I have the 17" runflat with the crownspoke factory wheels with 205/45/17 and I want to get the 18" wheels with 215/35/18 for a 2008 R56.

how much difference is the ride? should I stay with 17" runflats or go to 18" regular tires???

thanks

 

how about 18" with 40 series tires? It should give you a better ride as long as you're not lowered.

 

Stick with the 40 series tire especially if your lowered or plan on it.

 

215/35/18 is rough on the R53. Bearable though...but not easy on the back.

 

I got 215/35/18 on stock b4 & I can tell you it was harsh & steering is very heavy to me; now I switched to 215/45/17 & is completely different world. Much much better, just like my oem 15". If you preferred oem riding comfort then 205/45/17 or 215/45/17 both good & 215 gives you a little wider look which I preferred. And I think I am not going to take any run flat, just any decent performance will be fine.

 

It would be best for you to find a MINI owner in your area that has 18" wheels and go for a ride.

Having stock suspension will help some, moving from 17" runflats to 18" runflats in 205/40-18 is very similar on most streets.

Non runflats in 205/40-18 would work. 215/35-18 is also possible but a little smaller than stock tire diameter at 23.9". This would increase wheel gap. 215/40-18 would be tall at 24.8" but if you don't mind running this with stock suspension then you do reduce wheel gap and get a little speedo error.

If you decide to go with 215/35-18 you can try for a tire that has a more comfortable street ride.
Consider (at tirerack.com see Alex)-
General Exclaim UHP
Kumho Ecsta SPT
Kumho Ecsta ASX (all season)
BFgoodrich g-Force Super Sport A/S
Pirelli PZero Nero M&S

Tires that handle very well tend to be stiff and a little rougher for street use or daily driving. If you have rough roads then try for softer riding tires.

Or in the same size at edgeracing.com
Falken Fk452 Max Performance Summer tire
Falken Ze-912 Ultra High Perf All Season tire

 

thanks for the replys....I may go to the 17" and use my same tires and sensors (save me some money) and when they wear out go with a 215 size....

I really like the excel BK10 wheels but they are not available in gunmetal and 17 now only the 18"s.....may wait until they are available

thanks for your help, it really cleared things up

 

For what it's worth, I'm getting ready to put on 18" JCW's w/ 225/40-18 General Exclaim UHPs. I know it's a large tire, but there is another member on here running 205/50-17's (diameter of 25.1") w/o any rubbing and my tires have the exact same diameter. I know mine will be a little wider, but with the added offset of the JCW wheels, I think I'll be fine since I don't plan on lowering the car.

I went this route to get the tallest sidewall I could to help with the ride. We'll see - they should be going on mid next week when my car arrives.

 

225/40-18 has a tire diameter of 25.2" vs stock 24.3" so with almost one inch taller you have very little clearance even with stock suspension.

Anything that compresses your suspension will risk rubbing especially in the rear.

Each MINI does vary with clearance so if you do get any problems please report them on this tread so that others can benefit.

Common causes of rubbing with any 25" tire-
Uneven road surfaces
Any rear passengers even 100 lbs and certainly two people.
Any load in the car besides driver
Any high speed driving
Any dips
Any fast turns

You have stock suspension so travel on the shocks and springs is a bit more than a performance suspension.

A little rubbing is not a big deal, if you get too much rubbing then try trimming the inner wheel plastic liner with a dremmel tool- just look for where it is already worn down by the tire. Note that if you don't trim then your tire will get the outer tread edge worn down by the plastic.

Also note that you can get some speedo and odometer error with a taller tire.

 

Thanks Minihune. The local shop has agreed to swap them out if I have any clearance issues.

And if I do, I will certainly post them for others to read.

 

how about 205/40/18 like the JCW from the dealer. is this a harsh ride also? that size tire is the same diameter as the 205/45/17