Heavy rims

[Woofie]

 

I am still not sure if there will be a noticeable difference in reducing weight on the wheels compared to reducing weight elsewhere given that we talking about real world components (not concrete wheels etc).

 

 

 

 

Sorry' date=' I'm joining a very interesting topic late...

 

 

 

In my experience you'll feel 150g in the wheels immediately but not necessarily elsewhere. Experimented with that on my Mbuzi. The Kobra adjustable post weighs a ton so hacking 350g off it was fairly easy. Didn't feel much of a dif (complete bike weighs in at 15k's so it's a small % compared to RB weights).

 

Then I tried new tires. Dropped 319g and could immediately feel it. And the dif felt BIG. Yeah you have to factor in grip and things like that that also has an influence...

 

 

 

Educate away.[/quote']

 

And have you taken it on a flat course yet?

Can you feel a major difference there?

Obviously you will climb like a beast with such a big weight loss, but would you really feel the diff on level jeeptrack?

 

 

[bikemonster]

 
A 10kg bike with 1kg wheels will accelerate faster than a 9kg with 2kg wheels even though they will both weigh in at 11kg.

On a downhill when freewheeling this will probably be evened out as the laws of gravity will apply.

But as long as you have to pedal to get it going rotational weight will be the one where you'd wanna save as much as possible. That and smooth' date=' fast hubs with quick engagement.[/quote']

 

Nope.

 

It doesn't matter whether the energy is added by pedalling or taking advantage of gravity.  The point is that there is rotational inertia to be overcome.

 

Which, relating to another point is why lighter tyres really do make a difference.  Incidentally, I was sceptical of this last point until I happened to change over from some lardy-ass wire-bead tyres to Conti GP4K's.  My bike was transformed....transformed I tell ya.

 

Well, it was still a bike, but it accelerated and climbed much better.

 

[Willehond]

Man, the application of "science" on this thread is just too painful to even discuss.  Wow, Newton has had a couple of new laws ripped into him this week.  Everyone adds their bit of pseudo-bike-science, which makes some sort of sense if you read it really really fast, but somehow it all just smells a bit off.  A bit like BS methinks

 

(Not you of course Bikemonster. You have come back from the dark side so all is forgiven. For now...)

[bikemonster]

They say nobody likes a kiss-ass.

 

 

I say, WTF do they know?

[Sterad]

Only advantage of heavier wheels will be on downhills. Even on flats, light weight rules!! Period

[bikemonster]

Only advantage of heavier wheels will be on downhills.

 

How so?

[parabola]

 

Everyone adds their bit of pseudo-bike-science' date=' which makes some sort of sense if you read it really really fast, but somehow it all just smells a bit off.  A bit like BS methinks[/quote']

 

Well I am a few months away from a MSc in Mechanical Engineering. So I do like to think I know a little about "science"

 

[Sterad]

Roll a metal disc and a plastic disk of the same size and shape down a slope, which one will get to the bottom first?

[bikemonster]

Are we back at skinnies vs. fatties down a hill?

 

If the slope is the sort of experiment you set up on a desk, the disks arrive at the same time because although there is more force exerted on the heavy disk, there is also more inertia to overcome.

 

If we allow for the effects of wind resistance, the metal disk continues to accelerate for longer than the plastic disk.

 

If we steer the conversation back to bike wheels, lighter is ALWAYS better, all other things held constant.

 

Like I said earlier, there are aero advantages which can outweigh (oh I slay myself!) the weight disadvantages, but there is no inherent advantage in more weight.

 

(And for the pedants out there, we are on Earth, so mass and weight are interchangeable in this discussion!)

[Willehond]

Everyone adds their bit of pseudo-bike-science' date=' which makes some sort of sense if you read it really really fast, but somehow it all just smells a bit off.  A bit like BS methinks[/quote']

 

Well I am a few months away from a MSc in Mechanical Engineering. So I do like to think I know a little about "science"

Well, I got my Engineering degree 15 years ago so I like to think that I do too, but after reading this thread apparently not.  Looks like physics has changed a lot since then. Maybe my degree expired?

[parabola]

 

Roll a metal disc and a plastic disk of the same size and shape down a slope' date=' which one will get to the bottom first?[/quote']

 

Surely wheels are better approximated as are hoops, not discs.

And they would get to the bottom at the same time.

 

The speed at the bottom of the slope depends not on the mass of the object, but on the distribution of mass around its central axis. Thanks Sterad for asking this question, I had completely forgotten about this basic principle

 

[Sterad]

I would have thought that the metal disk would reach the bottom first, but maybe I am wrong.......need to put this to test...

[parabola]

 

Everyone adds their bit of pseudo-bike-science' date=' which makes some sort of sense if you read it really really fast, but somehow it all just smells a bit off.  A bit like BS methinks[/quote']

 

Well I am a few months away from a MSc in Mechanical Engineering. So I do like to think I know a little about "science"

Well, I got my Engineering degree 15 years ago so I like to think that I do too, but after reading this thread apparently not.  Looks like physics has changed a lot since then. Maybe my degree expired?

 

I got my undergrad only two years ago and I am shocked at how quickly I have forgotten some basic principles I learned in first year. A quick flick through the physics textbook reminded me that its still there ... somewhere ... I think

 

[parabola]

 

I would have thought that the metal disk would reach the bottom first' date=' but maybe I am wrong.......need to put this to test...[/quote']

 

I will put something up explaining this a bit later. Just need to get some work done first before I call the start of the weekend

 

[Slowbee]

the problem is the wheels get heavier ... or lighter with different riders.

 

 

 

[Taps]

After all this my brains are falling out