East Tennessee Region SCCA

JohnSmith wrote:If you are sticking with street tires then can you not move up to a 25" tall tire on a 17" wheel? A 255 wide Rival S or RE71R will definitely be better than the 225 offerings. The cg rise is small compared to what you will gain in tire contact area.

That's a pretty substantial weight increase per corner of a car that small. 32 lbs (15x9 Storm/225 Rival S) vs 41 lbs (17x10 RPF1/255 RE71R). I feel like you'd really notice that in a Locost.

I think I will be running Emod on some kind of r comps. Can't buy tires right now. My current tires are less than 200tw. It suck because I can get a 140tw it a 245x15.

I haven't paid attention in a while but I think 140s are still the rule for STM. Maybe one of those guys can chime in.

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I thought it was changing this year

What tire is offered in a 245x15 outside the Maxxis? Is the new RSRR offered in that size?

Chuck629 wrote:

JohnSmith wrote:If you are sticking with street tires then can you not move up to a 25" tall tire on a 17" wheel? A 255 wide Rival S or RE71R will definitely be better than the 225 offerings. The cg rise is small compared to what you will gain in tire contact area.

That's a pretty substantial weight increase per corner of a car that small. 32 lbs (15x9 Storm/225 Rival S) vs 41 lbs (17x10 RPF1/255 RE71R). I feel like you'd really notice that in a Locost.

Yes it is a weight increase, but there are a couple factors here. Since you are moving up to a taller tire all the bumps hit the suspension slower which improves grip and mitigates a fair bit of the unsprung weight increase. It doesn't help with acceleration for sure though. It will get you a lot more rubber on the ground which will improve cornering speeds, which is most of what autocross is about.

The gearing disadvantage is a big concern, although in a relatively powerful Locost that might actually be a good thing.

So the new Hankook RS4 will be produced in a 245/40/15 as well.





As well as the Rival-S



And semi-relevant, Dunlop Dizezzaz ZII
http://www.srigroup.co.jp/newsrelease/2 ... 6_117.html

That is good to know. I wish the rival would last longer.

flier129 wrote:So the new Hankook RS4 will be produced in a 245/40/15 as well.

Do you have any information on how that tire will perform?

JohnSmith wrote:

flier129 wrote:So the new Hankook RS4 will be produced in a 245/40/15 as well.

Do you have any information on how that tire will perform?

Nope, wish it was out there. I heard something about Pallota test driving a set sometime, somewhere, over the rainbow.