Sunday, January 2, 2011

One Rideable 650B Schwinn World Sport

Apart from some remaining accessory work (installing the rack, bell, front water bottle cage holder, and trimming the kickstand back an inch or so), Juliana's old chromoly Schwinn World Sport is now finished and ready to ride.  It's wet out there today, but she could take it out for a spin if she were so inclined.

The bike is set up as an all-around sort of ride, with slightly poofy (32 mm) Rivendell tires, centerpull brakes, drop bars, a Brooks B-17S saddle, a kick stand, and interruptor levers to give the rider braking capabilities from not just the hoods and drops, but also the bar tops.  As the bike is accessorized, it'll gain a rack, another bottle cage, a bell, and a saddle bag fitted with a blinky.  I can even hook Juli up with a basket if she wants a little more carrying capacity.  Basket or no, it should be a sturdy and user-friendly bike for Juli to use pretty much anywhere she'll want to go, whether the route there involves grassy or packed trails, or smooth or rough roads. 

The build itself was pretty straightforward, with really only two areas that posed a challenge.  I've already written about the unorthodox headset configuration I chose, so I won't belabor that.  I'll see how that setup holds up.  In the worst case, I'll need to find another chrome fork for the bike, but I'm not anticipating having to do that.

The brakes were the second area where a little thought was required.  It's a ladies'-style frame, as you can tell from the pictures, not a mixte.  The big difference is that the brakes are located at the usual position -- mounted to a brake bridge on the seat-stays, rather than where they might be mounted on a mixte -- on a brake bridge down on the mid-stays.  Mixtes normally have their brakes located there, because the brake cable follows the path of the twin top tubes, and run straight onto the rear brake.  This bike's brake cable followed the top tube, but that put the brake cable a long way away from and below the rear brake.

This bike was designed to use with a sidepull brake caliper whose cable routing is opposite the norm, in that the housing stop and adjuster are located where the cable nut normally is, and the cable nut is located where the cable housing stop and adjuster normally reside.  Brompton has a caliper like this for use with their folding bikes, but I didn't really want to have to buy a pair of sidepulls for the bike, I wanted to use a set of centerpulls I already had on-hand, and for those calipers, the cable needs to come from above, not below.  Some improvisation was called for!

My first thought was to route a length of housing from the cable stop near the top tube/seat tube lug, up to a seatpost clamp-mounted cable stop -- maybe using cable ties to hold it in place as it ran along the seat tube.  Unfortunately, I predicted this would provide for sloppy and probably stiff rear braking and really messy, in-the-way routing -- there had to be a better option.  Maybe some sort of pulley to redirect a naked brake wire to the caliper from below?

The good news is that back in the days when Mafac, Weinmann and Dia-Compe center-pulls ruled the road, there were plenty of ladies' and mixte-style frames, and not all of them used mid-stay mounted brakes.  Some of them used brakes mounted on a seat stay, just like Juli's Schwinn.  And for those types of frames, a neat solution had already been devised by at least Mafac-- a pulley, as it turns out, just as I wondered about.  Actually, I'd probably seen one before and half remembered.

I bought the pulley for maybe $15 on eBay, and it bolted right up to Juli's seatpost clamp, using a binder bolt I had on hand.  Then I picked up a clamp-on cable stop from Rivendell, which let me use housing to redirect the cable from the top tube up along the seat tube.  I inserted an inline adjuster, as well, having had great luck with them on the Schwinn, and needing some way to adjust the brakes.  The result is as shown, and it works just great -- not too much friction in the cable, despite the fairly tight bend.  I've got a long-reach Dia-Compe 750 on the back, and a standard-reach 650 on the front, and installed some Yokozuna pads with the Scott-Mathauser red compound.  They seem to bite just fine, either from the drops or the tops, and I expect they'll be more than adequate for Juli's weight.

The drivetrain is the same set of components from her Fuji -- Shimano 8-speed bar-end shifters (set to friction), RX-100 derailleurs, and a 165 Tru-Vativ crankset.  A standard-range 7-speed freewheel (13-28) and wide-set front chainrings should give her more than enough ratios, albeit a little more widely-spaced than with a contemporary 20-speed bike.  She'll be pushing through the Rivendell/MKS Grip King pedals I bought for the Schwinn several years ago, then opted out of.

It's not the best frame ever devised, with slightly hokey rear dropouts without alignment screws.  But it's a nice build by any reasonable measure.  Barring theft, major damage or something else unforseen, this bike should carry Juliana through her middle school years and into high school.  When she stops growing, and assuming she's still actively riding, I've promised her one more bike from Dad.  That'll likely be a new one, not a build-up of old parts like the Fuji was, or this Schwinn, and it'll come already built, not as a project.  It's my hope that at least some of the excitement of getting a new bike is tempered by the fact that it won't come in the form of a father/daughter project.

All for now,


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