SD what you say is absolutely right. But specialist riders like sprinters and climbers make up maybe 5% of the peloton. My question relates to the other 95%.

To those doubting the possibility of switching ... I repeat ... it was done by some pre 6.8kg rule.

A 4.5kg bike up a long climb followed by a rock solid 7kg bike optimised for descending could make sense.

Switchover can be done in 10 seconds or so at the top of the climb as long as team car is right on hand.

Switchover costs more time than just the amount of time the rider is stopped. There is time lost in decelerating to a stop and getting up to speed again. There is also some risk that the switchover will not go smoothly - what if the car is not there when needed?

You only do it at a relatively low speed point ... e.g. when about to crest a climb, and you only do it when the team car is right there beside you. Point being it's planned. In fact it's possible to have the change bike waiting on the road.

Bike switching... It's not that hard. Just do it CX or Cancellara style: http://www.youtube.com/watch?v=al22Nn-6yPs

Geez o flip!

Talk to Evens about how long a bike change can take. Planned or not, 10 seconds lost on a bike change is bogus even in the absolute best situation. 30 seconds is optimistic

Yes, folks tried it a few times and gave up on it. I mean it so 1990's dude

Anyone want to try and claim one TDF victory on having a light bike? Anyone

Fact is even today, many if not most tour bikes are over 6.8k. It just does not really matter much when looking at the overall picture. Fit, comfort and reliability count more. Why you may ask, it's the rider not the bike. More gains are to be made by making the rider perform better, with fit and comfort by reducing rider fatigue. Mechanical failure, in a machine with poor reliability, will set you back big time.

On an uphill TT, like the Mount Washington hill climb, provided the bike is stiff and reliable an advantage can certainly be gained. These limited applications are not the norm however. That race, all uphill, has no 6.8 and riders on bikes, purpose built in the 12lb range, have been seen on the podium. (Some of whom were also taking advantage of EPO BTW. So did the light bike win that race?)

Believe what you want. If you want think that every gram counts much in a stage race, well maybe it will, but I think the question will come down more to sports psychology then the physics

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WW Velocipedist Gargantuan

Drivel

I am not sure changing bikes is viable.

Firstly on a mountain stage there are often 3 or 4 big climbs. That would equate to over a minute change over time.

Secondly team cars often have to keep clear of mountain summit positions and quite often a rider having gained 30 seconds dragging themselves up a mountain will not want to give that time back on a switch.

Would a team car be able to travel with that many bikes ie lightweight and heavier bikes in the different sizes required to accomadate a team of riders. Even the 3 or 4 most important riders.

For me the gain of a super light weight frame is too marginal to make certainly switch over viable.