Mori

I went to the local Firestone tire place that said the largest tires I could put on my 16 inch rims were 225/55 R16 (for an 85 500SEC with factory springs). But the current 55 tires look small and do not fill out the wheel wells.

Can I use 225/60 or 225/65 size tires?

Untertürkheim

It depends on the offset and width of the wheels, maybe 215/60.

Mori

Centra wheels (with large [~8 inch diameter] center caps that bolt on with a special wrench) were a common aftermarket German wheel used in the middle 1980's for Mercedes. Not sure of the offset - I may need to look this info up if I can find it.

Untertürkheim

If you take one of the wheels off, there will be a code containing the wheel size, width, and offset.

whoover

The proper profile for those wheels is 225/50. That's a proper fitment from the stock 15" wheels with 205/65 series tires.

(Play around with sizings at http://www.canadiandriver.com/tools/...c/tirecalc.htm . The idea is to get as close to the original outside diameter with the new wheel size.)

The idea of going to larger wheels is to chose correspondingly lower profile tires to improve handling. Going from 15 to 16 inch wheels and leaving the profile at 65 is not a good idea. If the look with the 225/50-16 looks wrong to you, consider lowering the car. I used 225/50-16 on my W126 on those Centras for 150,000 miles.

Mori

The tire guy said that I could put the 225-60 R16 tires on the back but I should not go any larger than 225-55 R16 for the front. I am temped to do this because I already have an almost new Potenza 009 tire in the 60 R16 size and would only have to buy one new tire.

Any thoughts about putting 225-60 R16 tries on the back and 225-55 R16 tires on the front wheels? Will this look strange?

whoover

I have no idea what your tire guy is talking about. 225-50/16 was the standard W126 upgrade. I drove 250,000 miles on that size at all four corners. But what I don't get is that 225-50/16, 225-55/16 and 225-60/16 are all the same width (225 mm) and the 225-50/16 has the smallest diameter. In other words, 225-50/16 is the smallest tire of those three. But it's also the lowest profile, which means it will improve the steering response the most of the three sizes. I can't imagine what your tire guy means.

Mori

Well, I went with the 225 55 R16 on the front wheels (my old tires) and new 225 60 R16 on the back wheels. The back tires look a little larger but I don't mind the look. The tires guys warned me not to put the 225 60 R16s on the front because they might hit against the wheel wells during turns or bumps. They would probably also throw off the speedometer a bit. Thanks for all the comments and suggestions.