Group, Please - with help from above to spare me from wrath for what I am going to offer: I would offer comparisons of 4 bikes - all of which have spent a good bit of time intimately in touch with my physical personage. These are: '74 Raleigh RRA, '83 Rossin SL, '84 Trek 720, and (God protect me) '04 Lightspeed - with Campy Record, of course. 1. The Raleigh and Rossin were very comparable in ability to accelerate and attain top speed. I attribute this to both bikes having a tight rear triangle and light = sew up, wheels. I don't think bike weight is/was very different between them. The RRA (when I had it) sported Fiamme Gold labels, the Rossin, Arraya mild, early aero rims. The RRA was decidedly softer in the front end as it had more fork rake but I don't think this affected speed. It felt different over rough road, had more movement in the front end as I remember it. The front end of the Rossin feels more stable to me on rough road, not as much "bounce" as the RRA had and it corners slightly quicker, better by my reckoning. Both descended well but I prefer the Rossin. 2. The Trek is a touring bike and is the hardest road bike to make go fast I've had. Only a mountain bike is tougher for accelerating and reaching top speed. Why - it has a long wheel base and the frame flexes tremendously under hard acceleration, it has some pretty stout wheels that provide weight to resist acceleration and it's heavier overall. However, with a properly distributed load of up to 25 pounds, the handling improves, meaning it reacts quicker to a turn, stops bouncing off rough road, dampens bumps, settles down so to speak. 3. The Lightspeed Tuscany, dare I speak of it. 5 pounds lighter than the Rossin, somewhat similar feel despite the differences in Ti vs. Cr-Mo steel. I attribute this to the bent seat stays that soften the rear triangle. The wheels I built for this bike, clinchers for commuting work, are heavier than those on the Rossin and this part is very noticeable. I cannot accelerate it as well as the Rossin - overcoming the additional angular momentum is the issue. The Rossin has a higher center of gravity, CG, and it feels it but will clearly out accelerate the Litespeed due to the lighter wheels. Top speed is similar once you get there - have hit 56 mph with both bikes coming down Loveland Pass - 11,000 feet plus back down to 8,000ish, here in Colorado. Cornering is different in a very subtle way due to the different location of the CGs but both bikes are very well behaved and very useable at high speed. They inspire the confidence to reach those high speeds with the knowledge that the machine is not going to be the failure point if there is one. It's better than - both of them are better than - you are.
I hope the group does not mind and will be thoughtful about my input. I think it answers some part of the question of making a bike go fast, though clearly there are other pieces of the puzzle. Thanks
Dan Mazzeo Morrison, CO
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Tom Sanders Sent: Tuesday, July 26, 2005 7:19 AM To: Classicrendezvous@Bikelist.Org Subject: [CR]PX-10 and racing weight
Indeed, I recall that my PX-10 was 21#, just as Peter Kohler stated.
My
Masi 3V Volumetrica is 23#. Anyone riding the two would immediately
notice that the Modern Masi is faster and more responsive to pedal
pressure. I'm sure there will be those who would not agree with me, but
please, if you are going to be vehement about it don't do so without
having owned and ridden both bikes...folks speaking strictly from theory
would do well to be gentle.
Now why do you suppose that weight should not be the determining
factor...gearing? Stay stiffness? It sure isn't my 30 years older now
legs! I have long pondered just what makes one bike faster than another
(other than the rider) and I'll be darned if I can say for sure. I'll
bet some of the frame builders or racers can illuminate the issue??
Tom Sanders
Lansing, Mi