Over at Rivendell’s Peeking Through the Knothole blog, Grant Petersen has been conducting an informal class on how to design a bicycle frame using a pencil, ruler, calculator, protractor, and graph paper. I’m not participating, but I’ve enjoyed following along. You can view the introductory post here, and the successive lessons are listed reverse-chronologically here.
Today’s lesson on top tubes is particularly interesting. In it, Mr. Petersen talks a bit about level versus sloping top tubes and the advantages and disadvantages of both. Here’s an excerpt:
If you want a compact frame, you can shorten the seat tube a lot, get more crotch clearance (overrated), and still get the high head tube–or even higher, if you like. Then you’ll need a mother-of-a-seat post, but heaven knows they’re out there. It might seem as though you get all good stuff (lighter frame because of less material; stiffer frame becaus of smaller triangle, lower standover height, and just as high or higher head tube and handlebars) with no drawbacks. But there is one drawback: The bike is jumpier, less smooth, harder to control…just doesn’t have the luscious velveeta feeling. You can get used to it and may even come to prefer it, but I like a bike with a normal feel, and a higher top tube seems to help that. This is a subjective, not an objective observation.
I’m hopelessly stuck in the past on this topic, but I’ve been warming up to mildly sloping top tubes in recent years, partially due to the Sam Hillborne (see above).
How about you? Do you prefer an old school level top tube, or do modern sloping top tubes appeal to your sensibilities (aesthetic or otherwise)?