[72GMC]

Originally Posted by Tambohamilton

When you say reduce, do you mean more toe in? Or out? Because more toe in would help even out the tyre wear, *and* stabilise the handling.

Less toe-in.
Specified Rear Toe-in is 0.10 to 0.20 degrees each side, or 0.20 to 0.40 degrees total toe.

Agressive camber + agressive toe will eat the tires. Reducing the toe-in will de-stabilize the rear. But instead of thinking of it as less stable, think of it as more willing to rotate.

[Tambohamilton]

Resurrecting this thread since I had a bit of an epiphany the other day. Well, 2 I suppose...

1. I had assumed that toe in would help offset neg camber in terms of tyre wear, since toe in is (commonly) known to wear the outside of tyres. I assumed that it would do the same for camber-induced inside edge wear, and transfer the wear to the outside edge of the tyre... But that's probably a huge oversimplification. The reality is that toe in causes outside edge tyre wear when camber is essentially neutral; if camber is pronounced then the toe just serves to scrub the tyre more and increase (inside) wear overall. Correct logic?

2. I get fairly strong inner edge wear on my setup with -1.8deg camber (front axle). I have an e93 M3 rear sway, but only the stock e91 front sway... So, well the roll stiffness is fairly balanced front to rear, actually, when you add in springs, but I'm sure many people have way stiffer front roll stiffness than rear (stiffer springs, stiffer front sway, softer rear sway). Would that setup of having stiff front compared with rear lift the inside front tyre more aggressively during cornering, and therefore massively reduce wear on the inside edge of the inside tyre? Probably a minor effect for daily driven, not tracked, cars...but still worth considering?

How are all your tyres doing for wear now? Feuer have you made a dent in those 560tw's yet?

[72GMC]

Theoretically, camber and toe both contribute to stability.

With a track-oriented set-up, negative camber is essential. First, to optimize the contact patch during cornering (grip!) and Second, to not completely destroy the outside edges of the tire in one day. (BTW, -1.8 up front is not nearly enough for serious track days, fine for 1 or 2 days per year)

With aggressive negative camber, any toe-in or toe-out will continuously scrub the inside edges. Especially during highway driving.

My most recent alignment zeroed the front toe, and halved the rear toe.
It made the rear a bit more playful/willing to rotate, but still reasonably stable.
It's getting close to the sweet spot.

Other factors: 20mm rake, staggered setup (235F, 255R) M3 suspension rebuild, 10K front 12K rear springs, KW anti-roll bars F-27mm//R-24mm

[Tambohamilton]

How about for 0 track days per year, but some spirited driving from time to time?

Thanks for sharing your specs. Looks like your front stiffness/wheel rate is way above your rear, so that may agree with my 2nd point above. Any reason the 0.5deg of camber mismatch at the front wasn't zeroed?

[72GMC]

Originally Posted by Tambohamilton

How about for 0 track days per year, but some spirited driving from time to time?

Thanks for sharing your specs. Looks like your front stiffness/wheel rate is way above your rear, so that may agree with my 2nd point above. Any reason the 0.5deg of camber mismatch at the front wasn't zeroed?

Yeah, i don't recommend the 10K front spring rate, I'd back it down to 8K next time. And with the sways contributing, the inside wheels do get daylight under them in hairpins.

The passenger side camber is maxed out, but i'm ok with the mismatch as most my track days are clockwise.

[bmw335ie90]

I was running -2.5 front camber and -2.0 rear, 0.05 total front toe and .3 total rear toe. Front end was very twitchy over ruts in road but quick steering feedback. I’m at 22,000 miles on a set of square Pilot Super Sports rotating every 5,000 miles and seeing inner wear.

Alignment guy reccomended less rear camber and toe and more front toe to to ‘even’ out the inner wear. Against my better judgement I did this. He put the front toe at 0.30 total, rear at 0.30 total and within 1,000 the inner wear was considerably worse on the fronts. Zero front toe, or a very small amount of toe in is the way to go for me on future tire sets. I do not track but hit twistys and curved freeway on ramps pretty hard on the regular.

[Tambohamilton]

Just set my front toe to 0.1deg, as best I can measure. (Was about 0.25deg). Camber is -1.8deg (same as rear). Rear toe is about 0.33deg...I should check it as I haven't measured accurately recently. Got a 300+ mi round trip later this week, so we'll see how it goes on the motorway.

I use a homebrew spirit level camber gauge, and "track ace" for toe...and string lines to sanity check toe and set steering wheel. It's not ideal, but toe and camber should be decently accurate.