GrantG

The RA1's really get faster as they wear - once worn (or shaved), they are faster than MPSC's on a light car (as Late Apex shows). I would rate their stickiness as an 8 out of 10 on that scale. MPSC's are lowsy with a light car or in cool weather...

mark kibort

I dont think so at all. having more experience at one single track (laguna) than many, ive run my hoosiers for years now. my best times have varied only .5 second, and on lap on the RA1s, i cold have probably got down to .3 seconds as fast. this is for two sets of tires, RA1s and Hoosiers both with 2 heat cycles on them. (and many more older ones of both at varied ages) however i can say, that after many heat cycles the RA1 seems to not loose its stick, as the Hoosier becomes almost 2 seconds slower just before pitching them.

another point to back this up , is look at the Speed WC GT and Touring car times! (at a track near you !) the GT runs 1:31.1 at laguna seca. (2:14 at road america, 1:26 at road atlanta, 1:40.xx at Sears, and etc) this is faster than Rolex GT (porsche cup car) at a lighter weight and on REAL slicks! (only difference was a cup car vs motorsport upgraded cup car) the top teams seem to prove my point in showing only about a second or two max in the same car on slicks vs Toyo RA1s. One of PCA and POC's top cars (also a 928) runs only 1 second slower at a few tracks running Toyos vs his usual Pirelli or goodyear slicks.

that all being said, the difference between a hoosier and a toyo RA1 shaved is going to be sub 1 second, and thats a pretty accurate estimation in my opinion based on my experience and top pros that have a chance to do use both or slicks vs RA1s. also, all the NASA CMC (camero mustang challenge) racers that have made the jump to world challenge also say, that in their use of the RA1, they think the tire is good all the way to the cords, and is definitely not the case for the Hoosier. also, the RA1 likes to slide a little more, and it creates (and requires) a slight driving style change. Im sure all the speed world challenge drivers would love to think they are going to be 2 seconds faster than toyos, but this is not the case!! also, Grand Am Cup racers run a compound like the S04, and they all think they are very close to the S04 as far as stick, but dont go away as fast and last longer. sounds like they are very close to the RA1 now, right down to the fact that they use a steel belt now too! (vs the S03)

Now, make a chart for comparing used hoosiers vs other tires. I think the hoosie used, has got to be one of the worst. (and ive used a lot of used garbage can hoosiers!)

MK

mark kibort

kuhmo victor racers better than RA1s??? are you nuts???they are defintetly the king of durability, but they chunk, are not as sticky and go away fast . wear is ok overall. if you chart for street tires is 1 and hoosier is 10, thats a 5 second delta, as the World challenge folks have proven this. so, is a RA1 worn, 2-3 seconds slower than a Hoosier??? I really dont think so. if we are talking new shaved for both (or at least the RA1 which ive driven a lot on ) i would say, best case, 1 second.

Just noticed the Yoko Ao32R. dude! those tires are below the victor racer too, and are a real nice blend of street tire and DOT race rubber. absolutely no match for a victorracer or RA1.

I didnt realize that the V710 were that good. I may have to try them

my list / best time at laguna seca under similar conditions and usually run both

Hoosier 1:40.2
Toyo RA1 shaved 1:40.8 (1:41.0 giving up one turn to traffic)
used hoosier 4+ heatcycle (1:41.5)
toyo RA1 full tread ?? guess
Yokohama A032R ???? just know they are pretty slick tires vs hoosier class
toyo T1S street tire lots of fun if you like to slide ( 1:46.1)

Anderson
slick 1:34.1
toyo RA1 shaved 1:35.1
toyo T1S street 1:42.5

top pro teams' race time
toyo RA1 was 1:34. ('03) now down to 1:31 ('05)
toyo T1S 1:40.1 (2001)
rolex GT BMWs PTG that ran the 1:34 above, are now on slicks running 1:33.xx
in '05


MK

M758

Nope.
I think for one lap or two the Victoracers are a bit faster. Maybe 1/2 second or less. Some of this down to driving style too. I have seen more than few guys faster on Victoracers than RA-1s. So grip rating was about the same with slight edge to the Victoracers.

That said I think RA-1's are much better due to their long life.

Also A032R's are really nice tires. They are not as fast as the other, but better than street tires. In my experience Full Tread Toyo's take 5-6 heat cycles before the wear down and the rubber cures to allow them to be fast.

On race day was running mid 1:13 second laps on well worn Toyos in their sweet spot for qualfying. Rain appeared on the way and threw on a fresh off the truck set of unshaved RA-1's for the race. Had it continued to rain I would be in great shape. It dried out and I could only muster a 1:16 in the race. I should have been able to easily turn a 1:14 in race conditions, Possibly even a 1:13.

Fresh Toyo's Suck, Of cours I wore them down over the next few events and later turned 1:13's on that set at the same track.

mark kibort

Maybe the rain changed the surface of the track and it was a second slower overall. you also said that as they wore down, they were back to the same time. Im definitely talking about shaved toyoRA1s, like the World challenge teams use. believe me, (or not) the kumho are not as fast. did you look at my statitics of actual times in the pro arena? there is also proof on the T1 SCCA circuit, where Scotty White and his Kumho clad vet ran 2-3 seconds slower vs the winner Hienrcy on hoosiers S04s In world challenge competition in a lesser car than heinrcy, (viper comp coupe vs speedGT vet on toyos) he was in this range. (and thats probably not the victoracers either)

anyway,ive also run my share of new kuhmos too, and they were a solid second behind the hoosier when newish.
after awhile, they became hard as rocks.

MK

M758

Well it might add to it. I was really 3 seconds slower, but only attribute 2 seconds to the tires. This is consistant with my and others experience with the Toyo. This was just the most obvious case I have seen.

I guess what I am saying is Hoosiers are the fastest Tire.

I think there are 3 R-tire classes.

1) All out speed
- Minimal initial "shadow" tread (just enough to be a "DOT"), Best grip, lightest, lest puncture resistance, last for one weekend at most two, track use only. Ideal for those who have large budget,
Tires that fit here Hoosier (SO3, SO4), Kumho V710, Goodyear GS-CS

2) Good Value
- Tread depth from 4 to 8/32. Shaving is probably required for best performance. Can be uses as rain tires at full tread, Solid grip, Heavy carcass, ok puncture resistance, Could be use driving to/from track, reasonably long life. Good budget minded race tire. Performance can be different depending on tire size and car weight. Good DE tire for those wanting more speed.
Tires, Toyo RA-1, Kumho V700, Kumho Victoracer,MPSC, Hankook

3) Better than street tires
- Deeper tread depth 6 to 10/32. Really solid tires, but not superfast. Ideal for drive to/from the track DE guy. Sort of a compromise tire.
- Yoko A032R, Pirelli Corsa, Dunlop SSR

RJay

I thnk you've absolutely nailed it. Although I haven't driven all the tires you list, I've used quite a few of them. My experience supports your catagorization of types and I'd agree with the classification you've assigned to each tire as well.

mark kibort

I would love to think Im 2 seconds faster with a hoosier vs a RA1. (or a kumho vs a toyo ra1) believe me, if i could run 1:38.8 at laguna seca, i would be the fastest driver and car in the world at laguna for equal mods. (see Grand AM cup GS class 2005 ran a best of 1:39.1 in 3 days of testing and racing vs my speed GT toyo RA1 times of 1:40.8 last year and 1:41.0 this year ) we are talking about my 20 year old car, not a bolt turned since 1986 on the engine, a set of headers, as the only mod, 3 full race seasons, an alignment at wheel works 3 years ago and just a bunch of oil and pads since its racing life begain in 2002. Plus, we are also talking about the best drivers in the world, in a $150,000 '05 crate engined, 400hp mustang, and guys like Bill auberlen, Marks, Cronin, Hayner and others all drivng M3s, porsche 996/7s etc, with similar mods to mine. You think a set of tires of the DOT class would make me that much faster?? tell you what, if i buy a set and dont run 2 seconds faster, will you pay for them??

ah hahhhhhh. see, money talks, BS runs the marathon!!

on Hoosiers if the are so much faster and improve on his 1:33 PTG bmw time too on RA1s. oh yeah, i did mention that he ran 1:32 with the the same car, 1" wider tires on real slicks? guess the hoosier then , by your calculation is better than even larger slicks!

you guys better control your test environment better.

this is almost as bad as Kim Crumb's tire test of 6 seconds variance on the same grade tire at some test track conducted by Michelin a few years ago.

MK

RJay

Hmmm... no disrespect Mark, but if tires can't possibly make a 2 second difference how do explain recent results in F1 and WRC?

M758

Mark Tires do make a difference. Infact the are one of the biggest differences out there.

I can't say for sure that 2 seconds is always. Nope, but I do know that Hoosiers are faster. Remember that you may need to change your set-up and driving style to get the most of any tire.

Hey to counter this I know a very good driver with 2100 lbs Honda CRX with 175 hp or so. Well he said he was faster on Toyo vs hoosiers because the hoosier stuck too well. So there!

mikew968

I am planning on running my first PCA club race at Putnam in September. I currently have MPSC with newer fronts and cycled out rears (or close) and DSSR. I will finish the MPSC's at the nest DE and can run the DSSR's or buy new for the club race. The choice would be between MPSC's or RA-1's. The MPSC's are sure slow to warm up. It sounds like they are at least in the same league.

Mike

joey bagadonuts

I was all set to give the Hoosiers a try this year until I read this discussion started by Chris Cervelli, aka Premier Motorsp:

Hoosier R3S04 vs. Michelin MPSC

In a nutshell, Chris found that the Cups were as fast or faster than the Hoosiers on his 2,4000-lb C Class 993RS. He also noted that they were more consistent (half a second difference from new to corded), lasted significantly longer but did require significant heat, >200F, to produce the best results.

As you probably guessed, I'm a big fan of the Cups. I've been using them for the last two seasons and will be sticking with them for another. There's also another Chris I know who likes them. Chris Reinsborough races an F Class C4 and recently won this year's Club Race at Lime Rock on MPSC's. If I'm not mistaken, he also raced his 3,200-lb porker to the podium on 5 of 6 occassions last year while wearing Cups.

Given their price/heat cycle and performance, I don't really see a compelling reason to switch. $0.02

forklift

Great thread, I have been starting one along these lines. Hoosier’s are out of the question with my budget and after Chris C’s post, I would go with the Cups anyway. Which leads me to RA-1 vs. Cups. I am on my second set up Toyos’s and love them. They have great breakaway characteristics and seem to last forever. From what I have read the Cups can be finicky, and will last “only” about 30-35 heat cycles before they start falling off. There is a post in the archives where someone at Putnam said that RA-1s were only about 1 sec. slower than Cups. I also have traded some messages with another racer on this board out west who says that the RA-1s are only about a second slower than his Hoosier’s on a 2-3 mi. track on the same day. I have spoken to PCA racers around here who swear by the Cups and say they are worth 2 seconds. Paul at Radial Tire (ex Trans Am) strongly recommends the RA-1s over the Cups and says there is less than a second between them. A lot of different opinions on these, and I have searched the archives of other forums and found the same….

I wish some more of you rich guys would bring a few different brands to the same event and do some back to back testing! I am half-way tempted to buy some Cups for the DE at SPR this weekend and run them against the Toyo’s, but think that compro will have to wait (due to time and $).

Question for you MPSC guys: do you buy them shaved and/or heat cycled (or heat cycle them yourself)?

Thanks,

Jim

Bull

Not shaved, heat cycle myself.

DrJupeman

MPSC: Not shaved, heat cycle myself.