[NG329]

Hey guys,

I'm thinking about running Hoosier A7 at the track towards the end of October for a track day. This will be my first time running them.

Up here in the Northeast guys seem to favor these over the R7. I understand that traditionally these are an autocross tire but they are also capable of fast laps.

Do you guys think that 50-60*F weather might be too cool to run these? I will likely run 315/30/18 Front and 335/30/18 Rear.

The car is going to be running great in the cooler temps so I am aiming to set my fastest laps of the season. I am aiming for 1:24-1:27 at NJMP Thunderbolt.

Any tips on these would be greatly appreciated as I think it might be too cool for the Goodyear SC3R.

[Msquared]

You might need a lap to get some heat into them, but A7s are generally grippy from 80F and up, so you'll be fine. I would expect them to still get too hot for best grip within a few laps, so you'll need to bank a fast lap fairly early in the stint.

[NG329]

Originally Posted by Msquared

You might need a lap to get some heat into them, but A7s are generally grippy from 80F and up, so you'll be fine. I would expect them to still get too hot for best grip within a few laps, so you'll need to bank a fast lap fairly early in the stint.

Cool. Thanks for the tips. I imagine that the ambient temps will be in the 60s so I should be able to get them warm enough.

[20Bluezl1]

So you think 60⁰ is to cold for the SC3R ? I would think if you heat them up on the first 3 laps they will stay hit and have great grip.

[khcoaching]

I've run 3Rs in high 40s and they take a few laps to warmup, but work well in lower temps, just monitor pressures.

The A7s would love those temps and are a very very fast tire from the get go.

Ken

[SDF62]

Not wanting to hijack the thread, but to add to the discussion....Would R7's react in similar fashion to A7's in the 40-50 degree range for morning temps??

[cdrptrks]

A7 seems like overkill to me unless you are competing in time trials. Hoosiers (both A7 & R7) get slower with every heat cycle and I imagine that a heavy car like the ZL1 1LE will use their life up very quickly and overheat A7s way before the end of each session if they are typical 20-25 minute sessions.

[cdrptrks]

If you are confident that you can put together a really fast first hot lap at the beginning of each session and are willing to tolerate the high price and high wear rate of A7s, they should be faster than R7s but R7s should provide you with more opportunities to attempt fast laps without overheating them IMO.

This forum member seems to be competitive in his SS 1LE in the NASA ST3 class using Hoosier R7s for races (as of last year, unsure if he changed to a different tire this year) and his car is several hundred pounds lighter than a ZLE since it doesn't have the added supercharger weight.
https://youtube.com/c/ItsLewisracing927
I imagine he would use A7s if they had a better average lap time over the course of each race but I am not an expert on Hoosiers or the class rules.

EDIT: It looks like he would have needed to detune the car by another 25hp to run Hoosier A7 instead of R7 in the ST3 class with all else being equal.

[cdrptrks]

Tire Rack has this note in the Hoosier R7 description:
"NOTE: Radial A7 tires are also used for road racing on lightweight cars or when competing in cool ambient temperatures where Hoosier Sports Car DOT Radial R7 tires cannot be brought up to favorable operating temperatures."

https://m.tirerack.com/tires/descrip...r&tireModel=R7

[NG329]

Thanks guys for all the feedback. What pressures are you running cold and where do you like to keep your hot off the track pressures?

I like the SC3R to be 32psi hot off the track after a 20min session. Are the A7 similar or should they be higher?

[d15b7]

You are about to spend a lot of money if you purchase the A7s and run them for full sessions. They are very fast, and wear very quickly. They will come up to temp very quickly. I run them on my time attack Honda Civic (295 -30-15s up front) - (ran a 2:01.9 at VIR last time I was there. I usually do one out lap to warm them up and one flying lap and then perhaps a second lap (not usually though) and then an in lap. The tires will last me about 12-16 sessions like that. (So maybe 36-45 laps). Then they go downhill very fast.

I’d guess u stand a good chance of killing them in one weekend.

Note: I only use the As when it’s a really important competition/event. They are just too expensive otherwise