torsion beam rear suspension, tires show camber wear

nothing that I can see is bent in the back end of my car, and, as mentioned above, it has a torsion beam rear, making it basically un adjustable. My stock tires are 195/65/15 and the tires on it now are 235/40/17. so my question is this, could the camber built into the rear end from factory have been compounded over the 40mm wider tires to mak eit noticeable as tire wear? I'm putting the stockers on monday at work (just bought some falken ziex 512 for super cheap) and the old stock tires wore perfectly even across. I don't know much about alignment angles in effectively solid rears to know if my guess is right, but it's pretty obvious to me that either I'm right or something is bent in the rear end to cause this crazy tire wear. Look forward to your thoughts, thank you.

Maybe on the tire size, but I would look at the suspension as it cycles for a bind.

Put it on an alignment machine.

purplepeopleeater wrote: Put it on an alignment machine.

For most applications there are shims available to correct camber/toe issues on torsion beam axles. First thing first is to make sure there is an camber/toe issue.

What is the offset of the 17" wheels ? If the centerline of the wheel is moved out enough, it possibly could cause camber wear. Put the stock wheels on and get the alignment checked.

yeah, if the alignment rack shows something out of wack (check both camber and toe) , get some alignment shims. The rear stub axles are bolted to the torsion beam - the shims wedge in between the two. They come in a variety of angles : check the alignment -vs- the stock specs and make the correction.

Here's a DIY set for illustration:

Without putting it on an alignment machine - or at minimum a set of smart strings or smart strings equivalent, it's speculation.

I will off that everything I own except the Tacoma and Sprite (rear stick axles both) is aligned aggressively and alignment caused tire wear is rear only - the end w/ typically about a degree less - camber than the front - due to rear toe in. I run zero toe front usually.

So look for something bent astern.

What kind of car?

Older VWs were notorious for horrendous rear tire wear. As the cars got heavier, the problems lessened, but they still exist if you never rotate the tires. It's probably not a GRM'er problem because it generally only happened if you drove like a wuss. I understand the German term for the problem translates to "old woman driver wear".

You could do an alignment and it'd still wear the tires horribly because the SPEC was something like 1.5 negative camber with a whole lot of toe-in as well. OE alignment is generally for handling, not good tire wear. (90's Ford front-drives are bad for this too - negative camber and negative toe! Wonder why they'd chew through tires)

its a 2010 kia forte, and I can put it on a rack at work. due to time constraints I'm putting the stockers back on tomorrow at work and checking alignment with the stock size on there, I'm sure the front toe is out, at the very least, just due to the 50k miles I've put on the car.
I was just wondering if it could be tire wear due basically to a factory alignment spec, which was made to show up worse by wheels with a little more offset (i think about +3-5 mm) and a lot more width, but wasn't sure. Since you mentioned fords being really prone to rear tire wear I'm thinking that maybe this is a case of the same, gotta look at the rear specs again.
I can pretty much guarantee it isn't due to old woman driving, when I do get off the highway I don't generally slow down too much for curves lol (even for a front driver with a crap rear suspension it drives quite well)

Since you are not using stock wheels and tires, yopu may need to adapt the factory spec as well. They often add some really strange numbers to the spec sheet to compensate for some handling quirk...Ford Focus used some very odd toe settings that needed to be changed, even on stock tire cars.

I know the torsion beam on my 2009 accent has -1.0 degrees camber and some slight toe in on each side. If I don't rotate tires they do wear more on the inside.

Streetwiseguy wrote: Since you are not using stock wheels and tires, yopu may need to adapt the factory spec as well. They often add some really strange numbers to the spec sheet to compensate for some handling quirk...Ford Focus used some very odd toe settings that needed to be changed, even on stock tire cars.

was wondering about this as well. I'm sure, with it being a kia, they didn't anticipate anyone putting some big-ass tires on it lol
I'll have to troubleshoot through this when the time comes to put the big wheels back on. Been contemplating cutting the t-bar out and putting the elantra rear suspension under it (multi-link), plus sway bars and such in the back to bring some stiffness back. That'll be a big project though, and I'm going to be throwing money at the vair for now lol.
but yeah, there shouldnt be anything bent under there, but I'll check it all out and make sure the alignment is in specs for the stockers when I put them back on tomorrow.
thanks for your help, everybody

Bear in mind that the alignment specs take into account stock tire size. Wide low profile tires will be much more affected than doughnut-shaped tires.

A 185/60-15 can tolerate nearly 2 degrees of camber just fine. A 275/40-17 will destroy the tires at .8 degree camber. It also doesn't need that much camber, and indeed won't really like it very much.

I don't see a change in offset causing any change in tire wear. Maaayyybe it could hurt things on the front... but I ran 1" wheel spacers for roughly 15k miles and noticed no difference in tire wear.

thank you knurled, I was sure the tolerances would be different since it'd be spread out further, but wasnt sure of any real numbers. I checked the alignment once I put stock size back on today and all the numbers were good except rear toe by a minimal amount and front toe, which was adjustable, of course.
the spec for rear camber was -1.5*, so that kind of explains the wear on the much bigger tires. thank you all for your help