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For all you road racers out there....what do you or would you start a set of Toyo RA1's out at pressure-wise? I was confused at my first race I did and started them at low 30's then talked to the previous owner of my car who said you want to end at low 30's. So, I'm going to Moroso next weekend and am thinking about 24-25 in the front and about 25-26 in the rear. This sound about right?
So, I'm going to Moroso next weekend and am thinking about 24-25 in the front and about 25-26 in the rear. This sound about right?
I'd say a little higher- 28 to 30. Easier to take air out then add it back in. Just run a several laps in your first session until your tires are hot, then come into the hotpits and check the temps. Put your tire pressure gauge in your glovebox. It should only take a few seconds- you only really need to check one.
Well in my case I start with 36 front and 34 rear for a heat that just last maybe 25min but my car still weights 2400 maybe if you car is fully unguted you can go lower but in my case tires at around 31 or 30 starts to collapse de side wall with RA1, I might be wrong but 25 sounds too low for a 205 50 15.
For all you road racers out there....what do you or would you start a set of Toyo RA1's out at pressure-wise? I was confused at my first race I did and started them at low 30's then talked to the previous owner of my car who said you want to end at low 30's. So, I'm going to Moroso next weekend and am thinking about 24-25 in the front and about 25-26 in the rear. This sound about right?
with RA-1's you want to end up in the high 30's not low 30's. As a rule of thumb, you allow 1 psi of pressure gain for every 10 degrees of air temperature. So if your final tire pressure is 38 psi and its 80 degrees, you start at 30 psi cold.
with RA-1's you want to end up in the high 30's not low 30's. As a rule of thumb, you allow 1 psi of pressure gain for every 10 degrees of air temperature. So if your final tire pressure is 38 psi and its 80 degrees, you start at 30 psi cold.
Not to highjack, but what's your experiences with the Kumhos.
I start out at 38 to 40 cold on the V800 (the one with the single grove in the center). 2000lb, 350lb/in dual progressive front, 500lb/in linear rear springs. I have had the best performance here. Anything less and I get too much sidewall flex and bounce. I'm usually in the 90's ambient. 205/50/15. I have a 5 to 8 degree temp differential across the width of the fronts and rears. Front ends up at about 45 to 47, rear at 45. Nice rule of thumb, 1:10, is that your own exp.
Not to highjack, but what's your experiences with the Kumhos.
I start out at 38 to 40 cold on the V800 (the one with the single grove in the center). 2000lb, 350lb/in dual progressive front, 500lb/in linear rear springs. I have had the best performance here. Anything less and I get too much sidewall flex and bounce. I'm usually in the 90's ambient. 205/50/15. I have a 5 to 8 degree temp differential across the width of the fronts and rears. Front ends up at about 45 to 47, rear at 45. Nice rule of thumb, 1:10, is that your own exp.
My erxperiance is they like to run slightly more negative camber and slightly higher pressure than Toyos. They run about 10 degrees hotter, grip slightly better and are less forgiving to being over driven and are more likely to chunk. They heat cycle less well and don't recover to well if you get them too hot.
I don't run them myself but Naji sometimes uses them to qualify and races on Toyos.
The 1:10 rule is something someone told me once a long time ago which seems to work when the tire is dead cold. Its a great rule for getting in the ballpark. After my first session I normal readjust the tire pressure as soon as the car comes off the track and it stays their the rest of the weekend.
Well, just got back from Moroso today. We started them out mid-20's and ending pressures were 32 in front and 30-31 in the rear. The left side was consistantly hotter and higher pressure just cause the track set-up...More right turns. But the car felt better than ever, easily rotated, felt nice and squirmy (I like the car to feel that way), and there was no chunking of any sort. Tire wear was excellent and the temps stayed pretty consistent. We were running 2.0-2.2 degrees of camber up front and stock out back (1.5 or so). By the temps, it seems we should maybe take about .5 out of the front and try to put .5 more in the rear somehow, of camber. Laps times started at 1.53's-ish and by the end of the days I got them down to mid-1.48's. Should be able to run mid-to-front pack this year by the look of the lap times and considering that the car is way underdeveloped. I'm hopeful to see what Sebring times will be like now that we got the tire pressures correct.
Well, just got back from Moroso today. We started them out mid-20's and ending pressures were 32 in front and 30-31 in the rear. The left side was consistantly hotter and higher pressure just cause the track set-up...More right turns. But the car felt better than ever, easily rotated, felt nice and squirmy (I like the car to feel that way), and there was no chunking of any sort. Tire wear was excellent and the temps stayed pretty consistent. We were running 2.0-2.2 degrees of camber up front and stock out back (1.5 or so). By the temps, it seems we should maybe take about .5 out of the front and try to put .5 more in the rear somehow, of camber. Laps times started at 1.53's-ish and by the end of the days I got them down to mid-1.48's. Should be able to run mid-to-front pack this year by the look of the lap times and considering that the car is way underdeveloped. I'm hopeful to see what Sebring times will be like now that we got the tire pressures correct.
Generaly you want something like a 10 degree differential in tire temps with the inside hotter than the outside edge.
http://www.toyoracing.com/TireInfo/RA1_tires.asp
everything you wanted to know about RA1's. We usually end up at about 41 to 42 PSI hot, and about 180f at the outside, 190-200 on the center and inside edge
we got there by trial and error.We set the tires at around high 20's and went and did some hot laps, pulled the car into the pits, measured pressures and adjusted them to outr target hot pressure(mostly letting air out till we reached 41 psi). Then we parked the car and let it sit for about 4 to six hours and measured the pressure again. Voila, cold starting pressures
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David J. Gerryts
2001 Sentra SE (SR20DE)
Pre Production NX2000 race car #33 (now with GTi-R power)vin# 001003
Pre Production NX2000 race car #44 10.1, C3, HS header etc.vin#001002
Mine are too, haha. Oh well. I'm suprised that they were sooooo slowly. I'm wondering how many heat cycles these tires will take. I've already got 1 race weekend, 1 track event, and 1 autocross on the set ad they still look decent. I think I'm going to dismount them and sideways rotate them before the next race at Daytona.
