Confused About Single-speed Conversion & Rear Wheel Spacing
Is there a difference between 120mm spaced track hubs and unspecified 120mm spaced hubs for 5 speed or Suntour Ultra freewheels?
For a 5/6/7 speed, 126mm spaced conversion to single speed, it seems a 120mm spaced hub is ideal (maybe less so for a 130mm spaced frame?), as long as spacers can be added to each side, and enough axle remains to fit in the dropouts of the 126mm spaced frame? Would such a wheel have proper chainline using a single speed freewheel and track crank?
Can a 126mm spaced hub be setup to achieve proper chainline without dishing the wheel and without spacing that risks the axle breaking? If so, how?
If not, I imagine a 126mm spaced hub is a compromise, as the dished wheel will not be as solid as a purpose built, 120mm spaced, single speed wheel, where chainline should be good when using a single speed freewheel and track crank (assuming 126mm dropouts)?
Is the bike's dropout spacing relevant other than for axle width, i.e. will a 120mm spaced hub's chainline sometimes not line up, i.e. when used in wider (130mm+) spaced dropouts?
I imagine where an axle is not long enough on a 120mm spaced single speed wheel, replacing the axle with a longer one could be challenging, especially if the hub has cartridge bearings ?
Are 120mm hub axles (with added spacers) usually long enough to fit in larger spaced frame (126mm? 130mm?) dropouts?
Since many conversions will be with 126mm+ spaced frames, a 120mm-spaced hub could be problematic, e.g., if axle is not long enough ... or if wider dropout width throws off the spacing somehow?
Again, assuming proper single speed crankset and BB spindle width, can a frame's spacing still be too wide for a 120mm-spaced hub, even with a long enough axle, causing chainline to be off? Or, ... if given enough axle width and spacers on each side, would it still work and have proper chainline?
It doesn't seem like there are many prebuilt 120mm wheel options for sale that are specified to fit in a larger (126mm+) frame. A 27" wheel requirement makes this even harder to find.
Last edited by specialmonkey; 07-07-20 at 06:42 PM.