficiency

GOODYEAR ASSURANCE FUEL MAX 

Goodyear tires are affordable, and they offer long wear, wet traction, and low rolling resistance. Whether you own a coupe, van, or crossover vehicle, these tires would be ideal for your car. They are designed to provide year-round confidence in wet, dry, and winter weather conditions, specifically light snow. They are guaranteed to enhance vehicle fuel economy over the tire’s lifetime.

The tire’s tread design features distinct zones for optimal performance. The Inboard and outboard Dry Tread Zones have strong shoulder blocks to enhance handling in dry conditions. The central Wet Tread Zone has Dual Aqua channel grooves that evacuate water to promote wet weather traction. Additionally, the continuous notched center rib combined with circumferential shoulder grooves offer dry road stability and even tread wear. As well as traction in snowy conditions.

The tire’s interior has twin steel belts – with the H-speed rated sizes reinforced with spirally wrapped nylon belt edge strips on top of a polyester casing to enhance ride quality.

Features

• Dual Aqua channel grooves
• Notched center rib
• Twin steel belts
• Polyester casing
• Six-year Tread life warranty
• 1-year uniformity warranty

Pros

• Long-wear
• Wet traction
• Low rolling resistance

Cons

• The treads wear out pretty fast

Check it here: https://www.tirerack.com/tires/tires.jsp?tireMake=Goodyear&tireModel=Assurance%20Fuel%20Max&partnum=255HR7AFMV3

CONTINENTAL CROSSCONTACT LX20 WITH ECOPLUS TECHNOLOGY

These Continental Ecoplus tires are designed to help crossovers, sport utility vehicles, and light-duty pickup trucks perform optimally on the highway and in mild off-road conditions. The tires enhance driving pleasure, save fuel, and maintain grip when braking on wet surfaces. They also provide long term and all-season traction, even in light snow.

The tires are made using an all-season tread compound made of custom Continental’s Tg-F Polymers and +Silane additives. The material used improves tread wear and traction on slippery roads. The tire features an asymmetric tread design with notched outboard shoulders, independent intermediate tread blocks, and continuous center ribs.

These features ensure that the tires have on-road steering response and straight-line stability. As well as reduced noise and enhanced ride comfort. Additionally, the tire’s grooves promote three-dimensional snow-to-snow traction. The twin steel belts forming the internal structure are reinforced with spirally wrapped polyamide on top of a polyester cord casing for increased durability and ride comfort.

Features

• Material: Tg-F Polymers and +Silane additives
• Notched outboard shoulders
• Intermediate tread blocks
• Continuous center ribs
• Continental’s Traction Grooves
• Three-dimensional snow-to-snow traction.
• Twin steel belts
• Flanged lower sidewall
• 1-year uniformity warranty
• 6-year workmanship warranty
• 6-year tread life warranty

Pros

• Durable
• All-season traction
• Straight-line stability

Cons

• Does not provide traction on icy roads

Check it here: https://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=CrossContact%20LX20%20with%20EcoPlus%20Technology&partnum=375SR6CCLX20OWL

CONTINENTAL CONTI ECO CONTACT EP

Continental tire’s low rolling resistance design helps to save fuel and reduce vehicle CO2 emissions; while providing traction in dry and wet road conditions. These tires are not intended to be driven in near-freezing temperatures, through snow or on ice.

The tires are made from a silica-enhanced compound for increased durability. They have an asymmetric design with solid tread blocks and a continuous rib on the outboard shoulder. This helps to promote responsiveness and cornering stability.

The tires also feature a continuous center rib that provides constant rubber-to-road contact. This reduces noise and controls the longitudinal forces experienced when braking. The circumferential tread grooves and independent tread blocks on the inboard tread resist hydroplaning and enhance wet weather traction.

Lastly, the tire’s internal structure features twin steel belts cased in polyester, stabilizing the tread area for consistent ride quality.

Features

• 1-year manufacturer road hazard warranty
• 1-year uniformity warranty
• Six years’ workmanship and materials warranty
• Silica-enhanced compound
• Solid tread blocks
• Continuous rib
• Circumferential tread grooves
• Independent tread blocks
• Internal structure: twin steel belts

Pros

• Low rolling resistance design
• Provides traction in dry and wet road conditions
• Increased responsiveness and cornering stability

Cons

• Not ideal for snowy roads

Check it here: https://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ContiEcoContact%20EP&partnum=465TR5EC

MICHELIN ENERGY SAVER A/S

These fuel-efficient All-Season Passenger car tires are designed to optimize your vehicle’s fuel economy without abandoning dry, wet, and wintertime traction. They enhance vehicle performance and environmental impact by reducing fuel consumption and carbon dioxide emissions. The tires provide year-round traction, even in light snow.

The tires are made using Michelin’s Energy Saver Construction from a unique silica-based tread rubber. The advanced material helps to improve engine fuel efficiency by keeping the tire cooler. This rubber is molded into a symmetric design that features independent tread blocks for predictable handling and all-season traction.

The tire’s Circumferential and lateral grooves direct water through the tread design, which helps to resist hydroplaning and enhance wet traction. The tires are constructed using computer-optimized design and precision manufacturing. This, in turn, reduces vibrations and road noise.

The tire’s internal structure uses twin steel belts reinforced by spirally wrapped polyamide on top of a polyester cord casing for maximum strength and durability.

Features

• 6-year tread life warranty
• 1-year uniformity warranty
• 6-year workmanship and materials warranty
• Material; Silica-based tread rubber
• Symmetric design
• Independent tread blocks
• Circumferential and lateral grooves

Pros

• Year-round traction
• Low rolling resistance
• Enhanced wet traction
• Computer-optimized design
• Reduced vibrations and road noise

Cons

• Tread lifespan is limited.

Check it here: https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Energy%20Saver%20A/S&partnum=665TR8ESAS

BRIDGESTONE ECOPIA EP422 (H- OR V-SPEED RATED)

The Bridgestone All-Season tires are perfect for coupes, sedans, minivans, and small crossover vehicles looking to combine year-round traction improved handling and comfort, and fuel efficiency. The tires enhance vehicle fuel economy by reducing tire rolling resistance. Economic fuel usage, in turn, decreases the vehicle’s carbon dioxide (CO2) emissions.

The tires are made using an all-season tread compound using Bridgestone’s unique Nanostructure-Oriented Properties Control Technology. The compound is molded into a symmetric tread design that combines notched shoulders and intermediate ribs with independent center blocks for improved dry traction.

It also features four circumferential grooves designed to help water flow for better hydroplaning control, enhancing wet traction. The tire’s internal structure is supported by twin steel belts reinforced using spirally wrapped nylon in a polyester casing for optimal ride comfort and durability

.

Features

• 5-year tread life warranty
• 5-year workmanship and materials warranty
• Nanostructure-oriented Properties Control Technology
• Dry, wet, and wintertime traction
• Symmetric tread design
• Notched shoulders
• Intermediate ribs
• Independent center blocks
• Four circumferential grooves
• Twin steel belts

Pros

• Reduced tire rolling resistance
• All-season tread
• Higher ride comfort
• Durable
• 90-day Buy and Try Guarantee

Cons

• Not ideal for snowy roads

Check price: https://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Ecopia+EP422+(H-+or+V-Speed+Rated)&AID=10398365&PID=8751758&cjevent=d3140ee9017011eb815601990a18050e

Can tires affect fuel efficiency?

Yes. Tires affect fuel efficiency. But the answer is a little more technical than that. The relationship between tires and mpg is all about the tire’s design and how it helps the car reduce rolling resistance.

Rolling resistance

Physics laws dictate that stationery objects remain stagnant unless force is applied.

Simply put, this is the force that resists motion when the wheel hits the surface. This is determined by inertia, road quality, and air drag. Rolling resistance changes as the surface of the road changes and depending on the weather.

Any seasoned driver would know that driving on snow is not the same as driving on a wet or dry road. Similarly, driving on a dirt road is not the same as driving on an asphalt road. The speed of the vehicle also affects the rolling resistance. The gradient of the road also plays a role.

To reduce the rolling resistance, manufacturers have started to make tires with compounds that can increase traction to minimize resistance. The tread designs and sidewalls are also designed to reduce rolling resistance.

How does tire design affect fuel efficiency?

Here are elements of tire design that play a role in fuel efficiency.

• Tread depth and pattern

30-50% of rolling resistance comes from the tire tread design. Research shows that shallower treads tend to be better for fuel-efficiency. Treads grab the asphalt, which requires your car to burn more fuel to create the energy needed to keep the vehicle moving forward. This is why race car drivers use bald tires to reduce fuel consumption and increase car speed.

• Tire size

A car uses less effort to power the start up of a car with small tires than larger tires. However, when in motion, the smaller tire consumes more fuel than the larger tire because of the number of tire rotations per minute. But considering that a smaller tire is fitted in a smaller vehicle, the smaller car’s weight balances out the fuel consumed compared to a larger vehicle.

• Tire pressure

Did you know that deflating your tires by eight psi can reduce rolling resistance by up to20%? According to research, underinflating your tires by 20% can increase fuel efficiency by 10%. Lower tire pressure also leads to tread depreciation that leads to reduced rolling pressure.

• Tire status

As you tire get older, the treads wear down, which in turn reduces the rolling resistance. This is because the shallower tread does not grab the ground as much as a well-defined tire would. This, in turn, reduces the amount of fuel used to power the car.

This, however, does not mean you should drive worn out tires. The lack of traction due to shallow tread can be hazardous when braking, leading to an accident.

How much difference do tires make to fuel economy?

The United States Department of Energy estimates that 5% to 15% of fuel consumption is related to rolling resistance. A 5% improvement in rolling resistance might translate into around 2% less fuel consumed. This means that if you were previously spending $100,000 on energy annually, 2% saving is equivalent to $2000. That is a reasonably massive saving over time.

If this is not convincing, let us consider the fuel economy of different types of tires. All-terrain tires increase fuel consumption by 3% compared to highway tires. Suppose your annual driving distance is 15,000 miles, and your average mileage is 20 mpg, the extra fuel cost comes to $67.50.

Actual calculation = ((15000/20) *3/100) *3=67.5

The saving may seem minute, but why spend more on fuel when you can save it. This is highly beneficial if you need to cut your expenses or reduce fuel consumption for environmental saving reasons.

While the Eco branded tires may claim to be better for your car, you can still attain the same advantages with standard tires. All you have to do is consider the tread pattern, tire size, and tire pressure. Opting for eco tires is not a necessity. But you can still go for them if it will give you peace of mind and if the features are ideal for your vehicle.

Conclusion:

The best car tires for fuel efficiency should be durable while offering fuel efficiency advantages at the same time. It should also have enough traction to function on dry roads, snowy roads, and wet roads. Lastly, it should be able to reduce car vibration and road noise.

How Often Should You Check Pressure?

Since pressure fluctuates more in winter, keep checking your tires once in a couple of weeks or a month. You don’t depend only on your tire pressure monitoring system to warn you if pressure drops. During summer, heat causes the air inside the tires to expand but has less impact than in winter. The tire loses about one psi per month.

The rule to check the pressure once a month, even in summer it’s advisable. You can make it a routine to monitor your tire pressure every time you approach your vehicle. Find a handheld pressure gauge at a hardware store or online shop.

Why Should You Care About Tire Pressure?

• Overinflated tires can be hectic as they increase the number of treads in contact with the ground, meaning your car has less stability and traction.
• They are also susceptible to a blowout.
• Underinflated tires wear out faster because the wheels are compensating for the low pressure. Tires overheat, losing their trends more quickly.
• Well, inflated tires save you money at the gas pump and fuel too. Again, they are best for your safety when driving.

Tire Pressure Loss. What’s Normal?

It’s imperative to check your tire pressure regularly to avoid any inconveniences. Suppose a tire loses more than 25% of the manufacturer’s recommended pressure, possibilities of tire-caused crash increases. A loss of 1-3 psi per month is common, and you should always re-inflate the tires.

Neglecting the inflation for months may cause significant loss, which is risky. If the tire loss increases to more than 1-3psi per month, its an alarm; there may be other factors affecting. They include;

Temperatures

During freezing times, the tire loses 2% every 10 degrees F drop and rises with every 10 degrees F temperatures increase. One should re-inflate tires in winter as the temperature difference between summer and winter can be about 50 degrees F.

A Bad Pressure Valve

If the tire loses pressure overtime for more than 3psi, you need to replace your valves. The valves may get damaged due to chemical exposure, promoting pressure loss.

Bent or Damaged Wheel

A wheel wit a lost shape will not hold the tire on it. The bent area allows some air out of the tire, and it may become flat in a couple of days.

Tire Damage

The damage will let out air directly, no matter how small it is. Nails, beads, or other items may cause tire damage. Nails damage can let out 2-3 psi daily and even cause a blowout.

How to Check Tire Pressure at Home

Check your tire pressure through the following steps;

• Purchase a tire pressure gauge
• Find the required pressure level of your car. You can find the information on a yellow placard on the door jamb or owner’s manual. It may contain different pressure levels for the front and rear tires.
• Check tires pressure when tires are cold or in the morning when the ambient temperature is low.
• Unfix the valve cap and set it aside.
• Press the gauge onto the valve stem; it takes a few seconds to get an accurate reading. Get the pressure readings on the gauge screen.
• Compare the tire pressure readings with the amount as per manufactures guidelines. If the measured pressure is below the recommended, you need to re-inflate the tires.

Here are some other gauges you can use to check your car tire pressure or even hook them up to a compressor to inflate the tires where necessary.

1. AstroAI Digital Tire Pressure Gauge

It’s a gauge that helps measure correct tire pressure and also has a 12V compressor that you can use to fill up the tires.

Features

• Non-slip texture for easy holding
• Automatic resets when taking pressure
• It’s slim and portable
• Nozzle lights at night for visibility
• Ergonomic design for all gender
• Has four settings range
• Ability to measure up to 150 psi

How to Use It

Press the turn on button on the gauge and select the range. Then place the nozzle on the valve stem, and it will give quick and accurate in 0.1 increments. Note the readings before the gauge automatically shuts-off.

Check Price

2. Campbell Haus Feld (MP600000AV)

It a 3-tools in one compact contains an inflator gun, chuck, and gauge. You use it with your air compressor to achieve proper tire inflation.

Features

• 2 inches readable gauge with a range of 10-150 psi
• Inflation gun with side relief valve
• Flexible hosepipe

Pros

• User-friendly design
• Easy to operate
• Has a seamless connection

Cons

• The indicator may be inaccurate sometimes

Check Price

3. Tymate Tire Pressure Monitoring System

It is a digital TPMS that monitors tire pressure also senses high temperature and leakage. Its widely used on most 4-wheel like SUV, Minibus, and more.

Features

• Power saving mode
• Switch button
• Low power consumption
• Long working life sensor
• Five types of alarm modes
• Multiple charging methods

Pros

• Accurate in pressure measurements
• Easy to install
• Small to be obtrusive
• Low power consumption

Cons

• Display a bit smaller

Check Price

What is the Ideal Pressure for Your Car?

The recommended care tire pressure is between 30-35 psi. These numbers indicate the minimum amount of air pressure needed to support your maximum vehicle load-carrying capacity. When the tires’ air becomes less than the set level, fuel consumption increases and compromises your car handling. When overinflated, the tires have less grip on the road and are more prone to bursting.

You can check the correct tire pressure of your car in the following places;

• At Vehicles Door

On the door jamb, you will find a sticker with the numbers.

• Your Vehicles Handbook

Mostly for the old vehicles, they don’t have a sticker, but at least you can get the psi rating here.

• Online

You can search online, specifically on the manufacturer’s website.

• On the Fuel Filler Door
• On the Tire
• On the Sidewalls

It contains the maximum load capacity and maximum inflation pressure.

Here are some general pressure levels based on tire sizes. Note that you should still consider your car model’s recommended tire pressure especially if your car is still running on the tires it shipped from the assembly line with.

Tire Size	Front Tires	Rear Tires
205/55R16	2.5 bar/ 36 psi	2.4 bra/ 35psi
215/60R17	2.3 bar/ 33psi	2.3 bar/ 33psi
205/60R16	2.4bar/ 35psi	2.2bar/ 32psi
235/55R18	2.2bar/ 32psi	2.2bar/ 32psi
225/65R17	2.2bar/ 32psi	2.2bar/ 32psi

Can You Check Tire Pressure Without a Gauge?

Though using a gauge is the most accurate way to check tire pressure, sometimes you may not have it. Below are DIY ideas that can help check pressure manually ;

Hand Pressure

Check the pressure by pushing the tire with your hand. If the feel is soft, you need to inflate more gas. If the tire feels firm like a rock, it might be fine.

Weight on Wheels

You can put maximum load capacity on wheels. If the tire deforms by at least 10 %, it shows the pressure is low. It would help if you, therefore, inflate the tire until there is no room for deformity.

Eyeball Method

It’s easy, but one should be an expert to apply it. Watch tire pressure from a little distance. First, keep your vehicle on a flat level and then observe. If the tires seem to protrude out one or two millimeters on each side, they need more gas. But remember to avoid over-inflation.

How to Inflate Your Car Tire Without a Pump?

A flat tire may occur in the middle of nowhere, and maybe you don’t have a portable air compressor. Frankly, the easiest way out is being prepared and buying a portable air compressor that runs off your 12V battery or off a jumper pack. Here are some options:

• tire pressure gauge
• Find the required pressure level of your car. You can find >AstroAI Air Compressor Tire Inflator
• tire pressure gauge
• Find the required pressure level of your car. You can find >EPAuto 12V DC Portable Air Compressor Pump
• tire pressure gauge
• Find the required pressure level of your car. You can find >FORTEM Digital Tire Inflator

There is no safe and reliable way to inflate your tires well without using any form of a pump or a compressor. If you don’t have a compressor at hand and your car doesn’t have an onboard compressor, you could opt to use a tire pressure gauge

Find the required pressure level of your car. You can find >valve equipped bike pump (again, buy a portable compressor instead of buying the bike pump).

Here is how to inflate a tire with a bike pump.

• Park your car in a safe flat area.
• Remove the valve caps and keep them safe.
• Determine the optimal pressure for your car tires from either manual, placards.
• Check the pressure in the tires using a gauge and calculate how much the tires need.
• Attach the pump to the tire valve.
• Pump up your tire and adjust the pressure as necessary.

Conclusion

Keep it a routine to check your tire pressure regularly once in a couple of weeks. But you can still do frequently depending on the season and other road-related factors. The pressure review will save you cost on fuel consumption and replacing tires in case of underinflation. Again, you will keep yourself safe on the road and avoid the possibilities of crashing or even been stranded alone.

Do Tires Go Flat for No Reason?

No. While it may seem that way, mostly if the tire went flat overnight, tires do not go flat for no reason. Most often than not, the underlying cause is something you would never have thought could cause a flat tire.

Common Causes of Flat Tires

These are the most prevalent flat tire causes.

1. Puncture by Sharp Objects

Sharp objects on the road can rip your tire, causing it to lose air. What can puncture a tire? This can be anything from a piece of glass, branches, nails, screws, sharp stones, and so forth. Anything strong enough to pierce through rubber can puncture the tire.

2. Failure or Damage to the Valve Stem

A damaged valve system will lead to air leaks that may cause your tire to go flat. The valve can cause air leaks if it is loose around the stem that connects it to the tire or if the metal gets corroded and stope being airtight.

Check this too: Will a Donut Tire Fit Any Car?

3. Rubbed or Ripped Tire

A worn-out tire will ultimately start leaking air when it gets to the point where it is thin and flimsy. This can be blamed on the quality of the tire or the condition of the tire. The air leak can also be due to worn-out tread that results in air leaks along the tire’s tread line.

4. Tire Bead Leaks

This is leakage along the tire edge that rests on the tire rim. Sometimes, air will leak from the tire bead, which is the tire’s edge that rests on the rim. This can occur due to a tire slip or cracking of the tire around the rim.

5. Vandalism

A flat tire can be aa result of a cruel joke when someone decides to let the air out of your tires; fortunately, this cause can be remedied with ease. It is also the least expensive to fix as you do not have to worry about replacing the tire.

6. Too Much Pressure

Over-inflated tires can lead to a burst tire, especially if the over-pumping is a regular occurrence. Tires have a maximum pressure, and exceeding it will cause the rubber to expand and become weaker the same way a balloon bursts when overinflated.

Check this too: How Often Should You Check Your Car Tire Pressure?

6. Overloading

Exceeding the maximum amount of weight your vehicle can hold will exert excess pressure on the tire, causing them to become flat over time.

How to Avoid Flat Tires

Here are some tips to help you reduce your chances of getting a flat tire.

1. Keep Tires Inflated

Inspect your car tires regularly and ensure they are inflated optimally according to the manufacturer’s recommendations. Try to find a balance between the highest recommended pressure and the lowest recommended pressure. High tire pressure leads to poor road performance, while low tire pressure wears out the tires.

2. Check Your Spare Tire

Imagine going to replace your flat tire only for your spare tire to flake on you as well. Avoid this problem by ensuring your spare tire is inflated and does not have any air leaks. Inspect it for cracks to ensure it does not go flat while you are driving.

3. Replace Old Tires

Make tire inspection a habit to ensure you keep tabs of your tires’ wear and tear. This will save you the headache of handling a flat tire on the road. Which is avoidable if you change the tires as soon as you notice they are worn out.

4. Buy Good Quality Tires

Higher quality tires will have thicker tread, better quality rubber, and better warranties. This will go a long way in ensuring they have a longer lifespan. It also means the manufacturer can cover any damages. Additionally, they will be more resistant to puncturing.

Check this too: Best tires for Subaru Crosstrek

5. Drive Carefully

Be on the lookout for debris or any sharp objects that can pierce your tires. Drive around any object that can damage your tires. Be cautious when driving near construction sites as some of the destructive objects may be covered in dust, making it impossible to spot them.

6. Plan for the Worst

Always have a can of compressed air your car so you can reflate the tire when needed. You can also invest in a tire pump, but this will require a lot more effort to inflate the tire. You should also have a jack, wrench, and any other tool you may need to change your tire if it goes flat.

7. Avoid Overloading

Do not exceed the maximum amount of weight your vehicle can hold. And if you have to carry a heavy load, boost your tire pressure to enable the car to handle the excess weight. However, you should not exceed the maximum recommended pressure limit.

Can I make it Home on a Flat Tire?

It depends on how far you are from home when you get a flat tire. And whether you are willing to incur the extra costs of repairing the damage caused by driving on a flat tire. Your car rim will begin to get damaged after 1.497 miles.

On the other hand, if your tire is not entirely flat, you can be able to make it home if you drive at a snail pace. The speed should not exceed 20 miles per hour if you want to conserve the little pressure left in the tire.

To avoid accidents and to remain in control of your car, try to stay below 50 miles per hour if you are on a highway and have to drive at the regulated speed. In this case, you may only be able to get to the next stop or exit before you have to change the tire.

Can You Let a Car Sit on a Flat Tire?

Yes. But it is optimal to get is changed as soon as possible. The longer you let your car sit with a flat tire, the higher the chances of damaging the tire permanently. The pressure exerted on the flat tire may cause it to rip or develop invisible cracks that may be problematic when you resume driving the car.

Check this too: How Long Does it Take to Change a Tire

How Do Lug Nuts Get Stripped?

A stripped lug nut has its edges rounded off, thus difficult to remove it using a socket. A stripped lug nut occurs when it’s improperly torqued either overtightened or over-torqued without following the nuts lug specifications. Other causes of the stripped lug nuts include;

• Use of a larger socket to remove the nut causing slippage
• Use of wrong torque numbers. It’s wise to keep rechecking your specific torque number and informing your mechanic to avoid damage.
• When you expose your lug nut to dirt, debris, and water forming rust, corrosion destroys the threads and changes the nut’s exact shape.

Why is the Stripped Lug Nut a Bother?

The lug nut can lead to more significant damage when removing it, which adds extra repair costs.

How to Avoid It?

• Always dry your lug nuts after driving through the rain
• Store your car in a sheltered place or heated area to evaporate the water quickly
• Apply protective clothing to your car exposed areas
• Always observe a habit of replacing lug nuts occasionally

Getting a Stripped Lug Nut Off Tire

There are numerous ways used to remove the lug nut;

1. Socket and Hammer Method

Tools to remove the stripped lug nut are as follows;

• Breaker bar
• 1-inch diameter iron pipe
• Penetrating oil
• Hammer
• Nut/bolt extractor socket
• New nut lug

When changing a flat tire, ensure you park your car at a safe, leveled area. Also, apply parking braking for safety as you will significantly use more force to get off a tire with stripped lug nuts.

Apply Penetrating Oil

One of the reasons for a stuck lug nut is due to rust. You will require to spray the nut to remove the rust. WD-40 works fine, but you can still use any spray-type lubricating oil. If the rust is too much, use a hammer to strike the nut and break off some. Later spray the WD-40 on the nut and allow the oil to soak for 5-10 minutes.

Use the Nut/Bolt Extractor Socket

Use a socket to help free the seized nut. Make sure to use a socket that’s the correct size for your lug nut. Take your hammer and ram the socket head into the lug nut. Hammer it several times until it’s very tight.

Attach the Breaker Bar

Attach the breaker bar to the socket. As an extra measure, take the iron pipe and slide it over the breakers bar handle. Apply force in a counterclockwise direction to loosen the nut. Do it gently until the nut loosens up and turns smoothly.

Remove the stripped lug nut and replace it with a new one.

Blowtorch Method

What You Need

• Blowtorch
• A wheel spanner or pliers to wiggle out the hot lug nut

It’s applied in combination with other tools. Heat your lug nut slowly and allow it to cool. The nuts expand more than the wheel stud, thus becoming loose. You have to repeat the procedure severally until the nut becomes loose. Be careful not to oil and point a propane torch on it to avoid causing a fire.

Chisel, Screwdriver, and Hammer

What You Need

Penetrating oil

Sharp chisel

Flathead screwdriver

• Lubricate the lug nut to get rid of all the gunk. It helps loosen up the nut and remove rust.
• Make a notch into the nut using a chisel to allow the screwdriver to wedge into the nut.
• Loosen the nut- wedge the screwdriver into the notch. Take a hammer and tap the screwdriver in a counterclockwise direction. Keep tapping until the nut is loose to remove by hand.

Grinder and Pipe Wrench

What you Need

• Penetrating oil like WD-40
• Hand-held grinder
• Wrench

Method

• Spray a substantial amount of oil on the nut lug
• Create edges on the lug nut where the wrench can hold on. Make contours on the top and bottom parts of the lug nut using the grinder.
• Loosen the nut with a wrench that grabs onto the sides, and turn left to loosen it.

Use of Vibrations and Shocks

Tap the nut with a hammer to make it loose-fitting. Aim for consecutive small hits that will loosen the nut and break the corrosion layers. After ramming it a few times, use oil to reduce friction and increase chances of loosening.

Destroyed Lug Nut Removal

If the lug nut has lost its shape, it may be difficult to remove it. You will need to melt the nut and replace it with a new one. Melt the nut carefully from the wheel stud, be keen not to melt the wheel stud fully to ensure you can pull it out after melting.

Later remove the wheel, center locking nut, bearing, and nut. Use an impact pipe wrench to remove the wheel stud. Replace the damaged wheel stud and reinstall the wheel.

Removing a Stripped Lug Nut Without Tools

In a situation you don’t have tools, you will have to seek help from a mechanic. You may also use pliers to pull the lug nut as you loosen it. You can again ram it severally until its loose for you to remove. These methods may not be easy and require you to be patient if you don’t have another way out.

Conclusion

Probably a combination of two methods may help solve your stripped nut problem. But what’s important is that you need to be extra careful, especially when dealing with dangerous tools such as grinder, blowtorches, sockets, and pipe wrenches. If not familiar with any of the tools, seek help from a mechanic. Again, make sure to protect your care from rust by covering exposed parts, using correct socket size, and following its lug nut specifications.

However, sometimes the light stays on despite having proper tire pressure. You can drive your car for a while or relearn your TPMS. Fixing this is essential so that you can always know when your tires are deflated or under-pressured. This article will help you reset the Subaru tire pressure lights.

Top up your tire pressure

Check your tire pressure using a pressure meter and confirm the chart on your door jam for the recommended setting. If your tires have pressure below the recommended amount, you can pump it yourself or fill it up at your nearest gas station.

Drive for 25mph or more; the lights should go off after a few minutes. If they don’t, you’ll have to move on to the next stage on this guide.

Perform an OBDII relearn

You have to do a TPMS relearn using an OBDII scan tool if your wheels have been changed or rotated recently or your lights persist with adequate tire pressure. A TPMS relearn transfers the new sensor TPMS data to the vehicle’s Engine Control Unit (ECU).

This TPMS reset works for the following models

• Subaru Ascent 2019
• Subaru B9 Tribeca 2006-2008
• Subaru BRZ 2013-2019
• Subaru Forester 2008-2019
• Subaru Impreza 2008-2019
• Subaru Legacy 2004-2019
• Subaru Outback 2004-2019
• Subaru Tribeca 2008-2014
• Subaru WRX 2014-2019
• Subaru XV 2014
• Subaru XV Crosstrek 2013-2017

Steps to follow

• Set up your OBDII by selecting the make and model of your car.
• Start with the LF tire and place the scan tool on the tire’s side next to the valve stem to scan each sensor, not forgetting the full-size tire. Follow the order; LF, RF, RR, LR.
• Connect the OBDII module to the data link connector(usually located under the instrument panel on the driver side) to transfer the data.
• Without starting the car, turn the ignition on and upload the sensors’ data.
• Disconnect the OBDII from the connector and turn off the ignition, then on.
• The tire pressure should go off immediately. If it doesn’t, drive for 30mph for a few minutes, and it will reset your TPMS.

Check this too: Best Tire Brands for a Subaru Forester

Why is my tire pressure light on when my tires are fine?

There are other reasons why the low-pressure lights turn on besides the tires being flat or under-inflated. Some of these reasons include:

1. Extreme cold weather- When temperatures are very low, the air condenses and occupies less space, therefore reducing tire pressure. The solution is to hit the road, and the light will disappear after a while when the tire warms up, and the air expands, which increases the pressure.
2. Malfunctioned TPMS- The TPMS may have a deficient charge or may get damaged during a tire replacement. Before resetting your TPMS, check your tire pressure and confirm that it aligns with the recommended setting. If the tire pressure is sufficient, but the lights are still on, the TPMS may need replacing as they are relatively inexpensive.

Keep in mind that it is normal for the tire pressure lights to turn on when starting your car, only to go off after a few seconds. If the problem persists, get a certified auto-mechanic to help you.

You should not drive your car with a flat tire for more than fifty miles. Driving with a flat tire may damage your car’s transmission, gear system, axle shaft, drivetrain, or the CV and U joints. The engine exertion caused by driving with a flat tire will also increase fuel consumption.

How fast should I drive on a flat tire?

You should not exceed a maximum speed of 50 mph to avoid getting into an accident due to loss of control. Or worse, rolling or crashing due to poor braking function. However, it is best to change your tire for your own safety, even if you will replace it with a donut.

Check this too: How Can You Avoid Getting a Flat Tire?

This will offer you some cushioning and prevent you from damaging your car or getting into an accident. To ensure you never have to drive in a flat tire, always make sure you have a fully inflated spare or donut in your car at all times.

How fast should I drive on a donut?

It is advisable to drive at a speed of 50 miles per hour when your car is outfitted with a donut tire. This is because the tire is not that different in terms of pressure compared to a flat tire. The tire is not durable, and you can only use it for around 70 miles before it starts to wear and tear.

Most manufacturers give instructions regarding the maximum speed and distance you can go while using the donut tire. The top speed is also indicated on the tire. Donut tires have minimal tread, which makes them hazardous, especially if you drive on a wet road.

Additionally, due to its smaller size, it has to spin faster than the other three tires; this leads to a breakdown of lubrication grease due to heat production. Which, in turn, leads to wear and tear of the clutch plates and the gears.

What is the Difference Between a Spare Tire and a Donut?

A Donut

This is a smaller spare tire, also known as a space saver. They tend to be lightweight and do not take up a lot of space in the cargo area of your car. They are also easy to carry and install, which makes the tire change an easy one-person job.

They tend to be smaller than a standard tire, making them less stable than a full-size tire. They also have a limited maximum speed of 55 miles per hour. Essentially they are meant to get you to aa mechanic so you can get a full-size tire installed.

Check this too: Will a Donut Tire Fit Any Car?

A Spare tire

This is a full-sized tire similar to the other tires you have installed in your car. They tend to be bulky and take up a lot of room in your cargo hold. They are more durable and sturdier than donut tires.

Since most spare tires are generic, you may find that it may not be of the same quality as your other tires. They may have different tread patterns, and the quality may not be up to par with the rest of your tires. So once you get to a place, you can get a replacement, invest in a good quality tire similar to your other tires.

Can You Drive on the freeway with a Temporary Spare tire?

Yes. You can drive a temporary spare tire on the freeway. However, there are speed and distance restrictions for driving a donut tire on the highway. You can only operate at a maximum of 45-55 mph speed on the freeway when using a donut tire. On the other hand, there are no restrictions on driving on the freeway with a full-size spare tire.

Check this too: How to Get a Stripped Lug Nut off a Tire?

Removing tire marks from concrete

There is no specific way to prevent the stains from showing on concrete, so the best way is to eliminate them before they build up. Hosing alone won’t do it unless the marks are fresh, so it is essential to get rid of spots as soon as possible. There are various ways to clean, as shown below.

Water, a brush, and some elbow grease

This method to remove black tire marks from concrete is best when they are not very old. It doesn’t use any solvent if you suspect that the solvent may damage your driveway. To clean tire marks, you will require:

• Water in a bucket or hose.
• A stiff bristles brush

Start by clearing the concrete of any rubbish or dirt using the brush. Next, wet the area depending on your source of water. If you can, connect a hose since it guarantees you unlimited water. You can allow the water to set on the concrete since it will make the concrete easier to clean. Note that water doesn’t have any effect on the marks, so your hard work is needed.

Scrub the floor using the brush as you rinse away the removed pieces. If the marks on the concrete are old, this method may take more effort and time. Have patience and scrub as much as you can. Use a brush with a long handle to make it easier then rinse when finished.

Using dishwashing soap

If you try the water method and it doesn’t work, you may need some form of solvent. Dishwashing soap is a gentle option that you may want to try out before moving to much harsher products. For this, you will need:

• A bucket
• Water from a hose
• Liquid dishwashing soap
• Bristle brush

Mix some of the dishwashing soap into the bucket of water and wet an area of the concrete. Allow this to sit for at least five minutes. Mix some of the soap in a fresh bucket of water and use this as you scrub the floor. Use the water when an area needs more wetness and wash until the marks start coming off. Unfortunately, this may also not work for very old stains, but it does a better job than the water.

Use the hose water to rinse away the soap as well as the particles of tire marks. It is best to either use some pressure on the hose when rinsing or use a clean brush so it can get all the soapiness out. Once it is all done, inspect and repeat if there are areas with tire marks.

Using WD-40 Degreaser

When you have stubborn stains, and the above methods fail to produce excellent results, then you need to get a degreaser for concrete. These products are made to specifically clean concrete and are likely to give better results when cleaning. In this method, you will need:

• WD-40 degreaser
• Water from a hose
• Bristles brush

Degreaser for tire marks work in various ways and are best for different types of concrete. The WD-40 is one of the best, and it is easy to use since it comes in a spray bottle. It doesn’t corrode the concrete, so it is safe for use even on colored concrete. However, if you have a colored concrete driveway, some products may lead to bleaching and corrosion, so doing a spot test is crucial.

Some degreasers allow you to apply on concrete then rinse off without scrubbing, but depending on the stain, brushing is usually the best option. Therefore, apply the solvent on the concrete and leave for the recommended time, usually 10 to 20 minutes. Use a stiff bristles brush to scrub off the marks, then rinse using water.  You can also use a power washer, which is excellent for getting rid of stubborn stains. However, always check the condition of your concrete driveway to avoid damaging it when cleaning.

Check this too: 5 Best Tires for a Subaru Forester

If you are wondering whether skid marks go away on their own, the answer is no. However, there are many ways of cleaning them, depending on how nasty the stain is. In any case, ensure that the method you choose doesn’t affect the appearance of the floor. It is easy to trade one color for another. Avoid using bleach in any case since unless you want to clean the concrete thoroughly, it will leave the area with some unsightly marks.