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12-18-08, 07:34 PM
I just built a custom freewheel with 12,13,14,15,17,19, 21 sprockets. This should be great for my high speed pedal assisted BionX hybrid road bike.
Last summer, when I built my high speed BionX hybrid road bike, I installed a 11-34T MegaRange freewheel (11,13,15,18,21,24,34). I've since found the gear spacing too wide. With the MegaRange, I'm only using the 13,15, 18 sprockets and rarely the 11. Here's a link to my post detailing my my bike build with photo showing the MegaRange installed..
http://www.bikeforums.net/showthread.php?t=454963
For a customized freewheel, I'm using a used Dura-Ace MF-7400 and the sprockets from a new freewheel by Interlock Racing Design (IRD). Both are index shifting (SIS) compatible. I could have just installed the Dura-Ace unmodified, but some of the sprockets were excessively worn. Also, the IRD uses the later Hyper-Glide sprocket design, as compared to the Dura-Ace's older Uni-Glide sprockets.
The IRD freewheel is part number 23730, and costs $50 plus shipping. This is the 7-sp freewheel with 13-14-15-17-19-21-24 sprockets.
http://www.interlocracing.com/freewheels_steel.html
The used Dura-Ace MF-7400 that I bought on eBay for $40 including shipping, has the following sprockets: 12,13,14,15,16,17,18. If you buy one make sure it has a 17 on the 3rd or 4th sprocket as you'll need that to use as a template as shown here.
Basically, this customized freewheel was the Dura-Ace re-assembled using the first six sprockets from the IRD freewheel, while still using the Dura-Ace's 12 sprocket. But the individual 17 tooth sprocket takes some grinding to make it fit. The idea for this project came from this great writeup...
http://bellsouthpwp.net/k/a/kaeru41/freewheels.htm
Here's the two freewheels before disassembly.
http://img364.imageshack.us/img364/1300/customsprocket002mv4.jpg
You need two chain whips to disassemble them.
http://img367.imageshack.us/img367/4017/customsprocket004gc8.jpg
http://img515.imageshack.us/img515/8348/customsprocket005yc8.jpg
Notice the stepped arrangement. The three largest spockets have larger inner diameters. Take a look at the 17 sprockets from the new and old freewheels. Notice the inner diameter is larger on the Dura-Ace.
http://img523.imageshack.us/img523/5523/customsprocket006fl0.jpg
In order to enlarge the inner diameter of the new 17 sprocket, I used the old 17 sprocket as a template. Here they are stacked and held in place with screws.
http://img515.imageshack.us/img515/1432/customsprocket008yl2.jpg
I used a Dremel like rotary tool with carbide disk to do the grinding. If you do this be sure to wear safety goggles. I wore safety goggles and a respirator.
I also used a saber saw with carbide and hand files grind into the sharp corners and to do some finishing work.
http://img515.imageshack.us/img515/2276/customsprocket010tz0.jpg
Here's the finished 17 sprocket ready for assembly. Also on all the other IRD sprockets I needed to grind off the index notch on each, but that was really easy compared to the 17 sprocket work.
http://img210.imageshack.us/img210/5199/customsprocket016qc5.jpg
Here's the finished product. I'll install it on the bike when I get some free time.
http://img515.imageshack.us/img515/4598/customsprocket015rv5.jpg
http://img364.imageshack.us/img364/8653/customsprocket011uk7.jpg
Here's the freewheel installed. Shifts great too!
http://img70.imageshack.us/img70/1346/customsprocket022ef2.jpg
Last summer, when I built my high speed BionX hybrid road bike, I installed a 11-34T MegaRange freewheel (11,13,15,18,21,24,34). I've since found the gear spacing too wide. With the MegaRange, I'm only using the 13,15, 18 sprockets and rarely the 11. Here's a link to my post detailing my my bike build with photo showing the MegaRange installed..
http://www.bikeforums.net/showthread.php?t=454963
For a customized freewheel, I'm using a used Dura-Ace MF-7400 and the sprockets from a new freewheel by Interlock Racing Design (IRD). Both are index shifting (SIS) compatible. I could have just installed the Dura-Ace unmodified, but some of the sprockets were excessively worn. Also, the IRD uses the later Hyper-Glide sprocket design, as compared to the Dura-Ace's older Uni-Glide sprockets.
The IRD freewheel is part number 23730, and costs $50 plus shipping. This is the 7-sp freewheel with 13-14-15-17-19-21-24 sprockets.
http://www.interlocracing.com/freewheels_steel.html
The used Dura-Ace MF-7400 that I bought on eBay for $40 including shipping, has the following sprockets: 12,13,14,15,16,17,18. If you buy one make sure it has a 17 on the 3rd or 4th sprocket as you'll need that to use as a template as shown here.
Basically, this customized freewheel was the Dura-Ace re-assembled using the first six sprockets from the IRD freewheel, while still using the Dura-Ace's 12 sprocket. But the individual 17 tooth sprocket takes some grinding to make it fit. The idea for this project came from this great writeup...
http://bellsouthpwp.net/k/a/kaeru41/freewheels.htm
Here's the two freewheels before disassembly.
http://img364.imageshack.us/img364/1300/customsprocket002mv4.jpg
You need two chain whips to disassemble them.
http://img367.imageshack.us/img367/4017/customsprocket004gc8.jpg
http://img515.imageshack.us/img515/8348/customsprocket005yc8.jpg
Notice the stepped arrangement. The three largest spockets have larger inner diameters. Take a look at the 17 sprockets from the new and old freewheels. Notice the inner diameter is larger on the Dura-Ace.
http://img523.imageshack.us/img523/5523/customsprocket006fl0.jpg
In order to enlarge the inner diameter of the new 17 sprocket, I used the old 17 sprocket as a template. Here they are stacked and held in place with screws.
http://img515.imageshack.us/img515/1432/customsprocket008yl2.jpg
I used a Dremel like rotary tool with carbide disk to do the grinding. If you do this be sure to wear safety goggles. I wore safety goggles and a respirator.
I also used a saber saw with carbide and hand files grind into the sharp corners and to do some finishing work.
http://img515.imageshack.us/img515/2276/customsprocket010tz0.jpg
Here's the finished 17 sprocket ready for assembly. Also on all the other IRD sprockets I needed to grind off the index notch on each, but that was really easy compared to the 17 sprocket work.
http://img210.imageshack.us/img210/5199/customsprocket016qc5.jpg
Here's the finished product. I'll install it on the bike when I get some free time.
http://img515.imageshack.us/img515/4598/customsprocket015rv5.jpg
http://img364.imageshack.us/img364/8653/customsprocket011uk7.jpg
Here's the freewheel installed. Shifts great too!
http://img70.imageshack.us/img70/1346/customsprocket022ef2.jpg