You A052, first laps fastest?

[ZDan]

Watkins Glen on the 13th/14th! Brand new set of 245/40-17 A052s getting mounted tomorrow. I'll have them and a set of 235/45-17 A052s with six heat cycles on them (typically just 4-5 laps each).

Guessing the 245s will be quicker. Question is whether to save the new sticker 245s for the time trial, or run one or two practice sessions on them before the TT.

Anybody have any good info on how much lap time (if any) is lost between the first few heat cycles? I'd like to do at least one practice on them to get shift points down (235/45-17 quite a bit taller vs. 245/40-17).

[CSG Mike]

The 245 will probably be quicker. Do 1 session during the TT; practice on scrubs.

Time difference depends on how hot you get the tires during the cycles, so it's hard to say accurately.

[ZDan]

Originally Posted by CSG Mike

The 245 will probably be quicker. Do 1 session during the TT; practice on scrubs.

Time difference depends on how hot you get the tires during the cycles, so it's hard to say accurately.

I *try* to be delicate with the A052s, and keep stints short (~5 laps or so). They don't seem to tolerate being overdriven like some tires. Seem to really reward *careful* driving at 9.5 to 9.9/10ths but quickly start to fall apart at 10.1+/10ths...

Event format is 4 (or 5) sessions on day-1, then 2 (or 3) practice sessions on day-2, followed by 3-lap time-trial a couple/few hours later (plenty of cool-down time)

Tentative plan is to run all of day 1, and practice-1 on day 2 on the 235/45-17s, and do a brief time-trial simulation at 9/10ths for practice-2 on the sticker 245/40-17s to at least get the shift points down with the changed gearing.

Unless the first few laps are magical "golden" laps in the sticker tires, in which case I save them for TT!

I guess it's also a question whether the first heat cycle should be run day before the TT rather than a couple of hours before, or if that matters at all.

[racingfool]

Originally Posted by ZDan

9/10ths for practice-2 on the sticker 245/40-17s

I would treat them a little easier on the first cycle.

Originally Posted by ZDan

I guess it's also a question whether the first heat cycle should be run day before the TT rather than a couple of hours before

I would let them rest for 24 hours after the first cycle.

[CSG Mike]

Originally Posted by ZDan

I *try* to be delicate with the A052s, and keep stints short (~5 laps or so). They don't seem to tolerate being overdriven like some tires. Seem to really reward *careful* driving at 9.5 to 9.9/10ths but quickly start to fall apart at 10.1+/10ths...

Event format is 4 (or 5) sessions on day-1, then 2 (or 3) practice sessions on day-2, followed by 3-lap time-trial a couple/few hours later (plenty of cool-down time)

Tentative plan is to run all of day 1, and practice-1 on day 2 on the 235/45-17s, and do a brief time-trial simulation at 9/10ths for practice-2 on the sticker 245/40-17s to at least get the shift points down with the changed gearing.

Unless the first few laps are magical "golden" laps in the sticker tires, in which case I save them for TT!

I guess it's also a question whether the first heat cycle should be run day before the TT rather than a couple of hours before, or if that matters at all.

You can simulate by lowering your shift point maybe 400 rpms. No need to waste stickers.

Use the built in shift light.

[Icecreamtruk]

Originally Posted by ZDan

Watkins Glen on the 13th/14th! Brand new set of 245/40-17 A052s getting mounted tomorrow. I'll have them and a set of 235/45-17 A052s with six heat cycles on them (typically just 4-5 laps each).

Guessing the 245s will be quicker. Question is whether to save the new sticker 245s for the time trial, or run one or two practice sessions on them before the TT.

Anybody have any good info on how much lap time (if any) is lost between the first few heat cycles? I'd like to do at least one practice on them to get shift points down (235/45-17 quite a bit taller vs. 245/40-17).

The very first lap (after the outlap) on sticker yokos is magic. Save it for the time trial. Also, send it, hard, while the feeling on the yokos is a bit vague, you do need good slip angle on them to get everything out of them and they will give you considerably more grip than your practice tires. If you can adapt to the newfound grip in a corner or two, you will be much faster on the sticker yokos (not easy to do, depends a lot on driver).

[racingfool]

Originally Posted by Icecreamtruk

The very first lap (after the outlap) on sticker yokos is magic.

tire has a unique strip of wear right in the center

Seems a break in/heat cycle might be good, according to Andy Hollis.

I've also had several other sets that did none of that....all of which had
a solid break-in heat cycle before running hard. So that may be the key.

https://forum.miata.net/vb/showthread.php?t=745572

https://forum.miata.net/vb/showthread.php?t=745572

[ZDan]

How much faster would sticker A052s be vs with one short practice session? Watkins Glen, doin 2:15 on "used" 235/45-17s, savin sticker 245/40-17 for time trial Tomorrow but may run 1 short practice on them before TT...

[CSG Mike]

Completely depends on how you cycle them that short practice session.

[ZDan]

I threw two of the new 245/40-17 Yoks on the back only for one practice session (idea being to get familiar with slightly changed shift points while saving new sticker 245s for the more critical fronts). They felt a bit squishy relative to the old 235/45-17s. More so than expected based on full tread depth and a bit more "pooched". Expected some compensation from lower profile...

Anyway they were less confidence-inspiring and slower. TT'd on the old 235s and won by 2 seconds over class competitor I've been going back and forth with. Miatae R slo at Watkins Glen even on Hoosiers...

[ZDan]

I wound up running 2 of the new sticker 245/40-17s at the rear of the car for one practice session to determine shift points and whether gearing was different enough to affect speeds/lap times. Did a kind of time trial simulation (warmup lap and 3 hot laps). The rear felt less planted, rear tires felt a lot more laterally squishy vs. 6-7 heat-cycle 235/45-17s. Put 235s back on the rear and went back out, easily went 1 sec quicker, so ran the TT on those.

[Icecreamtruk]

Originally Posted by ZDan

I wound up running 2 of the new sticker 245/40-17s at the rear of the car for one practice session to determine shift points and whether gearing was different enough to affect speeds/lap times. Did a kind of time trial simulation (warmup lap and 3 hot laps). The rear felt less planted, rear tires felt a lot more laterally squishy vs. 6-7 heat-cycle 235/45-17s. Put 235s back on the rear and went back out, easily went 1 sec quicker, so ran the TT on those.

Were you using the 245s on a wheel the same width as the 235s?

[ZDan]

Originally Posted by Icecreamtruk

Were you using the 245s on a wheel the same width as the 235s?

Yeah, both on 17x9.
I expected some compliance squirm difference based on 245 being more "pooched" vs. 235, and also full tread depth vs. some wear, but expected that to be partially compensated for by shorter sidewall height.

I might try 225/45-17 on 17x9 next year and get a weight break!