OMG. Let's just acknowledge that you have no frame of reference to actually have any sense/clue to how different tubing materials or tubing diameters handle for a bike on say a 45cm frame or a 68cm frame, and realize I make that point because both those sizes are the +/- cm difference between what I ride and what you're trying to offer advice and seemingly expertise about.

If you have only ever worked on air cooled volkswagons my suggestion would be don't go to a Ferrari technical forum offering expert advice on sequence mistakes someone made trying to rebuild a vintage engine.

Quite honestly you don't have any frame of reference about BIG/TALL frames. You ride a small frame. There is a reason that Zinn, the tech guru for Velonews, who specializes in building custom frames for BIG/TALL riders has to use small triangles with tall head tube extensions.

Your point about oversize tubing and stiff frames being the solution locates that you completely just do NOT understand the issue. Cannondale frames of the era I ride were the stiffest frames ever tested on the Bicycling magazine 'tarantula' testing jig. I exclusively ride oversized tubing. I'm trying to say this politely, but you truly don't know what you are talking about, you couldn't possibly have any insight or understanding to the problem, and your attempt to communicate that the problem is that BIG/TALL people are just riding with their arms and elbows "stiff and rigid" is actually downright laughable.

Do me a favor. Send Leonard Zinn a note at his Velonews tech column and tell him that his design for all the custom BIG/TALL bikes he sells is all wrong. That he doesn't actually have to use top tubes that are absurdly low in proportion with goofy head tube extensions. Let him know that your insight has revealed that the problem is that we, including him (he's 6'5"), are all just riding with "keeping [our] elbow rigid and stiff [which] can exacerbate the wobble." He'll be glad to know you've got this figured out from riding 56/57cm frames. That those of us 6'5", 6'6", 6'7", 6'8", and 6'9" all just have bad bike handling. That your 56/57cm frames reveal how bikes handle when they are say 10-11 sizes smaller and larger.

I'm laughing reading your post. The internet is full of Expert Forums where people who have no frame of reference, knowledge, understanding or insight to someone's question/problem/issue post piping up to offer advice, that is then worth what people pay for it.

Zinn was a roadie, almost an Olympian on the Olympic developmental squad. He's still been a competitive cyclist on the road and in cyclocross since. He could probably teach you more about bike handling technique than any reasonable person's ego could bear. For those ignorant of this issue read some of Zinn's thoughts here and edumacate yourselves:

http://archive.constantcontact.com/f...577557261.html

The reality is that those of us on BIG/TALL frames do NOT have the same riding experience as those on small 57cm frames. Its like we're riding bikes with 24" wheels and everything is inherently unstable, especially at speed. Holding the handlebars FIRMLY is NOT the problem.

Which is why, for me, wanting to ask the OP what frame size he was riding made sense. If he's riding a 63cm the issues could be he's a large/tall cyclist trying to squeeze on a too small 63cm frame and there could be nothing wrong with the bike at all, just that a 63cm is more inherently unstable than something smaller, especially as the cyclist perched on top gets bigger/taller proportionate to the bike.