Hi all
So been playing with the wayward SA hub again..
Standard SA hub cut away ?
2 bearings sitting in shoulders cut into the SA hub centre tube [ Blue ] etc etc.
Where X= distance between shoulders and Y = length of centre tube ?
So we have 3 possibilities :-
a) X = Y assembly with new bearings , no drag from from wheel when spun we all ride off into the sunset ?
We have drag in one hub won't settle after swinging to and fro a bit with valve pointing down , just spins briefly and stops dead ?
So we either have :-
b) Y > X when assembled the bearings are a very tight fit and need persuading into the hub with a drift if Y is longer than X bearing 1 is put in to the shoulder in the hub. The bearing 2 tries to reach the shoulder but can't because Y is to big this takes up all the slack in bearing 1 and all the slack in bearing 2 the inner races bulging out and as the bearings are a tight fit they cannot back off till the wheel runs free ?
c) X > Y the bearings go in into the shoulders but inner tube is still loose [ Y maybe only a couple thou to short ?] so when axle slack is taken up inner bearing races are squeezed in producing binding in the bearings ?
So added a thick 12mm dia washer on top of the inner tube ensuring b) was true and hub just spins briefly and stops dead scenario b) ?
So removed inner tube altogether carefully added bearings and lo and behold wheel spins freely with some to and fro when coming to a stop !
Conclusion inner tube Y dimension is to long for X dimension ?
SA actually calls the inner tube a bushing , however there is no part number for it on any of the drawings I can find ?
I wonder if each one is specific to the hub it came from ? seems unlikely , however both my hubs [ used when bought ] have had bearing changes have the bushings been swapped over ?
Next make a new inner tube to dimension Y and try then filing it down a little...
Or of course I am barking mad ......
regards Paul