[attachment=3502][attachment=3503]The wife asked me to convert her ten spd to a single speed. The project was moving right along. I found a Shimano coaster brake hub to replace the freewheel rear hub. It comes with an 18T cog. Up front there's a problem. I wanted to set up a 42-18 gearing so a new chainring is needed. But the Takagi crankset does not have a spider on the drive crankarm. The outer ring mates directly on the spindle and the inner ring bolts to it. Searching for a Takagi compatable chainring has been fruitless. So change the drive side crankarm to one with a spider? OK, but what fits what in the world of cranksets? This spindle is 16.5 mm diameter and has a square taper. Is the taper on all crank spindles the same?
"dish the rear hub" ?????
typically the rear hub defines the location of the cog, and there is not any flexibility.
Is the OLD of the new wheel the same as the old? Things need to be fairly close for things to work. If the new hub is narrower, there is a potential to use washers if the axle is long enough.
At the front, the chain line is set by the BB axle length.
Nigel
Thanks y'all for the great advice. I'm thinking that nfmisso is right on; this is going to take some tinkering (with crank spindle lengths and rear hub spacers).
Xerxes asked, "why a coaster hub"? The wife's specification was for a single speed like the (cruiser) bike of her pre-college era. And, those existing brakes are the dual pivot type with the arms joined by a cable yoke. Not enough leverage to slow a runaway hamster.
I would scrap the center pulls, and get some Tektro dual pivot side pulls - MUCH more effective. Measure the reach carefully, see Sheldon's webpage on the subject.
Coaster brakes are not very good compared with modern dual pivot side pulls or linear pull brakes. The bike in the picture does not have provision for linear pull (aka V-) brakes. Dual pivot side pulls are the next best thing - unfortunately they are considerably more expensive.
Nigel
nfmisso, thanks for the direction to Shelton Brown/Harris Cycle webpage on brakes. Lots of good info' of how things have changed since the late ' 70's.
I've noticed that center pull brakes are back, but a much more robust construction, on some MTB models.
I do have a set of Shimano 600 side pull brakes that I could contribute to this project. The front bolts right on but a custom bracket would be needed to mount the rear. Of course if I did this then new brake levers would have to be sourced.
No, guys, I'm stickin' to the original spec' and building a new rear wheel around a Shimano coaster hub. I have the rim.... the mate to front in the photo. I'll add a new crankset sized on the gearing that suits the wife. Maybe incorporate that Shimano 600 front brake with a new lever.
Can't be sure from the picture, but I think you have a steel rim on the back at least. No brakes work very well on steel rims. Going to alloy with any brake will work better.
That said, coaster brakes are very powerful. If your wife liked them before, I see no huge reason not to do that. Note though that a strong rear brake only does so much. The front brake can give twice as much stopping power as the rear. If you have a better brake caliper, I'd put that on the front even if you don't change the lever. Or at least good new brake pads.
Just wanted to say thats a pretty bike
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Good maintenance to your Bike, can make it like the wheels are, true and smooth!