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6-7 speed to single/ fix(3 posts)

6-7 speed to single/ fixbuffalosorrow
May 3, 2003 7:00 AM
on my old motobecane mirage messenger bike, I have a mallard/ rigida ( yeah all french) fix, but I have destroyed the rear hub. I have a RSX 7 and suntour 6 spd rear wheel, aside from just tossing the wheel on the bike as is. Is there any way to 'fix' these wheels? I have heard about ramped spacers and using one cog, but this turns it into a single speed, correct? Or should I focus on rebuild the track hub?
re: 6-7 speed to single/ fixHumma Hah
May 3, 2003 12:58 PM
A 6-speed Suntour should have a 6-speed freewheel that screws off to reveal the threads onto which singlespeed freewheels or fixed-gear cogs will screw right on.

The catch with fixed gear is that the hub does NOT have the additional, slightly smaller, reverse-threaded section onto which a locking ring for the fixed-gear cog screws. Thus, really viscious braking action on the pedals while traveling at high speed could conceivably un-screw the cog.

However, there are thousands of folks out there happily riding fixed gear on hubs like that, simply using Locktite to hold the cog in place. As long as the bike has adequate brakes, and you don't need to worry about panic-stopping with the pedals, it should work fine.

Some singlespeeders will take a 5-7-speed hub apart and remove all but one cog, making a singlespeed freewheel, filling in with spacers (bought or scrounged from another scrap freewheel). To make a fixed-gear this way would require you to freeze up the freewheel by some method such as welding.
re: welded freewheelsukiahb
May 5, 2003 8:37 PM
I welded up a Suntour 5 sp freewheel when I first built my fixie, but had problems with the chain jumping (and breaking teeth off) as the chainline was a little off and multispeed cogs are not designed for FG applications. I then bought a Shimano BMX freewheel (only $15) and welded it, have a better chainline and no more problems. If you do want to try using the existing freewheel, the first two cogs probably screw on...once they are removed the others can be discarded and the #2 reinstalled...this was an 18t in my case, and probably would have worked OK if the chainline had been right...I also tack welded the cog to the freewheel body to prevent it from unscrewing FWIW.