Inside shoulder wear

[rationull]

I just discovered that one of the vehicles I maintain must have an alignment issue -- it's worn the inside shoulders on all its tires down ~4x faster than the rest of the treat. The worst part of the shoulder has less than 2/32" of tread left, while the rest of the tire (all of the actual tread grooves) is still at about 4/32". Nothing is actually bald yet though.

So obviously this vehicle is due for new tires (and at 4/32" would be due soon anyway even without the shoulder problem).

How much meat is there under the tread on the shoulder in general? I'm not sure how fast this will wear down and I need to know whether this is a "ASAP first thing Monday morning" thing or whether it can likely go another 1000-2000 miles until a more convenient time.

To be clear, the tire has plenty of tread elsewhere so I'm not worried about traction. Just about how much buffer there is if some of the shoulder tread blocks do wear all the way down before the new tires go on. I obviously want to do what I need to for safety so my first inclination is to shift things around and get it done right away but I may be over-reacting.

 

[Brybo86]

Either too much toe out if it looks like feathering
Or
Worn shocks/springs if it looks like cupping


I think Sears will do a free alignment check

 

[rationull]

Yeah I'm pretty sure it's just the toe setting. I figured I'll get the alignment checked anyway at some point soon. Just trying to decide how urgent the tire change is. TBH I think most likely nothing will wear down "bald" for a while longer but worst case, probably a half-inch section at the shoulder would end up worn down. I'm trying to ascertain whether that's dangerous in itself.

 

[eljefino]

I ran some uniroyal tigerpaws down on the inside edge without feathering or anything else. Like you, it was just a slight difference, eg, oh, that went first.

I DIY alignments and have improved my technique since before, set my toe a little further in, and bought some more $15 tires on craigslist.

Car handles better than ever, too.

 

[rslifkin]

Almost definitely excessive toe. If there's very little negative camber, it's likely toe-out. If the vehicle does have more than a 1/2 degree of negative camber, either too much toe-in or toe-out could cause inside edge wear (toe amplifies camber wear).

 

[Johnny2Bad]

There is enough rubber to keep running them for a little bit ... I would not panic over 1000 miles more, travelling in the city where help is available 24/7.

 

[rationull]

I managed to get a picture earlier:

The circumferential tread grooves are 4/32: and the lowest spot on the far right side of the picture (which is the inside shoulder) is between 1 and 2 /32". I think the circumferential wear bars on the rightmost non-shoulder tread block is a 4/32" replacement reminder bar.

Sounds like maybe not a big deal but I'm still debating the options.

 

[Brybo86]

Do you drive around with a bunch of weight in the back?

 

[rationull]

Originally Posted By: Brybo86
Do you drive around with a bunch of weight in the back?


Nope.



So it's OK to get down to the bottom of the tread like this? Bald shoulder leaves a little margin before the danger zone?

 

[rationull]

Eh, checked them out again after getting home today and I'm not going to chance it. New tires should go on tomorrow.

 

[Carbon]

Will you have the alignment done at the tire place, or at an independent alignment shop? I would lean toward the later.

 

[rationull]

I lean toward the latter as well, but I want to look at the options a bit first since it's been a while since I've had an alignment done and I'm not sure how the shops may have changed. The tire shop I go to has a pretty new rack and AFAICT does have some good, well qualified employees (at least for tire repair) so it's still an option, as long as they'll check it first and talk it over with me rather than just poking it until the numbers turn green.

 

[PandaBear]

If you are concerned because of the El Nino rain change it out. If it is just sitting around wait till the end of summer before the next rain season.

Not a huge amount off in toe, more like a slightly more than usual negative camber to me.

 

[HTSS_TR]

Originally Posted By: PandaBear
If you are concerned because of the El Nino rain change it out. If it is just sitting around wait till the end of summer before the next rain season.

Not a huge amount off in toe, more like a slightly more than usual negative camber to me.

Large negative camber is usually the culprit for rapid wear of inside tire.

Honda S2000 alignment specs:
Front Camber = 0º30' +/- 10'
Rear Camber = -1.5º +/- 0º.167

E430 alignment specs:
Front Camber = -0º60 +/-0º.40
Rear Camber = -1.2º +/-0º.40

The inside rear tires of both cars wear out at much faster rate than outside.

 

[tightwad]

Be sure to have the alignment tech check for loose parts. I had the same condition on my 2001 Caddy from a worn-out outer tie rod and almost ruined a front tire.

 

[rslifkin]

It takes a good bit of negative camber to cause significant inside edge wear unless there's also significant toe (toe greatly amplifies camber wear). With near 0 toe and some negative camber, it would take 1.5+ degrees of camber and being driven all highway miles or only cornered like a grandma to cause any detectable inside edge wear.