Re: [CR]Columbus KL tubeset


Example: History:Norris Lockley

From: hersefan@comcast.net
To: "brianbaylis@juno.com" <brianbaylis@juno.com>, fred_rednor@yahoo.com
Subject: Re: [CR]Columbus KL tubeset
Date: Wed, 20 Feb 2008 20:44:57 +0000
cc: classicrendezvous@bikelist.org

I wonder to what extent build practices made an impact on the Columbus weight restrictions. Columbus seems to take heat less well than Reynolds 531 - and the French builders used tubes lighter than KL with good results since the 1930's. With the greater risk of embrittlement when brass brazing Columbus, it seems like the light tubes were a risker proposition and therefore the recomonded weight limitations. Now with either silver brazing or with the air harndened materials, building with the light tubes is more easily accomplished. The chrome Herse we displayed at the handmade show is built with the true temper tubing that is certainly no heavier than the KL. And the bike rides absoutely fine and has been tested by riders in the 180lb range.

Of course, the lighter tubes such as KL will "fold up" easily on impact. This is one advantage of the modern tube alloys/heat treament - greater strength. So while the KL and EL frames may ride the same, the EL is likely to be slightly more crash and dent resistant. But this "advantage" quickly becomes less important for heavier tubes.

Mike Kone
Rene Herse Bicycles Inc.


-------------- Original message --------------
From: "brianbaylis@juno.com"

> Fred,

\r?\n>

\r?\n> >From my experience many of the "lighter" road tubesets needed a slightly

\r?\n> heavier down tube to have a real long service life on the road. Really

\r?\n> light bikes and the tubes that make them technically are for special eve

\r?\n> nts and purposes kind of bikes. Not your daily rider and all around raci

\r?\n> ng/training bike. It's not unusual for me to use a slightely heavier dow

\r?\n> n tube than what came in a bike if I feel it will help.

\r?\n>

\r?\n> Not sure the actual difference between KL and standard size EL, other th

\r?\n> an I think there is some heat treating involved in the EL tubes. I also

\r?\n> like bikes my size 50 to 52cm made from KL tubes, especially if the fram

\r?\n> e is built for 650c wheels (I have such a bike, one of my favorites and

\r?\n> it's 49cm c-t).

\r?\n>

\r?\n> For some applications a KL frame with an SL down tube would be ideal.

\r?\n>

\r?\n> Brian Baylis

\r?\n> La Mesa, CA

\r?\n>

\r?\n>

\r?\n>

\r?\n> -- Fred Rednor wrote:

\r?\n> > There are some listed weight limitations listed for

\r?\n> > Columbus SL tubes. I believe that recommended weight

\r?\n> > limit is 70kg IIRC. Around 154 lbs. KL is a lighter

\r?\n>

\r?\n> > tube set and would probably be around the same

\r?\n> > weight limit under smooth road conditions. PL tubes

\r?\n> > (the light track stuff) would be even lighter yet

\r?\n>

\r?\n> > and for smooth track use.

\r?\n>

\r?\n> So how does KL differ from the non-oversized version of EL?

\r?\n>

\r?\n> The dimentions appear to be the same. In my experience,

\r?\n> non-oversized EL was just wonderful for a small rider - I weigh

\r?\n> less than 130 pounds. But it's "crashability" was somewhat

\r?\n> limited, which is why I suspect my frame was repaired with an

\r?\n> SL downtube.

\r?\n> Fred Rednor - Arlington, Virginia (USA)