[CR]Question about geometry

(Example: Framebuilding:Restoration)

To: classicrendezvous@bikelist.org
From: "Grant McLean" <grant.mclean@sympatico.ca>
Subject: [CR]Question about geometry
Date: Thu, 7 Sep 2006 20:04:08 -0400


Hi John,

Welcome to the list!

Low trail is a good quality to have in a longer wheelbase design. Higher trail bikes came into fashion with shorter wheelbases.

If you can see my point, it's that wheelbase and trail are linked. The longer wheelbase (front center + chainstay length) give stability, and combined with low trail, the bike remains agile, well behaved, a joy to ride.

Short wheelbase bikes are less stable, and therefore benefit from the added trail to slow down their road manners.

Picking out "trail" by itself only tells part of the story.

Grant McLean Toronto, Canada

John Wood wrote:

Hi all, I'm a new CR list member - been lurking for a couple months - and this is my first post to the list. I am in the process of getting a new custom frame from Waterford (lugged steel of course) and am in that critical geometry decision mode. What first got me started down this "vintage" road was the acquisition of an early 70's Braxton. For those unfamiliar, Sam Braxton was a shop owner and frame builder in Missoula, MT who specialized in touring bikes made in the French Randonneur tradition. I really just stumbled into this bike and got it for a song figuring the campy hubs and pedals were worth the asking price. As a Missoula resident at the time, I knew who Sam Braxton was, but knew nothing about his bikes.
    But the more I rode it the more impressed I was. Not only comfortable and stable, as I expected it to be, but also a very nimble handler, which I didn't expect. It is now by far my favorite bike to ride. But seeing as I now live at the base of a 32 mile long climb with 5,500' elevation gain, I wouldn't mind getting a copy of the Braxton made with wholly unladen travel in mind (ie. about 5 pounds lighter). But obviously bikes with this type of geometry (touring bikes with very short trail figures) have fallen out of favor in modern times. My question for the group is simply why? Is there any reason that a touring bike with 6.0cm of rake and ~4.6cm of trail is a bad idea now? Is there something with the new tube sets that is incompatable with old style geometry? Or is it simply a matter of style, or the quest for ever lighter and stiffer frames? I notice that even the newer Singers highlighted in recent issues of VBQ have more "modern" trail numbers. Can somebody enlighten me please. I'd love to have a lightweight version of my Braxton, but I'd hate to make an expensive mistake.