DIY : Tire Tech

[Mister_Perkins]

There are many causes for uneven tire wear stringing from out of aligned tie-rods to under inflated and over inflated tires. Hopefully this thread will give you a better idea of what is going on with your tires. If you already know everything about tires, then thats great. This thread is for those individuals who might not

What is a Tire?

Tires are made out of flexible rubber which is incorporated with wire and fabric. The tires of an automobile support the braking, load, traction, and steering. Tires also absorb shock caused by bumps in the road and help provide a smooth ride to the passengers. Different styles of tires are available depending on application. Tire categories are solid, bias ply, and radial.

Reducing Wear and Tear

You can reduce the maintenance and repair of your vehicle by checking the tire pressure with a tire pressure gauge regularly. Your tire manufacturer specifies that maximum pressure COLD that the tire should carry. I typically run my tires at 35psi all the way around the car, and have no adverse tire wear patterns.

How to tell what is going on with your tires

Sometimes a tire will have unusual tread wear patterns like flat spots, cupping wear on one side of the tire. All these can be caused by balance problem, under-inflation, failed front end suspension components or misalignment.

Under Inflation

An under-inflated tire can be caused by a few things. You could have a foreign object embedded in the tire such as a nail, piece of metal, screw, etc.. or your valve stem can be leaking. To check for leaks relatively easy, grab an empty spray bottle and fill it with water, add a little bit of dish soap to it and spray it liberally on the tire. If you are leaking air, the soapy water will bubble where the leak is. Or, the pressures could just be wrong. Adjust accordingly

Rapid Wear

Rapid wear is caused by over-inflating the tires. If you leave your tires over-inflated it will cause the center of the tire to wear out before the outside, and the tire can blow-out without notice. Adjust the pressure to the tires as soon as possible!

Wear on one side
Toe wear - a feathered wear pattern across both front tires, and sometimes shoulder wear on the inner or outer edge of both tires. Toe wear is usually caused by worn tie rod ends, but may also result from worn or loose inner tie rod sockets on rack and pinion steering gears. Other causes include bent steering arms or misalignment in the rear wheels. Measuring toe out with the wheels turned 20 degrees to either side can help you detect a bent steering arm.

If toe wear is accompanied by steering looseness or steering wander, there's a very good chance the tie rod ends are worn. Proceed to the steering checks. If toe wear is accompanied by steering pull or off-center steering, rear wheel toe alignment or axle alignment may be out of specifications.

Camber wear - uneven wear on one side of a tire may show up when control arm bushings have collapsed, ball joints are loose, a spindle or strut is bent, or a strut tower is out of its normal position (due to factory misassembly, collision damage, body sag or severe corrosion).

You should make sure to check out all of the bushings, ball joints, tie-rods, struts, steering Joints if your tires look like this!


Feathered Edges
Feathered Edges on a tire are caused by incorrect toe. This is directly related to your front and rear end alignment, and you should have your car aligned as soon as possible.



Bald Spots

Bald spots are caused by an unbalanced wheel or an out of aligned Strut tower. You will have noticeable road vibration while driving down the road. The fix for this is to have your car aligned, and have the tires balanced. Its hard to see in the picture, but the light spots are actually spots that would start to get bald if left alone.

Dry Rotted tires
if you have Dry rotted tires, they are unsafe. Period. get them replaced.. they can blow out on the highway and cause injury to you or others on the road.



Tire Pressure Gauges

A tire pressure gauge is designed to check the air pressure inside a tire. they are relatively cheap and pretty accurate (+/- 3psi on inexpensive ones). There are more accurate tire pressure gauges out there that are +/- 1psi in accuracy.

How to Rotate your Cars tires Correctly

Most Tire Manufacturers recommend rotating your tires every 5,000 to 10,000 miles. Its a good idea to follow this rule, or rotate them earlier if you are experiencing any abnormal wear. Make sure to get the car looked at right away if you are experiencing abnormal wear!

Here is a diagram showing the proper way to rotate your tires on your car. Make sure to check and adjust the pressure after rotations as well, just to be safe

(Made in MS Paint)

Typical Rotation


Alternate Rotation


If I left anything out, please let me know !


Addition by Fenixus

directional tires need to stay on same side, so no crossing over (switching sides) when rotating from rear to front
otherwise they will start rotating against the direction (arrow) and can cause weird behavior when directional threads start rolling against the designed direction.

[fenixus]

directional tires need to stay on same side, so no crossing over (switching sides) when rotating from rear to front
otheriwse they will start rotating against the direction (arrow) and can cause weird behavior when directional threads start rolling against the designed direction.

[Mister_Perkins]

Good point Mind if i Add that to the original thread?

[fenixus]

go ahead bro, by all means

whatever is published here is public anyways

great info you posted here, lots of good stuff on tires. I like

[Mister_Perkins]

thanks man , i appreciate it I hope it helps some people out in determining what problems they have with their tires / car

[Chris Crash]

Another great post by brandon. Thanks man, this will sure help a lot of people out.

[Mister_Perkins]

Originally Posted by Chris Crash

Another great post by brandon. Thanks man, this will sure help a lot of people out.

Thanks Chris

[TRD95]

Thanks for bringing awareness to tire wear & safety Perkins! Tire condition always says a lot about the overall condition of a vehicle's suspension & overall driveabilty!

[camrynoob]

I have a question. If my tires have Max PSI at 44, what PSI should I give them? I have heard before do it a little less, like 4-5 less than max? Is that true? Also, what about seasons? Should I change tire pressure in the winter? Also, how quickly do tires deflate, and do the seasons make a difference?

E.g. I just inflated my tires to 40 PSI about 10 days ago, and now they are all at 37-38 PSI. Is that amount of deflation normal?

Thanks for the write up btw!

[camrynoob]

p.s. My driver side door says recommended PSI is 30, but I'm not using the tires that came with the vihicle. Should I assume that what the driver side door says is only for the the original OEM tires? Or is that for any tires I put on there?

[fenixus]

check this article (link to tirerack.com):
http://tinyurl.com/3xgpn3

it explains a lot per tire pressure vs ambient temperature difference. also ideally tires should not deflate at all, but oh well they all do over time

your reading difference might be coming from different tire and/or ambient temperature.

e.g. I usually inflate tires when they are warm or hot in Summer to 37psi which puts them around 32-33psi at cold tire with ambient around 70F.

In Winter I usually inflate tires (again warm, after driving) to 40psi which puts them around 35-36psi at cold tire with ambient around 30-40F (would be much higher at 70F but difference is not drastic, still in norm).

Originally Posted by camrynoob

I have a question. If my tires have Max PSI at 44, what PSI should I give them? I have heard before do it a little less, like 4-5 less than max? Is that true? Also, what about seasons? Should I change tire pressure in the winter? Also, how quickly do tires deflate, and do the seasons make a difference?

E.g. I just inflated my tires to 40 PSI about 10 days ago, and now they are all at 37-38 PSI. Is that amount of deflation normal?

Thanks for the write up btw!

[Silent Runner]

I wonder if it's worth mentioning that in many cases, tire pressure recommendations are also influenced by car manufacturers, and the ride characteristics they want their vehicles to have? IDA know, maybe thats a bit advanced, but characteristics like softer or firmer ride, transient response, understeer and oversteer can be influenced by tire inflation and front to rear differentials. Example: The Gen3 Camry's 30psi recommended inflation makes the car ride softer over harsh impacts, and its equal front/rear inflation rates, help keep the car understeering early as it approaches its cornering limits. - a higher front inflation rate would make the car more neutral as it approached its limits.

[fenixus]

oh and 1 more important thing per tire pressure. new tires (fresh install) stickers and recommendations always state a LOWER max pressure limit until the tire beads (or belts or something else inside) breaks in properly.

e.g. my Yoko tires allow 40psi max initially and let's say 500 miles later (easy driving under all conditions) after they are broken in, the max limit is 50psi.

more info on tire breaking in:
http://tinyurl.com/7qgycoq

also per Silent Runner's comment on under/over-steer and pressure relation, check this (another tirerack.com article):
http://tinyurl.com/6cx67y
more or less similar things SR wrote

for some reason this forum doesn't allow us to link directly to tirerack.com URLs.

[pmesfun]

Originally Posted by fenixus

for some reason this forum doesn't allow us to link directly to tirerack.com URLs.

If you copy the tire rack page link into tiny url, it works.

Like this.


http://www.tirerack.com/tires/tires....l&autoModClar=

http://tinyurl.com/itshouldworkthisway

[NapalmFTW]

My passenger side front tire was down to the steel on the inside of the tire.

I have no idea what I shoud be looking for with the wheel off to see what needs replacing/fixing on the car.

My drivers side front - when up on the stands and rotated by hand I can hear stuff rolling around in the tire/wheel.... can't be good!