Tire wear alignment question

[TheJDMan]

I'm running a DSE subframe with +5deg caster, 3/4deg negative camber and 1/16" toe-in. I was recently working under the car and noticed the inside edges of my front tires are wearing. My question is, for street driving what should I adjust to minimize the tire wear on the inside edges of the tires? I was thinking of increasing toe-in to 1/8" but I was also wondering if I should reduce the negative camber some. I would also like to add the car has a definate understeer when pushed hard and I have been doing a great deal of reading on suspenson tuning to try to fix that as well as the tire wear issue.

[andrewb70]

Drive it harder to wear the outside edge more :-)

Andrew

[TheJDMan]

Drive it harder to wear the outside edge more :-)

Andrew

That's when I get understeer! I have been following the Anti-rollbar thread and I have some more reading to do there.

[dontlifttoshift]

Drive it harder to wear the outside edge more :-)

Andrew

This^^

Toe wears tires, camber just determines where. I forget the math but a 1/16th of toe in may be a bit much. My alignment dude measure it in degrees and I try get between .05* and .1* toe in.

[R32Jordie]

^ What donny said. Adjust your toe settings and you should be fine.

[sinistir]

toe in will feather tires. toe out will tend to wear inside of tire. your 1/16" in is fine. when your car rolls the resistance will want to push the tires outward to the toe out position. so the 1/16" in should be close enough to zero while driving. before doing anything first check all front suspension components to make sure all is tight with no slop. toe is the biggest proponent of tire wear. so any worn tie rods or such will cause unusual tire wear. so start there and work your way around to all other bushings. if you are auto-x or pushing car hard a lot you could have a failed component. next big tire wear is camber. I suspect if your front end components are good you maybe running a tad too much camber for your current set up. since im not looking at your tires I don't know how much tire wear you are referring too. let us know what you find. hope that helps.

[Matt@BOS]

Hey Steve,

DSE might be the most helpful in answering this question. Their customer service is so good I always try to call them first to get their input, Wes, Dan or Allen seem to be able to answer 99 percent of the odd questions I throw at them.


That said, I've logged almost 20k miles on my car and 50 or so events. I started with +4.5/5.0 degrees of caster so that it would track nicely down the highway and about -.75 degrees camber and 1/16 toe in. The car pushed hard into corners and would just scuff and shred the edges of the KDW tread blocks. I don't know that I ever held onto a set of tires long enough to wear out the insides from street use though. I've increased negative camber to about -2 degrees and changed to 1/16 toe out. I think that might actually be what DSE recommends, but don't quote me on it. If you are attending events and driving the car a couple times a week to and from work, or for fun, I don't think the toe out will be responsible for killing your tires.

From my experience, upping the front spring rate to 550lbs and adding more negative camber really changed the way the car drove on the track. The jury is still out on toe. It may just be the placebo effect, but it felt better.

Matt

[TheJDMan]

I just got off the phone with DSE and they recommend the following. Zero toe and -.5 camber. They also indicated the subframe was supplied with 450# spring but they are finding a higher spring rate seems to work better. Since I currently have the engine out of the car fixing some anoying oil leaks and upgrading to a T56, my front end adjustments will have to wait till I get the car back together but at least now I have a plan. Thanks for all the help!

[Ron Sutton]

Drive it harder to wear the outside edge more :-)

Andrew

That is awesome funny !

That sounds a lot like one of the first wise ass remarks I'd make at the track, before I actually offered real help.

[MonzaRacer]

0.01 of a degree is 0.001"
Camber puts more pressure on inside of tire, personally as an alignment tech most times on modified cars I follow either manufacturer specs of majority of parts then adjust from there. On an autocross or road course keep toeing car out to mod the turn in ie make i t more aggressive. ACR Neons ran like degree toe out.
As for camber I would use temp gun. Depending on amount of bumpsteer I generally try to "zero it out" ie raise front end up to stops on alignment rack, take toe reading, lower it as for down to bump stop and take reading. At ride height I try to get as close to that as possible, but it also depends on how your shocks are valved. softer compression I would tend to "work" the toe settings. Basically I try to eliminate as much bumpsteer as possible.
NOW, when your at zero toe your car can get a little "twitchy" so either ta tiny bit of toe in or toe out should help that. ALSO I have found that while parts makers or car makers camber specs are a start but I hve one guy with ATS spindles and we found his car drove AND handled best using matching camber specs,,,-0.65deg, +6.5deg on RT, +5.5deg on left and I gave it 0.02 toe IN on each side, for 0.04 total. When he tries to do some sort of driving (never actually heard where or what type) he knows just how far to move both adjusters OUT to make it turn better.
He sometimes doers it on one side sometimes he splits it (which I recommend over one side as this jacks up center up of box).
Too his benefit I taught him to learn how to adjust to make car work better AND he has shim packs for daily driving, and others for adjusting to him handling needs, and he keeps adding toe in or out to help handling.
One weekend he had it toed out like almost 2 degrees but where ever he was at it WORKED. He also keeps records of what works and where AND tire temps, track temps and what changes did for performance.
Also he found his car works better on Asymmetrical tires over directionals.
His wifes car,,,well same year, 68 Camaro, similar parts to a point but it doesnt need quite as aggressive camber specs and tad more toe.
It has taken me 20+ yrs to become as good on alignments as I am,,,,even with older less fancy equipment. But I do love the new stuff.