New ai/cmc tire thread

[ShadowBolt]

I decided to start a new thread. I think the health of our series depends on something being done (but I doubt it will be).

I got a call from a former CMC racer the other day that ask me about the state of CMC today. When I told him about the tire issue he said no way he would come back. He remembers six to eight tires in a six race weekend season. He has a car but tires will keep him away. How many others are in the same boat? MSRH, then Cresson, two weekends at TWS, Hallett and ECR plus practice days and all done on six to eight tires. Will told me Toyo swears they changed nothing from the first RA1 to the new RA1.

With NASA Texas having the largest field ever at Cresson I doubt anyone with NASA Texas or NASA National gives a shit about this issue in CMC. I think we could double our fields in CMC (don't know about AI) with a different tire situation. What do you think the guys that started CMC would think about this?
JJ

[Al Fernandez]

Before anyone says "bring back the old RA1s"...they don't exist any more. RA1s exist but they are not the same as before.

[mach1]

Maybe they didn't change, maybe cars are faster, more power, driving harder etc. The RR's I've had on the miata look to "wear" 1/2 as fast as they did on the CMC car, after 2 weekends there is a ton of tread left, the HC fall off I don't know yet, but I can only imagine the lower power and weight doesn't take as much as a toll on the tire staying fast. The guy that ran a blistering 1.24.x in a 125hp miata at MSRC was on older tires fyi.

[t500hps]

I came into CMC (Mid Atlantic) mid 2013 so I have limited experience on the old RA1's. I was the first in our region on RR's at the beginning of 2014 and have tracked heat cycles for every tire since. Most I've gotten was 36 H/C out of a set of 4. Least was in the low 20's due to not rotating them well.....usually I get 30. I've found my car doesn't even like them the first 3 H/C. I've set track records at 2 different tracks, once on 22 H/C tires and another track using 18 H/C tires. I've learned how each corner of the car wears each tire differently and rotate them for longest life. A typical 7-8 weekend race season is typically 6 tires for me. (Due to stocking up for Nationals in 2015 and 2016 I ran the entire 2017 season without buying a single set of tires. My "newest" 2 sets have 2015 and 2016 dates codes. They have 14 and 21 H/C respectively and I'll use them til mid-season before buying another set)

Hopefully I can make it to COTA in Sept so we can see if I'm actually competitive (obviously I think I am :))

[mach1]

I came into CMC (Mid Atlantic) mid 2013 so I have limited experience on the old RA1's. I was the first in our region on RR's at the beginning of 2014 and have tracked heat cycles for every tire since. Most I've gotten was 36 H/C out of a set of 4. Least was in the low 20's due to not rotating them well.....usually I get 30. I've found my car doesn't even like them the first 3 H/C. I've set track records at 2 different tracks, once on 22 H/C tires and another track using 18 H/C tires. I've learned how each corner of the car wears each tire differently and rotate them for longest life. A typical 7-8 weekend race season is typically 6 tires for me. (Due to stocking up for Nationals in 2015 and 2016 I ran the entire 2017 season without buying a single set of tires. My "newest" 2 sets have 2015 and 2016 dates codes. They have 14 and 21 H/C respectively and I'll use them til mid-season before buying another set)

Hopefully I can make it to COTA in Sept so we can see if I'm actually competitive (obviously I think I am :))

We would love to have you at COTA, I have learned from CMC and SM, Texas has some GREAT competition/drivers.
Look forward to meeting you!

[ShadowBolt]

I came into CMC (Mid Atlantic) mid 2013 so I have limited experience on the old RA1's. I was the first in our region on RR's at the beginning of 2014 and have tracked heat cycles for every tire since. Most I've gotten was 36 H/C out of a set of 4. Least was in the low 20's due to not rotating them well.....usually I get 30. I've found my car doesn't even like them the first 3 H/C. I've set track records at 2 different tracks, once on 22 H/C tires and another track using 18 H/C tires. I've learned how each corner of the car wears each tire differently and rotate them for longest life. A typical 7-8 weekend race season is typically 6 tires for me. (Due to stocking up for Nationals in 2015 and 2016 I ran the entire 2017 season without buying a single set of tires. My "newest" 2 sets have 2015 and 2016 dates codes. They have 14 and 21 H/C respectively and I'll use them til mid-season before buying another set)

Hopefully I can make it to COTA in Sept so we can see if I'm actually competitive (obviously I think I am :))


I don't think anyone here in Texas has set a track record on 22 h/c tires. Here is what I know for a fact because I saw it happen. I hired a very well known driving coach a few years ago at TWS. After lunch he told me if I put on new tires I would pick up two seconds. I called BS but he said he had seen the same thing while coaching Tyler in a CMC car at the same track. I put on a set of stickers and yes I went two second quicker in the next session. Maybe spring rates have something to do with it. I know I'm hard on the RR's because everyone says if you get them too hot they will not fully recover. I have been known to slide the car way more than I should.
I have been wondering if maybe Toyo is telling the truth about the tires. Maybe we are all so much faster than we were back in the day. I know I was telling Bryan how damn fast Jeff Burch used to be at Hallett. He would be half a lap ahead of the rest of the field. I used to accuse him of smoking a cigarette during the Hallett races. I have never kept up with lap times much but I was shocked last year when BL told me that we were running lap times way quicker than Jeff used to (and we are certainly not one of the fastest guys). If running faster laps is causing the h/c issue AI should have had the problem we are having now even back when CMC was using "thin to win" tires in big races.


Oh and by the way if your car does not like the first three heat cycles I know a guy or two that would be glad to put those heat cycles on them for you......free of course.

JJ

[t500hps]

I don't think anyone here in Texas has set a track record on 22 h/c tires. Here is what I know for a fact because I saw it happen. I hired a very well known driving coach a few years ago at TWS. After lunch he told me if I put on new tires I would pick up two seconds. I called BS but he said he had seen the same thing while coaching Tyler in a CMC car at the same track. I put on a set of stickers and yes I went two second quicker in the next session. Maybe spring rates have something to do with it. I know I'm hard on the RR's because everyone says if you get them too hot they will not fully recover. I have been known to slide the car way more than I should.
I have been wondering if maybe Toyo is telling the truth about the tires. Maybe we are all so much faster than we were back in the day. I know I was telling Bryan how damn fast Jeff Burch used to be at Hallett. He would be half a lap ahead of the rest of the field. I used to accuse him of smoking a cigarette during the Hallett races. I have never kept up with lap times much but I was shocked last year when BL told me that we were running lap times way quicker than Jeff used to (and we are certainly not one of the fastest guys). If running faster laps is causing the h/c issue AI should have had the problem we are having now even back when CMC was using "thin to win" tires in big races.


Oh and by the way if your car does not like the first three heat cycles I know a guy or two that would be glad to put those heat cycles on them for you......free of course.

JJ

We all know it takes a combination of conditions to break track records......but i've run the same time (within .003) 2 years apart and both times were on "old" tires. I guess my car setup, etc. just seems to work better once the tires start to slide a little more than they do with stickers.


So sure, I'll let you run a set of my stickers on Friday and Saturday....then on Sunday we'll switch and you run what I was running for Sunday! LOL

[t500hps]

We would love to have you at COTA, I have learned from CMC and SM, Texas has some GREAT competition/drivers.
Look forward to meeting you!

I've followed TX a little on this forum since it seems to have the largest CMC field and the competition seems tight......between Mid Atlantic and Great Lakes not sure who is second largest. Last year we had between 6 and 13 CMC cars at our races. We paddock together, work on each others cars, and all live close enough that we get together outside of racing pretty regularly......and the ball bustin is brutal!

[39PitCrew]

I've followed TX a little on this forum since it seems to have the largest CMC field and the competition seems tight......between Mid Atlantic and Great Lakes not sure who is second largest. Last year we had between 6 and 13 CMC cars at our races. We paddock together, work on each others cars, and all live close enough that we get together outside of racing pretty regularly......and the ball bustin is brutal!

So, if say one of the the Texas region guys were to move to Ohio in the next
couple months, where might he connect with some of the Great Lakes CMC guys?

[t500hps]

So, if say one of the the Texas region guys were to move to Ohio in the next
couple months, where might he connect with some of the Great Lakes CMC guys?

I don't know.....I run Mid Atlantic and am in VA. (I did race at Mid-Ohio once and also ran against a group from GL that came to Nationals at Watkins Glen 2016)

[MikeP99Z]

I burn a new set of RRs in a weekend. 5 or 6 heat cycles max, after that, they aren't competitive. Usable for practice for heat cycles 7-10.

[Sook]

There's an R888R out now. 100 treadwear at ~6/32" tread depth (RR is 4/32" RA is 8/32"). I wonder if a higher treadwear tire will be more consistent across heat cycles?

Toyo/Nitto have a bunch of tires with varying tread depths in the 100 treadwear range, R888R, R888, RA1, and NT01. There's also an RS1 full slick, however it's non-DOT.

https://www.toyotires.com/tires/competition-tires

- Josh

[ShadowBolt]

I burn a new set of RRs in a weekend. 5 or 6 heat cycles max, after that, they aren't competitive. Usable for practice for heat cycles 7-10.

So what is the real deal? Gone after 5 or 6 heat cycles or still competitive at 20 heat cycles? It can't be both.


JJ

[Sook]

So what is the real deal? Gone after 5 or 6 heat cycles or still competitive at 20 heat cycles? It can't be both.


JJ

It probably depends on the load the tire sees. Mike's car with full aero likely puts significantly more load on the tires than a CMC car. A few degree temperature increase due to higher load per heat cycle might make them drop off much more dramatically, just a hypothesis. So when comparing across platforms it could be both. Tyler is seeing potential better life on the Miata.

I'm assuming the tires are 'curing' with heat cycles, (i.e. getting harder, would last longer rubberwise but have less grip). Does the length of the heat cycle matter? If you over cook a set by trying to pass Jerry for 10 laps can you use them up in one race by getting the tire temp to 250*F? If you don't get them up to 220* (max recommended temp) is it a partial cycle? Clearly, I don't understand tire design.

- Josh

[ShadowBolt]

It probably depends on the load the tire sees. Mike's car with full aero likely puts significantly more load on the tires than a CMC car. A few degree temperature increase due to higher load per heat cycle might make them drop off much more dramatically, just a hypothesis. So when comparing across platforms it could be both. Tyler is seeing potential better life on the Miata.

I'm assuming the tires are 'curing' with heat cycles, (i.e. getting harder, would last longer rubberwise but have less grip). Does the length of the heat cycle matter? If you over cook a set by trying to pass Jerry for 10 laps can you use them up in one race by getting the tire temp to 250*F? If you don't get them up to 220* (max recommended temp) is it a partial cycle? Clearly, I don't understand tire design.

- Josh

I certainly don't understand either Josh.

JJ

[Al Fernandez]

It was the fast miata guys that introduced me to the phrase "no more than five to be in the top five", so my guess is once Tyler is at full song in a Miata he'll have the same experience.

I am getting comfortable with the notion that the thin to win RA1s weren't actually thin to win, rather that we were just slow.

[Supercharged111]

It probably depends on the load the tire sees. Mike's car with full aero likely puts significantly more load on the tires than a CMC car. A few degree temperature increase due to higher load per heat cycle might make them drop off much more dramatically, just a hypothesis. So when comparing across platforms it could be both. Tyler is seeing potential better life on the Miata.

I'm assuming the tires are 'curing' with heat cycles, (i.e. getting harder, would last longer rubberwise but have less grip). Does the length of the heat cycle matter? If you over cook a set by trying to pass Jerry for 10 laps can you use them up in one race by getting the tire temp to 250*F? If you don't get them up to 220* (max recommended temp) is it a partial cycle? Clearly, I don't understand tire design.

- Josh

Every time I've probed my RRs they're in the 140s, even post Hallett final. Granted I probe them back in the pits when I get out of the car and not trackside, but still I never get them as hot as Toyo recommends unless my probe sucks?

[Sook]

Every time I've probed my RRs they're in the 140s, even post Hallett final. Granted I probe them back in the pits when I get out of the car and not trackside, but still I never get them as hot as Toyo recommends unless my probe sucks?

Tire temps drop fast, even one turn to a next they can change pretty dramatically. We had live IR temp probes looking at wheels on our FSAE car for test and tune. Not our car, but same idea: http://sine.ni.com/cs/app/doc/p/id/cs-722#

[petel]

So, if say one of the the Texas region guys were to move to Ohio in the next
couple months, where might he connect with some of the Great Lakes CMC guys?

One way is for him to come out to Mid-Ohio for one of the three races (April, May and August) there this year and hang with the group. He could also contact the regional director Bob Denton. His contact info is in the back of the CMC rule book.

Where in Ohio would this guy be moving to? We have a couple of racers in the north east ohio area.

[BryanL]

Spec Corvette is running a Falken street tire with a 200 treadwear rating. Those cars have to weigh 3,200 post race with driver at have around 320 rwhp.

http://www.falkentire.com/tires/passenger-car-tires/azenis-rt615k-tire

[AllZWay]

It was the fast miata guys that introduced me to the phrase "no more than five to be in the top five", so my guess is once Tyler is at full song in a Miata he'll have the same experience.

I am getting comfortable with the notion that the thin to win RA1s weren't actually thin to win, rather that we were just slow.

The thin to win were great at certain places like Eagles Canyon and Hallett and not real bad at TWS or Houston. They were not very good at Cresson for me.

[mach1]

The thin to win were great at certain places like Eagles Canyon and Hallett and not real bad at TWS or Houston. They were not very good at Cresson for me.

I've also had good luck with older tires at Hallett

[39PitCrew]

One way is for him to come out to Mid-Ohio for one of the three races (April, May and August) there this year and hang with the group. He could also contact the regional director Bob Denton. His contact info is in the back of the CMC rule book.

Where in Ohio would this guy be moving to? We have a couple of racers in the north east ohio area.

I'm in the process of moving to the Dover/New Philly area.
Wife is starting at a new job next week.
I'm probably 2 months away from actually relocating to Ohio
as I have a house to sell in Texas. I've been hanging out with
the Texas AI/CMC guys for several years but I don't drive, just
help mechanic on 3 of the guys cars, take lots of race photos and
eat brisket and ribs at Hallett. Once I get moved I'll have to
look up the race schedule and make an appearance at one of
the races up in the Ohio area.

PS Sorry about hijacking the tire thread. My bad.

[MikeP99Z]

So what is the real deal? Gone after 5 or 6 heat cycles or still competitive at 20 heat cycles? It can't be both.


JJ

For my car - aero, slip angle, ambient temp/surface temp, tire temp, load etc. contributes to degradation. I consider them "not competitive" when I've lost a second over the prime. Also, 250* will kill these tires. I cooked a set at TWS testing one year and they were complete junk the next day. I try to keep them below 225*. 200* is better.

[smitty328]

For my car - aero, slip angle, ambient temp/surface temp, tire temp, load etc. contributes to degradation. I consider them "not competitive" when I've lost a second over the prime. Also, 250* will kill these tires. I cooked a set at TWS testing one year and they were complete junk the next day. I try to keep them below 225*. 200* is better.

So "not competitive" is when you are only a second faster than the rest of us?

[MikeP99Z]

Related to the clock, not others...

[marshall_mosty]

So "not competitive" is when you are only a second faster than the rest of us?

Have you not realized that Mike started his own "AI-TT" group a few years back. He's in a class of one.

[Pranav]

How are you guys getting those tire temps?
Pyrometer in hot pits?

[smitty328]

Have you not realized that Mike started his own "AI-TT" group a few years back. He's in a class of one.

I remember once at TWS I could read stuff on his car at the finish lol

[marshall_mosty]

I remember once at TWS I could read stuff on his car at the finish lol

I was able to get decently close at MSR-C back in approx. 2012'ish...

[Supercharged111]

Tire temps drop fast, even one turn to a next they can change pretty dramatically. We had live IR temp probes looking at wheels on our FSAE car for test and tune. Not our car, but same idea: http://sine.ni.com/cs/app/doc/p/id/cs-722#

An IR probe measures the surface temp though. I know that changes very quickly, but the pokey probe that goes in gets a better idea of what went on all session long. Again, never checked balls hot without a cooldown lap. One of those things I always forget about and never seem to have a body around to do for me.

[Cody Powell]

It was the fast miata guys that introduced me to the phrase "no more than five to be in the top five", so my guess is once Tyler is at full song in a Miata he'll have the same experience.

I am getting comfortable with the notion that the thin to win RA1s weren't actually thin to win, rather that we were just slow.

Like they used to say "RA1's are slow but they are slow for a really long time"

[Cody Powell]

So "not competitive" is when you are only a second faster than the rest of us?

Buuwhahahahaha freaking Patterson and his shiny car!

[Cody Powell]

Every time I've probed my RRs they're in the 140s, even post Hallett final. Granted I probe them back in the pits when I get out of the car and not trackside, but still I never get them as hot as Toyo recommends unless my probe sucks?

Dude you are wasting your time probing tires or checking pressures in the pits.

[mach1]

Dude you are wasting your time probing tires or checking pressures in the pits.
I disagree, the data isn't the same but it's still useful (mainly deltas)

[Supercharged111]

I disagree, the data isn't the same but it's still useful (mainly deltas)

^^^ This was mainly what I was after. Now I'm curious as to how hot I'm actually getting them.