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54's are as fast as 28's on smooth pavement? I know 28's are as fast or faster than 23's, but 54's being as fast or faster than 28's is nonsense, I don't care how much data you compiled.
I was an academic for many, many years, and it is very common for scholars to construct elaborate data sets to "prove" theories that anyone with an IQ over 60 knows is BS.
And yes, I know Jan Heine is famous. It takes brains to come up with these ridiculous theories.
Angstrom wrote:This is interesting data on the effect of surface roughness on rolling resistance.
ljsmith wrote:
I'd say the RR looks pretty good when you consider how big those knobs are.
RadDogRoadWarrior wrote:54's are as fast as 28's on smooth pavement? I know 28's are as fast or faster than 23's, but 54's being as fast or faster than 28's is nonsense.
ccand51997 wrote:
I did some testing on a steep hill where I compared a number of gravel/fast mtb tires with a GP4000S2 as my control tire and the G-One Speed I used was almost as fast (like 2 sec over a five minute climb) as the GP4000. And that was at 25 psi.
Now, that only addresses the rolling resistence question. You are definitely going to take a hit in wind resistence when the tire is TWICE as big.
thumper88 wrote:Thanks for being gentle .... Many accurate points made, no need to be unpleasant about it, even if this is the internet.
Mensches Ben Adam.
chas wrote:
Yup. One way I think of it:
I can apply as much torque or force as I want against a wall (or a pedal). But if it doesn't move (0rpm) I have generated zero power. Power needs movement - more movement more power.
Power = torque x RPM. So yeah, the more RPM (at the same torque), the more power.
ccand51997 wrote:
Disc vs Rim brakes
A friend of mine contemplating his first bike in 25 yeas told me he had not ever in all his years needed more braking power than he had with rim brakes. True enough. But if I want to use very wide tires then I'm using discs. I've fought with cantis and vbrakes and the fight is not worth it to me.
ccand51997 wrote:He also obsesses with weight overmuch, which to me is the biggest myth that should be busted. The dfference in weight is not zero but its not very important either when you consider tires, aerodynamics, suspension and other factors.
TwoWheeler wrote:
He also conveniently overlooks the facts that disk brakes make wheel removal and installation much easier, that it’s cheaper and easier to replace a worn brake rotor than a worn rim and a disk brake doesn’t care how out of true your rim is - if you ever need to limp home on an out-of-true wheel.
TwoWheeler wrote:
I am living proof that light weight bikes don’t make you faster, but for me, there’s no denying that a lighter bike is more responsive and thus more fun.
John wrote:
I live an a 3rd floor apartment and use trains to get to most of my dirt/gravel routes. Having a 17 pound gravel bike is a lot easier getting thru turnstiles, one trains and up stairs than a 35 pound mountain bike.
TwoWheeler wrote:
....and here I piss & moan when I lug my bikes up out of the basement.
I’d be looking for a balsa bike!
John wrote:
I will say this, no bike I ever owned turned heads like my black Turner Sultan 29er.
I am an academic by training, and it is very, very common for individuals to come up with elaborate formulas and analysis to justify what any 12 year old with an IQ over 80 would know is nonsense. Outrageous/ridiculous theories build careers.
I put the "weight does not matter" claim in that basket. I just upgraded my rims (losing a few hundred grams in weight) and the difference is night and day.
The difference between a 19 lb bike and a 24 lb bike is also night and day. Don't put too much faith in elaborate theories built on nonsense.
RadDogRoadWarrior wrote:I am an academic by training, and it is very, very common for individuals to come up with elaborate formulas and analysis to justify what any 12 year old with an IQ over 80 would know is nonsense. Outrageous/ridiculous theories build careers.
RadDogRoadWarrior wrote:I am an academic by training, and it is very, very common for individuals to come up with elaborate formulas and analysis to justify what any 12 year old with an IQ over 80 would know is nonsense. Outrageous/ridiculous theories build careers.
I put the "weight does not matter" claim in that basket. I just upgraded my rims (losing a few hundred grams in weight) and the difference is night and day.
The difference between a 19 lb bike and a 24 lb bike is also night and day. Don't put too much faith in elaborate theories built on nonsense.
ccand51997 wrote:
So, how about some math from cyclist/engineer Kraig Willett
http://www.biketechreview.com/reviews/wheels/63-wheel-performance
Basically he took three power files and modeled them using a bunch of different variables. In one he compared the power required to move a regular 32-hole wheel vs. a Lew wheel that had 50 percent less mass. The reduction in power required to go the same speed was about 3/10ths of a watt. So I don't know how much Lew wheels weigh but let's say they are 900grams. By ditching your regular training wheels the weight savings going from 1800grams to 900 grams is about (combining both wheels) 6/10ths of a watt. It makes sense actually. People only talk about how much faster their light wheels feel, but its all a question of inertia. Those 1800 watt wheels have more inertia and will hold speed better than the 9000 watt wheels but even then the difference is not significant.
When he took out a slice of that ride that was only uphill, then the improvement jumped to two watts. Which also makes sense because an extra pound of weight on a hill adds about 1 extra watt required to maintain speed.
Even in the criterium example where you would think there was constant acceleration and deceleration, it was still only about a 1.5 watt difference.
I don't think anyone claims that weight does not matter. It just doesn't matter very much. Even that five pound difference you mention in a bike matters. I always use the computation made for 1 extra pound of weight from the bottom of the climb of Alpe D'Huez to the top. It is 14 seconds per extra pound, so your 19 pound bike would allow you to arrive 1:10 seconds faster to the lovely ski resort. Depending on rider weight that is a 5-6 watt difference.
As long as people know the numbers then they can make educated decisions about equipment. Folks with an unlimited budget can do whatever they want but most folks would be better off buying newer, faster rolling tires, or something similar. GP5000s with latex or tubeless vs old 4000s with butyl tubes will give you a bigger increase in speed than dropping five pounds on your bike (about 7 watts).