Re: [CR]Reynolds 753

(Example: Events:Cirque du Cyclisme:2007)

Date: Thu, 13 Jul 2006 10:00:00 +0100
Subject: Re: [CR]Reynolds 753
From: "Simon PJ" <simonpj@mac.com>
To: <Classicrendezvous@bikelist.org>
In-Reply-To: <9327C3B25BD3C34A8DBC26145D88A90702D004@hippy.home.here>


My experience with 753 was with a 1986 Peugeot which was far from stiff. I eventually gave up on it after a succession of very nasty experiences with vibration and violent wobbles on fast descents. I had the frame alignment checked, and confirmed that it was fine. My conclusion at the time was that the frame was built too light and flexible for me.

The close shaves that I had had when being thrown off that 753 Peugeot at high speed scared the living daylights out of me, and I replaced it with a frame that I had made in SLX with relaxed angles, which I was much happier with.

Wyndham Cambs., UK

On 13/7/06 08:29, "Mark Bulgier" <Mark@bulgier.net> wrote:
>
> Jack Romans wrote:
>
>> [...] a vintage bike mechanic and rider told me he
>> preferred the ride quality of 531 above all other tube sets
>> and 753 bikes were too stiff in comparison.
>
> There's nothing wrong with preferring 531, but you should know that it
> is almost always stiffer than 753. The only exception would be a 753
> tube that is thicker and heavier than the 531 tube you're comparing it
> to. Both steels came in a range of thicknesses, and the heaviest 753
> (tandem or off-road variants) might have been heavier and stiffer than
> the lightest 531. Not the regular stuff though.
>
> 753 is stronger than 531, but not a whit stiffer. And this is important:
> You can NEVER feel the strength of a tube while riding. (Except by
> exceeding its strength - and permanently bending or breaking a frame by
> hard pedaling is really too unusual a situation to bother considering.)
> The extra strength of 753 allows the builder to make lighter, more
> flexible frames that are still strong enough.
>
> In fact, 753 typically makes some of the most flexible steel frames ever
> made. The fact that some people think they are stiff is evidence that
> most people can't reliably tell if a frame is stiff or flexible.
>
> This gets talked about a lot here, but it bears repeating, because the
> myth-makers like your mechanic are always at work. The inherent
> material stiffness property of steel (modulus of elasticity) is very
> nearly constant - for practical purposes, within the realm of steel used
> for bike frames, you will not go wrong by assuming the modulus is
> exactly the same, regardless of alloying, heat-treating and/or
> cold-working.
>
> For two tubes of the same diameter (as most vintage tubes were), the
> stiffness and weight will both be proportional to the wall thickness.
> (I mean, comparing two 1" top tubes to each other, or two 1-1/8" down
> tubes.) There is no way to make the lighter tube as stiff as the
> heavier one.
>
> Mark Bulgier
> Seattle WA USA