Brian,
I hope this isn't seen as thread hijacking, but let me ask a question that is related to measuring standards:
The hard part in c-t measurement, if there is one, is to know where the top of the top tube is. Faliero's method removes this ambiguity, at the expense of generating practical data. Even on a lugless frame you have to eyeball it carefully to see the top, and skill and experience are important tools. If there is a seat lug, should you measure from the top of the lug where it covers the seat tube (which is at least visible), or should you measure from the top of the top tube even if you can't see it under the lug?
A friend and I were working together to try to understand why the standovers of our two Treks seemed subjectively so different to him. The actual difference was only a few millimeters. However, the difference in physical pressure was deemed to be significant to my friend, resulting in him not being interested in buying my frame (just as well, as it turned out!). But, it shows that a few mm can make a difference.
Ken Freeman Ann Arbor, MI USA
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of brianbaylis@juno.com Sent: Sunday, February 11, 2007 12:22 AM To: fatticbicycles@qtm.net Cc: classicrendezvous@bikelist.org Subject: Re: [CR] Frame sizes/standards
Doug,
Good stuff! Regarding how Masis were measured; they were measured to the top tip of the point of the seat lug, which makes absolutely no sense at all. Most c-t measurements are from BB center to top of top tube. That's my preference. If someone wants a frame speced on a c-c dimension; I draw it that way, but when I stamp the frame size in the BB shell it will say 55.2cm, which is a 54cm c-c frame with a 1" TT. In this way the customer gets the "size" frame they understand or prefer but my sizing is consistently c-t in cm.
Brian Baylis
La Mesa, CA
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 spo rt 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 th e biggest cities. Most likely somewhere on the list of bicycles owned wou ld be either a Schwinn Varsity, Continental or Super Sport. These were measured center to the very top of the seat tube (cut straight across) i n 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 actua lly smaller than one of the same size from Britain because it's top tube wou ld 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. Br ian 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 bac k and forth about my measurements and Masi made me a 57cm frame. When tha t frame got stolen, I asked for a 58 and got one that size. Faliero stamp s the size on the bottom bracket shell. When I measured it, it was more l ike a 57cm c-t but I thought that was because he was stubborn and made me th e 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 measure d 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 th is British way didn't have a precise point. For example my 22 1/2" Hetchin s seemed a little small. Where Jack measured from is where the very top o f the top tube touches the seat tube. When I started building frames, I u sed a center to top measurement in inches as well because that was the syste m 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 primar ily 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