Rear toe: is being in the green good enough ??

[Yury]

Hi, All

A couple of question. I recently had an alignment and everything is in the green. However, the toe on one of the rears is only 0.01 away from the spec limit (still being in the green). The rest is a bit more comfortably within the ranges.

Q1: Is being in the green good enough or can it still cause irregular tire wear? The car drives fine now. Neither can I detect any obvious feathering wear.

Q2: What would be the most typical cause? Manufacturing variances? The car shows no sign of accident whatsoever. The mileage is low (27.000 km or ~17.000 miles)


(The tires are kinda neglected, the fronts are quite lower than the rears and the rears have a small amount of what seems to be edge wear. One side a bit worse, but still minor. I don't think they were ever rotated and I know for a fact they have been ran on 20 psi for god knows how long (up to a year easily).

Thx.

[A-Dingo-Ate-My-Baby]

out of spec is out of spec

Q1: it will contribute to irregular tire wear. not much though, should be fine
but small variances will eat tires and monkey with handling. if you have
VSC the computer might not run the most effective routine when needed

Q2: cause can be a poorly made part, wheel, or knocking into a curb
(typical scenario: sliding a bit on ice and jamming/bumping the wheel hard on something)

[Yury]

thanks.

it is not out of spec. it's in the green, but too close to the limit. I mean, other numbers are obviously not dead center either, but this one is only 0.01 away from the limit.

hence the question...how are the limits defined and whether being very near already starts being a small issue. kinda like medicine defines fever, you may be below the threshold but you will feel crappy already.

[A-Dingo-Ate-My-Baby]

how are the limits defined ? don't know, Toyota knows

do you have a problem ? nope. green is green.

[Yury]

ok, thanks :)

PS and if I start getting feathering I will have that corner shimmed.

[cali yaris]

.01 is actually not measurable with any reliability. You are fine.

[Yury]

Originally Posted by cali yaris

.01 is actually not measurable with any reliability. You are fine.

following your statement if the precision is not high enough I may as well be out in the red. and yet you are saying I am fine?

[rayy]

0.01 degrees is very insignificant, if you imagine 1 degrees and divide it into 100 sections 1 of the 100 sectrions is 0.01 degress, thats how small the wheel is out

[Kaykogi]

Originally Posted by rayy

0.01 degrees is very insignificant, if you imagine 1 degrees and divide it into 100 sections 1 of the 100 sectrions is 0.01 degress, thats how small the wheel is out

No, that's how close the wheel is to being out of the green. That's pretty close, and if it is unreliable, he could have a problem.

[Yury]

Originally Posted by Kaykogi

No, that's how close the wheel is to being out of the green. That's pretty close, and if it is unreliable, he could have a problem.

bingo.

[Yury]

but then the manufacture's specs are always with 2 digit precision.

also, I just realized something interesting. Yaris factory manual (http://etimago.com/yaris/repairmanual/Suspension.pdf) when describing the alignment process does operate with a sum of angles of both wheels, not individual angles (page SP10). This is well in green. They don't limit individual wheel toe per se.
I suppose I can understand that. If individually the back toe is out, but the sum is ok the rear will move out a bit resulting basically in possibly slightly off center steering wheel (that I am not seeing at all). If the sum is ok, but both toes are significantly out, no amount of tie rod adjustment on the front will center the steering. And that may be there is merit in limiting individually. But as long as the sum is ok, it's a cosmetic issue.

Please correct me if I am wrong.

[Stove]

The real question is:
Is it worth the time and money to shim and pay to check the alignment again (and possibly again, and again to get it right) versus the insignificant tire wear you might see?

[Yury]

Originally Posted by Stove

The real question is:
Is it worth the time and money to shim and pay to check the alignment again (and possibly again, and again to get it right) versus the insignificant tire wear you might see?

In theory if a shop installs the shim while the car is on the rack it maybe done quickly and correctly. It would have to be a good shop though.

I am suspecting there will not be any detectable abnormality due to the fact that the combined toe is comfortably within specs. The lateral force caused by dog tracking of that small extent should be minimal. after all, only one individual toe is borderline and it is, after all, in green.

[cali yaris]

following your statement if the precision is not high enough I may as well be out in the red. and yet you are saying I am fine?

Yes.

[Yury]

Originally Posted by cali yaris

Yes.

still not getting it
(it being your logical construct more than the issue itself :))

[A-Dingo-Ate-My-Baby]

green is green, so it is fine

cars have variances

you can likely go have your tires remounted and spun
on a hunter road force balancer, optimized for all 4 corners,
and mounted in a specific pattern, and this alone can change
the way the car drives far more than .01 green in rear toe

or go get a thin spacer, have it planed, and put the issue to bed

[Yury]

^ yeah, you are right about the balance. it does optimize net pull.

I did study it some more. The effect of such variance is dog tracking which seems to be an issue mostly because the steering has to compensate for it. And when it's extreme the steering will toe out the front, which may introduce toe wear even with correct front alignment. An evidence of that would be feathering of the fronts and I have none, so it is negligible.

whenever I need to align it again, I will do the whole thing with spacers. and probably do the front camber kit as well.

[Viperoni]

Wouldn't worry about it.
My rears were toed in aroudn 0.5 degrees total from the factory, no feathering. I believe that was close to the limit.

Now they're sitting at 0.01 degrees toe in total, basically straight on.

Once the suspension components start flexing and all, I'm sure there's significant changes to all alignment specs, heck even caster.