I’m nearly there with the conversion to an underslung cantilever rear brake on my Mongrel 900SS project, but before I fire up the milling machine to make the parts I don’t have I thought I’d ask the question and maybe save myself some time. Does anyone have either the Caliper Hanger or engine to Torque arm bracket shown below that they’d like shot of? As fitted to the 900FE and other special editions. No’s ‘29’ and ‘50’ below. I was going to convert a standard fixed calliper bracket by cutting off the side arm and boring out the hole, but unfortunately the reinforcement webs etc on the back will be severely weakened by doing it that way. Thanks Nasher.
Alternatively it looks like I could modify a later type bracket that has more meat in it. ST2/4 Or similar aged monster etc with same casting but smaller shaft. Ta Nasher
I do not think there is enough meat on either the old or new type hanger if you intend using the larger axle/spindle. The spindle boss needs to accommodate top hat bushes (minimum thickness c 3 mm) to allow the wheel to be tightened without causing the hanger to seize. On the later axle this means a 31mm bore bearing pressed into the hanger so a minimum of 35mm hole in the hanger bracket.
I'm using the original 17mm rear spindle, as per the SL, FE etc, so should be OK. As mentioned the original SS fixed hanger that was made for a 17mm spindle does not have enough meat in the boss on the back, but the later fixed hangers intended for a larger rear spindle have a bigger boss on the back which should give me enough room to machine some top hats and fit a Glacier bearing. I need to be careful which one though, as some have the webs placed differently to others. Nasher.
Sorry, I should point out that I’ve measured a genuine FE hanger like the one I need, which is where I came up with the idea of modifying a fixed hanger as I found both have an outer boss diameter on the front of 32mm, and both are made for a 17mm spindle. They do differ on the back unfortunately, in that the boss at the back is smaller on the fixed hanger so it can’t be bored out to take the top hats and Glacier Bearing. It appears that on the later fixed hanger the boss is the same larger diameter on the front and back. Unfortunately the hanger I measured is attached to a rather nice track day bike, and the owner won’t part with it. Nasher
