Is there a science to building metal bike frames?

[martl]

Originally Posted by Mark McM

Just who is claiming that a frame cane save dozens of Watts of power? I think you are mis-representing the aero bike power savings that are being claimed. Generally, claims will be made for power savings of aero bicycles - which includes not just the frame, but also the wheels, the handlebar, stem, seatpost, etc. The aerodynamic drag differences between entirely different bicycles can be dozens of Watts - even if the savings of the frame alone is much less.

https://forums.thepaceline.net/showp...8&postcount=18

I rather think the opposite. I think most numbers advertised are for the bike alone, or even the frame/fork/handlebar alone. Can one build a *framest* that is 30% more "aero" than a classic lugged steel one? absolutely.
does that mean you get the same saving on the road? heck no.

Your comments that the claimed power savings of aero bikes can't be true because of the relatively low average power during an entire race is also a mis-representation.

True because you misinterpreted my point. Which was:
It takes 220W average to finish a TDF stage in the field.
This is the amount of power needed to overcome rolling resistance (maybe 10% of that) and Aero resistance of the full system Rider + Bike.

The frame or frameset alone -which is what was discussed- may be responsible 20-30W of that ("dozens of watts"), but you will not see 30W *difference* between Frame A and Frame B.

Savings of dozens of Watts are only claimed under certain conditions - for
example, in still air at 30 mph. Nobody is claiming that you'll have anywhere near dozens of Watts of power savings under typical riding conditions (which would drafting in pack when racing, or at lower speeds when not racing).

So when does the power savings of an aero bike make a significant difference? Under short duration but critical race situations, such as breaking away solo or with a small group, or in a final sprint. The rest of the time there are still real power savings, just much smaller.

The difference between a 650b cruiser with raised handlebars and a full TT bike may be "dozens of watts", but definitely not between a2020 "aero" racing bike and, lets say, a 2010 Cannondale with similar wheels.

[Mark McM]

Originally Posted by martl

https://forums.thepaceline.net/showp...8&postcount=18

I rather think the opposite. I think most numbers advertised are for the bike alone, or even the frame/fork/handlebar alone. Can one build a *framest* that is 30% more "aero" than a classic lugged steel one? absolutely.
does that mean you get the same saving on the road? heck no.

Your argument contradicts the reference you cite. The posting you cite talks about the Cannondale System Six, which is a bike that has been designed, built and sold as a complete system (frame, fork, wheels, stem handlebars, seatpost, etc.). The aero power savings claimed for the Cannondale System Six is absolutely not for just the frame. (View the System Six white paper here.)

Originally Posted by martl

True because you misinterpreted my point. Which was:
It takes 220W average to finish a TDF stage in the field.
This is the amount of power needed to overcome rolling resistance (maybe 10% of that) and Aero resistance of the full system Rider + Bike.

This is a strawman. So what if it takes little power to stay in a pack during a TdF stage? If that's your only goal, then an aero bike only helps a small amount. The point of a race is not to simply ride in the middle of the pack the whole way, but to be ahead of the pack (breaking away or sprinting), to chase down a break, or to help your team mates by pulling on the front to discourage a break. In those situations riders need to put out far more than 220W (often many times more). In those situations, riders can get significant benefit from the power savings of an aero bike. (These points are also addressed in the white paper.)

Originally Posted by martl

The frame or frameset alone -which is what was discussed- may be responsible 20-30W of that ("dozens of watts"), but you will not see 30W *difference* between Frame A and Frame B.

Who you are arguing against? You have yet to cite any frame producer who claims that a frame alone can save 30 Watts (at a typical riding/racing speed).

[martl]

Originally Posted by Mark McM

Your argument contradicts the reference you cite. The posting you cite talks about the Cannondale System Six, which is a bike that has been designed, built and sold as a complete system (frame, fork, wheels, stem handlebars, seatpost, etc.). The aero power savings claimed for the Cannondale System Six is absolutely not for just the frame. (View the System Six white paper here.)





This is a strawman. So what if it takes little power to stay in a pack during a TdF stage? If that's your only goal, then an aero bike only helps a small amount. The point of a race is not to simply ride in the middle of the pack the whole way, but to be ahead of the pack (breaking away or sprinting), to chase down a break, or to help your team mates by pulling on the front to discourage a break. In those situations riders need to put out far more than 220W (often many times more). In those situations, riders can get significant benefit from the power savings of an aero bike. (These points are also addressed in the white paper.)





Who you are arguing against? You have yet to cite any frame producer who claims that a frame alone can save 30 Watts (at a typical riding/racing speed).

The discussion was "are modern bikes significanlty faster", and one poster said yes, because of all the research and Aero put into them. It was said it would be noticeably faster even on a test ride across a parking lot.

Frankly, that is as true as making bikes more comfortable by modern frame building. It is 99% marketing bollocks.

[jlwdm]

Originally Posted by choke

I won't disagree that they are faster. But how much faster? Not much, if you look at the stats.

The 1952 Giro was 3964km long and the winning time was 114h 36' 43". That's an average speed of 34.59km/hr.

The 2019 Giro was 3547km long and the winning time was 90h 01 '47". That's an average speed of 39.40 km/hr.

So with carbon frames...
....more gears
....better rolling tires
....better nutrition
....advanced training techniques
....etc. etc

there was less than a 5 km/hr improvement in 67 years....on a course that was 417 km shorter.

You can't be serious trying to compare times for a three week stage race on a different course every year. Especially for the Giro which was famous for being a race that riders rode most of each stage at a relaxed pace and then raced hard at the end of the stage. A stage race is a strategic race not an all out race every stage.

Jeff