Handling differences between wheel sizes

[afromanbob]

As many of you know, I just specced my Cooper. However, I'm thinking that to cut costs I may ditch the Sport Package that has the 16" 5-Stars. My question is this: How much different is the ride and handling between the 15" and 16" wheels? Even if I do ditch the SP I could always buy some aftermarket wheels (though like I said money is an issue as I will be going into college and upgrading my wheels might not happen). Anyway, what are the differences?

[Iamamini]

Hi! I have the 15 inch wheels, and my experience is that even with those "small" wheels the ride is rather bumby sometimes, so I am glad I dont have bigger wheels since they often make the ride even stiffer. I use my car every day and not just as a car to have fun with, and even when I drive just for fun I think the 15 wheels work very good. I would say that if u mostly will use the car for fun driving, go for the 16 inch wheels and if u will use it as a "every day car" mostly the 15 is perfect.

[Paul]

We have (or do) own MINIs, Cooper, S, and One with the range from 15" to 17" factory alloys, with runflat and non-runflat tyre combinations. The 15" wheels on the Cooper handle just fine, they offer a good ride, but "let go" much sooner than the 16's do, and offer a much more slidey, throw-about driving experience than the larger wheels. Just as fun (more so on the MINI One in my opinion) than the other wheels, but probably not as "good". Best thing to do is try them and see (if that's possible). If you go for 15's, you'll have a brilliant time, and if you go for 16's, you'll still a brilliant time, they'll just be different.

That probably didn't help much did it.

[HarryHBMCC]

The 15's are lighter so the car starts off the line quicker but cornering traction is lower (as Paul says, they let go earlier) so you can't carry as much speed through a corner without sliding around as compared to the 16" wheels. If you want to save some money, just go with the 15's. The difference is not night and day. The ride is a little softer with the 15s but not as much as you'd think, going from runflat to non-runflat; the suspension is still tight.

Harry

[lightbody]

I have driven my Cooper with SS+ on both the 15s and 16s.

Like Paul says, the 15s are more "fun" and have less grip but also have an improved ride. In my view, they let you take advantage of the clever rear suspension - for instance getting it sideways on a roundabout is easy and then controllable. Its more 'chuckable' on 15s and therefore more like a Classic Mini and less like everything else on the roads!

16s, are much firmer and have much better grip and I can get from A to B faster on them due to the increased cornering speeds available.

[GregF]

I went from the stock 15" X 5.5" wheels with slippy all-seasons to an aftermarket 16" X 7" with stiffer sidewalled 205/50 summer tires. The heavy steering feel was what I noticed the most. I preferred the 15" wheels. The skinny tires were definitely fun too, but being able to corner at much higher speeds now is fun as well. I have a 2002 with sport suspension, not the plus, and the ride really didn't get any worse IMO. When cornering the MINI seems more evenly planted now, probably a combination of the wider tracking and the stiffer, shorter sidewalls.

[Ian Kuah]

My 2001 Cooper, 'Modern MIN' came with 15-inch alloys and Pirelli tyres. The ride was really choppy even on the normal sport suspension.

Grip was also lacking and the Pirellis squealed at relatively low cornering speeds, despite my using 30psi in front and 24psi at the rear. Years of testing all sorts of cars threw up the fact that front drive cars need to run higher pressures in front (by 6psi) to achieve a neutral handling balance. This is because the front wheels are doing the work of putting down the power and steering and take much more loading than in a RWD car. With so much weight over the front, if your rear pressures are too high, the car becomes nervous in fast cornering like a shopping trolley!

I have driven Cooper and Cooper S models with both 16 and 17-inch run-flats and was really turned off by the hard ride and sudden beyond the limit handling of the run-flats. (I am a professional motoring magazine road tester and former Formula Ford and Honda CRX Challenger racer by the way).

However, I had to do something about the lack of grip and weedy look of the 15-inch wheels/tyres so I bought a set of 7J x 16 Minilites to preserve the classic Mini look. I used the new Dunlop SP-01 tyres in 205/55R16 (non-runflat) size and lo and behold, the grip, handling and ride are now better than the smaller sizes. I now run 31psi front 25psi rear to compensate for the lower profile tyres.

Yes, 17s look cool, but I and other professional testers (including BMW Fahrer Training instructors I know) feel that the wider, lower profile rubber (especially the runflats) corrupts the excellent steering feel of the MINI.

All enthusiasts know that lower unsprung weight is good for handling and braking, but it seems that the valving on the factory sport dampers is set up for the heavier 16-inch/runflat combination, so the lighter MINI One style 15's are not heavy enough to make the damper valving work properly at low speeds.

The heavier 16-inchers allow the damping to work properly and the comfort orientated Dunlops improve the ride by about 20 percent over the 15-inch Pirellis. They also create no road noise to speak of, highlighting the recent advances in tyre technology. Wet and dry grip are vastly improved and there is now so much in reserve, I feel this combination would easily handle Cooper S levels of power.

I was initially looking at changing the suspension, but I am so pleased with the balance of the car now that I will save the money. In any case, most of my friends with lowered MINIs have problems with speed bumps.

[MINNOW]

My Cooper came equipped with the 15" R81 7-hole alloys and Conti tires. On this set-up the ride is very good, steering feel is excellent, great turn-in response, ultimate grip limited by the narrow tires. (std. sport suspension)
I recently bought a set of take-off 16" R84 X-lite wheels & Dunlop run-flats, and mounted these myself for a little comparison prior to the Winter setting in. The difference in weight of the wheel/tire combos is very noticeable when changing yourself.
My impressions with the larger wheels and tires are : marginally heavier steering feel, slightly more ride firmness and road noise, and very noticeably more grip when throwing the car into a corner, especially a high speed sweeper.
I'm happy to have both sets for alternate summer and winter usage, but if living in California, one year-round set I'm sure will suffice.
My advice would be to opt for the standard 15" wheel and tire combo, the R81's style suits the car to a tee, and if you find the narrow tires a limiting factor you could always upgrade to a 195/60R15 Yoko AVS ES100 for example at minimal cost. Also you would have to pay a ton of money to find a lighter weight wheel than the R81's at 12lbs. each.
I would be leery of the added weight of the 16" R83 5-spoke MINI wheels, these are even a few pounds heavier than the R84's that I added.
In summary there is no shame or serious shortcoming in going with the standard 7-holes, I think they are an awesome wheel, and a great buy at no additional cost!