How do you ensure you're getting the same depth every time? Do you wait until the 2nd or 3rd runs to take temps?

I fooled around with one this past weekend and we got some really odd readings. Like the tires were 15° cooler immediately after the first run then they were sitting still in the grid beforehand. It wasn't until the fifth and six runs when the temperature spiked above the pre-run temperatures. We took temps immediately after the end of the run (pulled off to the side after the exit chute).

Maybe we just need to be more consistent about where we take temps but I would appreciate any tips/tricks! We were using a Longacre probe type and tires were Azenis.

Andy

 

If you have another person with a notebook, take temps at the inside, center, and outside (keep it away from the sidewall). The temp profile can hint at what camber settings are effective as well as what driving style is effective (effective = gets the tires hot).

I also use a Longacre pyro and it does take a second or two to register. I've also noticed that it will give completely wrong temps sometimes, which is fixed by turning it off and back on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR &raquo;</TD></TR><TR><TD CLASS="quote">If you have another person with a notebook, take temps at the inside, center, and outside (keep it away from the sidewall). The temp profile can hint at what camber settings are effective as well as what driving style is effective (effective = gets the tires hot). </TD></TR></TABLE>

Did that.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
I also use a Longacre pyro and it does take a second or two to register. I've also noticed that it will give completely wrong temps sometimes, which is fixed by turning it off and back on. </TD></TR></TABLE>

Hmmm......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by maxQ &raquo;</TD></TR><TR><TD CLASS="quote">Hmmm......
</TD></TR></TABLE>

It got worse as it got older. Took longer to get a stable reading (temps kept climbing), which is not good for trying to get accurate results.

 

http://www.longacreracing.com/...16#Q1

I read that first... I just stuck mine in til it refused to go any further. I believe this to be when it hit cord or the housing, not sure. My readings were pretty consistent run to run though... and yeah, MXs seem to still stick when they're 150 degrees 3 minutes AFTER the run

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WRXRacer111 &raquo;</TD></TR><TR><TD CLASS="quote">

I read that first... I just stuck mine in til it refused to go any further. </TD></TR></TABLE>

Here's my problem with that. I wouldn't think you get an accurate reading in the depth of the tires with the short bursts of autocross. Especially with only 4 runs to warm it up.

But if the metal probe is reading the *air* temperature without it fully inserted, that's a problem.......

Andy

 

the problem is that the surface of the tread cool svery quickly, while the internal temperatures are more stable.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Safir &raquo;</TD></TR><TR><TD CLASS="quote">the problem is that the surface of the tread cool svery quickly, while the internal temperatures are more stable.</TD></TR></TABLE>

More stable = not indicative of autocross performance.

If you heat the surface of the tire up for one minute, then let it cool for 10 minutes. Then heat it up again for a minute and then let it cool for 10 minutes... what kind of internal heat are you going to get?

If you measure immediately after the run and punch the probe deep into the thread where the heat hasn't had the chance to convect yet, what is the meaning of your readings?

If I'm wrong and you can get meaningful readings, please elaborate on testing method, control, etc.


Andy - who has a sudden image of tree rings... maybe if I CUT the tire across the tread... I can read temperatures then! Yeah, yeah, that's the ticket!

 

Y'know, I thought about that too and couldn't come up with a good answer when I was trying to pick between probe and IR pyros. Wasn't sure if the surface readings might be more accurate for autox due to what you mentioned... then I gave up and got the probe type. Never tried to measure surface temps, but with two drivers running with roughly 2-3 minutes between runs, we were definitely cranking some heat into them.