I have successfully talked myself off the 19" ledge, however we found out recently that we are moving from South Florida to New Orleans. New Orleans doesn't really have streets with potholes, it has potholes connected by streets.

That said, I need to consider switching out the run flats in order to avoid cracking my teeth. Here's the question:

On my 18" wheels, could I expect any appreciable change if I used a 225/55 r18 instead of the current 225/45 r18(assuming non runflats on both). If so....what effect would it have on performance and ride?

Thanks!!!

 

There was either a post or I found on the internet a calculator on tire sizes and what the difference would be. All else the same the 55 vs 45 would be a larger diameter and should not interfere with the clearance to the strut. Higher sidewall run-flat or not should give more cushion and a smoother ride. It will have a little effect on the speedometer. I think there are others out there better able to comment on the ride quality.

Bill

 

I've got non-runflat 225/45 18's and we have massive potholes here in Ohio due to a terrible winter. Haven't had any problems so far (knock on wood).

 

What about the ride? Noticeably different?

 

Here you go:

http://www.miata.net/garage/tirecalc.html

Obviously the problem with increasing sidewall is while you would get the result desired (softer ride) if your keeping the same rim size your going to increase wheel diameter (by how much you can use the tire calc above), and screw up your odometer, and trip computer, and have to worry about rubbing issues (although probably not much of a problem with the CM), all to varying degrees I've always heard you don't want anything more than a 2% increase/decrease, some even say thats too much. If you really want a softer ride the better way is to get smaller rims and increase sidewall, or get softer springs/shocks.

 

I find the ride MUCH more comfortable than the run flats. Not as jarring.

 

Hmm who buys a MINI for the ride, go on buy the 19's you know you want too!

BTW what were you planning on putting on? I rather partial to a set of BBS CH's.

 

I will be swapping out the run-flats. Not sure to what yet. I had planned on using the run-flats until they were gone. Oh well.