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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 02-14-07, 11:14 AM   #1
dahc
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Weight Percentages

I've searched the site and can't seem to find what I'm looking for.

There are a lot of discussions about weight. But I can't find any that give an over all view of the percentage of total weight each major component makes up.

For example if a given bike weighs 20lbs what percentage of that is made up of the frame (4 pound frame would be 20%).

Maybe I can't find it because it is so different for any given bike. But still it seems to me like there should be some general rule of thumb info out there.

Why am I asking? I'm thinking about building up an old beater fixed gear bike. This would be my first attempt at building a bike. I'd like for the bike to not end up weighing 40lbs, but if I'm buying parts piece by piece, the frame off of an old Schwinn (that weighted 40lbs or so) is a lot cheaper than something "fancy" (ie light).

Thanks,

Chad
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Old 02-14-07, 11:16 AM   #2
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well, if the bike weighed 40 pounds, and you are replacing the parts with newer ones, you are almost guarunteed a substantially lighter bike. I don't know if what you are asking for exists though... You want the least weight in rotating parts such as the wheels, cranks, chain and pedals. Weight in other parts of the bike is not as important.
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Old 02-14-07, 11:20 AM   #3
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Quote:
Originally Posted by Shiznaz
You want the least weight in rotating parts such as the wheels, cranks, chain and pedals. Weight in other parts of the bike is not as important.
It depends entirely on what you are using it for.

If you want a moderately light bike don't get a 40lbs schwinn. It's a waste of money. Also don't try to buy everything piecemeal. Spend more on a decent frame with most of the components you need and just get a few things. You'll save money in the long run.
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Old 02-14-07, 11:20 AM   #4
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you seem to have it figured out pretty well..
if you are interested,
why not just do the math ?

Quote:
Originally Posted by dahc
For example if a given bike weighs 20lbs what percentage of that is made up of the frame (4 pound frame would be 20%).
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Old 02-14-07, 12:14 PM   #5
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Weight Percentages

Quote:
Originally Posted by dutret
If you want a moderately light bike don't get a 40lbs schwinn. It's a waste of money.
I guess that's my point. Why is it a waste of money?

Let's compare:
Frame A is made with gas pipe and weighs 8lbs.
Frame B is made with Reynolds 531 and weighs 3 lbs

If everything else is build up the same you could end up with bike A weighing 23lbs and bike B weighing 18lbs.

Granted 18 would be better than 23, but 23 doesn't seem all that bad.

Not trolling, just really don't understand the price difference in the frames I've seen.

Chad
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Old 02-14-07, 12:21 PM   #6
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dunno about percentages per se, but if you're looking for a place to cut weight, i'd say the wheels.
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Old 02-14-07, 12:43 PM   #7
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Look up your parts and do the math:

http://weightweenies.starbike.com/listings.php
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Old 02-14-07, 01:04 PM   #8
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Quote:
Originally Posted by dahc
I guess that's my point. Why is it a waste of money?

Let's compare:
Frame A is made with gas pipe and weighs 8lbs.
Frame B is made with Reynolds 531 and weighs 3 lbs

If everything else is build up the same you could end up with bike A weighing 23lbs and bike B weighing 18lbs.

Granted 18 would be better than 23, but 23 doesn't seem all that bad.

Not trolling, just really don't understand the price difference in the frames I've seen.

Chad
The price difference between a gaspipe schwinn and a decent cromo frame is going to be $100 dollars or so. To save 5 lbs anywhere else on the bike you're going spend a lot more then that.

More importantly however if you are trying to save money you shouldn't be looking for a bare frame. You should be trying to find a frame with most of it's parts attached. If you do that with a decent cromo frame you are going to get most of the parts you need to make a bike of reasonable weight. If you do it with some plumbers special you are just going to end up with more heavy crap.
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Old 02-14-07, 01:10 PM   #9
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Quote:
Originally Posted by Hobartlemagne
Look up your parts and do the math:

http://weightweenies.starbike.com/listings.php

Dude, for someone who is new to this that site is kind of like trying to learn Greek. There are TONS of mfgs and each one has different components. Thanks for the advice, but if that's what it takes I'd just rather not know :-)

How about a different approach. How far off do you think these estimates are on any given bike:

Frame = 20%
Wheels = 20%
Pedals/Cranks/Chainring/Cogs = 20%
Seat & Post = 15%
Handlbars/Stem/headset = 10%
Brakes/Levers/Derailers = 10%
Cables and other stuff = 5%
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Old 02-14-07, 01:21 PM   #10
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remember grammar school arithmetic? you add up all the, say.... stems, and then divide them by the total number of weights you added up... thats called an average. with these "averages" you can figure out your percentages, but really i have no idea what you will gain with that knowledge, as it has next to no real world application.
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Old 02-14-07, 01:24 PM   #11
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i think the percentage thing is approaching the problem backwards. i understand trying to do a little planning to make the build come out lighter, but really, you're going to get the wrong parts and spend too much money if you're looking to have the exact right percentage of weight.

phils laced to deep v's on an aluminum track frame have a very different weight distribution from formulas laced to zipps on a steel frame. either one would be a very nice bike, in my opinion.

most importantly, it's a fixed gear. there are like five parts that weigh more than wet bike shorts. unless something is boat-anchor heavy, the whole build should come out light.
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Old 02-14-07, 02:09 PM   #12
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Quote:
Originally Posted by dirtyphotons
i think the percentage thing is approaching the problem backwards.
+exactly. Why worry about the abstractions? Just build the bike with a decently light frame (under 5 lbs), and you will be fine.
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Old 02-14-07, 05:03 PM   #13
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Quote:
Originally Posted by Aeroplane
+exactly. Why worry about the abstractions? Just build the bike with a decently light frame (under 5 lbs), and you will be fine.
I'm not really "approaching the problem" I'm just curious about things. It helps me process it to know the details.

Thanks to everyone for the info.

Chad
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Old 02-14-07, 11:47 PM   #14
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it's not rocket science. find a light frame and the rest is easy. if you start with a tank it'll still be a tank when you're done. you'll never build a ferrari from a cadillac town car.

and the details? well, weight weenies.starbike.com is a good place to start. but its irrelevant really if you're never going to fork out for that kind of high end gear.

just build something, and then wait and see over the next year what else comes up that you can replace parts with. experience will happen, but you can't buy it.
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Old 02-15-07, 12:27 AM   #15
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for reference, i built up an old schwinn world as a beater with the following:

headset: cheapo 1" tange threaded
stem: nitto technomic
bars: old salsa moto ace
wrap: cinelli cork
levers: cheapest tektro
front brake: promax
post: kalloy
saddle: iro generic steel rails
crank: iro
ring: salsa 42T
cog: soma 16t
chain: kmc
bb: shimano un-53
lockring: formula
hubs: formula track
spokes: 32 double butted
rims: deep v
tire: panaracer pasela tg 700x28
tubes: cheapo butyl

and it came in at 10.3 kg or about 22.7 pounds

the thing WAS like a couch on wheels, and i loved it. this was for general thrashing around the rolling hills of boston.

the best advice that i can give is regardless of your pricing scheme, you should prioritize a beater build as follows:

1) fit (especially reach and saddle to bar drop)
2) cockpit - a race saddle, negative rise stem and naked 36cm track drops may look cool, but not feel so cool after 1500km
3) utility - fender mounts & clearance if you need them, water bottle mounts, geometry, durability
4) aesthetics/weight/material - it doesn't take that much green to make your ride your own and unique.

pounds, grams of drag (aerodynamics), and component flex/drag are likely going to mean less than a minute of difference over a large distance/steep climb when it comes to a a 16lb aero bike and a 22lb beater bike.

maintaining a good diet, trimming down, getting enough water and sleep will probably make more of a difference in your performance while having less of an impact on your wallet, especially when tooling around town
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Old 02-15-07, 03:45 AM   #16
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if you are trying to build a bike thats effecient (which im assuming you are) and not just light, dont forget about the quality and not just the weight of the components. barring that you have lots of hills to get up and you are very light yourself (making the bike weight a big fraction of your total weight) smooth, most likely new, bearings in the hubs and bb will go a long ways.

a 30lb bike with everything dialed in will be tons faster than a 15lb one with otherwise ****ty old parts.
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Old 02-15-07, 09:21 AM   #17
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Then again, since cheap and heavy seem to go hand in hand, it seems like it'd be hard to find a 15 pounder with ****ty components, unless you just neglected the hell out of them, i.e. took up to squirting apple juice in your hubs on the daily.
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Old 02-15-07, 09:39 AM   #18
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Building a 23 pound bike out of an 8 pound frame will take significant money. Building a 23 pound bike in general will not.
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Old 02-15-07, 09:56 AM   #19
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i don't think you can come up with any general breakdown of weight percentages. they vary so wildly based on what you're doing. i mean, for any given component - like a crankset - weights can vary enough to make the attempt to break down percentages impossible. i could put these cranks on that frame and other ones on another frame and get two very different weight percentages.

if you're thinking about building up a beater fix, then find yourself a decent old road frame. you can find ones made out of columbus whatever tubing, or reynolds 531 - in other words, lightweight (for that state of the art). put some decent components on it and you'll probably be under twenty pounds, which is well under the light-enough-to-carry-up-to-your-apartment level. and besides, riding frequently is going to give you muscles that you'll need to get up any hills where weight might be a concern.
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