what makes a light bike really light?

[dvt]

Mike Reed wrote:
> Oh, and aren't all bikes toys?

Nope. I have 2 toy bikes. The other is utilitarian... it gets me to
work, around town, etc. And sometimes it gets to go out to play.

I hear that many in third-world countries view bikes as tools rather
than toys, too.

--
Dave
dvt at psu dot edu

 

[David Damerell]

Quoting Paul Hobson <[email protected]>:
>David Damerell wrote:
>>Quoting Paul Hobson <[email protected]>:
>>Except you're going
>>to be one of those people who doesn't believe in elementary mechanics.
>Right that's clearly the case.

Well, yes, since you believe things happen which an understanding of
elementary mechanics makes clear are impossible.

>It's about 6 miles. The fastest I've ever gotten there on the slow bike
>is about 27 mins (vs. 45 in car<g>). On the fast bike, I've gotten
>there in 22 and 24 mins the past two times.

Which obviously cannot be explained by relative wheel weights, which would
effect only a tiny change in times.

>>>Initially? So what?
>>So when you say that "lighter rims are easier to move. period." you are
>>wrong, because there is a circumstance in which heavier rims are easier to
>>move.
>Such as?

The start of a climb when travelling at cruising speed on level ground.

>>That helps to illustrate how your perceptions are inaccurate. You can spin
>>a wheel, heavy or light, up to a good speed with one thrust of your arm.
>>That rotational momentum cannot be significant next to the much greater
>>force your legs can exert.
>Perceptions inaccurate? I don't think stopping distance of 50 ft vs. 75
>ft is insignicant?

It think it's very significant; obviously it is far too great a difference
for wheel weight to explain and it is ridiculous to attribute it to wheel
weight.

One explanation might be that your position is different on one bike,
moving your centre of gravity relative to the front contact patch. That
would affect the available braking.
--
David Damerell <[email protected]> Kill the tomato!
Today is Mania, March.

 

[Mike Reed]

Wait, so tools aren't toys? How do you explain how I feel when I see a
wall of wrenches at the local tool department?

-Mike

 

[A Muzi]

([email protected])
>>To get to 15 [lbs] you need to watch every piece. An uncomfortably slim
>>saddle, no computer, carbon bars ...

D'ohBoy wrote:
> Which carbon bar? All the ones I have seen (Easton, FSA) weigh as much
> or more than a triple butted aluminum one.
> Just wondering,

We used the 220g Kestrel EMS Pro for both. Yes there are
aluminum bars in the same weight range but the EMS bar has a
good track record here ( zero problems so far...)

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Doug Taylor]

On Fri, 03 Mar 2006 19:49:45 -0600, A Muzi <[email protected]>
wrote:

>We used the 220g Kestrel EMS Pro for both. Yes there are
>aluminum bars in the same weight range but the EMS bar has a
>good track record here ( zero problems so far...)

I used the same on my build; another e-bay special.

Opted for Ritchey WCS stem over anything carbon however. Yours?

 

[Ron Ruff]

Paul Hobson wrote:
> Wheels or not, the point (my point) stands. I go faster on my lighter
> rims. You say 2%, but keep in mind I only weigh between 125 and 130
> lbs. So that percentage is slightly higher than the average 165 - 185
> American male.
>

So you and your bike weigh 145 lb or so, and you would need a 1.45 lb
difference in rim+tire weight to get that 2% difference in the *rate of
acceleration*. For climbing a steep hill, that massive weight
difference would only make you 1% faster.

Unless your wheels are generating some cold fusion or zero point energy
effects, I suspect the placebo effect is at work.

 

[Paul Hobson]

Ron Ruff wrote:
> Paul Hobson wrote:
>
>>Wheels or not, the point (my point) stands. I go faster on my lighter
>>rims. You say 2%, but keep in mind I only weigh between 125 and 130
>>lbs. So that percentage is slightly higher than the average 165 - 185
>>American male.
>>
>
>
> So you and your bike weigh 145 lb or so, and you would need a 1.45 lb
> difference in rim+tire weight to get that 2% difference in the *rate of
> acceleration*. For climbing a steep hill, that massive weight
> difference would only make you 1% faster.
>
> Unless your wheels are generating some cold fusion or zero point energy
> effects, I suspect the placebo effect is at work.
>

If you go back and read my first post ITT, you'll see that was speaking
strictly qualitatively and from my personal experience. I fail to see
how any of the (valid) points brought up since then could possibly
negate any of that - placebo or otherwise.
\\paul