Hi all,

My MCS is almost due for some new tires, and while I'm at it I thought I'd replace the S-Lites with 15" or 16" SSR Comps. I run in BMWCCA autocrosses out here, so would like something that won't add to my points. I'm leaning towards 15's, just because they're lighter and will provide better handling (15" SSR Comps are 8.8lbs!).

Two questions:

1) 15" or 16"? Still trying to decide, and would love to hear pros and cons.

2) What tire should I use, and in what size? I want a good performance tire, I don't mind spending a fair amount. I've used Kumhos in the past and I've heard their newest tire is pretty good (can't remember the model #), but would be open to anything.

Thanks!

-mike

 

I don't know how points are given for various wheel options in BMWCCA autocross.

What is the breakdown given for:
15x5.5" stock vs 15x7" or 15x7.5" (optimal)
16x6.5" stock vs 16x7.5 (optimal)

Generally you autocross with the smallest wheel because:
It's less weight for both tires and rims given a specific width
Smaller outer diameter tires allow for better gearing advantage
It costs less for tires and rims than the same wheel in bigger sizes

If you use a 15x7.5" SSR Comp (miata fitment) you can use a Kumho V710 205/50-15 tire or even a 225/45-15 tire (Hoosier or Avon Tech Ra).

If you use a 16x7.5" rim try 205/40-16, 215/40-16, 215/45-16, or 205/45-16

You want to use the widest rim that will fit with the widest tire you can mount if it doesn't hurt you too much on points in your class.

Still undecided? Try calling Alex@tirerack.com to discuss the options more.

 

Thanks for the info, minihune. I have been trying to figure out from the points spreadsheet exactly how points work in this case. It looks like the only consideration is wheel width and tire width and how much they differ from stock. I have S-Lites so currently I have 17x7 and a 205cm tire. So it sounds like if I went to 15x7 and a 205cm tire, there would be no increase in my points, but if I go to 15x7.5, there will be a small increase. It's just a few points and won't put me into the next class, but do you think the difference between 15x7 and 15x7.5 is significant enough to add points, which I might later use for something else instead?

Also, is 205/50 normal for a 15" wheel? That seems like a large sidewall. Is that the only thing the Kumho is available in for 205 on a 15", or did you suggest it for another reason?

Thanks!!

-mike

 

You should check with someone from BMWCCA about exactly you would be getting on points if you choose 15x7 and 205/50-15 vs your stock 17x7 rims and 205/45-17 tires. If you get no additional points then great this becomes an option. The reason to consider 15x7.5" is not just the extra 1/2" rim width but that now you can mount 225/45-15 tires on that rim which are a perfect fit. The wider rim and much wider tire now give you maximum tire contact patch for the purposes of performance driving whether on the track or at autocross.

So the 15x7.5" (SSR comp- not many other light rims come in that size at a decent price) would also be a great tire for the track especially given a decent amount of negative front camber. If you are running stock camber for the front and rear then I'd recommend 15x7 rims and 205/50-15 tires as this would be lighter, cheaper , and you're going to wear out any performance tires with stock camber settings anyway.

In 15" rims there are not many tires that will fit a MINI and be good for autocross. As far as sizes go you want something less than stock diameter but for 205/50-15 this is the best you can do. There are no 215/40 or 215/45 for 15". It will be a jump to 225/50-15 or 225/45-15. The former will fit a 15x7" rim while the later fits a 15x7.5" or wider rim a bit better.

16" rims can also be used either 16x7 or 16x7.5 but I find it sometimes hard to find good tires that will fit. At tirerack.com when I search for:
205/40-16 I find nothing in competition tires but in
205/45-16 (22.8" outer diameter) there are-
Hoosier A3S04 $129
Hoosier A3S05 $190
Hoosier R3S04 $190
Kumho V700 $128-143 shaved
215/45-16 Nothing in competition tires
215/40-16 Kumho V710 $154 7-8.5" rim 7.5" perfect fit, 22.6" outer tire diam
19 pounds (a very good autocross tire but doesn't last as long).

 

Thanks again, minihune, your help is invaluable. After looking at these tires I realize they are competition tires. I guess I didn't make clear that I was hoping for a good tire to serve double duty on the street and the autocross/track. Any suggestions?

Thanks!

-mike

 

OK,
There are many tires that can be used for autocross-
1. Street tires- Like Goodyear Eagle F1 GS-D3 or Bridgestone Potenza S-03, Yokohama AVS ES100, Kumho MX, Talk to Alex@tirerack.com for more selections.
2. Street/autocross/track tires- wear OK for the street and give good performance for autocross or track but not to the level of an R compound dedicated track tire. On the street a little less comfortable and a little more noisy. They don't wear as long as street tires.
3. R compound competition tires- Hoosiers, Kumho V710, Some with softer rubber good for autocross and some with harder rubber good for track. Not for the street. Some wear very fast, only 6 to 10 heat cycles (uses).
4. Wet performance tire- Hoosier Wet or Kumho ecsta V700 full tread. Usually minimum tread tires aren't any good in the wet. 6/32" tread or more works better in the rain but isn't optimal for a dry track. A option for wet courses would be to use a Max performance street tire with good wet handling characteristics (see #1. above)

Sounds like you are looking for #2. Then check out-
Falken Rt-615 in 205/40-16 for $88 18.3 pounds tire diameter 22.5" fits rims 7-8" wide, load rating low at 83 http://edgeracing.com/tire/1533/
Hankook Ventus Rs2 Z212 in 215/45-16 for $85 20.5 pounds 23.6" outer tire diameter. Fits rims 7-8" wide. http://edgeracing.com/tire/1517/
Or same tire in 205/45-16 for $81 19 pounds 23.2" outer diameter, fits rims 6.5-7.5" But website says currently sold out.

Both the Falken Rt-615 and Hankook Ventus Rs2 Z212 are available in sizes for 15" rims (205/50-15 for $90 at 21.2 pounds and $78 at 19.5 pounds respectively)

I do know one MCS owner that uses Toyo Ra1 competition tires (tread rated 100) for street, autocross and track use- he just keeps them on. If you don't do too many miles driving all over these are nice but they aren't the best rubber for shorter autocross courses- they are best suited for the track with the tread shaved down to about 4/32".

In 225/50-15 they are $128 23 pounds, have 8/32" tread depth so they work in the rain or for street use, tire diameter 23.9". In 205/50-15 $120 20 pounds, rims 5.5-7.5", tire diameter 23.1"
http://edgeracing.com/tire/1121/