There were lots of alloy rings made for steel cottered cranks. Simplex and others made alloy 157 BCD rings to fit 3-arm cottered steel 116 BCD cranks, with Y-shaped "ring carriers" connecting the 3-arm 116 cranks to the 157 BCD rings.
3-hole alloy 116 BCD rings, like the TA Professional rings, can also be bolted directly to 3-arm cottered steel cranks. A variation on this was the Stronglight 6-hole 116 BCD alloy outer rings. These seem to have been designed for the 3-arm steel cottered Stronglight cranks. Three holes on the 6-hole outers bolted to the steel arms, with the bolts threaded into the steel arms from behind. The other three holes in the outer ring were used to mount the inner ring to the outer ring. The Stronglight inner rings were 3-hole rather than 6 and they were cut away where the other set of hole would have been so as to clear the heads of the bolts securing the other ring to the crankarm. The pros seem to have used alloy rings on steel arms for many years before the peleton accepted the use of of alloy cotterless crankarms. But I suspect the tourists and randonneurs probably led the way in use of alloy rings on steel cranks, just as they did with alloy cotterless arms.
Regards,
Jerry Moos
Big Spring, Texas, USA
> From: Ben Kamenjas <kamenjas@gmail.com>
\r?\n> Subject: [CR] a few pre-post war parts questions?
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Date: Saturday, June 6, 2009, 1:18 PM
\r?\n> Coolio's ...
\r?\n>
\r?\n> Is it Ok to attach alloy chainrings to steel cranks?
\r?\n> or better to stick with steel and steel?
\r?\n>
\r?\n> Is a TDC # 2 for cottered cranks the right width for a
\r?\n> single chainring application?
\r?\n>
\r?\n> I'm not very good with Imperial measurements as I grew up
\r?\n> with metric. What were the most common hub axles thicknesses
\r?\n> for this era?
\r?\n>
\r?\n> Lastly, I've read of seat pins with numbered sizes (ie #2,
\r?\n> #3 etc etc) what do these correspond to?
\r?\n>
\r?\n>
\r?\n> thanks
\r?\n>
\r?\n> ciao,
\r?\n>
\r?\n> Ben Kamenjas
\r?\n> Sydney, Australia