01-12-2018, 11:09 PM | #1 |
Drives: 2018 ZL1 1LE Join Date: Dec 2016
Location: San Diego, CA
Posts: 218
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RE-71R Auto-X Pressures
Getting my RE-71R's put on tomorrow (305 square) and was wondering what pressures people running 305's for both street and auto-x are? Trying to get a baseline starting point.
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01-13-2018, 02:47 PM | #2 |
Drives: 17 1SS 6MT, 09 Tacoma TRD Sport Join Date: Nov 2017
Location: Colorado
Posts: 149
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Sweeet.
Use some chalk or white shoe polish to see how much you are rolling over. I start a wee bit high, like 38 psi HOT(mebbe 36 psi before first run). A lot of tires have arrow markers on the sidewall that will tell you if you are flexing too much. I will knock it down 1-2 psi per run until either the car starts to feel greasy or I see fresh scuffs creeping onto the top of the sidewall from the shoulder. Then I back go up 1-2 psi from that point and look at tire temps to evaluate alignment. I ran 40 psi up front last season on the normal shmormal goodyear eagles to keep the tire churning around hairpins. The rears were maybe 36. RE-71s are stiffer, you will probably end up running much lower pressures, especially if you have a good dose of negative camber. YMMV, just my own experience, I'm sure there are better ways to optimise pressures. Good luck this upcoming season! May I ask your wheel specs? I'm planning a 305 square setup too... |
01-13-2018, 04:14 PM | #3 |
Drives: 2017 1LE - Blue Join Date: May 2017
Location: Texas
Posts: 220
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I start off at 28 cold and then bleed off to 35 after the first run. Depending on how many runs you have it should level off to where you don’t have to bleed anymore air off. I do this for both track and autox.
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01-13-2018, 07:01 PM | #4 |
ITCRNRS
Drives: 2018 ZL1 1LE Join Date: Jun 2012
Location: Wichita KS
Posts: 1,575
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Fast FS drivers have been running extremely low tire pressure with RE71's. On my 5th gen 1LE I was running hot auto cross pressures of 30PSI front and 26PSI rear with 305 RE71's this was copy catting the set up of a national level driver that was nice enough to let me know his shock settings, alignment and tire pressures. The tires at low pressure have an extreme amount of grip but you are sacrificing extremely accelerated side wall and edge tire wear with the low pressures but when every 10th or 100th of a second counts at a national level event you don't care about treadwear.
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2018 ZL1 1LE Ordered 6/29/17 Built 11/6/17 Delivered 12/7/17, Summit White, PDR, NAV, https://www.youtube.com/c/tylerpotter
SOLD: 2014 Summit White 1LE 2SS/RS, Recaros, NPP, NAV, KONI Yellow's SOLD: 2012 Black 2LT/RS, Fully 1LE swapped, Brembo swap |
01-13-2018, 08:10 PM | #5 |
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How's is the 1LE handling with a square 305 setup? Reduces understeer or what?
Are you running the same wheel size front and rear so you can rotate them? |
01-13-2018, 11:04 PM | #6 |
Drives: 2017 1SS 1LE Join Date: Aug 2017
Location: New Jersey
Posts: 391
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30 psi.
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01-14-2018, 03:05 AM | #7 |
HTCC Member
Drives: 2018 ZL1 1LE HBM Join Date: Oct 2014
Location: Houston TX
Posts: 326
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I have the same set up for street and autox, street I run 32 psi and for autox I run 27 psi.
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01-14-2018, 07:58 AM | #8 | |
corner barstool sitter
Drives: 08 Mustang GT, 19 WRX Join Date: Jul 2012
Location: Eastern Time Zone
Posts: 6,990
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Quote:
Norm
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'08 GT coupe 5M (the occasional track toy)
'19 WRX 6M (the family sedan . . . seriously) |
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01-14-2018, 10:41 AM | #9 | |
Drives: 2018 ZL1 1LE Join Date: Dec 2016
Location: San Diego, CA
Posts: 218
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Quote:
Running same wheel size because (and this may prove to be dumb, I have yet to compete in first event this year) I don't want to lose any grip in the front, and Bridgestone doesn't make the 71R any wider than 305 so I'm stuck with that for the rear too. |
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01-14-2018, 10:51 AM | #10 |
Drives: 2018 ZL1 1LE Join Date: Dec 2016
Location: San Diego, CA
Posts: 218
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Thanks everyone for the inputs. After I got them put on yesterday, the installer had them set at 37-38 PSI and I reduced them to 32 after I got home. I did a little spirited driving on the streets (I know, not the brightest thing to do) but after a couple hard turns I noticed the scuffing was just starting to reach the little arrow markers on the front. Now that I think of it I wasn't smart enough to check the rears, but can do that next time I head out somewhere.
A few other notes. These tires are LOUD compared to the factory Eagle F1 Supercar 3Rs. Not that I mind, I don't, but just noticed it. These tire have way more starting/cold grip than the 3R's. Before, when entering most onramps, 1/2 throttle would spin up the rears, but not with the 71R's. Looking forward to a good auto-x season this year. |
01-14-2018, 11:52 AM | #11 |
ITCRNRS
Drives: 2018 ZL1 1LE Join Date: Jun 2012
Location: Wichita KS
Posts: 1,575
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I plan on killing my 3R's and then swapping onto 305 RE71's before solo nationals this year.
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2018 ZL1 1LE Ordered 6/29/17 Built 11/6/17 Delivered 12/7/17, Summit White, PDR, NAV, https://www.youtube.com/c/tylerpotter
SOLD: 2014 Summit White 1LE 2SS/RS, Recaros, NPP, NAV, KONI Yellow's SOLD: 2012 Black 2LT/RS, Fully 1LE swapped, Brembo swap |
01-14-2018, 11:54 AM | #12 |
Drives: 2019 ZL1 1LE Join Date: Sep 2010
Location: Bastrop, TX
Posts: 438
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33 front, 28-30 rear depending on balance on 275 square RE71R in F-Street trim.
I've been running about the same on 315/30-18 Rival-S. I'll have 305 square RE71 on the car for at least part of this season, I expect it to be within 2 lbs. |
01-14-2018, 03:00 PM | #13 |
Drives: 2018 ZL1 1LE Join Date: Dec 2016
Location: San Diego, CA
Posts: 218
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