Nuts ‘n’ Bolts :: Keeping Your Freewheel Free
[[image:freewheel_mini.jpg::inline:1]]A significant trend at the Bike Oven is for newbie’s to show up sporting their newly (and cheaply) acquired UJBBTS (Universal Japanese Bike Boom Ten Speed).
Published April 6, 2007 by C.I.C.L.E.
Contributed by Harv
Photos and Assistance by Leticia Z
A significant trend at the Bike Oven is for newbie’s to show up sporting their newly (and cheaply) acquired UJBBTS (Universal Japanese Bike Boom Ten Speed). They come to the Oven because even a basic tune-up at an LBS (local bike shop) would cost more than twice what they paid for the whole bike. Frequently the bike needs more than a tune-up. It needs to get some deeper problems sorted out.
Lately we have been getting a rash of freewheel problems. Possibly unaware that this long-suffering component is protesting, the rider complains of one or both of these symptoms: drive train slips and/or chain gets sucked into contact with the chain stay when coasting.
Either of these symptoms may be caused by other problems, such as worn chainrings or cogs, or a worn or dirty chain. But they can also be caused by the lack of internal lubrication of the freewheel, which may have unworn teeth and look brand new on the outside.
After the three or four decades of use and neglect, such a bike is acquired, by our bright eyed young rider, from a thrift shop, a garage sale, or Craig's list. Thirty or forty bucks changes hands and our intrepid newbie airs the tyres, adjusts the seat and pedals down the road with great expectations.
Then the little bothers that have accumulated for decades rear their ugly heads. The drive train slips or the chain sucks. What has happened is that the bearings and/or pawls inside the freewheel have run out of lubricant, have gotten stiff, and are refusing
Dry pawls can stick in the up position and fail to transmit pedaling torque to the rear wheel. This manifests itself as a total loss of pedal power until such time as the pawls manage to catch the ratchet mechanism. Or the bearings drag to the point that the freewheel wants to follow the rotation of the rear wheel and sucks the chain down into contact with the chain stay. Either situation can be disastrous and quite dangerous.
Often, simply running some oil into the interior of the freewheel will solve either or both problems. Use a light machine oil for this purpose.
Squirt the oil where the spinning freewheel body rotates around the stationary center of the freewheel near the axle. It helps to position the bike (or wheel) on its side, with the freewheel facing up.
I recommend air tool oil as it contains a detergent. Once the mechanism is running freely, follow up with occasional squirts of regular machine oil.
Make this a part of your periodic chain lubrication, and lube the jockey wheel bushings and derailleur pivot pins at the same time.
If this treatment does not help, the freewheel may be saved by dismantling and replacing and adjusting the bearings. Access is gained to the bearings and pawls by unscrewing (clockwise) the bearing cone. The proper tool for this is a pin wrench, but a hammer and punch will do.
Just remember that this cone has a left hand thread and needs to be turned clockwise to remove. The eighth inch diameter ball bearings can be replaced after everything is flushed out with solvent and lubricated.Restore proper adjustment of cone by removing shims, if required, and then replacing cone.
In our example pictured, while the freewheel action was not very free, dismantling showed the bearings, cup and cone to be in good shape. After removing the cone, bearings, and shims, the ratchet pawls were squirted with light oil directly as shown. The clean bearings, cup, cone, and adjustment shims were lubed with white lithium grease and reassembled.
Final bearing adjustment was achieved by seating the cone then backing off a few degrees. Just a bit of working clearance was left in and the freewheel spun freely once again.
Rebuilding a freehub mechanism (for cassettes) is another matter. When these get to be 3 or 4 decades old, we will see how they have held up. But meanwhile, they are rebuildable. Consult the Park Tool website for details. Or wait until the Bike Oven gets one in for repair