Tristan wrote:

inzane wrote:

jeremyb wrote:

Robbie wrote: All the normal places: at the contact point with the cogs, and within the belt itself as it flexes.

More contact area = less friction I would've thought, plus no rollers in the chain to rotate and wear!

What sort of engineer are you?? More contact area is always going to equal more friction!!

Contact area has nothing to do with frictional force. Frictional force depends only on the coefficient of friction (basically how slippery the two objects are) and the normal (perpendicular to direction of motion) force pushing the two objects together.

Exactly what I was going to say. Although this in perfect in theory - but then why do drag racers use wide tyres?

I'm surprised that jb doesn't know about the inefficiencies of belt drives, seeing as he knows everything else

Increased surface area touching the ground = increased traction off the line = more power put down onto the road = drag racing is about acceleration not top speeed.

Bigfoot wrote: Increased surface area touching the ground = increased traction off the line = more power put down onto the road = drag racing is about acceleration not top speeed.

Correct.
Except that traction = friction (against the ground). And the arguement above says that friction is independant of area. Hence my question.

Everyone knows that wider tyres have more grip, but the theory tells us that they don't.

Its because physics is stupid and needs its unifying theory... I propose the unifying theory of physics is that physics is stupid.

I concur with your theory

From what I've read now it is not independent of surface area, two rough surfaces will have less surface area touching so less friction...

friction in physics is basically a coefficient that tells you how hard it is to move one thing across the surface of another.

The way that people are using the word friction above is talking about it as an efficiency.

Need to define what people are talking about better or the airplane will never get off the treadmill.

I think that there are likely to be many more losses of energy in a belt drive than in a chain drive under normal bike operating circumstances.

Conners wrote:

Bigfoot wrote: Increased surface area touching the ground = increased traction off the line = more power put down onto the road = drag racing is about acceleration not top speeed.

Correct.
Except that traction = friction (against the ground). And the arguement above says that friction is independant of area. Hence my question.

Everyone knows that wider tyres have more grip, but the theory tells us that they don't.

If the road surface was perfectly flat then wider tyres wouldn't have such an advantage, but because of the surface imperfections the tyre can conform to the surface and use each undulation as something to push against.

There is also hysteresis and heat dissipation to contend with.

Would be easy to test, power measuring hub and electric motor, try both and see what transfers more power... now put both thru a winter of mud and rain and see how well the chain does

jeremyb wrote: Would be easy to test, power measuring hub and electric motor, try both and see what transfers more power... now put both thru a winter of mud and rain and see how well the chain does

Singlespeed chain to match the singlespeed belt drive.

Bet you the chain would come through it very well!!

How about you set up this experiment and tell me the results?? I am betting the chain will come through more efficient!

Perfect setup?

Well apart from the Avids

Now Ducati and Moto Guzzi there is 2 bikes that make even a nun moist.

Not into motorcycles, but at a guess if those pieces of crap will make a nun moist than dont show them John Brittan's bike because it would make there pusseez gush like niagra falls. Sorry bro John set the bar, but thats just my opinion!
I still go into brain freeze when I look at that rig to long!

Astoria Paranoia wrote: Perfect setup?

Well apart from the Avids

yeh, coz an alfine hub is a thing of beauty??

no thank you.

bikeys wrote: Now Ducati and Moto Guzzi there is 2 bikes that make even a nun moist.

Not into motorcycles, but at a guess if those pieces of crap will make a nun moist than dont show them John Brittan's bike because it would make there pusseez gush like niagra falls. Sorry bro John set the bar, but thats just my opinion!
I still go into brain freeze when I look at that rig to long!

Meh just another nostalgic Kiwi. Who would have thunk it

Trail wrote:

jeremyb wrote: Would be easy to test, power measuring hub and electric motor, try both and see what transfers more power... now put both thru a winter of mud and rain and see how well the chain does

Singlespeed chain to match the singlespeed belt drive.

Bet you the chain would come through it very well!!

How about you set up this experiment and tell me the results?? I am betting the chain will come through more efficient!

OK, I've just done the experiment at work and the belt won, bet you feel silly!!