Toyo RR's, half the heat cycles, 2 seconds slower

General CMC discussion

Moderator: Al Fernandez

User avatar
BADVENM
Posts: 373
Joined: Tue Jan 08, 2008 4:00 pm
Location: Goodland, KS

Toyo RR's, half the heat cycles, 2 seconds slower

Postby BADVENM » Mon Sep 21, 2015 10:18 am

Just finished a great weekend of racing at Pueblo Motorsports Park. A little background first.

Just thought I'd see if anyone has had similar results as I did with my Toyo RR's. My previous best at that track was a 1:46.239. The track record for CMC is 1:44.06x set 2 years ago.

Had a cold front move through Friday, temperature early Saturday morning in the mid 40s. For our morning warmup track temperature when we got off track was in the upper 60s. I was on heat cycle 18, we just had the tires flipped a few days prior. I was shocked to run a 1:45.65, hot air pressures all around 36.5-37.5 pounds. Move on to qualifying, track temp in the mid 70s, heat cycle 19, ran a 1:45.086, air pressures similar...37-37.5. I'm now thinking a can crack into the 1:44's! A few others were also running just as fast if not faster. So for our first race, A Toyo bucks race and 30 minutes I don't touch the tires at all (now at heat cycle 20). I finished 2nd out of 7 or 8 and run a best lap of 1:44.95, hot air pressures rose to 40-41psi and track temp had rose to 107 degrees. I had the fastest lap of the bunch that race, something I've never done before. Race 2, track temp 110, ran a 1:44.994 for heat cycle 21, pressures were 39.5-41 hot.

For Sunday I don't change a thing, now heat cycle 22. In warmup track temp was 80, ran a 1:45.777, similar to warmup Saturday. Pressures also similar to Saturday warmup at 36-38psi. For our 30 minute race I changed over to another set of RR's (heat cycle 11) as the delaminating thing we see in the tires had me worried. I let the tires settle in the sun along with the ones in the car so the pressures would equalize over the course of a few hours. For this race I could only muster something in the 1:46.5 range (have to look at MyLaps) while the faster cars I believe stayed in the 1:44s, I'm about 2 seconds slower. Tire pressures were a little lower, in the 37.5-39.5psi range.

So for the final race (a 50 minute Hanksville Challenge Race) which starts an hour after we get off track from the first race, I decide to experiment and put the others back on (now on heat cycle 23), just curious whether the faster tires Saturday could repeat for Sunday. First few laps into the race (track temp around 98 degrees) I immediately drop into the 1:45's and generally stay there (plus or minus a second or two depending on traffic) for the entire race. Come off track and get 37-38psi in all four.

My question is, have any of you had similar results? My set with 23 heat cycle on them were 1.5-2.5 seconds faster compared to the set with 11 heat cycles on them. Will have to look at date codes out of curiosity but I thought it was odd that such a huge disparity in track times could occur with track temps and air pressures very similar. The air temperature was considerably cooler this past weekend (high temperatures 84 Saturday and 88 Sunday) compared to July (99 Saturday and 98 Sunday). My hot air pressures in July were never about 37psi and generally in the 33-36psi range.

EDIT: just checked the manufacturer date codes, if I read it right the slower set of tires (2 of them) were made the 10th week of 2015 and the other 2 the 11th week of 2015. The faster 3 of them, cant see inside number of one of them since its on the car) were made the 51st week of 2013. https://www.toyotires.com/tires-101/reading-a-sidewall

For those wondering what the Hanksville Challenge is, Hanksville Hot Rods sponsors a race where every race group is included. The field is reverse gridded and the cars are released from the pitlane based on their prior race times. Slow cars go first, fast cars go last, fast cars try to catch slow cars. The slowest car is often released a full lap ahead of the fastest car.

In theory, if everybody drives the ideal lap time all of the cars will cross the S/F line side by side.

Talk about a challenge! Not only are you trying to catch and pass the cars in front of you, you have to keep ahead of the faster cars behind you. Added bonus is that for CMC we made it a points race. Inverted starts are one thing but when a few of your CMC buddies are 6 to 12 seconds ahead of you and you have to catch and pass them it makes it VERY challenging! I think we had about 45 cars in the Hanksville Challenge.
Last edited by BADVENM on Mon Sep 21, 2015 12:01 pm, edited 1 time in total.
NASA Rocky Mountain - Camaro-Mustang Challenge car #8 Team Incidental Contact
3rd Place CMC - 2010 NASA National Championship
3rd Place CMC - 2015 NASA West Coast Championship PTB

t500hps
Posts: 129
Joined: Sat Aug 18, 2012 4:05 pm

Postby t500hps » Mon Sep 21, 2015 11:02 am

I've found that I'm not as fast on RR's in the first couple cycles but 11 to 21 heat cycles in should be about the same......I've run a set to 36 cycles without noticeable drop off. I also set the track record at VIR in July on the 20th heat cycle and ran within .20 at "nationals" using another set on their 5th or 6th cycle. New they just don't slide enough for me and I can't/won't set the car up for the few cycles when the tires grip the best (so why aren't we using RA1's anymore???)

User avatar
TX#11CMC
Posts: 623
Joined: Thu May 19, 2005 2:14 pm
Location: Dallas, TX

Postby TX#11CMC » Mon Sep 21, 2015 12:59 pm

I had a very similar experience with two sets of RR's. I ran a set last year and set the track record during the last race at the last event of 2014, this was the 22nd heat cycle on the set of tires. The tires still looked good from a tread standpoint but I moved them to my backups to start 2015 with a fresh set.

I then started the season with a brand new set and they did great for the 1st event. During the 2nd event they didn't feel good and I tried numerous crazy set-up changes but nothing worked. At the end of the 2nd event with 14 heat cycles the tires had way less tread than the 22 heat cycle tires from the previous year.
For the 3rd event, I ran both the 14 cycle tires and the 22 cycle tires and the 22 cycle tires were right at 1.5 seconds / lap faster.

I'm not sure on the production dates and unfortunately have already disposed of the tires.
-Michael Mosty
TX region #11
"Fox" driver and lovin it!!!
Texas Region - CMC Director

suck fumes
Posts: 458
Joined: Thu Jun 28, 2012 4:21 pm

Postby suck fumes » Tue Sep 22, 2015 7:53 am

The two factors that make the biggest difference is weather (track temp) and do you take care of your tires throughout the life of them. If they get slid around and show any kind of graining then they are trash. I've always found that new tires are a lot faster on my spec iron car for the first 4 cycles then drop off. However on my cmc car they seem to be a lot more consistent. I'm sure a lot of that has to do with the weight difference as well though.
2013 CMC NATIONAL CHAMPION

Motorsportheaven.com

philstireservice
Posts: 19
Joined: Fri Feb 01, 2008 2:29 pm

Postby philstireservice » Thu Oct 15, 2015 8:45 am

Make sure you guys are running enough air pressure!
philstireservice.com
Toyo BFG Hoosier Michelin
Enkei Apex Team Dynamics Jongbloed
845-647-7407

BryanL
Posts: 271
Joined: Tue Mar 20, 2007 6:12 am

Postby BryanL » Thu Oct 15, 2015 1:38 pm

philstireservice wrote:Make sure you guys are running enough air pressure!


What's enough?

suck fumes
Posts: 458
Joined: Thu Jun 28, 2012 4:21 pm

Postby suck fumes » Thu Oct 15, 2015 1:52 pm

At least 29-30 cold
2013 CMC NATIONAL CHAMPION



Motorsportheaven.com

User avatar
BADVENM
Posts: 373
Joined: Tue Jan 08, 2008 4:00 pm
Location: Goodland, KS

Postby BADVENM » Thu Oct 15, 2015 6:12 pm

I had been running 29-30 cold on both sets, reaching 38 to 40psi hot. I couldn't replicate the results last weekend at High Plains Raceway (2 seconds faster with higher heat cycle set of tires). Weather was warm, track temps were similar to prior event where the difference was obvious and mentioned at the beginning of the post. Oh well.
NASA Rocky Mountain - Camaro-Mustang Challenge car #8 Team Incidental Contact
3rd Place CMC - 2010 NASA National Championship
3rd Place CMC - 2015 NASA West Coast Championship PTB

Supercharged111
Posts: 372
Joined: Sun Jul 28, 2013 9:18 am
Location: Colorado Springs, CO

Postby Supercharged111 » Thu Oct 15, 2015 8:52 pm

Did you push at Pueblo with the slower tires? I oversteered like mad at HPR, probably would have gone faster by disconnecting the rear sway bar and fitting some heavier springs out back that I was carrying. Try to remember how the balance of the car shifts when your tires are good vs cycled out. Doesn't always work against you.
Rocky Mountain CMC Director
#45 Camaro Challenge Race Car


Return to “General Discussion”

Who is online

Users browsing this forum: No registered users and 1 guest