![]() ![]() ![]() ![]() Most "power" discs will work with either the 110 mm or the 130 mm size.Yeah! I get to beat Rob for a comment. ![]() This allows the use of high-quality 3/32" chainrings designed for derailer use. You can also buy a spider or "power disc" that fits onto the one-piece crank as a normal chainwheel does, but which has holes to accept standard 110 mm or 130 mm BCD (Bolt Center Diameter) chainrings. Triples are most often 28/38/48, but other combinations are available. The doubles and triples are usually riveted together units, with standard ratios. You can buy single chainwheels of various sizes, usually for 1/8" chain, or double or triple chainwheels for 3/32" chain. They have a 15/16" hole in the middle, and another, smaller hole for the drive pin of the right crank to engage. Virtually all one-piece-crank chainwheels are interchangeable. These are often worthwhile if you are trying to upgrade the performance of an older bike.Īn even better solution is to get a set of adaptor bushings that permit the use of modern threaded cups and three-piece cranks.Ī much wider variety of pedals is available for the pedal threading used on three-piece cranks. It is also possible to buy conversion bearing assemblies that will work with cotterless three-piece cranks. It is usually a good idea to buy a whole set (cones, cups, retainers) if there is serious wear to any of the parts. 28 TPI cranks use #64 retainers, with 9 5/16" balls.The pressed-in cups are also a slightly different size internally, though they both fit the same frame bottom brackets. No part of the bearing assembly is interchangeable between threadings.Ģ4 TPI cranks use #66 retainers, with 10 5/16" balls. made Schwinn and Mongoose models, use 28 threads per inch. The more common size uses 24 threads per inch, but some bikes, particularly older U.S. There are two major types of one-piece crank sets, differentiated by their axle threading. See my glossary entry on pedal threading. All other common cranks (except some older French cranks) use a 9/16" x 20 TPI threading. One-piece cranks fit pedals with a 1/2" x 20 TPI threading. It is extremely difficult to assemble a one-piece crank set with loose balls, I would not recommend trying. In most bicycle applications, bearings with loose balls are preferable to those that use retainers (cages.) One-piece cranks, along with headsets, are a major exception to this rule. If they are smooth and free from pitting, you can re-use them. If you try to pull the corners of the one-piece crank through without removing both retainers from their cups first, you may damage the retainers.Ĭlean and inspect the cones, cups and bearing retainers. Pull the crank partway out of the bottom bracket, then reach in and remove the right side bearing retainer. Pull out the ball retainer, then you will be able to withdraw the whole crank assembly from the right side of the bottom bracket. To disassemble a one-piece crank, start by removing the left pedal (turn it clockwise to unscrew it-everything on the left side of a one-piece crank is left (reverse) threaded.) Then remove the locknut on the left side bottom bracket (clockwise to remove), lift off the keyed washer, and unscrew the left cone (clockwise to remove.) The left cone usually has grooves that allow you to turn it with a flat-bladed screwdriver. ![]()
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