Track outer shoulder wear : sway bar upgrade?
 

I HPDE my BRZ, and with -3F/-2.4R camber on RCE yellow springs/stock shocks and MPSS tires.

My issue is I've worn through the outer shoulder, while the rest of the tire still has ample tread left - would like to maximize the tire life.

Would updating the sways front and rear be a inexpensive "fix" to this issue vs. going to a $2k+ coilover with much higher spring rates? Would prefer the $400 for sways vs $2k+ coilovers, and can't go much beyond -3F without additional hardware.

I think I know the correct way go would be springs (which means shocks matched to the higher spring rate), but wondering if sways would result in more even tire wear allowing me to get a few more track days out of them and only have minor drawbacks?

Thanks...

following

What are your tire temps? Get a needle pyro for the next track weekend and report back.

Front is zero toe, rear has just a little toe in.

Tires are stock size, 215/45-17 on the stock 17x7 wheels.

Have been running them 38 psi hot.

Yes - both sides, front and rear (front a little more so) - I've evened the wear through rotating. Drivers side sees the most wear on CW circuits, and passenger for CCW.

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Are you looking for temperature inside/middle/outside?

I can do get a pyro, but I'm not sure these tires will go another weekend - talking with other MPSS users at the track - I'm told this is near the point it wears through the shoulder and big chunks start coming off - so I'm considering new tires before the next event.

The outer shoulder "tread block" looks like it was hot and is textured - the rest of the rubber is relatively smooth, except for the chunking.

Yes, inside/middle/outside. Without the temps you are more or less guessing. For a car as light as a BRZ, you could run 28-32 psi hot.

Thought that would just exaggerate the outer shoulder wear. . . ?

Might give more grip, but... I'm willing to give up a bit of grip if I could get more life out of the tires...

mo camber, why not spend the ~$400 on camber plates instead of sway bars?

Every single time my outsides were hotter than mid/inside, it always helped to drop tire pressure. But you need to know the temps first.

I have plates and am running -3.1 up front as a result.

Thinking at some point just adding static camber starts hurting braking performance. Figured controlling body roll might be a better fix, but not sure... That's why I'm asking...

I've run up to about -3.6 without feeling like my braking performance has suffered, it only helped put the tire on the pavement the way it should be, I would have tried more if I could have at the time. I say try -3.5 if you can get it.

Even with very stiff springs/sways you might need that much camber or more, I know that some autocross cars are running that or more and they can put any spring or sway bar they want.

Well, you're issue is, you're running the wrong tire.

If you want to HPDE, get a tire that's more HPDE oriented. The sidewall of the MPSS in 17" is just too soft, and you'll constantly destroy outer shoulders.

Additionally, the rest of your tire shows extreme heat wear. Some of this is because you're tracking a tire that's not meant to be tracked, but also from a soft sidewall that is flexing under load, and generating heat.

Try something like the GT Radial SX2, which is both faster than the MPSS, and wears slower, while lasting longer. Why? Because it's designed to 1. handle more heat and 2. has a stiffer sidewall that in turn generates less heat.

I knew these were getting overheated and chunking - so was planning to switch tires, thought perhaps I needed to make some other mods at the same time to prevent the new tires from suffering the same shoulder fate...

Thanks to everyone for the suggestions and help...

Changing the tire one suited to HPDE use will fix the issue, as that's what the actual issue is!

Thanks Mike.

Know another 86 driver at the track with a similar setup running RE71R's and they are wearing the outer shoulder first - not as bad as my MPSS, but the trend is still there.

Is the RE71 sidewall soft as well?

In the paddock I get people recommending I run BS RE71R, HK RS4, and a few saying just go Toyo R888R since they wear nearly as well (not sure I'm ready for 888's).

I'd love to hear your inputs/rank those 3 tires and the GT SX2...