anyone know what years CCM used a 31mm steer tube bore? I went to change out the headset in what appears to be a 46 twin bar and the bore is 31 mm. My 64 and 67 CCMs have the common 30mm bore but I havent ever checked my older bikes.
My three 1960s parts catalogues show two different part numbers for CCM headset cups. While they do not detail the specifics, a couple catalogues mention that the change took place in 1959 and one mentions that the later version is stamped "59", though presumibly this practice would have been discontinued after a transition period. I assume the change was the mounting diameter.
Earlier catalogues show the headset to be unchanged (other than finish) from 1923-1958. There was an extensive change in 1923, with a new headset designed around larger 3/16" ball bearings, as opposed to 5/32" ball bearings.
It is also worth noting that the fork crown race has two different part numbers, starting in 1969. Again, the specifics are not detailed but I assume it is a change in the mounting diameter, as there are two common standards.
Awesome, thanks very much for the information. Looks like i am going to be using shim stock to make the newer style headset fit the older frame. Two layers of 0.010 stock should be about right
Thanks for that post, Tmar. I was not aware there was a change to the headset in 1923. I have two 1918s, a 1922, and two 1925s that are all works in progress so I'm happy to know this!
My three 1960s parts catalogues show two different part numbers for CCM headset cups. While they do not detail the specifics, a couple catalogues mention that the change took place in 1959 and one mentions that the later version is stamped "59", though presumibly this practice would have been discontinued after a transition period. I assume the change was the mounting diameter.
Earlier catalogues show the headset to be unchanged (other than finish) from 1923-1958. There was an extensive change in 1923, with a new headset designed around larger 3/16" ball bearings, as opposed to 5/32" ball bearings.
It is also worth noting that the fork crown race has two different part numbers, starting in 1969. Again, the specifics are not detailed but I assume it is a change in the mounting diameter, as there are two common standards.
Awesome, thanks very much for the information. Looks like i am going to be using shim stock to make the newer style headset fit the older frame. Two layers of 0.010 stock should be about right
Thanks for that post, Tmar. I was not aware there was a change to the headset in 1923. I have two 1918s, a 1922, and two 1925s that are all works in progress so I'm happy to know this!