Cyclopath! - Keiron said:Quoted message said:Art gave an excellent description of how to use a dishing tool.
Since you're moving ("redishing"😉 the hub to change from multiple
freewheel to single freewheel, it may be you're missing this step:
1. Change your hub's axle spacing (usually by adding and removing
spacers) so that (a) the freewheel threads are positioned where you
want (for your single speed freewheel) and (b) the over lock nut
dimension fits your frame.
Then follow Art's instructions to use the dishing tool.
Hi Dianne, Thanks. I should have been more comprehensive initially. I had
had read about this step but was further advised that spacing was less of an
issue if the hub was instead centred on the axel (solid axel), is this the
case or wheel this throw the wheel alignment out of sync? What i had
proposed to do, more precisely, is have the hub centre on the axel, the rim
centred to the flanges of the hub, then the bmx freewheel in place and then
the axel appropriately placed. Would this work or would it affect the wheel
alignment? i thought not (?) Or do i need to relocate the axel as is and
then follow arts description?
thanks
Keiron,
Here is the way I do this (set up a singlespeed rear wheel using a
typical freewheel hub, either existing or before it's built, and then
set up the bike as singlespeed using a BMX freewheel)
1. Space the hub so that the midpoint between the flanges is the same
as the midpoint between the locknuts, and so the hub's overall spacing
(over-locknut dimension) matches the frame's. I do the measuring for
this by just holding calipers and a ruler alongside the hub, and
usually make a little diagram of the hub as I go along to help keep
track of everything. This is a somewhat clumsy and imprecise way of
measuring, but any dish (uneven spoke tension) introduced by the
imprecision is very tiny and won't affect anything as long as you're
pretty close.
2. Either build or re-dish the wheel. The wheel will be virtually
"dishless" (equal spoke tension on either side of the hub), which is a
very good thing. You don't do anything unusual here - just get the rim
centered between the 2 locknuts.
3. Install the freewheel and measure what chainline it's giving you.
Here I would also check the rear triangle alignment of the frame and
either align it or take note if it, as misalignment directly affects
chainline. (It's basically okay to skip the frame alignment part, but I
don't because I like perfect chainline).
4. Set up the bottom bracket, cranks, and chainring to give a chainline
that matches the rear.
This is the most expedient way I know to set up a
random-freewheel-hub-based-singlespeed with perfect chainline and a
dishless wheel. In the case of most hubs that are intended for
singlespeed or fixed, you'll have a way of knowing what chainline
they'll have ahead of time, and little or no tinkering will be required
to get a front chainline to match, but this is generally not the case
with what you're doing.
