My wife is in need of a new set of tires for her '06 MC (R50). The factory tire is a 175/65/16. There isn't a tire dealer around that has this size tire, but can order. I talked to the Yokohama guys last year at The Dragon about this and they said we could easily step up to a 185/65/16. This is a common tire size most everyone carries, however, no one will install it since I am finding that all the tire dealers I talked to all have a policy to replace what is on the car or factory recommended.
One place told me yesterday the reason is that by changing the tire size it charges the torque on the transmission and will cause premature wear, and they didn't want to be responsible for a mechanical fix. This is why they only put the factory recommended tire on the cars they service. I heard this same story from a Goodyear store, Sears & Sam's Club.
First off, why did MINI put such an odd size tire on the R50? My guess is to make it unique so we have to buy it from the dealer. I'm finding special ordering tires from most tire dealers come in at or around what the MINI dealer charges for mounting and balancing 4 new 175/65/16 tires.
I appreciate any input on this. And I hope I am not breaking any NAM rules that cause me to receive yet another infraction for opening up a topic I'd like to get some input from other MINI owners!
Thanks!

 

The MINI oem tire sizes are 175/65/15 (not 16), 195/55/16, 205/45/17, or 205/40/18.
People very commonly use 185/65/15,or 195/60/15 instead of 175/65/15.
If you are talking about 16" rims, 205/50/16 are often used instead of 195/55/16.

You can often get tires shipped to you very quickly from TireRack for less
than the local price. They won't give you grief about an alternative size, if
infact it is an appropriate fit, and you can find friendly local places that will
mount them without giving you grief on their site.