<<...and very rare chainstay rub. >>
What's that?
Dale Brown Greensboro, NC USA
-----Original Message----- From: freesound@comcast.net To: Mark@bulgier.net; greenjersey@ntlworld.com; classicrendezvous@bikelist.org Sent: Sat, 15 Jul 2006 8:35 AM Subject: RE: [CR]Was 753 and stiffness, now Kirkbride's style?
A branch topic inspired by this thread: Is Ted Kirkbride's build style considered flexible? Is that a common characteristic of his frames?
I have a "probably" Kirkbride Masi in a special geometry. When I first got it I was a 175 pound weakling, just edging back into biking after a 2+ year layoff. I never noticed symptoms of flexing, though I probably still can't recognize the more subtle effects. This year, much stronger but up to perhaps 180 pounds, I'm hearing derailleur rub, getting occasional ghost shifting, and very rare chainstay rub. I gather from 'listers and the various good books that I have BB flex, it's not stiff enough for my weight and style. I find it hard to believe my strength is great enough to cause a problem by itself, since I've never raced and am only now approaching the metric century level of capability. Such problems are much less pronounced or even non-existent on my other frames (several vintage Treks, a Woodrup, and an OT Mondonico).
So are Kirkbride frames typically flexy, and could it just not a suitable rider for me?
Ken Freeman Ann Arbor, MI
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Mark Bulgier Sent: Friday, July 14, 2006 11:20 PM To: greenjersey@ntlworld.com; classicrendezvous@bikelist.org Subject: RE: [CR]Was 753, now is stiffness desirable?
Ray Green wrote:
> Big Magnus is 1m92 tall and weighs 95kg. He churns out 1750 watts
> (today on Eurosport Floyd Landis said his max is 1100 watts).
> Bianchi gave Magnus his standard issue team bike. He said it was too
> flexible. I think it was superlight alloy. They made him another (I
> think made out of titanium) and in tests he was putting 150 more
watts
> to the back wheel.
I'm all for an appropriate amount of stiffness, and for big powerful sprinty-type dudes, appropriate means Very Stiff.
I don't believe story of the 150-watt increase in output though. What was the test protocol? Both tests the same day, with identical equipment? Any attempt at disguising the frames, to rule out psychological effects?
I built two sprint frames for 5-time US national champion Ken Carpenter (1988-92). I mean, he won Natz 5 times on my frame. He came to us because his previous two custom sprint frames, a Kirkbride Masi and a Serotta, were "way" too flexible. Both those estimable builders knew the guy was 6'6", 220 lb and extremely powerful even for his size, but they still thought too much "in the box" (for instance, normal tube diameters or only slightly oversized). I knew I would have to make one of the stiffest track frames ever, to please this guy.
The plan was to make two way-oversized tubing frames, where the first would be his eventual training bike, with bomb-proof thicker tube walls -- but he would race on it a bit to try out some of the ideas and the geometry. Then with that feedback we'd pull out all the stops and make the second, optimized bike, presumably lighter.
He was very pleased with the first one, which he proclaimed "almost stiff enough" (!) Egads, I thought even this fast-twitch freak of nature would find that frame overly rigid, but no - the plans changed, and now the full race bike was to be made even heavier! Like the princess and the pea, if he felt ANY flex, the frame wasn't good enough.
The heavier one is the one he rode to 5 national sprint championships, the last year or two with it painted to look like titanium because his team was sponsored by Merlin. :)
I don't think the reason he won is because of his stiffer frame though. Even if we take as given that the extra stiffness made him faster, I think at least some of that effect was in his head. That is, if you think the bike is faster, you may well go faster because the of the psych factor. It seems to me (broad generalization follows) that sprinters are even more prone to the psych factor. I have heard stories of sprinters beaten before the race even starts, by being "psyched out". At least some sprinters I know believe in that.
Mr. Ernst, care to comment?
Flipside of the "thinking inside the box" problem, Ken's then-girlfriend Renee Duprel also came to us for a sprint frame, and I determined the main problem with hers was that it too was made with regular sprint frame tubing, and she needed lighter. I made her bike a full 3 lb lighter than her previous bike, and she went on to Silver at the Olympics. She felt the amount of spring in the frame was well-suited to her and made her faster than the old, overly-stiff bike. She *was* measurably faster, but it could have been training, or the psych factor - no way to really compare the intrinsic speed of the two bikes.
Mark Bulgier
Seattle WA USA