joekr

Will 245/45-15 Hoosier R3S03 work on a 924S?
(Koni Sport, Weltmeister front swaybar,
15x6 Front, 15x7 Rear phonedials)
I found someone to mount them if they will clear the fenders/suspension.

thanks,
joe

M758

don't think a 245 will fit on a 6" wheel and is not good for a 7" wheel either.

225's will fit on 7" wheels and will fit in the rear. The front will need 7" wheels for 225's and will be a tight fit depending on you front spring and negative camber.

joekr

The Hoosiers are 225.45--not 245.45 (sorry for the typo)

Hoosier specs recommend 7-9" width for 225.45. I know it's pushing it to mount them on 6" but I think it can be done. I know a guy who runs 225.50.14 on 5" wheels. I can't go to a wider wheel in SCCA stock.

My question is whether they will rub if I do get them mounted. The car had 225.50 Kumho VictoRacer on 6x15 front with no problems (except the tires were old and hard). Has anyone run 225.45 on the front of a 924?

The tires are R3S03 closeouts. Can't get A3S03 anymore and I am reluctant to buy S04s with all the short lifespan reports around.

The front springs are stock and I think camber is at -2.0.

nile13

I know the same guy (Chang?)

I think R3s will be just fine on abrasive asphalt at Ft. Devens, so I woudn't worry about it. A3s actually get a little greasy when it's hot.

M758

I still can't say 225's on 6" rim are any good. In fact you probabyl be better off with 205's on a 6" wheel as the tire's side walls will have a much better shape. Just because some guy ran 225's on 5" rim does not mean they worked very well.

As for rubbing. I have seen a 924S with 225's in front rub stock diamter the front springs. I have also seen them clear. It really depends on the car.

joekr

yup--and they seem to be working well--he has been competitive SCCA H-Stock at the national level (but I cringe at the pressures he runs)

I ran A3s on the TT last year and loved them. I do believe the R3s will be less grippy than the A3's for autocross unless it's a blistering hot day...but I won't have to hose them down after each run (or halfway through the run on last Sunday's course ). I heard the Road Race Hoosiers are popular among southern autocrossers in the hot months. Is this true?

I have the same concerns about the sidewall shape and the resulting effect on steering response. I am also thinking of running the 225.45 R03s on the rear and 205.50 VictoRacers on the front (since I can get take-offs cheap or free from the Miata guys at the track).

Do you think the 225.45 on 7x15 will work on the rears?
Is mixing tires like this for autocross a good idea?

I am now thinking of mounting two of the 225.45 R3s on 7x15 rims, then:
1) see how they fit both front and rear
2) try mixing the 205.50 VictoRacer front with the 225/45 Hoosier rear and see how it works.

I have serious doubts that the 225.45 will fit on the front and some doubt that they will even work on the rear (which is why I posted--hoping that someone has already tried it)

FWIW, I currently have 205.50 VictoRacer on all 4 corners (well 3 corners really since I flat-spotted one last Sunday)

M758

YES!
NO!

I infact think that 205/50's all 4 corner is better than 225 hosiers and 205 kumho's. You will have lots of understeer. Remember that 225 hoosiers are really wider than 225 kumho's. It seems that Hoosier's definition of size is a little different than most.

The 225's will fit in the rear, but I can't say about the front. I personally would not autocross on two types of tires. I'd bet you will have tons of understeer for these reasons

205 vs 225 = understeer
Hoosiers have more grip than Kumho's
A Hoosier 225 is probably like a Kumho 235 thus more understeer.
You will have alot of rear grip and not much front. I'd bet that it would be slower on the track with this set-up than 205 Kumho's at all coners simply due to better balance of the 205 kumho set-up.

PedalFaster

I wouldn't make a blanket statement. There have been examples of drivers successfully mixing brands front and rear, most notably Z06 Corvettes before sufficiently wide Kumhos came out -- many people were running Kumhos in front and Hoosiers in back.

You'd of course have to choose your tires and setup carefully, and could still be subject to strange handling effects as the tires responded differently to heat, but I wouldn't rule out the possibility altogether.

Steve

nile13

Good observation My car behaved decidedly different after coming back to the main runway on Sunday (say, about 1:20 into the run with 30 seconds still to go).

joekr

yea...at that point, I still had 40 seconds to go--I overcooked that 180 every friggin time and even worse on my last 2 runs when I had my best scratch times, but coned near the finish. I think that 180 is where I flat-spotted the Kumho. A friend said he saw the smoke from the other end of the runway.

nile13

That, btw, was the most important point of the course. I figured out during the walk that you had to take a hard right from the taxiway to the runway. Very counterintuitive, as the line seems to be going right at the cones. But if you go at the conse, your exit will be completely messed up. So, lift off, make a hard right, brake hard. Then stay as far to the right as you can, brake in a straight line, come around the three cones of the hairpin wide and get _very_ tight and angled in on the way back by them, pointing to the next gate. Overcook that turn, and you are slow the entire back straight, losing full seconds by the handful. That's because the offset gates had to be taken either early or slow, no alternative to that.
There was a funnier thing there. Right around that pivot is where I would finally remember to breath. I usually don't breath on a 60 second course, at least not more than once. Coming to that turn it would hit me that I need to breath and I would lose concentration for a moment.
Well, there's always next two weeks and now there's always that Super7 that should be PAXed as DM

M758

I guess this is where road racing and autocross differ.

I know for a fact that doing this tire thing on road course is asking for trouble. You might get it to work for one lap, but after than I bet you be chasing an unpredictable car. The way the tires come-up to temp and their chacterisitcs during runs are all different and would not feel comfortable racign like that. For me balance is more important that grip. I am not a top dog autocrosser, but have my fair share of class wins in road racing. I did notice that as I prepared my 944 for racing it got worse at autocross. I think this was due to driving style and set-up. You do strange things in autocross that you would not dare to do on a race track. Heck on race track it is much better to give up .5 of sec in peak speed to gain consistancy of speed.All you need is one error in race to lose 10 spots and never gain them back. Autocross is different. All you need to do is to handle the instability for 1 or 2 good laps. Then you are done. Plus screw the pooch in an autocross and all you eat is cones. Do that at the track and It can mean far worse.

ljd-924SE

a fellow '88 924SE sport edition autocrosser from the 924board shared his setup with me which included 225/45/15 - A3SO3 all around, but he required a 1/4 inch spacer up front for the tires to clear the stock springs with camber at -3 degrees.

i like to be able to switch to my auto-x tires the night before and drive on them to the site - about 45 minutes away. so i'm probably going to go with Toyo RA-1's for their durability and price.

however, i'm undecided on tire size. definately 225/50 for the rear, but i don't know if i want to risk the 225/50 up front. i'll probably go with 205/50 for the front and sacrifice a little tread so that steering response doesn't suffer due to poor sidewall support.

then, there is the arguement that the sport edition's M030 suspension was designed with a narrower front tire as well.

joekr

Well, I mounted two of them on the 7" rims. They fit fine on the rear. The handling was far better than I hoped for with the 205/50 VictoRacers on the front. The combo did not cause the understeer that I expected. In fact, the car still felt quite balanced (but with more grip than with the Victos on all four corners). I test fitted the 225/45 Hoosiers on the front, but they rubbed the coil springs. Spacers would alleviate the rubbing but are illegal for SCCA E-stock (as are the 7" rims on the front.) I'm wondering if mounting then on 6" rims would reduce the section width enough to eliminate the rubbing. However, I doubt it would make that much difference and I still have my reservations about the steering response. I think for now I will remain content that they work as well as they do with the Kumhos on the front...

joe

Eric Schall

How competitve are you guys with your 924s's in autocross? This spring I switched from running a 1974 914 - 1.8 in C-Stock to 1987 924S in E Stock. I was faily competive with the 914 but now I can not seem to get hooked up. My 924 came with Tubo S sway bars and Koni Sports and I am using 205/50 V700 Victos on 15 x 6 Phondials.

I really could throw the 914 around but now I am not as confident with the 924S and I am getting spanked by everthing in H Stock and then some!

My Victos had 10 autocrosses on them from last year on the 914. They are just beginning to get down to the wear bars now. What kind of pressures do you run? Should I be looking for a different brand of tire?

Eric