N00b question time: What's the best wheel size for track, Auto Cross, Rally Cross, or lively commuting? I've heard from a few folks that they get better handling out of 16"s but I'm not so sure.

 

16" size is generally acknowledged to be the optimum size for autox, especially if sticking within SCCA rules, as the wider 6.5" wheel affords a wider tread tire compared to the 15" size.
17" are fine for street (although personally I feel that's overkill) but they weigh more and that doesn't help bring down times.
There was a good article a few months back in Grassroots Motorsports magazine on this topic specifically about improving the Cooper's handling.

 

16inch wheel in my opinion is the best "all around" size rim (for the mini). I believe there was an artical about this in Grassroots motorsports not to long ago for the MINI.

to explain the differences and how they effect the car look here at post #6

https://www.northamericanmotoring.co...t=quarter+dime

 

Anything beyond 16 and you're sacrificing performance for looks.

 

Actually, I should also add that many people strongly believe that 15's are the best for performance.

 

depends on what you are doing, if you are autocrossing alot of people will argue and say 13's are better then 15's.

Some track cars with high HP/TQ like a slightly taller rim to help with their top speed on the straights. With the added hp/tq they have no problems turning the larger rim and tire and it actully helps them with wheel spin off the start.

It all depends on what you are doing and how your car is setup. But i agree that anything over 16's on a MINI is just for looks are starts to hurt performace. Unless you have some 250/300hp twin charged car.

 

Everyone seems to run 205/55/15's besides like 1 or 2. I bought a set of 15x7 Konig Rewinds and falken 512 M+S , 205/60/15's. I did the calculations and the proper measurements are between the two for matching exact ride height. (in other words, no exact match is possible in 205 size tire)

question is: does a larger side wall reduce the ability to corner? Dont say yes obviously, as that would make 15's perform worse in general to 17's which they do not. Is there a limit to this though in increasing sidewall?

 

One size rim and one size tire will not do well in all of the applications you listed above.

For each purpose there can be a number of good solutions. Otherwise everything done is a compromise.

Track-
Any wider rim will work: 15x7 or wider, 16x7 or wider, 17x7 or wider and even 18x7 or wider. Wider is harder to find and some owners go custom with Kodiak rims that are 8" wider or more. The biggest limiting factor can be which tire and what size does it come in. Sometimes it makes sense to pick the tire and the size then sort out the rim size that fits both the tire and the MINI given it's suspension limits.

Autocross
You must consider which class you will drive in. Rules limit the rim sizes if you compete in stock classes. Otherwise the same rims as in track can be used but smaller rims are also lighter in weight for the same budget. Plus tires must be considered and usually R compound give the best results but cannot be run on the road without wearing them out. Good street and autocross tires are available from Falken (ST-615) or Hankook Z212.

RallyCross
Same sort of rules and rims as autocross but with tires that are knobby and more durable for offroad use. That would not be so quiet for street use.

Lively commuting
You can use less than comfortable tires and rims but you'd risk some damage if you hit a pothole. Performance tires tend to be noisy, more expensive, run harshly and wear out faster. 40 to 50 series tires will work ok. When using 15" wheels you can use 50,55, or 60 series tires, while with 17" rims you use 40 or 45 series tires.

Street use
If you choose tires for comfort they won't give the same level of performance. They will be fine for wet or dry conditions and even some light snow if they are all season tires. 55 or 60 series tires offer enough cornering performance and good ride comfort and lower noise levels. They have good wear and good prices. They do not do as well and wear out if you take them to the track or to autocross regularly.

13" or 14" rims will not fit the MINI- there is no room for brake caliper clearance. 15" or 16" rims will work fine for most uses. 17" will also work but lower side walls will increase ride firmness.

Other considerations-
When on the track or driving for performance, the Stock MINI suspension alignment has insuffient front camber which will lead to severe tire wear under most circumstances. When using street tires on the track you will risk chunking of the treads once heat builds up after a few laps. Track driving usually is best when using dedicated track tires that are built for higher speeds, higher temperatures, and are shaved down on the treads to only about 4/32nds of an inch. They are not for street use.

When you force a tire to "do everything" you will be either drive the cost up or wear out the tire more quickly. A good example of a really good tire for everything except Rally Cross would be the Goodyear Eagle F-1 GS-D3. Talk to Alex@tirerack.com and some MINI owners that use this tire for their opinions. It's moderately expensive but a really excellent street tire that can be used in performance applications without having dedicated track or autocross tires. You'll get quicker more responsive turn in with lower profile sizes but I think even a 55 series GS-D3 would be pretty good along with providing a smoother ride for street use/Daily driver use.

Good luck.

 

that's a pimptastic response. Perfect you even mention 60 sidewall ratios. that like a complete explanation.

 

I could not agree more with Minihune. That was a great response!

His choice in tires for overall performance is a great one. The F-1 GS-D3, are NICE! But just like he said, if you are looking for a tire to "do it all", it will drive up the price.

For someone like me, the F-1 GS-D3 are too expensive. I tend to go through tires quickly and im not looking to spend $100+ a tire when i know they are only going to last 15-30k miles.

So in my situation i look for a "cheap" performance tire that is almost as good as the more expensive tires. I plan to use Sumitomo HR Z II tires when my run flats wear out. You can look at the different ratings for the tires on tire rack, and read reviews.

F-1 GS-D3 = $128 a tire. ($512 for 4)

HR Z II = $71 a tire. ($284 for 4)

The performance of the F-1 GS-D3 is better, hands down. But...i dont think its a HUGH difference and the saved money could help go towards other mods: sway bars, brake pads, brake fluid...ect. Maybe if i was sponsored, or winning money for racing, then i would buy somethnig a little more expensive. But i just do it for fun.

But if you got the money to spend, by all means get the good stuff!

just my .02

 

So true, so true. In March I put new Proxes T1Rs on my MC. Great tires. Over the past 6 months I did 4 lapping days and watched the wear on the tires, rotating once. At the end of the final session, which was a hot day, the front right tire overheated and chunked--several quarter sized patches and one over 2" long. Belts clearly visible.

Yes, I should've known. Yes, I've gotten too agressive at the track to risk street tires. Moral: Time to buy rims and R-compunds and spend my money wisely!

 

Last year I did an experiment on the track to test the effects of stock vs more negative camber in front.

The same new Michelin pilot sport cup tires in 205/50-15 were mounted on 15" holey rims and installed on the fronts of two MINIs at the track. Same inflation about 34-36 psi.

One was a stock MC with no upgrades. Alignment was stock.

The other was a moddel MCS with front camber plates running -2.2 degrees negative camber, PSS9 Coil overs, front BMP tower strut bar and -1.8 degrees rear camber with adjustable lower rear control arms. Front toe was 1/8" out and rear toe was zero.

Both cars ran on the track with different drivers for 15 minutes or about 14 miles total distance (0.8 mile short track).

The stock MC wore out the right outer treads at least 50% more or about 1 inch more towards the mid tread than the MCS with camber plates and the MC was going slower each lap. It wasn't due to driver error. The left tire treads did ok because the track was counter clockwise. The tread wear on the left was greater on the stock MC as well but not as severe as on the right tire.

This was 15 minutes on the track.

So just be careful then running on stock alignment with any tires- it's pretty hard on the tires.