Yes I did search!

Need help on how far past the wear bars RA1's will go.

I bought a used set from John Berget Racing tires. 3 of the 4 tires were good, one is almost a slick. I am instructing at a PDE mid June at Barber Motosports Park for two days, running in group 5, and do not want a tire going south during that weekend. The tire size that I bought in the RA1's is 225/50-16 and 245/45-16. The tire in question is a rear. JB tire does not have anything at this time to replace the one in question but offered a pair of Kuhmo 700 something in the correct size for the rear only.

I have found info indicating 35psi as a starting point on the RA1 and not allowing them to go over 40 hot. Not really into mixing tires but thought I would ask the pros for some help.

Another question is that my car is a '00 with only a Muegen big bar on the front and a good track alignment. 1.7 neg front with 1/8" toe out and 2.7 neg rear with 1/8" toe in. Is this enough camber to properly use the RA1's?

The car is was very solid and neutral with stock size RE01R's but they would heat up and get greasy after 3 hot laps. I would slow down let them cool and do it again....this is during 20 min. sessions. I just need more grip to run with the other cars in this group.

Anything else I should be looking at?

 

RA1's last forever if its almost a slick it should have more than a weekend in it

Run it on the side thats likely to get least action at that track, 38/39 hot

 

ditto what dan_uk said.

Also, RA1s prefer lots of neg camber (>2) because the sidewall is flexy.

 

Run them until they cord - they fall off a bit as they heat cycle, but the falloff is minimal compared to most R-compounds.

More camber may help performance and evenness of tire wear, but RA1s aren't prone to evil groove of doom or anything either.

 

Garry... let's make sure those tires are in check, as I'd hate for my instructor not to be getting in his track time!

Chris

 

What everyone said already. Run them until you see cords.

 

Thanks for the replies!
The challenge is knowing when that one tire will go.
The surface is great, smooth and progressive. No real tight turns.
The tire is showing one grove, but bairly.

I have time to see if jb comes thru with a replacement.......anyone have a decent 245/45 16???????

 

Agree - run them to the cords. You don't care about the wear bars, that is for the street. The track wear indicators are those little round holes. When they are gone, it will cord fairly soon. They run as slicks for awhile before cording.

 

Keeps the pressures below 40 hot or they get greasy. You will need to start with about 28-30 psi cold.

 

do NT-01s have similar properties?

i think both are on the more entry level of r-compounds correct?