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Tire Wear with GT350 and PP2 wheels on a PP1

Mikepol2

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Passing this along mostly so you all can see the PP2 factory alignment specs, but also for any ideas on why the inside edge of my front passenger tire is worn to the cords at 6,600 miles - maybe that's normally where they wear? Here's the timeline and mileage:

968 car miles: Install set of take-off GT350 wheels & tires that the seller claimed had 2,200 miles on them, so I'll reset the mileage clock based on the tire mileage.

2,873 tire miles: Since I was running GT350 wheels on a PP1, I had a custom alignment done by a Ford dealer to set the car up with specs that matched both packages. The toe was out of spec on both sides for a PP1 (0.17 and -0.23, when it should have been -0.10 to 0.10) AND for a GT350 (should have been -0.15 to 0.05). So I put about 700 miles on them with the toe out of spec. The numbers after alignment were -0.03 on both sides and camber was -1.1 and -1.2 both sides, before and after.

5,843 tire miles: Swapped the tires onto OEM PP2 wheels, and installed 7/8" front drop springs. Right around this time (can't remember if it was before or after) started noticing an intermittent humming from the passenger front that sounded like a bad wheel bearing.

5,947 tire miles: Had a different Ford dealer align to PP2 specs but they didn't give a printout. Noise still there but I wondered if they actually did a PP1 alignment. Put 100 miles on the tires with the drop springs and PP2 wheels before the alignment. Anyway...

6,360 tire miles: Replaced the springs and struts with GT350 springs and FP Track struts, which reducing the lowering to about 3/8".

6,600 tire miles: Went back to dealer #2 and asked them to re-check the PP2 alignment because it's still making the noise, and I want a printout this time. They said I the wheel bearings are fine but I need 2 new front tires for $800 installed. I said I'll get the tires somewhere else, just do the alignment, but they said it can't be aligned without the new tires! Morons. Went there thinking I might get the alignment free since it was 2 months after they had allegedly aligned it. Next day went to a shop I trust who did the alignment, printout below. The passenger toe was out a little.

So I guess the question is, since the camber has always been within spec, can the toe being out for around 1,500 of the 6,600 total miles on the tires cause them to wear like this? It's a little hard to see but the cords are the curved white line in the mirror.

IMG_2876.JPG
PP2 alignment.jpg
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Rapid Red

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I think the offset or back spacing of the two sets of wheels are in play. A 350 will not run the PP2 wheel.

I'd suggest you speak with an after market wheel manufacture. They will be more informed regarding the spec requirement and differences between the 2 cars.

Ford dealers are not custom shops, part replacers at best.

My .02

"I said I'll get the tires somewhere else, just do the alignment, but they said it can't be aligned without the new tires! Morons."

Maybe, if they try to spec the front end the WORN tires will give FALSE readings..... And is the reason, when new tire are installed. Most times an alinement is the best practice ......... think about it.
 
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Mikepol2

Mikepol2

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Hmm well the alignment machine works off the wheels, not the tires, so not sure the worn inner edge would make a difference when aligning it.
 
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Rapid Red

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Even if that is so and it is.. Then why is the first step is to also insure all tire pressures are equal?
 

NightmareMoon

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That much toe will accelerate tire wear, yes.

IDK why but my car likes to eat the front inside shoulder on street tires, but they usually last 15k before I have to chuck them, not 6k. It seems to be not uncommon.

If there is an issue with the hubs or anything else loose in the front suspension you can get additional dynamic toe at speed which is also bad for your front tires.
 

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kz

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As NigthmareMoon says, toe can accelerate wear. Wheels really don't matter almost at all as long as they fit on the car and don't rub.
 

ModularKid21

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I had oem gt350 wheels/tires (mpss) on for around 9k miles and I noticed the front starting to cup around 5k miles. As stated above, alignment specs will affect the wear but mpss tires inherently wear the inner edges quickly. The gt350 guys know all about that
 
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Mikepol2

Mikepol2

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Holy crap, guess that PP2 alignment and wheel offeet just eats those inside edges.
 

Troutwrangler

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Holy crap, guess that PP2 alignment and wheel offeet just eats those inside edges.
That was my thought exactly.
I'll take it to an alignment shop and have them double-check the alignment before I put new tires on it.
I really appreciate all the info on this thread in regards to alignment, tire wear, etc.
 

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D Bergstrom

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Anyone have the specs for the PP1 and PP2 alignments as how they come from the factory? I know the supplement manual that came with my PP2 mentions for track use, change the front camber to 1.5 degrees, but put it back prior to street use. My gut feeling, PP1’s and PP2’s come with the same specs from the factory, based on the PP2 supplement. Just curious.

Doug
 
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Mikepol2

Mikepol2

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See my original post above for the factory PP2 specs.

PP1 coupe specs are (taken from 2016 specs):
Front camber -1.03+/-.75 each side, total 0.0+/-.75
Front caster not adjustable
Front total toe 0.0+/-.20
Rear camber -1.50+/-.75 each side
Rear toe .12+/-.20 each side, total .23+/-.20
 

Troutwrangler

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zero toe is the key. And Ford's factory alignment is generally garbage.
:thumbsup:
I'm going to have the alignment shop set the toe as close to zero as possible.
If my tires are going to wear out this fast, I want it to be caused by twisty mountain roads, track time, or autocross.... not from terrible front end alignment.
 
 




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