[CR]Frame strength, new vs old

(Example: Framebuilders:Masi)

Date: Wed, 05 Mar 2003 05:28:13 -0800
From: "Dennis Young" <mail@woodworkingboy.com>
To: <classicrendezvous@bikelist.org>, <LouDeeter@aol.com>
In-Reply-To: <CATFOODfYDovvQ0Puz6000001bf@catfood.nt.phred.org>
Subject: [CR]Frame strength, new vs old

Lou,

I have a Tomassini Columbus Nemo steel lugged road frame, and when I purchased it, he cautioned me that this frame was for a rider of maximum 60 kilograms using the smallest diameter downtube, on up to a maximum of 78 kilograms using the largest downtube available. This was some years ago, and thousands of miles past on this bike, and I'm still trying to get down to the recommended weight! My understanding (list members please correct if in error), is that the new lightest steel frames are made from material with relative high resistance to breaking under load, but the walls of the tubes are very thin to reduce weight (as thin as 0.4mm in the center section of the down tube Nemo), so the susceptibility to breaking or fracture is increased compared to a thicker walled tube that may have a somewhat lesser tensile strength, as used in the older frames. Therefore, the cautions are in order. If we stick to the timeline, we might be safer too.

Dennis Young Hotaka, Japan


>
> We've discussed lightness in lugged steel bikes recently, but just today, a
> friend of mine (who will join us at Cirque) told me that the modern Derosa Neo
> Primato, which is lugged steel, has a recommended weight limit of 175 pounds
> for riders of such frames. This sounds to me like a lawyer must be involved
> as I would think it strange that any company, particularly one as renowned as
> Derosa, would sell a frame that might hazard a rider. While this frame is
> made by a traditional company, I realize it is out of the CR timeline. My
> question is whether any of you have heard this and if so, is there some
> superlight tubing that has such weaknesses that might justify this? Lou
> Deeter, Orlando FL
> ------------------------------