Re: [CR]lurker question

I dunno Mike, but retrofrictions may be just a bit high-tech for this list! But, Campy did prototype an NR/SR version, so we're in under the wire.

I assume that by "preload" you are refering to the tightness of the friction-screw-wingnut-thingy (tm). Set that as you would on any friction lever, so it is tight enough not to slip and loose enough to move smoothly. (I usually just crank it down, since there are some cupped spring washers in there that provide forgiveness in the setting.) On upshifts (to smaller cogs) all of the internals on this model rotate around an axle formed by the boss and a steel insert that engages the boss. There are bronze washers on either side of the lever to let things run smoothly.

The retrofriction-ing takes place on downshifts when the center of the lever's internals stays fixed relative to the boss/insert/washers while the lever moves freely thanks to a clutch mechanism. The clutch is actually three tiny springs that force three tiny ball bearings into the alloy of the lever causing the whole mechanism to turn during upshifts, whereas the springs compress and the bearings roll allowing the clutch to slip during downshifts. It's the steel- bearings-forced-into-soft-alloy feature that causes these levers to wear out and begin to slip. At that point the slippage is in the clutch and no amount of wingnut tightening will help.

If you are having any difficulty with these levers, first make sure that they're not shot (slipping at the clutch), then give them a good lubing with some viscous oil. Also, make sure that the spring washers (two on each side) are set with the concave faces together. Some of the early instruction sheets had this wrong.

Tom Dalton