Bicycle Freewheel - Page 2 of 6
Figure 5 - The hub axle hardware
The complete axle assembly is shown in Figure 5 after removal of the left side nuts and all of the bearings. The hardware on both sides of an axle are the same, but the spacer on the freewheel side is much longer in order to allow the lock nut to clear the inside of the freewheel. This is necessary because the lock nut must press against the inside of the rear dropouts when mounting a rear wheel to a frame.
Figure 6 - The inside spline on a Shimano freewheel
Figure 6 shown the internal spline on the Shimano style freehub, which is where your removal tool must lock in order to unthread the freewheel from the threaded hub body. You can purchase a tool from many bike shops that will mate with this spline, allowing you to adapt a wrench, but be warned - these tools are easy to strip, and often fail to remove an old freewheel that has been torqued on from years of use. The home built tool shown next is much better.
Figure 7 - Find a bolt that is slightly too large
To create your own hub busting tool, start by finding a bolt that is slightly too large to fit into the freewheel spline. The tips of the bolt head should sit over the spline as shown in Figure 7. The bolt I found that worked well was about 7/8" across from one flat side to the other as shown in Figure 7.
Figure 8 - Making the bolt fit into the spline
The freehub removal tool is ultra simple; a bolt ground to fit into the spline and then welded to a lever with a length of at least 12 inches. As you can see in Figure 8, a little work with the angle grinder on the edges of the bolt will make it fit snugly into the freewheel spline. It should be easy to press into the spline, but not so tight that you need to hammer it in. Just work at the bolt with your grinder a bit at a time until it fits as shown in Figure 8.
The bolt is then welded to some type of steel rod or arm so that it can be used like a long wrench to muscle off the threaded freewheel from the hub. I used a retro crank arm from my scrap pile, as it was easy to weld the bolt into the axle hole. The arm was the perfect length to allow good mechanical advantage.
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You can build it yourself from our easy to follow DIY plans!