My car needs a state inspection and I have just discovered that one of my rear tires will not pass and the other is very close to not passing. The fronts still have considerable life left. My question - can I safely install and run 225/50s on the rear until the fronts (215/55s) wear out? At that time I'll put the 225/50s up front as well to even things out. I know the rolling diameter is almost a perfect match with the 215/55s and the 225/50s and will temporarily, at least, give me a "staggered" setup. Any input, other than to tell me that I should have rotated sooner (sic), is appreciated.

My understanding is that as long as the rears are matched, no problem. I don't think a small difference in rolling diameter will make any difference at all unless it is on the same axle.

I see some guys in sports cars who deliberately run much larger diameter tires in back. Not sure what they carry for a spare, but they do.

You shouldn't have any problems if the rolling diameter is exact. I would put them side by side. The mfg numbers are not always equivalent across brands or even within brands.

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

Please tell us what size wheels you are using. Please tell us the diameter, width, and offset of your wheels.

I think you must be running 16", based on the sizes you mention. Based on a 16" wheel and the numbers at the Tirerack website, 215/55/16 is NOT the same diameter as 225/50/16. We have been talking about this in another post and trying to figure out what tire we can stuff under a W124, without rubbing. The consensus was that the larger diameter of the 215/55/16 causes rubbing on the lower plastic cladding at the front wheel wells. The 225/50/16 is virtually identical to 205/55/16, which is virtually identical to OEM 195/65/15. It may seem counter intuitive, but you can fit a wider tire without the rubbing caused by the narrower, although slightly taller tire.

There is also another problem with different diameter tires. I once used slightly different diameter rear snow tires and it caused the cruise control to malfunction. I learned my lesson and I will always use matching tires at all four corners.

If you do get 225/50/16s, I would love to know that they fit without rubbing. I want the widest tires possible, but I definitely don’t want to rub. Please help us if you learn anything.

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I just couldn't give up on my 1995 E320.

I think it might be like always going back to that same bad relationship with an ex girlfriend.
You feel you love them too much, or you are just too stupid to know any better.



Flickr slideshow of my 1995 E320
http://www.flickr.com/photos/24145497@N06/sets/72157616572140057/

I have 16 x 7.5 et 35 wheels. I think that I've decided to just go ahead and buy 4 new 225/50s (or maybe even go back to 205/55s) and keep a closer eye on inflation and rotation. I agree that, in theory, the 225/50 should not rub due to the more "correct" sidewall size. If I do the 225s, I'll keep you guys posted.

safe

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