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Author Topic:   Tire help
Steph
Member
posted May 18, 2001 10:22 AM
Last weekend we (and almost everyone else) ran a high-high line, and held the lead for 23 1/2 laps of our 25 lap feature. Actually, most people were down a half a groove. During yellows, other top drivers were cooling their tires in the infield, but we didn't - our driver didn't feel like the tires were not going away from him.

With a yellow at two laps to go (and a slight jump from the very talented driver in second), we were passed and ended up taking home second.

When the car came in, the tires were actually cool! Ten degrees (at least) per tire cooler than normal. The RR (an A) appeared, by temps, to be slightly under inflated, although none of the lettering was worn off, so it hadn't been rolled too much. The RF and the LR were worn away on their driving surfaces. The RF was the worst, and was very feathered (thinner on the outside edge than the inside - yet the temps were the opposite, slightly hotter on the inside). Temps were actually quite balanced across each tire, not more than 2 degrees different from any outside/middle/inside measurement. And the two rear tires were actually quite balanced to each other as well... our RR always runs hotter than the LR - don't know if that's good or not, but we do well that way, so...


Granted, driving that top line is a much faster line than where we normally drive the inside... but with the car handling as well as it was, I can't understand this tire wear. Could it just be that it was an abrasive track?

The car was a little tight going in, but after the first few laps (where we were using the top rim to push off of while it was still a little tacky), when the track started taking rubber he really looked like he was "just driving" around there.

If there is enough info here, please help me to understand and give any pointers on what we could have done to be better and to better preserve the tires. I can't figure out why we would need to "cool our tires" on the infield, when after the race, they were actually cool? Was the car just too tight? Thanks!

[This message has been edited by Steph (edited May 18, 2001).]

Flatfoot
Member
posted May 18, 2001 12:00 PM
Thanks for the tip.
Surprisingly, the A did not glaze over. We do watch for that. Oh and only the RR was an A dont know if I mentioned that. The weird thing is that the A is now softer than it was to start, and it was a brand new tire this week. Isn't that weird, or is that how A's trend? It was worn down as well, just not as much as the LR & RF.


Limited5
Member
posted May 18, 2001 10:22 PM
I'd like to know how anyone can accurately get a tire temp on a dirt tire anyways.


wfoondirt
Member
posted May 19, 2001 12:19 AM
i tend to look at wear patterns more than the temperatures, temps can be deceiving on dirt cars. Sounds to me that the car was a tick tight. If you normially setup to run the bottom it could be the case. depends upon the track but generally the car needs to be looser to run the top groove. As far as the tires go, i personally do not think that the a-40 is worth a ****. As mentioned they tend to glaze over once they are heat cycled. Once the tire is hot its usually best to keep the heat in it to avoid glazing it. Usually it is the ones using d-40s are the ones cooling tires off. I run d-40s almost exclusively except on tracks that are extremely abrasive or long races (50+ laps), in that case i will often goto the h-40. The h-40 doesnt glaze over like the a-40 and will usually come back once it is cooled. I assume your speaking of charleston and with all the rocks and sand it is an abrasive track but i have been able to make the d-40 live there when i have been there over the past few years. Alot of people swear by the a-40 but they cost me many races because of glazing over. Have never lost a race because of the d-40 going away. my 2 cents.

[This message has been edited by wfoondirt (edited May 19, 2001).]

Steph
Member
posted May 21, 2001 07:53 AM
After much discussion on this and other boards last year, I went with a probe type, computerize pyrometer that can take all 12 measurements in a very short amount of time. I start with the RF and work my way around to the LF. I don't have a problem seeing trends. Thanks for your concern though.

New related question: The reason we went to A's on the RR on a dry track was because the D would pick up too much heat and start to expand (often five or more pounds). Do people use bleeders, or nitrogen, or what to combat this problem?

[This message has been edited by Steph (edited May 21, 2001).]

Iowamod20
Member
posted May 21, 2001 08:03 AM
I have had a weird thing happening with my
Hoosier tires the last few races.

I also take tire temps on the rears after each race, and lately the LR's outside edge has been a lot hotter than the rest of the tire and the RR.

After the feature this weekend:
LR: 220, 179, 181 RR: 180, 181, 179

We have been increasing the air pressure, because that outside edge was starting to blister and come apart when we ran 8 to 10 psi. Running 13 psi now, and the tire stopped blistering, but still getting the high temperature on that edge.

Any ideas would be appreciated, thanks.

Steph
Member
posted May 21, 2001 08:15 AM
Actually, with the weird things the tires have been doing (and feathering worse than last year), I'm beginning to wonder if Hoosier has changed their compounds or something.

Iowamod20 -- Just for comparison, we run 8# in our LR. Are you measuring with a probe? Those temps a lot hotter than ours. If our RR gets above 150, I know something was really wrong (and it's proven by the time I get to the LR and find that it's much cooler). We normally run around 130 on the R and 120 on the L when we're "hot". Interesting readings you are getting there!

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