Originally Posted by
clubman
Yup, a select number of Shimano 7 sp freehubs fit 126, depending on the dropout design. Sometimes you had to futz with it.
+1
A few years ago- having in the moment actually forgotten that I did indeed knew better (certainly a sign that I'm getting older), I made the assertion that
all 126mm Shimano freehubs were UG, & incompatible with later HG systems.
Doh!!
I'd totally spaced off the fact that about 4 years before, I'd actually converted a 126mm, Shimano 105/1055 HG 7sp hub to 130mm/ 8sp, that is, to the same spec as the 105/1056.
All it took was swapping out the hub body, and swapping out the axle & spacers. Shimano's 126 & 130mm hub shells have the same dimensions (I can't remember offhand if the shell interface itself is different for UG & HG hub bodies. It's been a while; I seem to recall it's the actually same for both types).
The HG 7sp hub bodies are Bronze & slightly shorter (about the same length as a UG body) to fit the 126mm spacing; the HG 8sp are Black & about as long as 9sp body. If they have a little indelled line encircling the body, about halfway down, it's one of the UG/HG bi-compatible transition bodies. The latter also have both types of lockring threadings.