RA-1 tire wear question
#31
Originally Posted by Veloce Raptor
Yes.
RA1's will be back on the car next weekend.
RA1's will be back on the car next weekend.
#32
Originally Posted by joseph mitro
You wanna buy my 235/40s RA-1s with no shaving and 1 heat cycle? I'll be at TWS in two weeks and didn't like the first session i used the RA-1s for. maybe they'll get better, but they felt worse than either the hoosiers or the hankooks
#34
Yeah, what Greg said. When full tread, they are great in the rain, but in the dry, they get way too hot way too quickly due to all the tread squirm. You have to sort of underinflate them until a bunch of the tread wears away. The Kooks are even worse in this regard. I started the Kooks at 23 front cold & 21 rear cold at Barber last weekend, and they were they best they ever got. Anything higher, and they went ****-up after 2 laps.
Hoosiers will be slightly quicker than RA1's, IMO, depending on car set up (it will be slightly different for them vs. RA1's), but much less predictable after the first heat cycle, and much shorter lived. The R6's are, I hear, much better than past Hoosiers, but still the above remains true. If you want that extra second & have $$$, buy Hoosiers. If you want to win an enduro, especially in warmer weather, use the RA1's or the Kooks.
Hoosiers will be slightly quicker than RA1's, IMO, depending on car set up (it will be slightly different for them vs. RA1's), but much less predictable after the first heat cycle, and much shorter lived. The R6's are, I hear, much better than past Hoosiers, but still the above remains true. If you want that extra second & have $$$, buy Hoosiers. If you want to win an enduro, especially in warmer weather, use the RA1's or the Kooks.
#35
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From: At the track. I reside, however, in Navarre, FL.
As well, the RA-1s can chunk in dry conditions when at full tread. Either save them for wet weather track days or just have them shaved.
#36
Originally Posted by Bonster
I don't personally use a pyrometer, but the psi you want to shoot for is between 39-41 pounds. Keep a little notebook -- what track, weather that day, etc., and the recordings of cold and hot pressures. Eventually this will become committed to memory, but in the beginning, it's a really good tool to use.
I think the target temps for RA-1's are somewhat car dependent. On my S2 I find that 37 PSI is perfect for me with 36 to 38 being my envelope. At 39 I start to get serious squirming under threshold braking and turn in. Depending on the track and ambient temps I usually start out at about 30 PSI.
Of course, like everyone has said I have them shaved to 4/32" to start and use alot of negative camber in my setup.
#37
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From: At the track. I reside, however, in Navarre, FL.
That's REALLY good to know, Eddie, as I have had a lot of Porsche students lately for some reason. So is this on full treads or shaved? Is this true for just 944s or all Porsches? Would it be true for both the turbo and non-turbo 944s? 944s are front engines, if I've done my homework. So would this target psi tend to also be true for mid or rear engined cars? Most of my students don't run RA-1s but it's still really good knowledge to have under my hat. Thanks!
#38
I beleive you will find the target pressure to be similar for different models, but the cold starting pressures will vary by car...weight, tire size, engine placement, set-up, etc.
#40
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From: At the track. I reside, however, in Navarre, FL.
Well, here's a bit of irony for you. You know how the psi's that I suggested were apparently too high for Porsches? Well, it worked like a charm in a Corvette Z06 that I instructed (and was "forced" to drive). It's also worked in a number of other cars, actually. However, most of those cars were front engine. Weird. No matter, it's very useful information and I'll remember to ask my Porsche students to start at a cold temp more around 30 from now on and just work from there. Thanks again! This is good information, indeed.
#41
Originally Posted by Bonster
That's REALLY good to know, Eddie, as I have had a lot of Porsche students lately for some reason. So is this on full treads or shaved? Is this true for just 944s or all Porsches? Would it be true for both the turbo and non-turbo 944s? 944s are front engines, if I've done my homework. So would this target psi tend to also be true for mid or rear engined cars? Most of my students don't run RA-1s but it's still really good knowledge to have under my hat. Thanks!
Here's a good setup guide I found a year or so ago for Toyo's..
http://www.toyo.com.au/Pit%20Lane.ht...on%20Pressures
#42
Originally Posted by Bonster
Well, here's a bit of irony for you. You know how the psi's that I suggested were apparently too high for Porsches? Well, it worked like a charm in a Corvette Z06 that I instructed (and was "forced" to drive). It's also worked in a number of other cars, actually. However, most of those cars were front engine. Weird. No matter, it's very useful information and I'll remember to ask my Porsche students to start at a cold temp more around 30 from now on and just work from there. Thanks again! This is good information, indeed.
#43
Originally Posted by smlporsche
Here's a good setup guide I found a year or so ago for Toyo's..
http://www.toyo.com.au/Pit%20Lane.ht...on%20Pressures
http://www.toyo.com.au/Pit%20Lane.ht...on%20Pressures
#44
Originally Posted by Veloce Raptor
I never worry about hot pressures any more. I take hot tire temps with a probe pyrometer, adjust pressures accordingly, and viola! Perfect GTG set up!
How are people adjusting tire pressure based on temps? i.e. what sort of temps cause you to make a change on your pressures? Radial race tires are usually stiff enough that pressures don't seem to affect the difference in temperatures across the tire.
#45
Bryan, I am lazy. I have no interest in changing my alignment or camber at the track. Thus, I change tire pressures to get no more than a 10 degree F variation between inner tread, center tread, and outer tread when I come into hot pits at full pace. Seems to work pretty well, and I am getting such even tire wear that I never rotate the tires. I run them until they cord, and they usually cord 3 or 4 at the same time.
For your 2nd question, if, for instance, I see the center tread is 20 degrees higher than inner or outer, I lower pressure on that tire.
For your 2nd question, if, for instance, I see the center tread is 20 degrees higher than inner or outer, I lower pressure on that tire.