Of course a frame needs to have flex - the questions are where and how much.
Too stiff a frame is wasting energy just as too soft is.
Handling and comfort are critical to performance and the experience of riding a bike.
Everything goes hand in hand.
The bike is a system that has to work in conjunction with the rider, a designer obviously needs
to make choices and compromises. To KGT's point, we feel that comfort seems to be commonly
neglected in the pursuit of light/aero/stiff.
I simply wanted to show that too much flex would waste energy and that the returning pendulum or
spring analogy is overly simplistic and not very accurate or even directly applicable.
The rocket analogy was simply a lighthearted attempt at conjuring up a dramatic image of efficiency on a trajectory,
in contrast to a crabbing rear wheel of a bicycle. It was also a wink at Ruegamer who famously used to sport the slogan :
'INFUSED WITH ROCKET SCIENCE'
(As I'm sure you would agree, the most efficient means of launching a rocket on a ballistic or orbital trajectory is
a vertical launch. An airplane like takeoff would obviously also be achievable but would require significantly more energy.)
Will be bowing out of this conversation at this point.
Let the arguments rage on!
Franklin wrote:4. Frame flex is countered and made worse by body flex. The joints of the cyclist are not static. When a rider flexes his frame, he also will flex his body. It remains to be seen if taking away the flex in the frame simply means all that flex will all of a sudden become forward speed instead of being transmitted towards the riders body.
That's exactly to the point. People selling bikes try to persuade us that the rider "does not exist". We can only make valuable studies by studying the rider-bike system and not just the bike itself.
Thanks in advance!
Love the look of the R3, ideally I would want 38mm tubulars for the low weight+ rotational inertia, but would they be stiff enough?
fitnessfiend wrote: I am 6'2 (188cm ) and probably 190lbs (86kg) in riding gear.
As it happens I do the bike fitting for the national rowing program here in New Zealand (so I've set up a few current olympic champions). Based on that I'd suggest you go for heavy and aero - making power will not be your problem - overcoming drag and the risk of breaking things are bigger problems for you. If you want to optimise your competitive chances make some sensible component choices to keep the weight down and maybe 50mm tubs for racing so that you don't feel too compromised on the weight front.
Yes I know Thor rode it successfully in 2011, but good for him, I'm a similar size to the OP and always prefer something more connected on the front end - perhaps in this case the aero bikes to look at then would be a Madone, Foil, Venge or Propel.
when you look at pro teams, some have their material selection affected more by marketing, some by actual testing and listening to riders. when you look at the second group of teams it's pretty obvious that they rather go with the stiff and light frameset combined with the perfect wheel setup for the race they enter, that is weight one day and aerodynamic the other day. think about zakeens bike. aero everywhere but he uses the classic round tube frame. positioning on the bike is of huge importance!
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