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      06-26-2018, 09:27 PM   #1
dschultz
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Excessive outer edge tire wear

Iím getting excessive outside edge wear on front tires on track and would love some advice. Iím running 3.5 front 2.5 rear camber. These are re71rís, hot pressure 36. Jrz rs pro coil overs, GC camber plates. Picture is the front right (passenger) after 5 track days. As you can see, edge is EOL, while rest of tire is barely worn. Driver side about the same. I was previously running TCK D/As with 3.7 camber and the wear was a bit better, but still not good. Note that Iíve already had the fronts swapped side to side once. I think there may be three reasons/solutions...

1. More camber? The GC plates are maxed out so maybe put in camber washers and go to 3.7 or 3.8?
2. Square setup to reduce push and allow tire rotation? Not that rotating will fix this problemójust lets me wear out all 4 tires faster!
3. Am I entering corners too fast and pushing? I donít think so, but are my tires telling a different story?

Suggestions?
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      06-26-2018, 09:46 PM   #2
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What’s your front spring rate? What’s the ride height as measured from top of wheel arch to center of roundel?
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      06-26-2018, 10:58 PM   #3
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650# front and rear. Car is in the air with no wheels so I canít measure ride height at the moment. Hereís a recent picture if that helps...
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      06-27-2018, 10:01 AM   #4
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This one is tough to figure out. At first I thought it's possible that the springs are compressing past roll center and you're losing camber, but you have plenty stiff springs and the car does not look TOO low. If it's too much toe-in then the bulk of the wear would be concentrated on or near the sidewall, not evenly distributed across. I think throwing more camber on it might help, but based on the picture you'll need more than just -0.2 degrees.

I would actually just flip the tires on the rims so the inside is now outside and keep driving it.
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      06-27-2018, 11:15 AM   #5
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Thanks. Sadly Iíve already done that once and the other tire is already worn the same. Most days are at Thunderhill and Laguna, both CCW tracks, so that edge just gets killed. I donít think I can risk a two day weekend at Sonoma on these tires.

Itís been suggested I should try nt01s instead, as being more of a track tire vs the re71rs that are more autocross... not sure I buy that, but willing to try.
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      06-27-2018, 12:34 PM   #6
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What other mods do you have up front (suspension-related). FCABs? sway bars? what's your Toe?
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      06-27-2018, 02:49 PM   #7
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Quote:
Originally Posted by dschultz View Post
Itís been suggested I should try nt01s instead, as being more of a track tire vs the re71rs that are more autocross... not sure I buy that, but willing to try.
It's possible the stiffer sidewall of a true R-Comp might mitigate the sidewall from rolling over creating an unfavorable tire profile as you corner. Can't hurt to try as these RE-71Rs appear toast anyway.
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      06-27-2018, 02:52 PM   #8
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poly fcabs, replaced last year, .06 degree total toe
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      06-27-2018, 03:05 PM   #9
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Quote:
Originally Posted by The HACK View Post
It's possible the stiffer sidewall of a true R-Comp might mitigate the sidewall from rolling over creating an unfavorable tire profile as you corner. Can't hurt to try as these RE-71Rs appear toast anyway.
I guess I'll do one more set of RE-71Rs for the front and try to wear the back tires out at the same time. Then start experimenting.
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      06-27-2018, 08:01 PM   #10
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What's the tire psi hot?
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      06-27-2018, 08:04 PM   #11
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NVM 36 hot. Wheres your compression settings at?

I think you bought it used right? Did the shop who installed it; checked the psi in the canisters? If so where is it at?
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      06-28-2018, 10:35 AM   #12
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Quote:
Originally Posted by AriuSen View Post
NVM 36 hot. Wheres your compression settings at?

I think you bought it used right? Did the shop who installed it; checked the psi in the canisters? If so where is it at?
Front compression 3, rebound 12 (clicks from full soft)

Hmm, shocks were serviced and dynoed good before install. I donít know for sure if shop that did the install set the pressure correctly. There were some other issues that lead to believe they may not have had there best guy on the job so will check. I have played with the settings and have definitely felt it too hard, at least so it seems to me, so adjustment does seem to be working.
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      06-28-2018, 01:53 PM   #13
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I don’t know if this will help or cause more confusing variables, but I’m experimenting as well, so here goes.

I’m running RE-71s as well. I just had my 5th day in the last 2 weeks on a new TCK double adjustable with 500 springs front and rear. My front is -3.6 with 0 toe, the rear is -2.4 with 0.40 degrees toe (0.20 per side). I try to run around 34-35 hot. The one big difference is that I’m running 265 square (4 rear wheels).

The wear pattern I was getting with 235 in the front is similar to yours. With 265, it seems to be better...not perfect, but at least I’m using more than the outside 25%. I know everyone says the Z needs stagger setup, but it seems to me that the car will push on corner entry if I have 235s. The 235 also has a slightly less stiff sidewall than the 265. I purchased a pyrometer to test some temps...I have 2 days this coming weekend at Summit, then 3 next weekend at Summit, and then 3 again at Pitt...so I’ll take some logs.

36-37 pressure seems to be high to me, especially in the rear. On exit, the rear seems “active” if I’m around that pressure. Yes, the square setup is contributing, but I find that 34-35 seems better. At 37 front, I get more understeer in the front, 34 seems to quiet this down as well. I’m running stock everything else, bushings, etc.

I do the flip tire as well. Local Costco keeps the RE-71s in stock for me and they see me just about every other week for a flip or new tire.
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      06-28-2018, 02:10 PM   #14
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I was playing around a little last weekend and some guys caught some pictures. Not because of square setup.
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      06-28-2018, 08:57 PM   #15
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This seems to be pretty characteristic of the RE71s on the E85/86 and in some cases RE71s in general.
The compound Bridgestone uses is actually from their motorcycle tire line and it's got a pretty low melt temperature. When you get them hot they wear really quickly in those areas. Serious auto crossers I know get theirs side swapped every 20 runs or so to ry and keep the wear somewhat even on both sides.
I've had much better luck with Hankook RS4s for track use than with the RE71s if you're wanting to stick with a 200 tread wear tire.
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      06-30-2018, 10:43 AM   #16
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Quote:
Originally Posted by Ryan13 View Post
I donít know if this will help or cause more confusing variables, but Iím experimenting as well, so here goes.
Thanks. Great info. Youíre running virtually the same suspension I had before. I loved the TCKs but like the easy adjustablility of the JRZs even more. I will try lower pressures next time. I also noted serious ďsquirrelinessĒ at higher pressures. Iím also moving to a square setup on 9.5Ē wheels so glad to hear that should help, too.
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      06-30-2018, 10:51 AM   #17
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Quote:
Originally Posted by dc_wright View Post
This seems to be pretty characteristic of the RE71s on the E85/86 and in some cases RE71s in general...
Good to know. Iíve run the Hankooks and Direzzaís, too. Both with better wear than the RE-71s, but the grip of those tires is addicting! I think I may give the Falken Azenis 615Ks a try. Canít beat the price and itís time to spend money on track time instead of tires.
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      06-30-2018, 01:26 PM   #18
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Quote:
Originally Posted by dschultz View Post
Good to know. Iíve run the Hankooks and Direzzaís, too. Both with better wear than the RE-71s, but the grip of those tires is addicting! I think I may give the Falken Azenis 615Ks a try. Canít beat the price and itís time to spend money on track time instead of tires.
The RE71s are one lap wonders on the track but once you get them hot they really give up grip quickly, and they heat cycle out pretty quickly too. The RS4s get just as grippy as the RE71s once you get them up to temp and if you have the pressures high enough. I ran them for most of last season for autocross and got to spend a bit of time experimenting on a skid pad. At any pressure below 38 psi they weren't very good. Once they were warmed up they came alive with pressures in the 40-41 psi range.
The problem with them for autocross was not being able to get them hot enough for them to be in their optimum range. The couple of times I ran with a codriver we both saw a significant increase in grip around the 6th cumulative run and times dropped significantly from there on.
I run a cold pressure of 36 psi for track days which nets 40-41 psi once they're warmed up and they just get better and better as the session goes on.
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      07-01-2018, 02:17 AM   #19
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Quote:
Originally Posted by Ryan13 View Post
I don't know if this will help or cause more confusing variables, but I'm experimenting as well, so here goes.

I'm running RE-71s as well. I just had my 5th day in the last 2 weeks on a new TCK double adjustable with 500 springs front and rear. My front is -3.6 with 0 toe, the rear is -2.4 with 0.40 degrees toe (0.20 per side). I try to run around 34-35 hot. The one big difference is that I'm running 265 square (4 rear wheels).

The wear pattern I was getting with 235 in the front is similar to yours. With 265, it seems to be better...not perfect, but at least I'm using more than the outside 25%. I know everyone says the Z needs stagger setup, but it seems to me that the car will push on corner entry if I have 235s. The 235 also has a slightly less stiff sidewall than the 265. I purchased a pyrometer to test some temps...I have 2 days this coming weekend at Summit, then 3 next weekend at Summit, and then 3 again at Pitt...so I'll take some logs.

36-37 pressure seems to be high to me, especially in the rear. On exit, the rear seems "active" if I'm around that pressure. Yes, the square setup is contributing, but I find that 34-35 seems better. At 37 front, I get more understeer in the front, 34 seems to quiet this down as well. I'm running stock everything else, bushings, etc.

I do the flip tire as well. Local Costco keeps the RE-71s in stock for me and they see me just about every other week for a flip or new tire.
I'll second everything you said regarding pressure and a square set-up. 265 front works well. I'm at -2.7 front stock suspension and I'm happier than with 235 or 245 front. Car is more neutral. Over 36 psi is really greasy feeling to me with the RE71s. Larger tire might dissipate heat better too than a 235 at the faster pace Dietrich is running. He's not over driving the tires, and he's reasonably quick! I drive with him quite a bit

As for me preferences I'm a bit better driver than I was a few years back (ok, 8-10 seconds better at Thill lol) so that may have some bearing on my opinions and likes stagger vs. square.

These RE71s wear quickly. After two track days mine look like the OP pics. I'm running less camber but with Direzzas the wear was more even and slower.
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      07-01-2018, 02:24 AM   #20
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Quote:
Originally Posted by dc_wright View Post
Quote:
Originally Posted by dschultz View Post
Good to know. I’ve run the Hankooks and Direzza’s, too. Both with better wear than the RE-71s, but the grip of those tires is addicting! I think I may give the Falken Azenis 615Ks a try. Can’t beat the price and it’s time to spend money on track time instead of tires.
The RE71s are one lap wonders on the track but once you get them hot they really give up grip quickly, and they heat cycle out pretty quickly too. The RS4s get just as grippy as the RE71s once you get them up to temp and if you have the pressures high enough. I ran them for most of last season for autocross and got to spend a bit of time experimenting on a skid pad. At any pressure below 38 psi they weren't very good. Once they were warmed up they came alive with pressures in the 40-41 psi range.
The problem with them for autocross was not being able to get them hot enough for them to be in their optimum range. The couple of times I ran with a codriver we both saw a significant increase in grip around the 6th cumulative run and times dropped significantly from there on.
I run a cold pressure of 36 psi for track days which nets 40-41 psi once they're warmed up and they just get better and better as the session goes on.
Interesting! That's such a high pressure compared to most things I've tried. I wonder if the higher pressure keeps the sidewalk stiffer too resulting in less roll. Hmm

Might give these tires and the higher pressure a go. Enough heat at Thill in the summer isn't an issue—it was 106 on Friday!
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      07-01-2018, 08:27 AM   #21
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Iím not sure about the higher pressures at the track. A while back and many track days ago, i didnít have camber plates and could only get -2.2 or so in the front. I was running 235s Super Sports and had the same wear problem. There is a post somewhere on here...I had pressure as high as 42 to try and counter the wear problem. The tires just got greasy and I still ďburnedĒ the outside quarter. Iíve only tried the SS and 71s, Iíve not had any problems with the REs.

Even today, there is no remaining tread on the REs. They are not corded yet, and that may happen today since it supposed to be 100 here are Summit...I just put down a personal best 1.22-ish.

The square setup seems work for me. The car will definitely oversteer first, but I really got tired of pushing on corner entry. Rather throttle steer exiting the turn.
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      08-18-2018, 09:25 AM   #22
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How much toe? that's possibly too much for a car that has stiff bushings.

I also suspect too much pressure and heat and you're over driving them. use less pressure and substitute pedal techniques to manage rotation (late apex, use braking to plant the front, turn, then late on the gas and hard to unwind the wheel and basically let it float while you continue a bit of inertia rotation out of the corner) if you cranking the wheel hard from the top, your over-driving a very very light steering rack. I'm guessing you have upgraded lower control arm bushings, your setup is stiff, you can get the roll enough to over work the outside edge. Look next to try and lower your roll center.

Like everything in racing it's balancing the trade offs.
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