Interesting...I agree about tall + standard diameter sucking. But before I could buy or make a custom frame all I could get that were big enough were old steel frames. I'll have to get this little project going soon and give a report. Incidentally, I am building a 64cm frame now with oversize tubing, if I end up with the same situation I might try the double top tube experiment on that too.
Originally Posted by
unterhausen
Actually, some students in the lab I work in measure bike vibration modes and showed that they are well above the vibration frequencies you see in shimmy. I think I may have actually mentioned that earlier in this very thread. You can have a 5'3" rider on a 49 cm frame, and if shimmy starts there is an optical illusion of the tubes bending. They aren't. I used to ride a 55cm frame that would shimmy at the drop of a hat, and it looked like the front of the top tube was bending =/- an inch. If it really was, I would never have ridden that frame.
That being said, if I was tall I wouldn't mess with standard diameter tubing.