Could I put 185 65 R15's on the stock 122 rims?
Thanks again.

You can look up recommended rim widths for specific tire sizes on Tire Rack's website, http://www.tirerack.com, clicking on "specs" for each mfr's tire model of interest. The same info is in brochures at tire shops. (Note that rim "width" in the tire and wheel industry is the inside dimension between the rim flanges that confine the tire bead, not the extreme edge-to-edge width, which is typically about one inch more.)

Old tire brochures I have give 4 inch width as the minimum for 165 R 15 tires, and 5.5 inch max. Current specs for 185/65-15 tend to show 5 inch min and 6.5 inch max rim width range. Others have replied that they have gotten away with what you propose, but it seems not to be what the tire mfr's recommend.

Wider steel rims can be installed on original center sections. See http://www.stocktonwheel.com/wheel_widening.htm for an account of how this is done.

Check out the "Wheel Swaps/Bolt Pattern" thread of approx Feb 15, 2002 in the Brickboard archives, especially Jim Hekker's post, with website link, for comments on wheel widening alternatives for 120's.

I have been considering the same tire size for my 544, which cannot accept significant extra rim width to the inside (ie, extra "back spacing") because of its suspension front upright's design, proportioned in the 1940's for 16 inch wheel diam. 120's and later seem not to have this problem.

I have 185 series tires on stock 122 rims. It works, but barely I guess. At one point at the yearly tech inspection the technician told me the tires were too wide for the rims, because the sides look too round. He didn't make a big deal out of it though. I don't know if this impacts the tires' stability, I never had other tires on my 122.

From my own limited experience:

185 tires on 4 inch rims will have slightly better grip, but a slightly 'spongier' breakaway once you exceed their traction limit. 165 tires have lower traction but a slightly 'crisper' breakaway, so are a little more controllable. Very subtle and probably mostly subjective difference vs. a slight but noticable increase in traction.

Of course, the traction and sidewall stiffness if also greatly dependant on the tire itself, the aspect ratio, and the pressure. Lots of variables there.

Yes - they fit just fine. I wouldn't go any wider, however, on stock 4 inch rims.

Hello...
A question, what kind of tires would you think won't be too wide for the 5inch rims. I am thinking of 205/65 or something, maybe 195/60. What would you recommend?
Thanks.

The 1800 rims were 5" wide.

I have a set on my '67 122, and the rim book at the local tire store says that 5" is minimum width for a 195/65/15. - gary

I wouldn't go wider than a 195 on 5" rims. Even that would be a stretch. Even stock Volvos with the 5.5" rims used a 185/70 (impossible size to find). But...keeping in mind there is a lot of variation in same sized tires... I would go with the skinniest 195/65 you can find.

-Matt