Re: [CR] Frame sizes/standards

(Example: Framebuilders:Norman Taylor)

Date: Sat, 10 Feb 2007 18:42:34 -0500
Subject: Re: [CR] Frame sizes/standards
From: "Doug Fattic" <fatticbicycles@qtm.net>
To: "classicrendezvous@bikelist.org" <classicrendezvous@bikelist.org>
In-Reply-To: <E1HFr5I-0005ve-J4@elasmtp-galgo.atl.sa.earthlink.net>


Roman Stankus asked:

Here's a question that relates to framebuilding and history of the craft so I will beg forgiveness to cross-post to Framebuilders and CR list.

Does anyone have any insight about using c-c vs c-t dimensions for seat tubes lengths when describing a frame size. It seems that most Italian builders used c-t dimensions. Was there a reason for this vs c-c dimensions? Did it have to do with the build process itself in some way? Did these methods of measure change over time for any reason. Are there any build traditions where the top tube is not measured c-c as is the norm now?

Roman Stankus Atlanta, Georgia USA

Hi Roman,

I suppose I have some obligation to answer this question since it unfortunately dawned on me I might have probably been around good bikes longer than about anyone else on the framebuilder list (but not the CR list, whew). My dad got me my first 10 speed in 1963 and that was after having to wait a couple of years for it while we were in Rwanda and I went to high school in India. I got my first used Italian frame with Campy (gran sport derailleurs) parts in 1966.

At that time in the states, everything I knew about was measured center to top in inches. And it fact we (as in American enthusiasts) tended to believe we needed bigger frames that what was necessary because of the dominance of Schwinn in the American market - particularly outside of the biggest cities. Most likely somewhere on the list of bicycles owned would be either a Schwinn Varsity, Continental or Super Sport. These were measured center to the very top of the seat tube (cut straight across) in inches. Schwinn seat tubes stuck up quite a ways above the top tube so a collar with a bolt could be slipped over it to tighten the seat post (as is common today on tig welded frames). This made a Schwinn 22" frame actually smaller than one of the same size from Britain because it's top tube would be lower down. I remember framebuilders in England in the 70's would complain to me all the time about Americans wanting frames that were too big for them. If a person's bike history included a Schwinn and he used that as a sizing guide, he was likely to ask for a frame 1" bigger than what he needed. It didn't help that those bikes were made in only even sizes.

I've always thought that the way Masi frames were measured (c-t) was the exception for Italian frames and not the rule which was usually c-c. Brian B. could say where that top point actually was/is. When I got a Masi in Italy in 1972, several letters in Italian (I used a translator) went back and forth about my measurements and Masi made me a 57cm frame. When that frame got stolen, I asked for a 58 and got one that size. Faliero stamps the size on the bottom bracket shell. When I measured it, it was more like a 57cm c-t but I thought that was because he was stubborn and made me the size he thought it should be anyway and put the size I wanted on it just to please me. It wasn't until I was on the CR list I discovered he measured frames differently.

One of the first questions I asked Jack Briggs when I was learning in England is where exactly is the Point where the "top' is. He thought this British way didn't have a precise point. For example my 22 1/2" Hetchins seemed a little small. Where Jack measured from is where the very top of the top tube touches the seat tube. When I started building frames, I used a center to top measurement in inches as well because that was the system most customers understood. In my own records, I would record the center to center measurement. Sometime in the 80's in the states, the culture changed and customers started to expect their frame size to be given c-c in centimeters. I think this also reflected a change from Americans primarily getting English frames like a Bob Jackson to Italian ones like Colnago.

I will add that on many frames I've made, the controlling factor in determining frame size is it's top tube height. This is because of the need for some customers to get the handlebars up at a comfortable height compared to the seat. I will set the top tube at whatever height off the ground gives the right clearance. The result is odd c-c seat tube sizes.

Doug Fattic
Niles, Michigan