How much difference is there in weight between frame sizes?

[MichaelW2]

What about smaller but heavier riders?

On average.

 

[Sittingduck]

Tell it to Cav - not that's he's particularly heavy but at 5' 9" and likely on a 52-54 frame he surely generates more power than the average bear

 

[KneesUp]

Did your friend ever wreck a frame?

I'm pretty sure he cracked his Pace RC100 from memory. (Like this one - not his or my bike)

Manufacturers can't afford to assume shorter riders are less powerful when making their frames, because not all of them are.

 

[Citius]

Did your friend ever wreck a frame?
On average, it is true. If you add in the use of shorter cranks for short riders(ie levers on the bottom bracket), this magnifies the effect. And visa-versa
Mostly, XS and XL riders don't know what a well designed frame should feel like since they rarely experience one. A few custom builders may get it right, but sourcing tubes of the correct profile is not easy. Carbon maestro Parlee build each frame with specially selected tube of the correct diameter and stiffness.

You're going to be falling into a lot of traps here, if you're not careful. How much effect do you think 5mm off the crank length will have on leverage? Also, what is your evidence that XS and/or XL frames are not 'well designed' ?

 

[MichaelW2]

Tell it to Cav - not that's he's particularly heavy but at 5' 9" and likely on a 52-54 frame he surely generates more power than the average bear

If Cav is using a stock frame, that would indicate that it is overly stiff for non-sprinters.
Do Specialized sneak in some extra wraps of carbon for him?

 

[Citius]

If Cav is using a stock frame, that would indicate that it is overly stiff for non-sprinters.

Says who?

 

[Sittingduck]

I just don't understand your assumtion that shorter riders are less powerful.

 

[MichaelW2]

I don't have any numbers for leverage but longer levers apply more torque (which takes more work from the longer circumference). You can't assume that a change in lever length has no affect on torque.

"Also, what is your evidence that XS and/or XL frames are not 'well designed' ?"
1. They mostly use the same tube diameter so shorter tubes are stiffer.
2. Throughout the size range, all manufacturers use identical chainstay and BB height dimensions.
XL frames use slack seatpost angles, so tall riders have their weight much further back over the rear axle.
XS frames use steep seatpost angles, so short riders have their weight much further forward towards the BB.

If the M size is well designed with good balance and weight distribution, extreme sizes will be different.

 

[MichaelW2]

I just don't understand your assumtion that shorter riders are less powerful.

In Olympic weight-lifting there are classes for different weight of athlete.
Heavier classes can lift heavier weights.
Heavier classes have taller athletes.

When designing stock, factory bikes, you should design around a statistically valid population, not unusual outliers.

 

[Citius]

I don't have any numbers for leverage but longer levers apply more torque (which takes more work from the longer circumference). You can't assume that a change in lever length has no affect on torque.

So in other words, your answer to my question on 'how much effect do you think this will have' is "I don't know".

"Also, what is your evidence that XS and/or XL frames are not 'well designed' ?"
1. They mostly use the same tube diameter so shorter tubes are stiffer.
2. Throughout the size range, all manufacturers use identical chainstay and BB height dimensions.
XL frames use slack seatpost angles, so tall riders have their weight much further back over the rear axle.
XS frames use steep seatpost angles, so short riders have their weight much further forward towards the BB.

If the M size is well designed with good balance and weight distribution, extreme sizes will be different.

And your response to a request for evidence is to give me a series of opinions.

 

[KneesUp]

In Olympic weight-lifting there are classes for different weight of athlete.
Heavier classes can lift heavier weights.
Heavier classes have taller athletes.

When designing stock, factory bikes, you should design around a statistically valid population, not unusual outliers.

Are you suggesting cycle racing should be graded by rider height?

 

[Sittingduck]

I like the sound of this - I deffo fancy my chances in the 'pussy power 5'9" Category'

 

[Drago]

I just don't understand your assumtion that shorter riders are less powerful.

Less skeletal area to carry muscle mass. Look and see how many 5'8" athletes you'll see in WSM in a few weeks time. Indeed, those under 6' are pretty unusual in top flight strength athletics.

Remember what your Dad taught you? The bigger they are, the harder they hit you.

 

[Citius]

Less skeletal area to carry muscle mass. Look and see how many 5'8" athletes you'll see in WSM in a few weeks time. Indeed, those under 6' are pretty unusual in top flight strength athletics.

Remember what your Dad taught you? The bigger they are, the harder they hit you.

WSM doesn't have much in common with endurance cycling though.