Monday, December 24, 2007

Fork It Over

What happens if receive your Frame-Neutral Replacement Fork™ and really like it? This is the story of a customer who recycled his low-trail fork into a new bike designed around that geometry.

I originally built a low-trail replacement fork for Jay’s Rivendell Canti-Romulus, designed with a 60mm offset that produced about 44mm of trail. Soon after receiving this new fork, Jay telephoned to say that he wanted to commission a new frame, incorporating this fork, if possible. He had some fit issues which could be addressed with a made-to-measure frame. He also had a wish list of small details, including a kickstand plate, which would be easy enough to get just right on a custom frame.

No problem. Every frame that I design begins with the fork. There certainly wasn’t anything to prevent Jay’s fork from being recycled, as long as it passed my inspection for damage or misuse.

Jay planned to strip the components from his Romulus to use on this new frame, which would be built with cantilever bosses. Before those rear cantilever bosses had been brazed into place, he sent an e-mail saying that he’d unexpectedly sold the Romulus complete, and would be buying all new components. I pointed out that brake technology now was an open option, and asked if he might like to consider using extra long reach (55-73mm) dual-pivot sidepull caliper brakes. Jay already was familiar with the beautiful “Silver” model from Rivendell, and jumped at the chance to use brakes which would match so nicely with the style of bicycle he envisioned.

But wait … doesn’t the fork have cantilever bosses? It sure did, but those were removed with some very careful hand work with files and sandpaper. No additional heating on the fork blades, and no trace that the canti bosses ever were there. Spoiling the fork’s paint wasn’t a concern since the new frameset was going to be painted in a different color.

So there it is, a second life for a Frame-Neutral Replacement Fork™ and a happy customer with a new bicycle designed to fulfill a dream. That, I propose, is why I do this.

And, finally, a few details, starting with that mounting plate for a fancy Pletscher kickstand.

Friday, December 7, 2007

Small Details

This fork started out as a low-trail Frame-Neutral Replacement Fork™ for a Rivendell Rambouillet. As we discussed the customer’s current setup and future plans, the fork’s specification expanded to include some neat custom features.

The customer requested separate under-crown mounting points for both a fender and the new Velo Orange randonneur front rack. This rack, intended to be used with caliper brakes, features a center tang made from a flat strip which attaches underneath the crown. With the limited space available in the open end of the steerer tube, this called for a carefully designed piece to provide two threaded sockets with enough separation to be functional, enough depth-of-thread for a solid connection, and no interference with the brake’s center bolt.

The mounting solution shown above provides a 6mm socket (front) for the rack, and a 5mm socket (rear) for attaching the fender. The spacing between the sockets is maximized, and the socket depth provides 5mm of full contact thread. The bridge that carries the sockets is about 2mm thick, and, with this crown, provides the extra bit of vertical drop required to allow the rack’s tang to pass cleanly beneath the arch of a Tektro R556 caliper brake. With the additional fork length built in to compensate for the added fork offset, all of this stuff underneath the crown won’t interfere with the clearance needed to properly position the fender over a 700Cx30 Grand Bois tire.

The customer will use a generator hub, running the light wire all of the way up the right fork arm, then down the left arm to a low-mounted light. To eliminate that whole unsightly zip-tie and p-clamp scene, this fork received a full set of brazed-on lighting wire guides, along with a dedicated light mount low on the left arm.

Small details like these really clean up the appearance of a bicycle. In doing so, the details themselves tend to disappear from the casual observer. But they’ll always be there, providing a perfect foundation upon which to carry your load, keep you dry and light your way.