Tire Wear and Wheel Alignment

[Spartan_Stang]

I just ordered a set of MRR M350 19x10 with 285/35/19 rubber for my GT/PP and I have a few questions for when they arrive.

I want to get an alignment done and I'm not sure what the right camber/toe/etc.. would be for a good starting place. I daily the car but also run AutoX (~6 or so events a season). What would be a decent starting place? Will the camber wanted for AutoX destroy the wear of the tire while DDing? Will I need a mod (camber plates?, bolts?) in order to get the desired camber?

Also another question, after 2 AutoX this season and my normal DDing, I have noticed the rear tires have an uneven wear with more wear on the outside of the tires. What exactly does this mean? Will an alignment with the new wheels fix this issue or make it worse? Could it be caused by too much or not enough PSI when at AutoX? FYI I'm on stock PP wheels with OEM P-Zeros atm.

Sponsored

 

[Competition Orange]

1. Read the alignment thread in this section.

2. Toe kills tires more than camber does

3. Stock suspension?

Note our front camber is not adjustable in stock form. You'll have to oval out the strut hole, get camber bolts or camber plates up front for adjustability, both stock and aftermarket springs. With lowering springs, you should have something close to -1.5 front camber. I was -1.7 on BMR handling.

I'd run the stock GT350 track pack alignment to start with. Its in the alignment thread I mentioned.

Outer tire wear is from a lack of camber, and "overdriving" the fronts. Camber helps this greatly, as does learning better turning techniques.

Good luck.

 

[SteveW]

I have seen very good rear tire wear patterns from -2 camber and .20 deg total toe-in.

Up front I am having inside edge wear from -3.1ish camber and -.20 deg total toe-out. My RE71s are wearing great but they are 95% autocross duty and minimal street time. My all season front tires are the ones I am concerned about so, I backed off the front toe-out slightly to see if that helps my tire wear on the street.

I think settings of up to -2.5 camber and 0ish front toe would have good tire wear from a combo of light autox duty and street miles. Up to -2 camber and .20 deg toe-in is working well for me in the rear this year.

 

[cobrakid]

FYI only.

I run just front BMR drag springs, nice look to the car!

I race with 2011 Shelby 19 inch GT500 wheels.

I have Nitto NT05 315,35r19s on the rear. (I am talking about rear only now)

They are about burnt up now, but noticed they are wearing the insides badly.
I am getting ready to flip the tires, to get about 15-20 more drag strip passes out of them.

I guess the car squats so much (front sway bar off) when doing burn out & leaving line. (?)

I am going to just adjust toe slightly myself, until I can afford adj toe links for rear.

just my 2 cents worth.

 

[NightmareMoon]

-2.4' of front camber (and zero front toe) seems to wear fine on the street. My stock PZero tires did mixed duty autox-street-track, and the only tire wear issue I had was too much inflation pressure on the rear tires (from a track day) and a resulting band worn down the center of the tire. Inside/Outside edge wear was ok. With 2.4' front and like 1.8' rear, I still get a bit more wear and heat on the outside shoulder than the inside shoulder when doing autox/track, which probably evens out with slightly more inside wear on the street. I think those camber numbers are a pretty good starting point.

FWIW, in F-Street, slotting the top strut to spindle bolt hole up to 2mm is the only allowed way to get more front camber. If you're in FSP or something I think you can run camber plates.

 

[Norm Peterson]

I guess the car squats so much (front sway bar off) when doing burn out & leaving line. (?)

FWIW.

Your car squats because the rear springs and shocks are a bit too soft for that kind of driving. Not because you removed the front bar. Removing the front bar on an IRS car like yours does not give the same benefits as it does to a stick axle car like mine. Losing a few lbs off the front end is really all you're gaining here.

All that squat drives your rear tires even further negative than factory stock (or the number you might have read off an alignment printout sheet if you've had that done). Get somebody to take a picture from as close to straight back from your car as possible next time you launch and you'll see this.

The combination of big negative camber with heavy acceleration loading is going to beat up the insides of your rear tires even if the toe back there is correct for that kind of driving (and I agree that rear toe probably isn't right for your use, either).

For drag racing, you want rear camber that's much closer to zero than Ford's preferred value. Maybe even outside the factory range. Front camber settings can depend on whether you're running OE tires up front or drag racing skinnys.


Norm

Sponsored