Greetings,

I am new to this forum and recently picked a 72 Cota 123. My first trials bike, actually it is for my wife but I get to work on it. I have been doing some basic tinkering and got it running, rebuilt the carb, replaced the fork seals, bunch of little repairs and I am patiently waiting for new rear shocks to arrive.

Next on my hit list, is replacing the small (17” and 20”) wheels with an 18” and 21”. I am told that most folks do this and the wheels and tires on the bike have had it. So I just measured the width of wheels that were on there and the outside measurement of the front is 2.375” and the outside of the rear is 2.50”. These both seem like oddball sizes the front being somewhere between a WM0 and WM1, and the rear being between a WM1 and WM2. So my plan is to order a WM1 for the front and a WM2 for the rear, but before I do so I just wanted to see what size other folks have used. Based on the measurements I took I don’t think I will have any clearance issues but was looking for some advice before I order the new rims. A side note, I am planning on ordering a set of chrome Radaelli’s for it. They are not the best, but generally last a long time.

Thanks,

Kevin

Do they not measure the width on the inside ?

Most rims I have, have the WM marked on them somewhere.

Edited August 30, 201213 yr by b40rt

Didn’t think the cota123 could be fitted with 18” & 21” wheels, I thought there were some issues with clearance on the larger wheels?

B40rt,

You are correct, the WM sizes are measured on the inside, but for each size there is also an associated outside measurement. Because my wheels still have the tires on them, I measured on the outside. The inside and outside measurements for each size are;

Size Inside Dimension Outside Dimension

WM0 38MM/1.5” 56MM/2.20”

WM1 40.5MM/1.60” 61MM/2.40”

WM2 47MM/1.85” 69MM/2.72”

WM3 55MM/2.15” 78MM/3.08”

Thanks,

Kevin