Re: [CR] Round fork blades

(Example: Framebuilders:Bernard Carré)

Date: Fri, 26 Jun 2009 13:01:28 -0400
To: <classicrendezvous@bikelist.org>
From: "John Betmanis" <johnb@oxford.net>
In-Reply-To: <005f3577967348bca5bd99945e19a3b4@comcast.net>
Subject: Re: [CR] Round fork blades


At 12:47 PM 26/06/2009 -0400, Bianca Pratorius wrote:
> From what I'm reading I would imagine that round fork blades would be
>my choice and that of many others for road bikes. I feel the need for
>increased lateral stability on the tight corners but I feel no need for
>less flex in the vertical plane. I enjoy the feel of soaking up the
>bumps and I think that normal or even full out pedaling doesn't require
>increased vertical stiffness because not too much pressure is put on
>the fork during hard pedaling.

The only time lateral loads would be applied to the fork would be when sprinting or vigorous out of the saddle hill climbing. That is why round blades are better than oval ones for a track bike. When cornering, the resultant force is straight down the fork to the tire contact patch. As for vertical stiffness, all on-topic forks usually have a round cross-section lower down, where the flex would take place.

John Betmanis
Woodstock, Ontario
Canada