Building a modern internal 5 or 8 speed hub into a Skiptooth (possible?)

I wanted to ad a 5 or 8 speed "Modern" internal hub into a 1939 Colson. I've seen it done before and was just hoping someone might have a few tips on the conversion process (to add the skiptooth sprocket). Or where to buy a pre built set up ? Thanks

I am not sure about this but couldn't you just "cut" out every other tooth on the modern cog and make it skip tooth that way? However, I believe to do that there would need to be an uneven number of teeth on it so there would not be an extra tooth somewhere at the end

1/2 inch pitch sprockets are thinner than 1" pitch. Someone makes inch pitch 3 lug sprockets that will fit at least Shimano and Sturmey Archer hubs.

Andrew is right- what you want is a conversion cog that is 3-spline in the center, and profiled for skip tooth on the outside. It's a better solution than just grinding teeth off a regular cog. My advice is to spring for a good quality, new Sturmey Archer multi-gear coaster brake and attach a conversion cog in the size of your choice. The bigger the rear cog, the more climbing power you will get, but the more top gearing you will lose. Ichibike was selling conversion cogs awhile back, but I am not sure if they still are. I would not be afraid to lace your own wheels. You're not going to do better than nice, vintage rims that match your bike tied to a modern hub that will have enough guts to climb a hill. The modern, pre-made/factory ballooner wheels I've seen are no match for a good set of vintage rims laced to a quality multi-gear hub.

Ichi still has them- 9 and 11 tooth:
http://www.ichibike.com/shop/?catid=50

Andrew Gorman said:

Ichi still has them- 9 and 11 tooth:
http://www.ichibike.com/shop/?catid=50

Click to expand...

Nice, I have the 11 on a Sturmey Archer 3 speed, and it's a nice combination. The Ichi cog may take a small amount of finish filing around the splines to fit just right, but they're nice to have. 5 minutes with a file to smooth the splines on mine and it slid right on the hub driver.

A bigger cog on a SA hub is always a good thing- I have always found them way overgeared. One other trick for 1/2" pitch chains is that early-1930s and 1940s AW hubs used a driver that takes a standard threaded cog. A 22 tooth SOMA track cog spun right on to my 1938 Gazelle, was the right width and made it a much nicer bike! Occasionally these old drivers will show up on eBay or in boxes of random parts. Snatch them up when you can!

Andrew Gorman said:

Ichi still has them- 9 and 11 tooth:
http://www.ichibike.com/shop/?catid=50

Click to expand...

Great info. I was thinking about doing this but thought I was going to have to cut and weld two cogs together.

Hello everyone. Thanks for the advice. This is exactly what I was hoping to learn. For basically $125 I can buy the rear sprocket ($25) and a 3 speed hub ($100 on eBay) and I'll have a easy conversion. ANd I have a feeling the new brake will be better then what I have now.

Looking at a Sturmey Archer 5 speed that has the following speeds....

•Gear 1 - 62.5% (-)37.5%
•Gear 2 - 75% (-)25%
•Gear 3 - 100% Direct Drive
•Gear 4 - 133.3% (+)33.3%
•Gear 5 - 160% (+)60%

This is going on a 1939 Tandem which is heavy (and I suspect the girlfriend may not be do 50% of the pedaling... so the extra gears may be needed if I'm doing most of the work)