I'm considering trading in my 08 ESV for a 2010 ESV Platinum (had a 2005 ESV Platinum before the 08, liked it better), and I'm trying to get a straight answer on the Magnetic Ride Control system. I want to replace to factory installed 22" wheels with a wheel and tire combination that gives me better traction in the snow, probably a set of nice 20s with a grippier tire. I may keep 2 sets of wheels and only use the 20s in the winter, and keep the 22s on the rest of the time. The Caddy dealer can't give me an answer in writing that says it is OK to replace the factory installed 22s with 20s, and that it won't alter the performance of the Magnetic Ride Control or any other system. I just want to make sure I don't have any safety, warranty, or performance issues with the swap. Any guidance on how to get an official answer out of Cadiallac? Anyone else swapped out the factory 22s on a vehicle with MRC?

go with a 2009.. the 2010 they take a bunch of features out like rainsening whipers for example.

I know the dealer has calibrations for different tire sizes ... pass by service dept. and ask someone with a clue.

I stopped by the service department first, but the service manager was unsure. He brought in one of the mechanics, and he initially was concerned about speedometer calibration vs. MRC. I went to the sales department and also spoke to the sales manager, and they are attempting to run it down through Cadillac corporate. They told me today that it is very unlikely that I would get anything in writing from either the dealership or Cadillac. The sales literature has footnotes everywhere that MRC is mentioned that basically state "see your dealer for Cadillac approved wheel and tire combinations". Apparently there is no official wheel/tire combo approved other than the factory 22s. It shouldn't be this hard to get a basic answered, I can't be the only one who's asked it - and I'm sure some people on this site have made the change, I'd love to hear from someone how it worked out...

You will not get anything in writing that can be used against GM in terms of warranty issues, and since they have no money it probably does not matter anyway. I have 20's on my 09' for the winter to clear my Baer Claw big brakes and have no issues after almost 2k miles using Cooper Discoverer STT 33 x 12.5 x 20 tires on 20 x 10" wheels

Thanks Carl. I put Revos on my 18s (at your suggestion) on my 2008 ESV and they work great. Does your 2009 have MRC? If so, have you noticed any difference in the handling/response/ride etc?

Thanks Carl. I put Revos on my 18s (at your suggestion) on my 2008 ESV and they work great. Does your 2009 have MRC? If so, have you noticed any difference in the handling/response/ride etc?

Yes it does have mag ride, I tried all my GM friends and they could offer me no reason why I could not use 20's with the same basic overall diameter of the stock tire even though it states not to use anything smaller than a 22" wheel.