Very hot RR tire?

[missile07]

After a 8 lap heat race and 15 lap feature on a small 3/8 mile track the RR tire was extremely hot. I usually take tire temps but I forgot meter at home, so I am not sure on temperature but hotter than normal. Track was rough and greasy/slimy all night.

Driver says car was great the first 4-5 laps of heat and 6-8 laps of feature. Finished 2nd in the feature but car was fading very quickly. These are American Racers (USMTS/USRA) rules. The RR tire had one previous night on it and was not grooved or siped at all.

I guess I am asking would siping the tire across the tread have helped cool it off any? Any other tire tricks to help cool? Driver says car was not overly tight but he was having to pinch it down a little to dodge holes. Could this have been just too tight and sliding RR? Or is this a symptom of a abnormally greasy track and car just spinning on top of the ground?

Thanks in advance!

[powerslide]

I think the car was too tight, free up entry.

At the start of the year our car was tight and killing RR's like that. It worked ok until the tire overheated then it went away quick, you are probably ok to run it like that for a 15 lap feature but if it was a 20lap feature you would be free falling if anyone behind you had a more balanced setup.

[SRXSRULE]

what was the tire wear like on outside, center, and inside edge. Siping across the tread will build heat, siping around the tire will cool the tire. Eric

[missile07]

I meant to put around the tire not across. Tire was worn a little more towards the outside but nothing overwhelming.

[riddle28]

a little more air would help it run a little cooler, and some small grooves. did it blister the tire or just lots of heat?

[missile07]

Just hot. That is something else we considered because right before feature we dropped air pressure to 12-13 lb versus 14-15 that we normally would run. I think a lot of it was overly tight entry and scrubbing the tire getting in.

[25drtrkr]

We had the same issue a few yrs ago. What we found worked the best, was just adding 25lbs of bite at a time, until the temps evened out. Basically, you just have too much weight transfer.

[missile07]

So your thinking that the LR is transferring too much over onto the RR? Just throwing this out there but would a lower compression or lower pressured shock on the LR help this? Currently running 250lbs of pressure in the LR.

Or would hanging a weight on LR lower to keep it from transferring?

[Dirtrunner35]

Isn't a rr tire to hot a loose car ?? or a track that is really slick and the driver is on the gas too much ?

[25drtrkr]

So your thinking that the LR is transferring too much over onto the RR? Just throwing this out there but would a lower compression or lower pressured shock on the LR help this? Currently running 250lbs of pressure in the LR.

Or would hanging a weight on LR lower to keep it from transferring?

Shocks do not change weight transfer, only the timing of it. Lowering lead, increasing left side and/or bite all help to reduce RR heat issues. The compound could be too soft for the feature track conditions, but I would try to reduce the load on the RR before using a harder compound.

[missile07]

Not sure on j-bar rake....

shocks

RF 3-6 50lbs
LF 5-6 50lbs
RR 3-5 75lbs
LR 8-2 175-200lbs (I cant remember off top of my head)

RR offset started off the night with a 3 off and ending up on a 4 off for feature

Trailing RR 1/4 inch

[missile07]

I agree on being overly tight. Once we scaled it the left side weight was 1.5% low. Gonna start there and work on loosening it up in case track were to be similar to this again. Usually smooth and slick but we have had a lot of weekend rains in our area.