Front left suspension rubbing issue

[michaelmosty]

I took off my wheels today to get the tires flipped and noticed a rubbing issue on the front left. I now have a destroyed tire and I need to determine the cause.

Here is the front left tire. It has multiple chuncks taken out, some are down to the cords. It also has a large amount of wear on the inside vs. the outside.


These next two pics. are where the tire was rubbing.


There is no wear on the control arm.



These tires were new full treads at the start of the season.
I switched the tires front to back after MSR-H and noticed no issues what so ever.

Any suggestions are greatly appreciated.

[Mike Bell]

First thing I'd check are the wheels themselves, is there any difference in the offset? I had this problem on my AI car, turned out two of my wheels were different from the other ten!

With the wear on the inside, I'd say that might be due to camber but I'm not sure of your setup or if other tires have done the same. If you run a bunch of negative camber is it possible that the wheels are hitting under load when turning? Has your camber changed suddenly? CC plates good and tight up top?

[j3ffbrooks]

I can't believe you didn't notice that from driving the car.

Like Mike suggested its most likely the wheel offset with the combination of your camber settings.

Are you running SN95 A-arms? They might give you a little extra room as they are 3/4" wider that FOX A-arms.

[MikeP99Z]

Is the car square? Is the K-member offset to one side?

Looks like an upper or lower control arm may also be out of place based on the wear.

Either way, verify equal clearance on both sides. Then take a BFH to that lip area that's grabbing the edge of the tire.

I'd also say your car was probably handling like crap through rattlesnake and especially littlebend. Front left, completely loaded - did you have major steering wheel vibrations with jerky feedback? Suspension loading/unloading rapidly (are you coil binding?)

Measure everything.

[Adam Ginsberg]

Michael - that tire damage looks nearly identical to Wayne's tire @ Hallett last year.

All of the other suggestions are great ones....but I'll add 2 more.

1. Are you running any wheel spacers?
2. Do you have rack limiters installed on the steering rack?

At a minimum, you should have at least one rack limter per side installed with the size and width of our tires. They are Ford parts, available over the Ford counter - part #: N804842-S. Get a pair.

[MikeP99Z]

Now if Ford only made spin limiters for Adam - he'd buy 'em by the case...

[MikeP99Z]

That inside edge is getting way overheated to chunk the tire that bad. Also - I'm now guessing that the rub area is the back side of the left front, and rubbing under left hand turns.

Is the left front wheel toed-out?

Explain briefly what the car was doing in each of the major corners at MSR.

But, go with the above measurements/parts suggestions first.

[CMC17]

I don't have any scientific data to back this up, but will throw it out for discussion.

I've heard that with full treads they are more sensitive to heat cycles and are more prone to "chunk" than shaved tires. I think this is due to how much heat is generated or lack of thermal dynamic spacial heating with the full treads.

I will also mention that in the MSR-H trackside video when you went off in T1, the rear left tire made a very noticable gripping/ripping sound. This could have been the start of then end for that tire, especially on the inside. Now, when you switched tires on the left side, the weakened tread is now going to see a lot more heat. This along with some tire rub was enough to chunk the tire.

Yes, Wayne's tire looked very similar to this tire. However, he was running on 7.5" rims which created a lot more tire flex plus his off going into T9 allowed the tire at full lock to contact the A-arm shreading/chunking the tire. Unless you were at full lock out in the weeds or bumps, I don't think it will be the same cause. I'm not sure if Wayne was running full treads or not.


.02

[NASA13]

Expert opinion:
I have lots of experience destroying tires.
That tire was with near certainty destroyed by your control arm.
During an exciting off course excursion or big bumps your tire was chewed up by the sharp edge on your control arm. It will not show up as wear on the control arm because it is eaten by the sharp edge only during huge bumps with near lock to lock correction. Think back to an exciting moment with lots of sideways motion and lots of correction with lots of suspension travel and then you have the moment that the tire was killed. I killed a brand new shaved tire this way at TWS when I left the pavement at 700 mph.
Rack limiter is a solution or do what I did;
Stop sliding and and hitting bumps so much. =)
You could also spend some time taking the edge off the CA and then weld a piece of smooth sheetmetal over it.

[michaelmosty]

Thank you everyone for all the feedback!! I have checked many things and here is what I have seen.
-all wheel offsets are the same, I am not running wheel spacers (I think the wheels are 32mm offset)
-I do have the SN-95 control arms
-both front wheels are ~1/16" toe out
-cc plates were tight
-I do NOT "yet" have rack limiters (big mistake, fixing that problem)
-I think I had way to much neg. camber. After watching DD's R4 video he passes me in Big Bend on the inside and my front left tire is tilted greatly on the inside edge. I was also pushing very badly through BB almost the whole weekend.
-I can't remember turning the wheel to "lock" during any of my offs but I could very easily be forgetting.
-I didn't feel any vibrations or wierd feedback during the weekend. The only corner I had "problems" with during the weekend was BB. The car actually felt pretty good going through r/s, l/b, and the corner after l/b.

The tires looked perfect after MSR-H and I know that I drove the car alot harder @ Cresson than at Houston. (Apparantly too hard)
The rack limiters are a must and I am going to take some camber out of the drivers side.
I don't think I have the clearance to run wheel spacers unless I do some extensive fender mods. I have already rolled the finders and pulled out the upper fender areas and the tires still rub slightly up top.

Thanks again for the info, I'll keep ya posted on how she turns out.