Re: SunTour 'New Winner' freewheel; state of the art in 1978
Posted: 19 Jun 2020, 11:58pm
just use a small hammer and (correctly shaped) drift to tighten/loosen the lockring. The adjusting race can be prodded round using a small screwdriver and doesn't need to be held (there is a beefy tab washer that stops it from turning).
You don't need to go nuts when tightening or loosening the lockring. If the lockring doesn't loosen when tapped for the first or second time, turn the freewheel body 180 degrees and try again on the other notch. Repeat as necessary until it loosens.
The correct shaped drift is close to the shape of a flat blade screwdriver, but with the end ground at a slight angle so that it bears against the notch correctly.
The correct adjustment is the first increment which gives no free play with the lockring tight. Increment the adjusting race tighter by no more than 1/30th of a turn at a time, and assess the free play with the locknut tight (it alters the clearance of course). 1/30th of a turn seems like a small amount but even this increment is ~30um clearance change. This is a barn-door clearance variation, in precision bearing terms.
As is almost invariably the case with freewheels, this work is best carried out with the freewheel still (tightly) on the wheel.
The 'correct spanner' is liable to get rounded off or slip more easily than it should, IMV, so it certainly isn't any better than using a hammer and drift. I have the correct spanner and I still find it easier (and probably better) not using it.
The only negative thing I would say is that if you raise burrs on the lockring of a 7s New Winner they can contact the inside of the #6 sprocket (or I suppose likewise #5 of a standard 6 spaced NW), which is bad; you need some clearance here so keeping the adjustment correct and dressing any burrs there might be on the lockring is important.
cheers
You don't need to go nuts when tightening or loosening the lockring. If the lockring doesn't loosen when tapped for the first or second time, turn the freewheel body 180 degrees and try again on the other notch. Repeat as necessary until it loosens.
The correct shaped drift is close to the shape of a flat blade screwdriver, but with the end ground at a slight angle so that it bears against the notch correctly.
The correct adjustment is the first increment which gives no free play with the lockring tight. Increment the adjusting race tighter by no more than 1/30th of a turn at a time, and assess the free play with the locknut tight (it alters the clearance of course). 1/30th of a turn seems like a small amount but even this increment is ~30um clearance change. This is a barn-door clearance variation, in precision bearing terms.
As is almost invariably the case with freewheels, this work is best carried out with the freewheel still (tightly) on the wheel.
The 'correct spanner' is liable to get rounded off or slip more easily than it should, IMV, so it certainly isn't any better than using a hammer and drift. I have the correct spanner and I still find it easier (and probably better) not using it.
The only negative thing I would say is that if you raise burrs on the lockring of a 7s New Winner they can contact the inside of the #6 sprocket (or I suppose likewise #5 of a standard 6 spaced NW), which is bad; you need some clearance here so keeping the adjustment correct and dressing any burrs there might be on the lockring is important.
cheers