Re: [CR]Frame Flex Testing

(Example: Framebuilders:Jack Taylor)

In-Reply-To: <000601c5c4fe$e7ba9830$6400a8c0@Presario>
References: <>
Date: Thu, 29 Sep 2005 08:13:27 -0700
To: Neill Currie <>,
From: "Jan Heine" <>
Subject: Re: [CR]Frame Flex Testing

>1.....If frames are essentially trusses with little, distinguishing
>deflection to set them apart, then I ought to be able to take the
>wheels, tires, and other components that do "matter" from a nice
>riding De Rosa, and assemble them onto a similar angled and raked
>gaspipe frameset, and make that feel almost exactly like the De Rosa
>(excepting weight differences). I think we would all aggree that
>this wouldn't be the case (but has anyone actually tried it??), so
>this argument seems false.

I haven't switched the individual components, but the harsh-riding Singer mentioned before has the same components as my other, lovely bike: Philippe bar, Singer stem, Ideale saddle, Super Champion rims, Wolber tires, TA cranks and pedals. Even the geometry isn't very different (if anything, the slacker head angle should make it more comfortable). Of course, the fork blades are different, and the low-rider racks attached to the front rack probably further stiffen the fork. The rest of the frame also seems harsher, but that is harder to tease out. I am certain that if the components were put on a lightweight randonneur frame, the bike would be totally different.

The whole flex issue is complex. Front derailleur rub occurred on my Mercian, certainly not the lightest of my bikes. The superlight ones - which should provide more flex - don't seem to suffer from this. Clearly, it seems to matter which tubes are thin-wall and which aren't. Also, longer tubes flex more - which may be important especially for chainstays.

If somebody can tease out all this and what makes a bike wonderful, please submit an article to VBQ.

Jan Heine, Seattle
Vintage Bicycle Quarterly
c/o Il Vecchio Bicycles
140 Lakeside Ave, Ste. C
Seattle WA 98122