Framebuilders - 5'4" women geometry possible with Lugged steel?
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10-31-08, 05:50 PM
This is the beginning planning stages for me to build some one off frames. I haven't dug down into geometries or materials or methods yet. What I've determined so far is that I want to build some lugged steel road bikes. I have access to oxy/actl as well as some other power tools through work so I think I'll be ok on the tools side. My main question is about geometry.
For me, it's no problem as I already have a couple production lugged steel frames in my size to copy and tweak. What I want to do is build a steel frame for my fiance who is 5'4". She like the feel of the steel frame bikes we have around but they are all a little too big for her. I'm 5'6".
The question is, before I go down a dead end road, could I create a bike with the right geometry for her with standard tubes and lugs and such such as ones available through Nova. Here's the kicker, I'd prefer it to be 700c if at all possible. In fact, that may be a deal breaker if it's not as all of my Finace's current bikes are 700c. Any suggestions would be useful.
Not my kind of thing, but since nobody else has answered... I would just draw it up. It is always useful to have the diemensions of some stock parts like BBs and head tubes. Then just use a 1.125 straightedge to draw in all the tubes, or do it in cad. Once you have the main triangle, and you can copy one of your forks (actually that is backwards, you need to know the fork and headset height to place the head tube), wheels and so forth, it is easy to see whether there are any odd angles you can't lug. It takes a little time to get set up, but once you have a few parts either in your CAD or in your drawing kit, you are ready to make any drawing you want in a few minutes. By hand, get a BB, they are only a few bucks, then a tube/straightedge as mentioned above, and another one the size of the head tubes you use. With those you can make a plan for any frame you want. Every time I get a new part, I take the time to CAD it for my files, then I can insert the "real" parts in my drawings. But for a full size plan you really only need to know the main triangle tube position, and the locations of key parts. The shape of the chain stay, say, is not important for the drawing, though it doesn't hurt to have it. But most folks work those parts to fit rather than strictly taking them off the drawing.
Other ideas are to go to FF and ask there, only be real careful what you say since they tend to jump on folks who ask this kind of thing if they figure they don't deserve to build it and might kill someone. :)
The Paternek vids include construction of one really small frame, can't remember whether it was the lug or fillet tape. I think it was the lug. But you could ask Tim, and order that tape. Also you can ask Pacenti, Henry James, and probably Nova, and they will put together what you need for the size you want. They can tell you if it is doable.
Sounds like your frame is close enough and the changes minor enough you ought to be able to eyeball it.
11-01-08, 01:23 PM
It depends on the length of her legs. I'm 5'2" and I ride a custom-made lugged frame with 700c wheels, but then, my legs are longer than you would expect for a person that height. You can design a good road frame down to about 49 cm centre-to-centre (as many fine Italian stage racing type frame prove). Now, it's going to have more fork rake, but appropriate trail will ensure good handling. This is where a custom-made fork appropriate for that size of bike comes in. Smaller than that, and then you need to get into smaller wheels if you want to maintain reasonable road bike proportions. If you don't, then yes, you can still build a frame with 700c wheels, but the bike will have to be ridden with the bars higher than the saddle (because you can only make the head tube so short).
All this assumes that you don't want to make her a criterium racing type of bike with super tight angles. Then you would have a lot of toe overlap with the front wheel. You may even get that with the 49 cm frame (which is about 51-52 cm when measured centre-to-top).
11-01-08, 04:49 PM
Why murder the geometry for the sake of 700c wheels? It makes sense to scale wheels to the frame, and there is nothing wrong with 650c wheels.
11-01-08, 07:03 PM
I think it's doable if you can go with a sloping top tube.
11-03-08, 06:06 PM
If you give me her inseam and her desired seat tube length I can draw this up and tell you if it is possible with a traditional lugged geometry. The make or break issue here will be the standover height, because sure, with a high bottom bracket you can make almost any small seat tube work, but it will be higher than the riders inseam, which is obviously no good.
I have built frames for tiny women who were willing to tolerate a very small crotch clearence and gave them a sloping top-tube to make it work, so it is likely possible.
Again, give me her inseam, what seat tube length she wants, and fork specs if you have them, and Id be glad to draw it up and let you know if it is possible with a traditional lugged frame. With fillet brazing or TIG it is possible because you can really slope the top tube.
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