I know that some of the compounds of Michelin slicks can be different front to rear on Cup Cars so I'm wondering if I could do the same with some Hoosier slicks. Well of course I can but would it be deemed problematic.
The situation being that I have a set of R80s for the front and want to go to a slightly larger size on the rears but they only come in the R100 compound. Background on the car. Highly modified 951 with large rear wing.
I'm thinking that with the large rear wing and slightly wider rears (305f / 320r) the car will hedge towards understeer so therefore having a bit of a softer compound on the front may not be a bad thing. This is also for short events so
I don't have any fears of overheating the fronts.

 

How short are the events Patrick? I ask because I have seen some repeated evidence of folks running the same R80 front / R100 rear combo on 911 getting excessive and premature wear on the fronts.

 

I run Hoosier 265/R80s in front and 305/R100s out back - it was recommended by JR and the combination works for my car just fine in both enduros and sprints. I think our motors are in different places though, so YMMV as a result.

 

The tires that Hoosier sells for the GT3 cup specifically are 80 front and 100 rear, the Michelin cup tires are like that too. Works great.

I have a set of used 285/310 Hoosiers but they are very tall rears (710).

 

Dave,
Well some of the events will be 1 outlap, 3-4 hotlaps and a cooldown lap. I've run smaller R80s all round before but really didn't do enough laps to come up with a considered opinion. I think this will come down to the front aero as much as anything.

Thanks for the feedback Ritter.

 

I can't imagine how tall those 710 tires must be!! Way too tall for my car.
Looks like there maybe a 320/650 x 18" in R80 after all, or so I'm told by the Hoosier guy down here. Now I'm wondering which rear to run....

 

I resemble that remark. My R80 fronts from TWS were sent back to Hoosier for evaluation. Hopefully they will credit me for the 4 HC destruction I saw.

In the mean time, I have switched to R100 in the front of my 996. Car seems OK in the turns, not real signs of understeer, but there is a very noticable difference under braking. Car just does not stop like it used to with the R80 up front.

 

Rob, I have also seen this on one other client's 996-based race car. They have switched to full Yoko/Michelin style slicks.

 

I also ran R80/R100 on a 6GT3 - no problems, and actually my rear let go first, relatively untimely, so also sent to Hoosier to review.

Big deciding factor for us in states is contingency, Michelin doesn't offer one and Yoko has a minimum of 5 per class. Plus I hear A005 are not as sticky as Hoosier slicks and only come in 250 - 280 width in 650 ratio, so a bit narrower that comparable 265-305/645 tire. I'd be game to try some if I start hearing they got better.

 

I have plans to try Michelins, just need to find the time to do the testing. It's not a cheap test, besides the cost of the tires they require a different suspension set-up so there will also be the cost (and time) associated with getting it dialed in. I don't get much testing time in these days so that has probably been the biggest barrier to trying them.

The Michelins are narrower than the Hoosiers and in the rear they are also taller, but everyone says they are a faster tire.

 

Anyone ran R80 front and rear on a 911? I do the 3 hot lap sessions as well and am about to order a set. Trying to decide between getting R80 or R100 for the rear. Like more rear grip vs longevity.

 

I ran a set 80/100 Hoosiers on my 04 cup. Corded the fronts when the rears still looked real good. Wierd. They push more than the Michelins thus the wear? They were my last set of Hoosiers.

 

If I ever ran Hoosiers again, which is pretty unlikely considering Yokohama's generous contingency program, I would try the R80's front and rear. The one set I ran was 265f in R80 and 305R in the R100's. The rears lasted forever like over 20 HC's but the front were way more slippery from 12 HC's on. I would like to wear them out more evenly hence I'd try R80 rears which should have more grip....

 

Exactly what I was looking for thanks.


I've thought about the Yoko Contingency, going to try the Hoosiers first though since I have some tires I can order via contingency and my A6's didn't work so well for me when the track got hot this past weekend.

 

I liked the r80 r100 combo, found less understeer than Michelin as the fronts were bigger. Hoosier told me not to use the R80 on the rear of a heavy gt3 cup.