Bullwhip

Archive for August, 2012

Cindy’s Featherweight Cross Bike

Monday, August 27th, 2012

Cindy is one of the luminaries on the Bikes Not Bombs-Circle A Cycles ‘cross team, and for this season she wanted something with a better fit and lighter weight. Something to win on. She’s not tall, and was eager to engineer in some toe/tire clearance. This is what we came out with.



The frame consists of a True Temper S3 front triangle, with Dedacciai rear triangle featuring Zero chainstays and Zerouno s-bend seat stays, and weighs in just a tick over 3 lbs. The fork is by Enve. I’ll be building a steel rando fork for her as well, so I’ve included rack and fender mounts. Putting the “light” in light touring.

        

The S3 tubeset is a bit tricky to work with; only the seat tube is round, and the extremely thin walls (.5 mm at the butts!) make it easy for it to tear in the mill, so every miter is done by hand. And they have to be tight if I’m not going to burn through while welding. Also the small size of the frame demanded a funky compound miter at the head.

     

Next: Dan’s single speed MTB, Charlie’s ‘cross machine, Bert’s rando rolls!

Rohloff Rising

Monday, August 13th, 2012

Allow me to introduce Bryan’s 14 speed Rohloff-equipped tourer. He just completed an 8 day tour of the Great Divide on his Tout Terrain Silkroad (also a Rohloff rig), and we’ve spent the last several months coming up with a custom bike that will be similarly suited for adventure touring, but more nimble and lightweight – as well as providing toe/fender clearance, which bedeviled Bryan on the TT.

  

  

  

  

Here are some frame details. It’s a TIG welded frame of True Temper and Dedacciai tubing, with clearance for 40c tires and fenders. The Rohloff-specific dropouts are from Paragon; one of the advantages of the Rohloff compared to other internal-gearing systems is that’s very easy to disconnect in order to remove the wheel to fix a flat – you simply pop off the black box that holds the shifting mechanism, and you can drop the wheel out (with the sliding dropouts, you don’t even have to worry about re-adjusting the chain tension).

Bryan is running a Schmidt SON 28 Dynohub, with Busch & Müller lights. Because the twin Rohloff gear cables were running to the back of the bike anyway, I ran the wire to the rear light bundled with them; but it does run inside the fork and the rear rack. There are disconnects so that Bryan can remove the racks, fenders or fork easily for service or shipping.

  

  

  

I also did a disc tab installation on Mike’s IF, and am finishing a superlight cross bike for Cindy, just in time for the D2R2! Here are some pics, but more on that next week! Then, Dan’s mountain bike, Bert’s Rando, and Charlie’s cross bike!

  

Circle A Cycles   |   523 Charles Street   |   Providence, RI   |   401.831.5221
background: bullwhip demonstrates fun on a bicycle. (reveal)

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