How stiff?

by tony_farrelly   September 11, 2008  

People, well bike journos, are always banging on about the importance of lateral stiffness and a rigid bottom bracket, for efficient power transfer, but is it?

Van Nicholas had Delft Technical University test the stiffness of their bikes and what they found was that their was no real loss of power whether the rear stays flexed or not - what there was was a difference in the immediacy of the power delivery.

So, big lad sprinters need everything to be stiff and immediate - in power delivery terms at least (hence the extra stiffening give to the chainstays their new Astraeus, while tourers and commuters might be better off with the smoother delivery you get from a slightly less stiff set up…

Basic physics innit, you put power into something to bend it in one direction it is going to return the same amount of power when it flexes back in the opposite direction. You can't really 'lose' power anyway. Okay, pedants can quibble that a tiny amount of that power will be dissipated as heat and even noise but we're talking infinitesimally small amounts.

Makes you think… which is generally a good thing

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many of the Silence - Lotto team riders dont ride the Ridley Noah as it is too stiff! Instead the majority of the team take the option of using the Ridley Helium. When I told this to a rider from Quickstep, he was amazed, stating "for me, there is no such thing as a bike that is too stiff"

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jay cee's picture

posted by jay cee [17 posts]
30th September 2008 - 22:01

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Or maybe it just depends where it is stiff. The point of that research above seem to be that if a bike isn't as laterally stiff you still aren't losing the energy it's just taking longer to get to the back wheel. It's not less efficient, it's just less immediate.

On a bike somewhere…

thebikeboy's picture

posted by thebikeboy [138 posts]
30th September 2008 - 22:44

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yes he was/is a sprinter, Wouter Weylandt.

If it is over then it is not the end, if it is the end then it is not over yet
www.rouleur.cc

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posted by jay cee [17 posts]
30th September 2008 - 22:53

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Can imagine stiffnessi isn't an an issue for Wouter
http://www.wouterweylandt.be/
he's going to hurt himself with that hair though

On a bike somewhere…

thebikeboy's picture

posted by thebikeboy [138 posts]
30th September 2008 - 22:59

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he's had it cut now.

If it is over then it is not the end, if it is the end then it is not over yet
www.rouleur.cc

jay cee's picture

posted by jay cee [17 posts]
30th September 2008 - 23:15

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It was special

tony_farrelly's picture

posted by tony_farrelly [4049 posts]
1st October 2008 - 11:50

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