Re: [CR] Measuring Frames


Example: Events:Eroica

References: <mailman.7831.1242205273.1323.classicrendezvous@bikelist.org>
To: <classicrendezvous@bikelist.org>, <brianbaylis@juno.com>, <raydobbins2003@yahoo.com>
Date: Wed, 13 May 2009 10:42:16 -0400
In-Reply-To:
From: <bobhoveyga@aol.com>
Subject: Re: [CR] Measuring Frames


Brian writes;
>> I had no idea there might be others who used the tip of the seat lug as the measuring standard. Any idea why those who choose this method prefer it? It seems center to top of top tube makes sense, as does center to center. But why to the tip of the seat lug? Maybe someone has an explanation...

Brian, I think there might be a clue in Ray's earlier message... when asked why the measure was made to the tip of the seat lug, he said that Alberto replied that it was "consistent."? But consistent with whom?? Certainly not other builders... Ray suggests that he meant consistent with his dad.?

But I suspect Alberto may have meant "consistent from measurement to measurement."? After all, the tip of the seat lug is a single, discreet point:? Easy to see, no way to get it wrong.? But consider the C-T measure as performed by various folks... builders, bike shop personnel, or newbies... sure, the center of the bottom bracket is pretty obvious, but where exactly is the top of the top tube?? Is it at the point where the top of the top tube and the front of the seat tube intersect?? Or is it the projected line of the top of the top tube where it intersects the centerline of the seat tube?? Or is it a vertical line, straight up from the bottom bracket, as one would measure standover height?? I've always measured the second way (along the centerline of the seat tube), but I've seen folks measure the first way (to the tube intersection at the front of the seat lug) and the resulting measurement is a bit different.? And though I don't know anyone who measures a vertical line, I suppose it actually kinda makes sense to measure frames this way because if you know the BB height, you could just add the two measurements to get a standover height.

Same goes for C-C measure... you can take it at the point where the tubes intersect, or project a line to the center of the seat tube, or measure vertically (again, I don't know anyone who actually measures vertically, but an inexperienced person who is told to measure "from the center of the bottom bracket to the center of the top tube" might well take the shortest distance, not knowing he is supposed to follow the seat tube).??

But a measure "from the center of the bottom bracket to the point of the seat lug" leaves little room for misinterpretation.? So in a way, the Masi (and Confente, Paramount, Woodrup, Bob Jackson and whoever else) method does kinda make sense.

Bob Hovey Columbus, GA USA http://bhovey.com/masi