Good tire, Bad tire

[tracer]

Here's a small table that sums up the differences between my Bad Tire and the Good Tire. If anyone has any idea on why the truck was pulling towards the ditch when the Bad Tires were on, pls let me know. When I put the Good Tires on, the truck's steering became perfect (all-wheel alignment was done twice when the Bad Tires were on).

BAD TIRE
Michelin 11R22.5" XZA-3
Diameter: 41.3"
Loaded radius: 19.3"
Sidewall: 9.4" (41.3 - 22.5 / 2)
Width: 11.1"
Weight: 117.7 lbs
RPM: 502

GOOD TIRE
Michelin 275/80R22.5 XZA-3
Diameter: 40.1"
Loaded radius: 18.6"
Sidewall: 8.8" (40.1 - 22.5 / 2)
Width: 10.9"
Weight: 112.9 lbs
RPM: 518

I think a steer tire's width is the factor that affects truck's steering. Weight is probably important too. My original factory size tire was 295/75R22.5

[bob h]

When an all-axle alignment is done properly, and the vehicle still has steering pull, a tire is usually to blame.

Are you thinking that you had a bad tire? ...or, that 22.5s are bad tires?

[tracer]

When an all-axle alignment is done properly, and the vehicle still has steering pull, a tire is usually to blame. Are you thinking that you had a bad tire? ...or, that 22.5s are bad tires?

No, the tire was fairly new and in perfect condition. I just call it "bad" because it caused the truck to drift towards the ditch, while the "good" tire cured that. The guy who did the all wheel alignment wasn't able to explain this curious effect of the 22.5" tire on the truck's behavior on the road.

[Fredog]

when a belt breaks in a tire, it will cause pulling problems, it will usually pull to the side opposite of where the bad tire is, no amount of alignment or balancing will fix it. it's possible you had more than one bad one, but not likely, one separated tire can cause a lot of trouble

also, the tire your truck calls for is a low profile.. your "bad" tire is a regular height, the wrong tire can affect performance too. they recommend a certain size for a reason

p.s, for those who say " what do you know?") I was service manager at a truck tire service center for 3 years

[allan5oh]

I agree with the two posters above. It's not the size difference. It's possible the other tire hit something and damaged it. XZA3's are the best steer tire out there IMO. I usually get 240,000 to 250,000 miles out of them. Right now I'm at about 180,000 miles and there's absolutely NO funny wear whatsoever! I think the shallowest point I could find was 8/32's.

Anyone know why my drivers side tire seems to have a little more rubber on it? Both were changed at the same time.


I assume yours were as well tracer.

[bob h]

I agree with the two posters above. It's not the size difference. It's possible the other tire hit something and damaged it. XZA3's are the best steer tire out there IMO. I usually get 240,000 to 250,000 miles out of them. Right now I'm at about 180,000 miles and there's absolutely NO funny wear whatsoever! I think the shallowest point I could find was 8/32's.

Anyone know why my drivers side tire seems to have a little more rubber on it? Both were changed at the same time.

it's normal for the tire on the high side of the road to wear a little faster.

[bob h]

when a belt breaks in a tire, it will cause pulling problems, it will usually pull to the side opposite of where the bad tire is, no amount of alignment or balancing will fix it. it's possible you had more than one bad one, but not likely, one separated tire can cause a lot of trouble

also, the tire your truck calls for is a low profile.. your "bad" tire is a regular height, the wrong tire can affect performance too. they recommend a certain size for a reason

p.s, for those who say " what do you know?") I was service manager at a truck tire service center for 3 years

When both of the steers tires are the wrong size tire (11Rs instead of 80series), it may affect steering feel, handling, etc... but, it should NOT cause directional pull on its own.

[bob h]

No, the tire was fairly new and in perfect condition. I just call it "bad" because it caused the truck to drift towards the ditch, while the "good" tire cured that. The guy who did the all wheel alignment wasn't able to explain this curious effect of the 22.5" tire on the truck's behavior on the road.

I have seen brand new tires installed that have radial pull... the size or aspect ratio has nothing to do with it.

A competent alignment tech would have recommended that you swap your steer tires side to side to see how this affects your pull; it will usually be eliminated or pull slightly towards the center line. Then, you will KNOW a tire is the cause.

[Fredog]

a defective tire usually separates when it is pretty new, people think it cant be the tire it's new, but that's when it happens, I agree, swapping them from side to side would tell you right away

[ralcotruck]

I have seen brand new tires installed that have radial pull... the size or aspect ratio has nothing to do with it.

A competent alignment tech would have recommended that you swap your steer tires side to side to see how this affects your pull; it will usually be eliminated or pull slightly towards the center line. Then, you will KNOW a tire is the cause.

This is 100 percent accurate. I own a repair shop that specializes in truck and tractor alignment. Several things can cause a pull or drift, only one of which is the tire. When your truck was aligned, did you have all three axles checked and aligned? Rear axle thrust or geometric angle depending on which alignment company you bow to can cause inner and outer tire wear on the STEER axle and can cause the truck to push to one side or the other. A difference of more than .5 degree on the caster value on the steer axle will cause the truck to drift or pull to the low side caster reading. Even a dragging brake or wheel bearing can cause the problem. Step one is to make sure that all of the above or ok. If all is in check, rotate the tires and eliminate them as the problem. Many, Many, Many times I have performed a full alignment and after verifying that all of the readings were good, rotated two brand new steer tires to correct or "better" the pull or drift.

Optimum tire wear on over the road trucks is 125,000 miles for the steers and 250,000 for the drives. I am getting 150-175 on steers and 275-300 on drives, with regular maintenance and rotation. Alignment and full balance works-it just needs to be maintnaned. For example, as one of the upper posts says, the left tire is the lead tire, it will wear quicker than the right. Rotation and balance will extend the life of that tire. Tires are way to expensive to waste!!!

[tracer]

I agree with the two posters above. It's not the size difference. It's possible the other tire hit something and damaged it. XZA3's are the best steer tire out there IMO. I usually get 240,000 to 250,000 miles out of them. Right now I'm at about 180,000 miles and there's absolutely NO funny wear whatsoever! I think the shallowest point I could find was 8/32's.

Anyone know why my drivers side tire seems to have a little more rubber on it? Both were changed at the same time.


I assume yours were as well tracer.

The thing is that the "bad tire" wasn't bad at all. When I bought the truck, it had defective tires on (bold spots due improper mounting) and I put on NEW 22.5 STEER tires. Steering was bad despite the many many many alignments. So I finally noticed that the sticker on the cab said my tires was supposed to be a low profile 295. I switched it (275 on steers, 295s on drives) and steering became 99.9% perfect. Same tire, Michelin XZA 3, just a low profile size. By the way, alan, it wears great. I don't see any abnormalities. The only thing I don't like is it's a 275 size, and my drives are 295s, so the trucks sits at a slight angle towards the front When it's time to change them, I think I'll go to GoodYear or Bridgestone that do have 295 steers...

[tracer]

This is 100 percent accurate. I own a repair shop that specializes in truck and tractor alignment. Several things can cause a pull or drift, only one of which is the tire. When your truck was aligned, did you have all three axles checked and aligned? Rear axle thrust or geometric angle depending on which alignment company you bow to can cause inner and outer tire wear on the STEER axle and can cause the truck to push to one side or the other. A difference of more than .5 degree on the caster value on the steer axle will cause the truck to drift or pull to the low side caster reading. Even a dragging brake or wheel bearing can cause the problem. Step one is to make sure that all of the above or ok. If all is in check, rotate the tires and eliminate them as the problem. Many, Many, Many times I have performed a full alignment and after verifying that all of the readings were good, rotated two brand new steer tires to correct or "better" the pull or drift.

Optimum tire wear on over the road trucks is 125,000 miles for the steers and 250,000 for the drives. I am getting 150-175 on steers and 275-300 on drives, with regular maintenance and rotation. Alignment and full balance works-it just needs to be maintnaned. For example, as one of the upper posts says, the left tire is the lead tire, it will wear quicker than the right. Rotation and balance will extend the life of that tire. Tires are way to expensive to waste!!!

So, are you saying that using wrong size tire on steers shouldn't cause the drift by itself? I mean, if the truck came from the plant with 295s on steers, and the previous owner changed them to regular 11R22.5s ... are you saying IT SHOULDN'T AFFECT THE STEERING by itself?

By the way, while I was looking for the "cure" for that drift, I did ALL WHEEL alignment not once but ... twice. I even went to Shop #1 and asked them to do another custom alignment and increase my caster ... The guy did what he could, but nothing had changed. Only when I put on 275/80R22.5 Michelin XZA 3 on the front, the steering improved dramatically - no more drift. But from what you're saying, it's not as simple as changing the tire size back to the factory?

[tracer]

So, are you saying that using wrong size tire on steers shouldn't cause the drift by itself? I mean, if the truck came from the plant with 295s on steers, and the previous owner changed them to regular 11R22.5s ... are you saying IT SHOULDN'T AFFECT THE STEERING by itself?

By the way, while I was looking for the "cure" for that drift, I did ALL WHEEL alignment not once but ... twice. I even went to Shop #1 and asked them to do another custom alignment and increase my caster ... The guy did what he could, but nothing had changed. Only when I put on 275/80R22.5 Michelin XZA 3 on the front, the steering improved dramatically - no more drift. But from what you're saying, it's not as simple as changing the tire size back to the factory?

Did search online for "wheel alignment". Found an interesting article, which says this about CASTER

"Caster is the tilting of the uppermost point of the steering axis either forward or backward (when viewed from the side of the vehicle). A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering but does not affect the tire wear and is not adjustable on this vehicle. Caster is affected by the vehicle height, therefore it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging rear spring will affect caster. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster."

That answers why my truck improved steering with 295 tires! It was designed to use shorter tires, and then Owner 1 put on taller 22.5 tires. When I reinstalled the original 295s (smaller radiius), the caster changed back to normal because the truck was sitting lower, the way it came from the factory. Eureka!

[allan5oh]

That's more for four wheelers with cut coil springs. Lowering the suspension on the car always affects caster/camber.

[bob h]

So, are you saying that using wrong size tire on steers shouldn't cause the drift by itself? I mean, if the truck came from the plant with 295s on steers, and the previous owner changed them to regular 11R22.5s ... are you saying IT SHOULDN'T AFFECT THE STEERING by itself?

By the way, while I was looking for the "cure" for that drift, I did ALL WHEEL alignment not once but ... twice. I even went to Shop #1 and asked them to do another custom alignment and increase my caster ... The guy did what he could, but nothing had changed. Only when I put on 275/80R22.5 Michelin XZA 3 on the front, the steering improved dramatically - no more drift. But from what you're saying, it's not as simple as changing the tire size back to the factory?

Your original post stated; "If anyone has any idea on why the truck was pulling towards the ditch when the Bad Tires were on, pls let me know." Now, you've turned that into; "changing from 11Rs to 275/80s should or should not AFFECT THE STEERING". The answer to your NEW question is YES, changing the rolling diameter of the tires WILL 'affect the steering'. But, again, the answer to your original question is NO, it will not cause the vehicle to pull to the ditch: you had an 11R with radial pull.

[bob h]

Did search online for "wheel alignment". Found an interesting article, which says this about CASTER

"Caster is the tilting of the uppermost point of the steering axis either forward or backward (when viewed from the side of the vehicle). A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering but does not affect the tire wear and is not adjustable on this vehicle. Caster is affected by the vehicle height, therefore it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging rear spring will affect caster. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster."

That answers why my truck improved steering with 295 tires! It was designed to use shorter tires, and then Owner 1 put on taller 22.5 tires. When I reinstalled the original 295s (smaller radiius), the caster changed back to normal because the truck was sitting lower, the way it came from the factory. Eureka!

By making a small change in tire height, caster will likely NOT go "out of spec". Your alignment tech would have noticed incorrect caster, that's one thing he does measure. The caster angle usually has an acceptable 2 - 4 degree range that allows for changes in suspension and frame angles due to loading, spring sag, etc. otherwise, you would have steering issues everytime you hit a bump or dip in the road.

Next, caster does NOT cause pull. Extreme caster angles can cause shimmy, wandering, darting, etc... handleability concerns. A DIFFERENCE in caster angle from one side to the other does cause steering pull, but that problem is very rare in I-beam axles (non-independant suspension). Steering pull with these vehicles is usually cause by drive axle thrust angles... or by steer tire radial pull. By changing steer tire size, you make a small change in the caster angle, and that change is equal on both sides resulting in no change to directional pull. you had 1 bad 11R, if you had swapped them side to side, the PULL would have went away... IMO.

[ralcotruck]

I agree with BOB H, the tire size will NOT effect caster other than raise or lower it equally a minor amount.

Your question was initially tire size, by that you switched out two tires of one size and install two smaller tires and think that corrected the pull when the problem was not the tire size, it was the tires that were pulling you, as Bob H says had you switched the tires from left to right, this would have eliminated or drastically reduced the pull.

If you had the custom alignment reduce the caster on the opposite side of the pull by one degree and left the tires in the orignal position, you would compensate for the tire pull, however, you would create steering wheel return issues and/or wandering problems as well as the need to cetner your steering wheel.

I guess that what I am trying to say is in my opinion, the answer to the orignal question is that the tire size has nothing to do with your pull.

[ralcotruck]

Did search online for "wheel alignment". Found an interesting article, which says this about CASTER

"Caster is the tilting of the uppermost point of the steering axis either forward or backward (when viewed from the side of the vehicle). A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering but does not affect the tire wear and is not adjustable on this vehicle. Caster is affected by the vehicle height, therefore it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging rear spring will affect caster. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster."

That answers why my truck improved steering with 295 tires! It was designed to use shorter tires, and then Owner 1 put on taller 22.5 tires. When I reinstalled the original 295s (smaller radiius), the caster changed back to normal because the truck was sitting lower, the way it came from the factory. Eureka!

Can you post what your alingment readings were, what they changed them too, and what they are currently? Just curious too see what the readings are.

Ted

[tracer]

you had 1 bad 11R, if you had swapped them side to side, the PULL would have went away... IMO.

both steer tires were brand new Michelin XZA 3. you think one tire was defective? and the pull with 11R22.5s was not to one side, it was to whatever side the arch in the road was pointing too. If I was in the left lane, and the highway sloped left, the truck would go left. If I was in the right lane, and the slope was to the right, the truck would go right. ON a perfectly flat road it would stay put and continue in a straight line.

[ralcotruck]

both steer tires were brand new Michelin XZA 3. you think one tire was defective? and the pull with 11R22.5s was not to one side, it was to whatever side the arch in the road was pointing too. If I was in the left lane, and the highway sloped left, the truck would go left. If I was in the right lane, and the slope was to the right, the truck would go right. ON a perfectly flat road it would stay put and continue in a straight line.

Sounds like you did not have any problem then.

The most important thing is you like the way your truck handles. However you think you have gotten to that point is irrevelant. Good luck and hpe that your truck continues to stay straight no matter what side of the road you are on....