Tandem Hub Conversion

This could just as well be titled, “How to make stuff work.” In a previous article I explained the choices I faced when trying to decide what to do about a new higher-performance wheel set for our tandem. Now that the parts are here I am going to take you step by step through the conversion process that I used for the Shimano FH-M760 rear non-disc hub. (See pictorial gallery below)

There are a few tools, parts and documents that you will need first in order to make the conversion. The parts are of course the hubs. A replacement axle, Wheels Manufacturing AXLE-29. Some axle spacers, also available from Wheels Manufacturing. The Shimano Technical document EV-M760-2265 gives you an exploded view of the hub and its components. This will be very helpful in knowing how to disassemble the hub and remembering how to put it all back together. The tools you will need include a 17mm Cone Wrench, a 15mm cone wrench, and a small flat blade screwdriver. That is not a lot of tools. Also helpful would be a small ruler so measure exactly how far the axle extends beyond the serrated lock nut at the end of the axle. All tools are available from Park Tools.

Once you have everything within reach the first step will be to pry the rubber cover off the axle on the non-drive side of the hub. It should come off fairly easy. Set the rubber cover aside. This will expose the two left hand axle spacers (4mm and 8mm) and the left hand cone. The cone has two landing surfaces machined for a 15mm cone wrench and the outer serrated lock nut also has machined surfaces for a 17mm cone wrench. Make a note of the distance the axle protrudes beyond the serrated lock nut.

Using both wrenches hold the 15mm still while using the 17mm to loosen the lock nut. Once the lock nut is removed you may remove the spacers and the left hand cone. Carefully remove the axle from the hub shell, being careful not to disturb the loose ball bearings inside of the hub. Now with the axle out of the hub shell you can repeat the process for the right hand cone and serrated lock nut. We have unassembled as much as we need to complete the conversion.

A small amount of grease is all we need on the threads of the new axle, we will add more later, but it will be easier to assemble and a whole lot cleaner if we use the grease sparingly at this point. We will start reassembly with the right side. The axle is actually threaded identically on both ends so there is no need to know right from left. First thread on the right hand cone making sure that it is threaded well beyond its final setting. Next the right hand axle spacer and seal ring slide on. The right hand dust cap and washer are next. Finally the right hand serrated lock nut is threaded on the end of the new axle.

Position the right hand serrated lock nut so that the axle extends beyond it by the amount you noted before. Use the 17mm cone wrench to hold it in place while you secure the right hand cone against it. Make sure the assembly is tight. Now lather up the axle with a good coating of grease and insert it back into the hub body.

Reverse the disassembly order of the left hand cone with dust cover and seal and the 8mm axle spacer. Now insert two of the new 5mm axle spacers then replace the existing 4mm axle spacer. Replace the left hand serrated lock nut. For a good set of instructions on how to properly adjust hub cones see the Park Tool web site.

Once adjusted, replace the rubber seal. Finished, now all that is left to do is built us a rear wheel!