333pg333

After an aborted attempt with some Falken slicks I have found some well priced Michelin ones. I am having difficulty finding out more specific information on them though. What I know so far is that they're 270/650 r18" Radial X S7A compound and there are some 300/65 R18" Radial X S8C Compound. I get the size of them but I'm wondering about the compounds.
I also can't find out the differences in the compounds plus I thought I read that Radial slicks were a bit old hat (at least in regards to Hoosiers), so are these a good tire to go for?

Car is NOT a rear engined vehicle so I guess I'll lose a few responses but I expect that. It is approx 3100lb with driver / fuel and it is used primarily for very short sprint events where we have to get the tires up to temp ASAP. I have some R6 that I believe will be better suited to our events but these look to be a great bargain and you know about bargains, hard to pass up.

Thanks for any advice.

Geoffrey

The 27/65 S7a tire is designed as a front tire. We tried them on the rear of a 964 Cup at about 2500lbs and the car was 5 seconds a lap slower than the Dunlops we were running. The 7A is the compound and is the softest compound with an S8 being harder and S9 even harder. I would have some concern about the loading on the tire with a 3100lbs car, even if it does have the engine in the wrong location...

Yea, they are inexpensive, however, they work best as front tires, the way they were designed.

333pg333

Good info Geoffrey and I was intending to run the 270s on the front. Push understeer is an issue with my car at worst so some extra grip might help, however they might get too hot as well. The only thing is that when viewing the recommended rim sizes they say to use them on 11-12" rims which I found a bit odd. I plan to run them on 10"s front. They want the 300s on 11.5-12.5" rims. I will need to get my rears widened to at least 11's to run these I would think. Having said that we need to get to heat real quick and over only 3-4 hot laps so maybe I can run the 270's on 10's all round? I would think that you were suffering due to racing for a lot more laps than that?

Patrick

Geoffrey

The tires were awful from the beginning (on the rear). On the front they are a great tire. You really want a minimum of 10.5" wheel, although they will fit on a 10" wheel. I don't believe they will fit on a 12" wheel The 27/68 barely fits on a 12".

Bryan Watts

Sure you aren't confusing radial slicks with bias-ply? Bias-ply is "old hat", but still a great tire for certain cars and certain setups. Radials are what your street tires and all of the high performance R-compound tires are. Bias-ply is mostly used for vintage cars, some auto-x cars, a few open wheel cars...and your trailer tires.

The new Hoosier slicks ARE radials.

333pg333

Yep, you're right Brian. I did get the terminology mixed.
Do you have any experience with these tyres? Sounds like Geoffrey has had mixed results although the rear of his car and mine will be totally different so.....maybe...

Bryan Watts

No experience with Michelins...I've run Dunlops, Hoosiers, Yoko's, and Pirellis.

333pg333

Any idea how many heat cycles these soft compound 7A's are good for anyone?

DrJupeman

Apparently they also fit on a 9.5" wheel?

333pg333

Where are you reading that Charlie? Looking at the Michelin pdf they state 11-12" from what I can see??
http://www.michelin.com/corporate/fr...133020&lang=EN

Accelerator

I ran the sizes you are considering in the 8 compound. They are slow to build heat. I had a high-speed separation on the left rear after 2 sessions. It was at the inside where the carcass joins the treadless area. I understand others had similar experiences. I was told IMSA placed a camber restriction on these tires some time ago. My grid weight is 3475.

I even spoke with a Michelin USA rep before purchasing them as I was concerned about the weight, especially on the rear tires (996 turbo) and he said no problem.

gums

I ran those slicks on 17" wheels on my 924GT car and found them to be very driveable and durable. I still have them on it, the car is very light at 1950 wet.

333pg333

Holy hell!! 1950 wet?!?! That's crazy light. Sounds like these tyres prefer a lighter car. The only thing is that the guy that I was buying them from said he had them on a Nissan 350Z which was 1600kgs and loved them, but this size / compound were on the front only. He had 305s on the rear in the harder compound.

gums

Yeah, I know that's light, that's why I mentioned it relative the tires's behavior. It's a full tube frame GT car and I'm trying to post a picture with the tires on it, but R-list is problematic right now.

333pg333

Full tuber, wow. So what motor?