Re: [CR] Frame "stiffness"


Example: Events:Eroica

In-Reply-To: <3040DB77AB8B431EBB91B39B412EA1E7@ownerd556865ac>
References: <241072.25443.qm@web84101.mail.mud.yahoo.com>
Date: Wed, 7 Jul 2010 17:22:50 -0700
To: "paccoastcycles" <paccoastcycles@sbcglobal.net>, "Anthony Taylor" <ajft1942@yahoo.com>, <Classicrendezvous@bikelist.org>
From: Jan Heine <heine94@earthlink.net>
Subject: Re: [CR] Frame "stiffness"


At 9:31 AM -0700 7/7/10, paccoastcycles wrote:
>Of course there are differences among frame material
>characteristics. Materials that have been used successfully for
>frames are subject to being made within the narrow parameters that
>will make a workable bike. I'm really trying to say that the
>differences are smaller than the flex in the tires and wheels.

To test the effects of frame stiffness, we had four frames built, with three tubesets. (Frame four was a duplicate, to test whether it would feel the same.) One frame used superlight standard diameter tubing (walls like Reynold 753 first generation, roughly), the other a standard Columbus SL-type tubeset, the third an oversize superlight tubeset.

Same angles (same jig), same lugs, same components. Same rear triangle, same forks. This was a double-blind test.

The performance (sprinting, climbing, etc.) of the frames was different. The comfort and handling was indistinguishable.

From my experience, the fork blades make the biggest difference in comfort (after tires). (We measured flex of different fork blades, and it was quite a bit different.) I am willing to believe that seatstays also can make a difference, but haven't investigated this in a repeatable test. The rest of the tubes is so well triangulated that I have a hard time seeing how they could affect comfort.

Jan Heine Editor Bicycle Quarterly 2116 Western Ave. Seattle WA 98121 http://www.vintagebicyclepress.com