Bimota Guy

Ran the V710s on my Super Stock Z06 at Fontana yesterday. I heat cycled the tires by putting about 35 freeway miles on them and let them sit overnight. Other than that the tires were not scrubbed in. The edges on these tires are significantly rounded.

I went with 39f and 36r pressures. The car spun off the line about as much as a broken in Hoosier. The first turn (left hander) I took at any significant speed I almost ran over the apex cone, but missed it after a huge correction. And I don't mean almost hit, I do mean almost ran over. The car turned in MUCH quicker than I expected. Must be very little sidewall flex there. A few other turns the same thing happened and I came up 2 cones dirty. The car was putting the power down well.

My scratch time was however in the thick of things, although not nearly where I expected the group to be based on earlier SM2 times (I estimate we were slow about 1 second.) The tires were not scrubbed anywhere near the edges due to the rounded corners.

I bled the tires down to the same 39/36 I tried on my first run. On my second run I was a little more cautious but ran too deep on one corner and nailed a cone on the outside which really slowed me down. I also hit another apex cone but it was in a tight chicane, so not really due to the turn in issue. Still my scratch time was only 0.2 seconds slower than my first and no one else made any big gains. So a clean run with a few tenths gain could win it.

Before my 3rd run one of my friends (who is also an SS competitor) came over and told me I was overdriving the first part of the course. I agreed. I also spoke to some others and decided to lower the pressures. I went 35f and 31r. I was very cautious and came up with a clean run and a 0.3 second improvement over my 1st run. Good enough for the win.

The tires worked well at those pressures. The front was not as abrupt and the car was putting the power down well. The fronts were now scrubbed much closer to the edge and might be able to go a little lower. And the rears could still go lower as well.

At $144 less than a set of Hoosier "3's" they are a good buy assuming they last as long as the Hoosiers.



[Modified by Bimota Guy, 8:06 PM 1/19/2004]

BrianCunningham

thanks for the report :cheers:

Bill Dearborn

Bimota,
Thanks for the report. I would like to make a suggestion on how to do your tire pressures. Measure your cold pressures at the start of the day and write them down. From that point on only make changes based on cold pressures not hot pressures. What I mean by that is change pressure by no more than 1 or 2 pounds from cold by measuring the hot temp and changing it by that 1 or 2 lbs. If the cold pressure is 40 and you your hot pressure is 45 and you want to go down 1 take the pressure to 44 but write it as 39, etc. Keep track of each change and keep track of the air temp, etc. The next time you go to an AutoX you will be able to start with a cold pressure that is closer to what you want and you will be managing your tires and handling better. I know that Hoosier pressures are supposed to be tracked while hot but on an AutoX course you very rarely ever get them to operating temp and a warm Vs a hot temp is sort of useless. On other comp tires its recommended to use cold pressures all the time. The process of bleeding back down to your starting pressure that you mentioned above doesn't take into account the change in stiffness (spring pressure) that occurs as your tire heats up. Even though the tire may not be up to operating temp it still is elevated in temp and is softer than before you started. The combination of air pressure and temp is sort of a constant and using cold pressures makes it easier to treat them that way in that warm area that exists between cold and hot.

I used to have a very good write up on how to do this from Team T/A but wasn't able to find it.

Bill

Bimota Guy

Bill, Thanks. I knew that bleeding down to starting pressure was effectively lowering it. I just had to make a quick decision. I finally dropped it a whole bunch and was still likely a little high. Having a practice session where we typically get 8-10 runs would have been a nice way to test new tires.

Tworacy

Bimoto,

I was at Fontana on Sunday also. As I still haven't seen any results, what was your winning time in SS? I was in your run group but running my '89 in AS on my year old V700s. It looked like I was one of the few that was still on the 700s. I know the AS winner whooped me on new 710s but that wasn't the only reason. :cry I take his National Champ car away from him and he still kills me. Hmmm. What can I try next? Maybe practice, practice, practice..... ;)

7Bob3

Yeah. I'll say they worked!!!!! Tom probably thinks so too. :D

Bimota Guy

Tworacy, I ran 60.015. The top 2 AS guys ran faster than SS. They are national caliber guys. I don't know the winner Tom M (58.247 !!), but the 2nd place (59.796) guy, James G-W, won SM2 in 2002 and came 2nd in SM2 in 2003.

I have all the AS times. Are you T.M. (4th - 60.995) or M.P. (5th - 61.036)?

I am curious to see what Gary Thomason ran in his ASP Vette in the PAX group.



[Modified by Bimota Guy, 6:24 PM 1/23/2004]

Tworacy

Thanks. I'm M.P. I was wondering where I finished. Not one of my best days, but OK I guess considering all the National folks that were there practicing for AZ and those year old tires of course. :lol: I was wondering where the heck all those AS cars suddenly came from. :confused: I think that the "Tom" that took first in AS is actually Scott M. but since I haven't seen the final results I could be wrong. Yep those AS guys & cars are very fast at the top echelon.

I think you mentioned that you won SS, I'll figure out who you are when I see the results. Did you run in AZ? How'd it go there? Any results for SS, AS, ASP & BSP?


[Modified by Tworacy, 3:28 PM 1/26/2004]

SLandstra_Z06

Bimota Guy... I'm looking for a co-drive in an SS Z06 for the San Diego Tour. Any interest in having a tire warmer? Live in the Philadelphia area and need to be in LA for business March 1-12 and would like to do the National Tour while I'm out there. I compete regularly in my '02 SS Z06. Finished 8th in Topeka in 2003, NEDIV Champ in 2002, PA State SS Champ in 2003. I'm running in Ft. Myers, D.C., Toledo, Peru and Topeka this year and would like to add San Diego to the mix. I could make my car available for one of the east coast Tours or work out something else if interested.

Let me know if you would be interested in a co-driver for the San Diego Tour on March 5,6,7.

Steve Landstra
Stlandstra@aol.com

Bimota Guy

M.P., You are right it was Scott M. Don't know what I was reading. He won AS in Arizona over James G-W by 0.009! Full results at http://www.scca.org I did not go. I figure I can get beat by national level guys at the SD Tour event (4 miles from my house), rather than drive to AZ for the pleasure. :rolleyes:

If you like, PM me with an e-mail address and I can e-mail you digital pics of the Fontana SS and AS results (preliminary results posted at the event.)

-Steve

Bimota Guy

More like me being your tire warmer! I'll give it some thought.

-Steve

Tworacy

Steve,
I can relate to the not driving all the way to AZ, when you can get beat by the some of the county's best right here in our own backyards. :smash: Not sure if I'll make the S.D. tour event but being the glutton for punishment that I am, I'll probably try the Pro at Norton again this year. I guess we should consider ourselves lucky that we don't have to go very far to run against some of the best in the country. :lol:

SLandstra_Z06

Steve -

Maybe I could help you with set-up, alignment, ride heights, etc... I have my car setup very well sorted. I run Penske single adjustable shocks. I have been a Hoosier tire guy except for rains, which I run Kumho Victor Racer's front and Ecsta's rear. I'm interested in trying the Kumho 710's though.

I hope you seriously consider the co-drive.

Steve

VettesRule

Thanks for the report!! How was the wear after the event?

Kumho looked pretty strong in AZ. Are the new s04s out yet? I couldn't find them at Tire Rack?!

Bimota Guy

Hard to tell since they do not come with the "picture of tread" like a Hoosier '3' does. I'll be driving this Saturday at a test and tune event, so we'll really see after that as I will probably do about 10 runs on a short course.

Tworacy

The new 710s do have depth holes scattered around the tread don't they? If you're as finnicky as I used to be about my tread wear, you can get one of those tread depth gauges and measure them after each event to get a real good idea of what's left. Unfortunately, from what I hear, the 710s won't be lasting anywhere near as long as the 700s which were good until they corded. Anyone out there have a better feel for this yet?


[Modified by Tworacy, 8:50 PM 1/27/2004]

TooManyIDs

Excerpt from The Tire Rack, "....ECSTA V710 radials are designed to provide quicker “turn-in” response, as well as increased traction and cornering speeds....trading longevity for performance. Achieving the best performance requires that fresh ECSTA V710 tires be used as their performance level will drop off after a typical race weekend’s use...."

stroyer

Hey Steve,

Just curious, but why the 4lb difference from front to rear pressures? Does your car tend to push? Are you running the stock front bar?

thanks,

Scott Troyer
2001 Z06, SS#71

Bimota Guy

Stock front bar. Pushes a little. More when I screw up! :eek:
Not sure this is the right difference. Was with the Hoosiers.

-Steve


[Modified by Bimota Guy, 8:53 PM 2/3/2004]

Tworacy

I believe the pressure differential is to help with traction out of the corners. Softer = more pliable. Got to get all that HP to the ground. Don't know the proper variance though as I run a C4 on the "old" 700s. I run those with 2-3 lb difference.