[CR] front wheel collapse, was Re: Phil Wood Disc Brake

Example: Production Builders

Date: Tue, 06 Jul 2010 20:05:05 -0400
From: Harvey Sachs <hmsachs@verizon.net>
To: Mark@bulgier.net, Classic Rendezvous <classicrendezvous@bikelist.org>
Subject: [CR] front wheel collapse, was Re: Phil Wood Disc Brake

Mark Bulgier wrote <snip>

We did have one team that buckled their front wheel (taco / potato chip / pretzel depending on your geographic region). When the disc is crammed into a 100mm front fork it results in a dished wheel, weaker on the disc side due to the narrower center-to-flange spacing. This poor tandem team rode their brand-new custom bike about 10 feet and buckled the wheel before they got off the sidewalk, an inauspicious first ride. IIRC we switched them to a rear disc and rebuilt the front wheel symmetrically.

I think Phil did offer a symmetric F disc hub, but the fork has to be built for it. Was it 105 mm? 110? Someone here will remember.

++++++++++++++++++++++++++++++++++++++ I saw a similar collapse on the front of a triplet. Three folks just starting out, turned the wheel quite far to regain balance, and boing, there went the wheel. I'm pretty passionate about not using dished front wheels, and about respectably far apart flanges on front wheels. The killer is the possibility of huge side loads at very low speeds; we had a narrow flange front wheel on a tandem that lasted decades since we never had such an incident. Won't try that again.

your mileage may vary, and I'm glad some folks had fewer bad experiences with Phil disk brakes than I saw and experienced.

harvey sachs
mcLean va