Weight

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NATURAL ANKLING
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Re: Weight

Postby NATURAL ANKLING » 26 Jun 2014, 10:52am

Hi,
OnYourRight wrote:They might be simplistic, but are they misleading? I think they paint an accurate picture of the effect of losing a couple of kilograms, i.e. significant if times matter, but probably irrelevant for people merely wanting to get from A to B – even if they’re in a rush!


And thats the point, if you are not racing why would you ride a bike that is stripped so bare just so you can look the part :?
And be as unpractical as you can be, on one of my last long day rides I broke a spoke :o Thats because the last time was probably 30 years ago, I had spare spokes and a key.
Without I would have been stuffed as even with cable off, the rim was still hitting the brake shoes.

You should see the junk I carry.....why ? because its easier to carry the same stuff than it is to edit the list and get it wrong when an unexpected Thing happens.

In the last week I have had a broken spoke and a first time ever derrailleur wrap around :shock: Different bikes.
Tool kit with two tubes is over 1.3 kgs.
Edited - Was on my way home on the last day at that factory and I took my two ten inch G clamps with me in the panniers, I did my best time that day, and there were hills, I live in devon.
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
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Mick F
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Re: Weight

Postby Mick F » 26 Jun 2014, 10:55am

I carry a mobile phone .........
Much lighter than a tool kit.
Mick F. Cornwall

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al_yrpal
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Re: Weight

Postby al_yrpal » 26 Jun 2014, 11:00am

Mick F wrote:I carry a mobile phone .........
Much lighter than a tool kit.


Does it serve as a spanner then? Or do you use it to call the AA? :D
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NATURAL ANKLING
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Re: Weight

Postby NATURAL ANKLING » 26 Jun 2014, 11:00am

Hi,
Mick F wrote:Also, my Campag freewheel is almost silent. The high-end ones are, it's just the cheap low-end ones that click loudly.

I use second hand cheap shimano ones, but you would'nt hear me as I seldom coast :)
Mind you-you would probably hear me as the trainer will not go above 25 on the flat, so I would be coasting down hill as I come past on the runaway train :lol:
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
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al_yrpal
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Re: Weight

Postby al_yrpal » 26 Jun 2014, 11:12am

Whar I have gleaned from this is that I probably have a cheap Campag freewheel, changing my tyres (which I have just bought) might up my Mercians speed a fraction and its very sensible to lose even more weight thus increasing my aerodynamic efficiency and boost my hill climbing speed.

The lust for a new road bike is diminishing which is a good thing considering the eye watering prices for very light ones. I remain happy with the Mercian and will put new tyres and tubes on my birthday list. :D

Al
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squeaker
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Re: Weight

Postby squeaker » 26 Jun 2014, 11:21am

OnYourRight wrote:
PDQ wrote:Richard Ballantine (New Bicycle Book) wrote " a cyclist moving at 20mph displaces some 1000 pounds of air a minute, a task which consumes about 85% of the riders total energy output"

I think that figure (85 %) might be a fraction high for a road bike (not by a lot, but by enough to make tyres considerably more important). Also, 20 MPH is fast. Average speeds tend to be lower on long rides, and drag falls off rapidly as speeds diminish.

Can always have a play on here if you are that interested :wink:
PS: 175W 'on the drops' = 20mph, if that helps - the sort of power output that gets me warm, quickly :oops: :lol:
"42"

OnYourRight
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Re: Weight

Postby OnYourRight » 26 Jun 2014, 11:22am

al_yrpal wrote:Whar I have gleaned from this is that I probably have a cheap Campag freewheel, changing my tyres (which I have just bought) might up my Mercians speed a fraction and its very sensible to lose even more weight thus increasing my aerodynamic efficiency and boost my hill climbing speed.

Ha! And you were probably enjoying those tyres! They might be nice ones for all I know. It’s just that Schwalbe itself doesn’t give them top marks for rolling resistance.

NATURAL ANKLING wrote:And thats the point, if you are not racing why would you ride a bike that is stripped so bare just so you can look the part :?

I think looking the part is vital to some (though everyone has their own idea of what looks the part!), and others believe weight makes a greater difference than it really does (the whole road-bike industry depends upon people believing 10 grams matter), and still others just prefer a light bike for reasons not directly related to speed. And a few probably do care about those 18 seconds per ride, or whatever the light weight gives them.

I confess I do like how a light bike feels and handles, especially in heavy traffic. It’s easier to fling it about, and it’s easier to bunny-hop a pothole or drain cover if you don’t have 5 kg of stuff rattling about at the back.

On a related note, heavy bikes tend to be noisy bikes. One very pleasant thing about a stripped-down road bike on a country lane is the taut silence of it.

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Mick F
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Re: Weight

Postby Mick F » 26 Jun 2014, 11:25am

al_yrpal wrote:
Mick F wrote:I carry a mobile phone .........
Much lighter than a tool kit.


Does it serve as a spanner then? Or do you use it to call the AA? :D
Phone home.
"Come and get me, my bike is broken!"
"Where are you?"
"I don't know, my Garmin's broken too!"

:lol: :lol:
Mick F. Cornwall

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mjr
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Re: Weight

Postby mjr » 26 Jun 2014, 11:36am

OnYourRight wrote:Ha! And you were probably enjoying those tyres! They might be nice ones for all I know. It’s just that Schwalbe itself doesn’t give them top marks for rolling resistance.

That site rates Marathon and M+ as the same for rolling resistance. I want some of whatever mind-altering substances they're on, so I can use M+ without feeling it's draggier (I still use it because the protection is that good, but both M and DC feel nicer).

On a related note, heavy bikes tend to be noisy bikes. One very pleasant thing about a stripped-down road bike on a country lane is the taut silence of it.

But nothing beats the gentle ticking of a SA hub gear in overdrive, does it? ;-)
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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LollyKat
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Re: Weight

Postby LollyKat » 26 Jun 2014, 11:38am

Try a Rohloff in gear 7. Who needs a bell on a shared use path! :lol:

Brucey
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Re: Weight

Postby Brucey » 26 Jun 2014, 12:31pm

mjr wrote:
OnYourRight wrote:Ha! And you were probably enjoying those tyres! They might be nice ones for all I know. It’s just that Schwalbe itself doesn’t give them top marks for rolling resistance.

That site rates Marathon and M+ as the same for rolling resistance. I want some of whatever mind-altering substances they're on, so I can use M+ without feeling it's draggier (I still use it because the protection is that good, but both M and DC feel nicer).


wow. If I had some of that stuff I'm not sure I'd be able to find my bike, leave alone ride it.... Maybe they test tyres on perfectly smooth surfaces or something. I am sure that the lumpiness of real-world roads makes a big difference.

On a related note, heavy bikes tend to be noisy bikes. One very pleasant thing about a stripped-down road bike on a country lane is the taut silence of it.

But nothing beats the gentle ticking of a SA hub gear in overdrive, does it? ;-)


My present town bike weighs nearly 50lbs and it is one of the quietest bikes I have ever owned; just the faintest rustle of the chain inside the chaincase , and a (muted, it runs semifluid grease) tick-tick-tick from the hub gear. Lovely.

Almost anything with a derailleur gear sounds quite noisy to me.

cheers
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recordacefromnew
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Re: Weight

Postby recordacefromnew » 26 Jun 2014, 12:57pm

al_yrpal wrote:
quilkin wrote:the article on bike weight, I partially agree with it but, as an ex mechanical engineer I think the calcs are rather simplistic.


If you are referring to that formula by McCraw, where he suggests climbing speed is inversely proportional to total weight, I agree with you. I think it is wrong.

Absent strong wind, for a recreational cyclist to maintain the same speed power requirement doubles as the incline reaches around 1%, needless to say when the incline reaches a couple % more the lion's share of power must end up expended on hauling weight up vertically.

So for slopes of more than just a couple of %s, to maintain the same power output (which is energy over time) one can simply use the formula of kinetic energy (which is converted to potential energy stored in vertical elevation) to estimate the impact on speed. Since kinetic energy is directly proportion to mass but square of speed, an increase (say 10%) in rider+bike mass will be cancelled by a reduction in speed of only roughly 4.6%.

The implication, is that not only are relatively weights of bike parts of little consequence on hill climbing speed, but more importantly cakes and pies are slowing us down less than we think! :)

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NATURAL ANKLING
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Re: Weight

Postby NATURAL ANKLING » 26 Jun 2014, 1:26pm

Hi,
Yes a light bike even my old Koga-Miyata @ 10.5 k would be dream and reminds me of all my new bikes on the first outing :D
It keeps screaming to me put my wheels on, then I would be back up Haytor like in the past killing myself on the 42 22 He-Man gears 8)

And I am the same weight as I was when I was 23................at now 55...................
NA Thinks Just End 2 End Return + Bivvy
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Brucey
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Re: Weight

Postby Brucey » 26 Jun 2014, 1:36pm

recordacefromnew wrote:.... one can simply use the formula of kinetic energy (which is converted to potential energy stored in vertical elevation) to estimate the impact on speed. Since kinetic energy is directly proportion to mass but square of speed, an increase (say 10%) in rider+bike mass will be cancelled by a reduction in speed of only roughly 4.6%....


This isn't right at all. If you are going to neglect air resistance then power required for climbing is very simply proportional to speed.

cheers
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al_yrpal
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Re: Weight

Postby al_yrpal » 26 Jun 2014, 1:51pm

Blinged up cyclists in multicoloured lycra riding eye poppingly gaudy bikes have a strange effect on me, they make me snigger. In fact they make me laugh out loud if they are being ridden by some old bloke trying to look cool and missing it by a mile. My interest in a new road bike wasnt the bling factor but the thought of being able to fly along more easily. At some point I will try some lighter easier rolling tyres, but the decrease in puncture protection worries me because all our local roads are presently covered with flint gravel that cuts your tyres to pieces.

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. Make a difference...