first997

All,

Another tire question....

I'm looking for 18" center lock wheels (9x18 in the front and 12x18 in the back) for a 2010 RS. I have not decided yet. I'm looking at all different tires in 18" and the Hossier look good. The overall diameter will almost match the 2010 RS factory overall diameter. However, the width of the Hossiers may be a problem for the rear tires.

Has anyone tried Hossier 345/30-18 in the back?

They may not clear the 2010 RS. Has anyone has some ideas?

I'll appreciate your comments

85Gold

Can't answer that 345/35 offhand but why not try 245/35 18 24.7" and 335/30 25.6" which are both shorter but keeps the front to rear ratio very close.

Peter

TRAKCAR

Not yet, but I'm curious, I ordered 18" 255 and 335 Hoosiers..

Carrera GT

I'd be wary of 18's in terms of smaller overall diameter (revolutions per mile) as well as the ratio front to rear. All in all, I think I'll stick with 19's.

Are they running 19" BBS on the Rohrl 24 'ring car?

Nugget

No, 18".

rmag

255/335 hoosier 18" combo has almost identical front/rear ratio as stock, but diameter about 1" smaller. Just about everyone runs 18" on 7GT3s/RS on the track with no issues.

Yes, Walter is running 18".

first997

General data


Porsche 2010 RS Michelin Pilot Sport Cup
Front: 245/35-19 Overall diameter= 25.79"
Rear: 325/30-19 Overall diameter= 26.73"

Hoosier R6
Front: 245/40-18 Overall diameter= 25.70"
Rear: 345/30-18 Overall diameter= 26.8"

I know it may be confusing, but when you look at the tire specification the Hoosiers overall diameter are almost equal to the OEM.

In the front, the Hoosiers are 0.35% smaller in diameter than the original equipment. For all practical purposes this is the same as the OEM.

In the rear, The Hoosiers are 0.26% bigger in diameter than the original equipment. For all practical purposes this is the same as the OEM.

The Hoosiers are the best replacement in terms of overall diameter. The question is: Can the rear tires fit in the back because of the width?


Cheers

Carrera GT

At present. From BBS. I'm told they're 18 centers on 19 rim halves. Running 19 slicks. Presumably they have intermediate and rain too. The "justification" for not running factory wheels is the need for multiple wheel sets and limited factory production inventory of 2010 RS wheels. Who knows? But from what I've learned thus far, they're on 19's.

mdrums

What about
255-35-18 front
315-30-18 rear

This keeps the ratio in line but shortens the diameter.

mdrums

I've always wondered about this 18 vs 19 thing. I asked around during a Porsche/Michelin event and Sebring a couple of years ago and was told that they stock car suspension is set up for 19" wheels. I explained to them what I see most track guys doing and they bascially only said that is because they either see the race cars running 18's per the rules or the 18" tires are less money. I was told that the 18" tire might be better on a bumpy track like sebring and will put more rubber down.

Thoughts and opinions? This 18 vs 19 thing seems to be a secret or a black art?!?!

rmag

I was going off what Chris Harris wrote:

malmasri

Who is currently running Hoosers R6 18" on RS II ??? please advise the tire size F/R...

rmag

Hoosier R6
Front 255/35/18
Rear 335/30/18

TRAKCAR

I have when I just got the car, same size.

sin911

I think this is the best combo as well.

245F/345R seems like a recipe for understeer.