RS America and Wheel/Tire Recommendations
05-17-2003, 03:57 PM
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RS America and Wheel/Tire Recommendations
This is my first post but I have lurked for some time. I just bought a 93 Porsche RS America and it should be here within 10 days....the first thing I am wanting to do is put track wheels and tires on it. Keeping the OEM wheels and the brand new Bridgestone's for street.
I am a previous BMW E46 M3 driver at BMW CCCA drivers events and need some advice as I am new to Porsche.
I would like to start by listing what I think I need and then you can make suggestions with this wheel/tire package which will be used at DE events on road courses. I am hoping to avoid a mistake.
WHEELS
I would like to keep 17's on the car
I would like to go 8" front and 9.5" in the rear
I like the following 2 wheels....
Fikse FM-10's
Kinesis K20's
TIRES
What is the largest sizes I can fit on the RS America with one of the above rim selections and not have to roll the fenders or flatten the oil lines in the right wheel well?
Is is 225/45 and 275/40?
Which tires do you recommend....
I like the Hoosier F3S03 but what are some other alternatives....as I can always move up to these later and it might be nice to be able to drive my car to the track....
In addition, where can I find the best prices?
Thank you in advance...
Doug
I am a previous BMW E46 M3 driver at BMW CCCA drivers events and need some advice as I am new to Porsche.
I would like to start by listing what I think I need and then you can make suggestions with this wheel/tire package which will be used at DE events on road courses. I am hoping to avoid a mistake.
WHEELS
I would like to keep 17's on the car
I would like to go 8" front and 9.5" in the rear
I like the following 2 wheels....
Fikse FM-10's
Kinesis K20's
TIRES
What is the largest sizes I can fit on the RS America with one of the above rim selections and not have to roll the fenders or flatten the oil lines in the right wheel well?
Is is 225/45 and 275/40?
Which tires do you recommend....
I like the Hoosier F3S03 but what are some other alternatives....as I can always move up to these later and it might be nice to be able to drive my car to the track....
In addition, where can I find the best prices?
Thank you in advance...
Doug
05-17-2003, 06:03 PM
#2
Technical Specialist
Rennlist
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Doug,
Congratulations on your purchase!
On the track, I run 8.5 and 10x17 BBS racing rims, with 225's and 275 Kumho Ecsta's (which I don't recommend for track use, unless you only run 10 minute sessions - they get greasy after that). I'm mounting a set of Michelin Cups 225's and 255's, which will see their first use in late June. The Michelin 255 is like .2" less section width than the Kumho 275's. From a wear standpoint, almost anything wears better than the Hoosiers (which are really best for racing). Kumho Victoracers and the Michelin Cups are two popular tires to consider.
In terms of the max tire sizes, I know some who run 235's in front, and 275-285's may be about the largest in back (although I seem to recall someone running 315x18's in back). Note wheel offsets are critical as you go with larger tire sizes. With wider tires, in the rear you'll need to flatten the body at around the 10 o'clock position, to prevent rubbing. You may have to further flatten, or reposition, the flat oil line on the right side. If there are any mold edges on the main rear swing arms, you may need to file those to prevent rubbing, too.
If you want to avoid banging the body in the rear for clearance, 255's may be about as large as you can go. I know several people running 275's and all have had to put hammer to body to prevent rubbing. With 255's, you should be fine with your oil line too. If you go with Michelin 255x17's, however, note they are pretty wide, and may require the body mods in the back.
Also, the above discussion assumes you've got your alignment at RS specs or greater. RS is around -1 degree camber front and rear. I'm running, for example, around -2 to -2.5 camber.
Congratulations on your purchase!
On the track, I run 8.5 and 10x17 BBS racing rims, with 225's and 275 Kumho Ecsta's (which I don't recommend for track use, unless you only run 10 minute sessions - they get greasy after that). I'm mounting a set of Michelin Cups 225's and 255's, which will see their first use in late June. The Michelin 255 is like .2" less section width than the Kumho 275's. From a wear standpoint, almost anything wears better than the Hoosiers (which are really best for racing). Kumho Victoracers and the Michelin Cups are two popular tires to consider.
In terms of the max tire sizes, I know some who run 235's in front, and 275-285's may be about the largest in back (although I seem to recall someone running 315x18's in back). Note wheel offsets are critical as you go with larger tire sizes. With wider tires, in the rear you'll need to flatten the body at around the 10 o'clock position, to prevent rubbing. You may have to further flatten, or reposition, the flat oil line on the right side. If there are any mold edges on the main rear swing arms, you may need to file those to prevent rubbing, too.
If you want to avoid banging the body in the rear for clearance, 255's may be about as large as you can go. I know several people running 275's and all have had to put hammer to body to prevent rubbing. With 255's, you should be fine with your oil line too. If you go with Michelin 255x17's, however, note they are pretty wide, and may require the body mods in the back.
Also, the above discussion assumes you've got your alignment at RS specs or greater. RS is around -1 degree camber front and rear. I'm running, for example, around -2 to -2.5 camber.
05-17-2003, 07:56 PM
#3
See my table at this thread:<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=10;t=000941#000009" target="_blank">DE tire sizing; Here is some tire size info I have measured for tires I have run on my RSA. </a>
To run the 285/30/18 Michelin Cup you will have to roll your rear fenders. Keep in mind that you will get some rubbing on the inside with the 285. Also I made a guard for the oil line. You can also fit the Hoosier 245/40/17 up front.
Here are the wheels and offset I run:
BBS RS GT 8x18 50 mm offset
BBS RS GT 10x18 65 mm offset with 21 mm spacer, offset w/spacer equals 44 mm
Kinesis K20 8x17 52 mm offset
Kinesis K20 9.5X17 48 mm offset
Factory Cup 8x17 52 mm offset
Factory Cup 9x17 55 mm offset with 5 mm spacer offset w/spacer equals 50 mm
To run the 285/30/18 Michelin Cup you will have to roll your rear fenders. Keep in mind that you will get some rubbing on the inside with the 285. Also I made a guard for the oil line. You can also fit the Hoosier 245/40/17 up front.
Here are the wheels and offset I run:
BBS RS GT 8x18 50 mm offset
BBS RS GT 10x18 65 mm offset with 21 mm spacer, offset w/spacer equals 44 mm
Kinesis K20 8x17 52 mm offset
Kinesis K20 9.5X17 48 mm offset
Factory Cup 8x17 52 mm offset
Factory Cup 9x17 55 mm offset with 5 mm spacer offset w/spacer equals 50 mm
05-17-2003, 09:03 PM
#4
Rennlist Member
Larson:
I also have a RSA (and an E36 M3). Bill's 8.5s and 10s are as wide as you want to try to deal with, and the offsets have to be perfect. The sizes you mention are a little safer, but you could still get some rubbing somewhere if the offsets aren't just right. I have 8s and 9s with 225/45/17 and 255/40/17 Kumho Victoracers on Kinesis rims. The Kinesis are the best rims I've ever owned; very nicely balanced. The Fikses are similar in weight; both being forged. The Kinesis have twice as many fastening bolts (can't see the Fikse bolts from the "outside"), but I'm not sure that makes them any better. BBs also has an excellent reputation, but are a bit more expensive.
For track, I like what I hear about the Michelin Cups, but for autocross they just won't heat up, or so I've heard.
I also have a RSA (and an E36 M3). Bill's 8.5s and 10s are as wide as you want to try to deal with, and the offsets have to be perfect. The sizes you mention are a little safer, but you could still get some rubbing somewhere if the offsets aren't just right. I have 8s and 9s with 225/45/17 and 255/40/17 Kumho Victoracers on Kinesis rims. The Kinesis are the best rims I've ever owned; very nicely balanced. The Fikses are similar in weight; both being forged. The Kinesis have twice as many fastening bolts (can't see the Fikse bolts from the "outside"), but I'm not sure that makes them any better. BBs also has an excellent reputation, but are a bit more expensive.
For track, I like what I hear about the Michelin Cups, but for autocross they just won't heat up, or so I've heard.
