Tire wear problem.

[pawa_k2001]

Need help with tire setup on E46 M3 on Michelin PS4S tires.

- All suspension components are in great condition.(checked religiously)
- 265/35/18 on 18x9.5 wheels
- 2.9 degrees of negative camber, 0 toe, stock caster
- 38 psi hot

The inside of the tires are on metal cords, outside is blistering. Middle on the other hand has 4/32nds. This usually means under-inflated but at 38 psi thats hard to believe. Rears are wearing perfectly, fronts are the problem.

Ideas?

[bigjae46]

Looks like toe wear combined with excess negative camber. Understand why you have more negative camber. I'd check your ball joints and the tie rod end.

[pawa_k2001]

All suspension mounting points are in perfect condition, most are monoballs.(all double checked) The car is not a daily, its usually driven aggressively on twisty roads like Tail of the Dragon.

[bigjae46]

It looks like toe wear...not sure what else to say except redo the alignment.

[timmo]

This one is a very odd one. How much mileage on those tires? Blistering on the outside is indicative of positive camber wear, but then you still have corded inners. How much caster are you running, perhaps -2.9 deg static camber on the front with some toe (though I know you say you have zero) caused the inner tires to wear quickly, but then pushing it hard on the mountains (with very little caster) caused outer wear? Or, perhaps there is some compliance somewhere that is contributing to excessive camber/toe compliance, though you did say that all your suspension components are fine.

Just sort of spitting ideas and rambling, but it is a mystery

[pawa_k2001]

Caster is maxed on Vorshlag camber plates. I have been running a very similar setup for a long time, what changed recently is the tires (PS4S compared to previous RE71) and softer front spring(to get flat ride). I am starting to think the softer front spring is causing more bump steering problems.

Will definitely double check the alignment.

[Tbonem3]

You may have got zero toe on last alignment, but if you lower/raise the car or touch the camber, you'll affect toe.

Cording is usually a toe + camber issue. Too much toe alone would cause exacerbated wear across the whole tire. Camber puts it on the inside only like pictured above.

[pawa_k2001]

Suspension hasn't been touched since last alignment. Alignment is done with every new set of tires but a shop I trust and to my spec, I even add weight to drivers seat so corner balance and alignment can account for my weight.

[rbg]

If you check you suspension religiously how fast this wear happened?

[r4dr]

The inner wear is definitely the camber. -2.9* for the street on Super Sports is over cambered. I would suggest throwing it on an alignment rack and seeing where your measurements sit. If the toe really is at 0, then that rules the simplest cause out.

[rbg]

I've been having -2.7 with 0.01ish in and do not have such a massive wear. I've had similar wear when I was DDing with -3.7 and some toe in.

[pawa_k2001]

If you check you suspension religiously how fast this wear happened?

Alignment and new PS4S tires were done at 57,884 miles on 10-26-18, I am at 61,721, I usually get 5,000 out of a set of tires. Car is never daily driven, only driven on weekends when I want to run some twisties. For example, I just finished a 2 day, 3 state drive, it was supposed to be 3 day, 4 states but I had to head back due to unsafe tires. (roads like Snake in TN, Tail of the Dragon, Back of the Dragon VA, Dragon Slayer Hwy 160 VA, etc)

I am not complaining about how fast the tires wear, I am trying to figure out why the fronts wore the way they did.

Complete alignment setup:
Front: 2.9 degrees negative camber, 0 toe
Rear: 1.9 degrees negative camber, .30 degrees of toe-in(factory is .37)

[pawa_k2001]

The inner wear is definitely the camber. -2.9* for the street on Super Sports is over cambered. I would suggest throwing it on an alignment rack and seeing where your measurements sit. If the toe really is at 0, then that rules the simplest cause out.

It will go back on the alignment rack once the new PS4S tires come in mid-week. If alignment didn't move(I am really hoping it did), I am at a lose why I am getting this kind of wear.

[Casa de Mesa]

Are you feeling any slop in the steering? Could be inner tie rods. Could be FCABs.

I'd check every nut, bolt, and ball joint. You are getting excessive toe SOMEHOW and because it's on both inner and outer extremes of the tire, it's likely something loose or shot.

I have corded countless r-compund tires (DOT radials) on the track trying to eek every last cent out of a set of $1200 tires. The only time you get wear like what you are describing is if something is moving that shouldn't be. If it's one tire, I'd say balljoint, tie rod end, or a camber plate is moving on you. But you said "tires" so my thought goes to the center of the car. Have you done the simple checks like feeling for lateral movement by grabbing the left and right side of 1 front tires and trying to move / shake the tire along that axis? Have you looked at you front "subframe"?

Check anything and everything that is somehow connected to steering. Everything.

[Casa de Mesa]

PS. Bump steering that bad shouldn't be springs. Springs shouldn't cause bump steer unless the car is rolling MUCH farther than it was with stiffer springs and you're now uncovering a seriously flawed steering arm/tie rod angle.

How low is the car?