(2015) 200+ Treadwear Autocross Street Tire Thread - Page 28 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

cjd · 05-14-2015, 12:41 PM

Quote:

Originally Posted by renfield90

Try it and let us know!

Of course. May try to work out a swap with someone more seasoned to, well see.
I'm registered, just have to let the 24th roll around.

this weekend is a road trip, and that'll be on PSS.

autoXracer · 05-14-2015, 01:44 PM

Might just try the 255. STR s2000's run that size. Hope there won't be any rubbing issues with +45 wheels on the front inner fender wall and Strano sway bar.

48Spoons · 05-14-2015, 07:06 PM

I've been running the the RE71 in 255 and so far they feel really good. I've had 3 events on them. I have the new TRMotorsport wheels with are +45 and I did have some trouble clearing the stock perches(I have the koni inserts) in the front. If you have full aftermarket coils it should be fine.

RedBRZ80 · 05-14-2015, 08:02 PM

Quote:

Originally Posted by autoXracer

Does the RE-71R in 255/40-17 benefit more than 245/40-17 for STX? Trying to decide between the 2.

The "fast" guys are running 245/40 in STX for the RE71Rs. Lighter tire and better turn in.

autoXracer · 05-14-2015, 11:28 PM

Appreciate the input. Wasn't sure what everyone was running.

RedBRZ80 · 05-19-2015, 08:16 PM

70 runs into my first set of RE71rS. They might be about 90% of the grip when new. Still very solid.

Already have a second set waiting to go, if the Georgia Match Tour happens I'll probally go with the new ones.

SeanRTR · 05-20-2015, 09:45 AM

Quote:

Originally Posted by RedBRZ80

70 runs into my first set of RE71rS. They might be about 90% of the grip when new. Still very solid.

Already have a second set waiting to go, if the Georgia Match Tour happens I'll probally go with the new ones.

Test a new set against an old set for an actual delta on the watch, and I'll send you $6 via paypal.

Locust · 05-20-2015, 12:24 PM

Sitting at Discount Tire waiting for my RE71Rs to get installed. For those of you running them what pressures are you starting with on pavement? And what about in the rain?

SeanRTR · 05-20-2015, 01:04 PM

31 dry
25 wet

Biggins · 05-20-2015, 01:14 PM

Quote:

Originally Posted by SeanRTR

31 dry
25 wet

What he said... I have my rears a little lower.

Locust · 05-20-2015, 01:53 PM

Quote:

Originally Posted by SeanRTR

31 dry
25 wet

Quote:

Originally Posted by Biggins

What he said... I have my rears a little lower.

Thanks guys

rx3 · 05-21-2015, 10:42 AM

Quote:

Originally Posted by SeanRTR

31 dry
25 wet

Granted that I don't know the RE71R. But the consensus here for any tire is that in wet conditions tires should be run at higher pressures.
For following reasons:
An overinflated tire has a reduced contact area and is therefore displacing water superiorly. But more importantly: This reduced contact area is apparently also getting more heat into the tire (and a warmer tire will be grippier). This sounds counter-intuitive but the reason could be that less contact area also reduces the heat transfer to the road (the cold road can't cool the tire as quickly). Some also say that a harder tire slides more initially and this generates more heat.

SeanRTR · 05-21-2015, 10:57 AM

Quote:

Originally Posted by rx3

Granted that I don't know the RE71R. But the consensus here for any tire is that in wet conditions tires should be run at higher pressures.
For following reasons:
An overinflated tire has a reduced contact area and is therefore displacing water superiorly. But more importantly: This reduced contact area is apparently also getting more heat into the tire (and a warmer tire will be grippier). This sounds counter-intuitive but the reason could be that less contact area also reduces the heat transfer to the road (the cold road can't cool the tire as quickly). Some also say that a harder tire slides more initially and this generates more heat.

I always hear this. Your thinking is correct if the autocross conditions look like this:

But when it's not a monsoon (most of the time), dropping the tire pressure to soften the sidewalls and make the tire more compliant is what you're looking for. If you're autocrossing in several inches of standing water, you probably should have stayed home....but if not, THAT is the situation where you would run more pressure.

rx3 · 05-21-2015, 11:06 AM

No, I'm not just speaking about hydroplaning.

As I said:
More importantly: This reduced contact area is apparently also getting more heat into the tire (and a warmer tire will be grippier). This sounds counter-intuitive but the reason could be that less contact area also reduces the heat transfer to the road (the cold road can't cool the tire as quickly). Some also say that a harder tire slides more initially and this generates more heat.

I also noticed that a narrower tire in damp cold conditions is faster than a wider tire.

05-20-2015, 12:24 PM	#386
Locust Custom User Title Join Date: Oct 2014 Drives: 2015 Scion FR-S, 2012 OB Evo X MR Location: Seattle Posts: 807 Thanks: 13 Thanked 424 Times in 272 Posts Mentioned: 13 Post(s) Tagged: 2 Thread(s)	Sitting at Discount Tire waiting for my RE71Rs to get installed. For those of you running them what pressures are you starting with on pavement? And what about in the rain? __________________ LOCUST 2015 FR-S (STX) and 2012 Evo X MR Instagram: LocustAutoX Sponsors:DSGPerformance Drift Office Evil Apex Racing

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05-14-2015, 07:06 PM	#381
48Spoons Member Join Date: Mar 2013 Drives: Ultramarine FR-S Location: Boston, MA Posts: 73 Thanks: 9 Thanked 23 Times in 19 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	I've been running the the RE71 in 255 and so far they feel really good. I've had 3 events on them. I have the new TRMotorsport wheels with are +45 and I did have some trouble clearing the stock perches(I have the koni inserts) in the front. If you have full aftermarket coils it should be fine.

05-21-2015, 11:06 AM	#392
rx3 Senior Member Join Date: Mar 2013 Drives: BRZ Location: Europe Posts: 350 Thanks: 53 Thanked 114 Times in 71 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	No, I'm not just speaking about hydroplaning. As I said: More importantly: This reduced contact area is apparently also getting more heat into the tire (and a warmer tire will be grippier). This sounds counter-intuitive but the reason could be that less contact area also reduces the heat transfer to the road (the cold road can't cool the tire as quickly). Some also say that a harder tire slides more initially and this generates more heat. I also noticed that a narrower tire in damp cold conditions is faster than a wider tire.

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