I need advice on choosing the correct tire size for my JCW Cabrio's 18" R105 wheels. Currently I'm running Dunlop 205/40/18 Run Flats which I want to replace with Non-Run Flats.

I've heard that 215/35/18's will work. Anybody out there have advice on this choice or should I stay with 205/40's?

Also, my JCW is a daily driver with occasional brisk runs up the canyons near my home is So Cal so I'm looking for a tire that will give me good traction and a reasonable tire life. Because it hardly ever rains here I'm not concerned about all-weather performance. Any tire recommendations?

 

I also have the R105 wheels and when the run-flats run-out will probably replace them with 215/35/18s non-RFTs due to greater selection and nice width+sidewall. I talked to somebody at MAMA recently who was running 215/35/18 General Exclaim UHPs and was very happy. Firstly they were cheap and the road noise was significantly less than the stock Dunlop SP Sport 01 (although what isn't). He also said that although he was expecting the ride to be stiffer with the reduced sidewall, the opposite was true because the run-flats are so unforgiving. I'm looking at BFGoodrich g-Force T/A KDW 2s, BFGoodrich g-Force Sports, Bridgestone Potenza RE760 Sports or for more comfort Kumho Ecsta SPTs or Yokohama S.drives.

 

My 06 MCS is at stock height, and I'm running 215/40/18 Nitto Neo Gen tires on a 18x7 wheels with no rubbing what so ever.

I first tried the 215/35/18 size, but didn't like the ride, the short sidewall, or the wheel opening gap.

Click on pic to make it larger.

 

Careful now.

Different brand and model tires have vastly different side wall stiffness. Any tire model and size needs to be evaluated on a car like yours with the same suspension set up.

In case you decide to take a third party's advice be sure that they are experienced drivers and have driven that exact tire size on a car like yours.

 

I went with 215/40x18 because I did not want the shorter sidewall. I currently have Toyo T1-R and like them. Stick much better than run-flats and should last just as long.

 

+1

Unfortunately the universe of tires is too large. Look at the tirerack.com evaluations. At least there is more info there.

 

I just put: 225/40-18, Bridgestone Potenza RE760's on my 09 Clubman with R105's. I am running Cross Coilovers, dropped 2" - 15MM front spacer (to clear the Brembos) and 7MM spacer, rear. Fills everything out perfectly. Rides so much better than the RFlats - can't even describe the improvement - massive.

 

Thanks for the info... I'm running the R105 with 15mm spacers front and rear on my JCW cabrio. I'm anxious to ditch the run-flats.. glad to hear it makes such an improvement.

 

Use caution in the rear - I am using a 7mm spacer (rear) has a slight rub on heavy dips with a 200# passenger. You might be better with no rear spacer.

 

Please excuse my total ignorance but if I change from run flats to standard tires do the tire pressure sensors still work OK?

 

Which year MINI do you have? Rubber or metal valve stems?

 

If you have any MINI up until Aug 2007 you have the older rubber stems. Late 2007 is when they started to used TPMS sensors around the stem itself. These are the metal stems. No matter which TPMS you have they will both work with RFT and non-RFTs. Early MINIs use the ABS sensors to monitor the tire pressure thus it doesn't make a difference what tires you use. With the newer system, the sensor is built around the stem and does not interact with the tire thus working exactly the same with RFT and non-RFTs. The only issue you sometimes run into is if you have a late-2007 or newer MINI and try to use non-OEM wheels as a few aftermarket wheels may not fit the TMPS sensor and stem in the wheel.

 

The year of my car is 2007, It has 18" John Cooper Works wheels which I think you guys are refering to as R105? The stems are rubber and the tires are currently RE05A RFT Bridgestone Potenza. These combined with the sport suspension give a VERY hard ride and if possible I would like to change them for something a little more complient. Problem is the full set are nearly new!!
Your advise would be helpfull.

 

This question would be best posted in another thread as it is getting off-topic, but do a search and you'll find that any non-RFT is going to run softer than RFTs. I have JCW R105 with Dunlop SP Sport 01s RTFs and the JCW suspension and like the ride in Boston, call me masochistic. The turn in with run-flats is very quick and I've had mine on the track once and they weren't bad. The Dunlops are supposed to get unbearably loud around 10-12k miles according to BMW drivers so I'm just going to run them out. If you've got the cash, get some non-RFTs and stay with the 205/40/18 or possibly go up to 215/40/18. I think 215/45/18s would rub but you could ask Alex@TireRack.com You could try to sell your old tires although as many people are trying to off-load RFTs, it might be a hard-sell.