Very insignificant. Aerodynamics is much more important. Explained quite well by Jim Martin

http://home.hia.no/~stephens/aero.htm

My only complaint with a heavier bike on a flat course has been acceleration out of the turns. 21 v 18 lb is pretty minor though, try it with a 30 pounder. Aerodynamics will be much more important.

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Marty Gaal, CSCS
One Step Beyond Coaching
Triangle Open Water Swim Series | Old School Aquathon Series
Powerstroke® Freestyle Technique DVD

Analyticcycling.com has a model for this, and finds that, jumping out of a crit corner, adding 10 pounds to the bike weight will result in "At the end of 100m Standard Rider is ahead by 0.04s and 0.53 m". Do you think you can feel this difference?

As you also indicate, aerodynamics are much more important. An H3 will get you there faster than a lighter, less aerodynamic wheel.

Ken Lehner

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"Go yell at an M&M"

my only thought is this: heavier bikes tend to be lower quality bikes, and have lower quality components. Thus, it is possible that a heavier bike, due to inferior quality, could have higher internal friction. Just a thought, though if the only difference is weight, there is no difference.

Very little effect. Urban legend has it that Rominger actually added weight to his bike for his hour record.

But your main concern at Eagleman should be aerodynamics. That, and avoiding the 10 zillion other racers out on the course.

Interesting computation. It also says that, for two riders equal in all respects going into a corner at 17mph, except the 1st is on a 20lb bike, and the 2nd is on a 100lb bike: "At the end of 100 m Test Rider is ahead by 0.10 s and 1.50 m."

Do you think that's right?

http://analyticcycling.com/...CritCorner_Page.html

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Marty Gaal, CSCS
One Step Beyond Coaching
Triangle Open Water Swim Series | Old School Aquathon Series
Powerstroke® Freestyle Technique DVD

I plugged in the numbers for a 9kg bike and a 45kg bike, using the same aero numbers for each wheel, and a starting speed of 7.6m/sec (your 17mph), and got:

"0.57s and 6.14 m"

which seems in the right ballpark.

Ken Lehner

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"Go yell at an M&M"

Very interesting thread for someone living in FL where it's always flat. I guess no penalty in packing my alien multi tool for long races instead of just a few individual allen wrenches...

"Going into the corner at 17mph."

Is that the speed before slowing down to negotiate the corner, and then trying to accelerate back to 17mph?

90 degree corner?

That is the speed coming out of the corner. The model does not address cornering; the point was to determine the effect of aerodynamics and weight on the acceleration involved in jumping out of a corner in a crit.

http://www.analyticcycling.com/...CritCorner_Page.html

Ken Lehner

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"Go yell at an M&M"

For Eagleman I would concern myself with comfort under windy conditions. It is a very windy course.

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The Cuban Comet
(Comets are unbelievably slow over Cuba)

Goodtime, if there are no major ups and downs and corners to accelerate out of, for the same frontal area, the heavier rider+bike for a given power output will be able to handle the wind better. So just get into a position that is max comfort while being as aero as possible. 3 lbs on the bike is not going to change much of anything. If you can loose 3 lbs off your body and maintain the same bike power output, you'll also run faster :-)