5 ms·

In the late 1980s, early 1990s, sub-30 lbs was the reference for a high-quality off-road bike. That'd be aluminum alloy rims, steel frames (cro-mo alloy) and al

by bch 11y ago

In the late 1980s, early 1990s, sub-30 lbs was the reference for a high-quality off-road bike. That'd be aluminum alloy rims, steel frames (cro-mo alloy) and aluminum bars/stems/seat-posts. A principle that applies at all times (1800's, 1900's, 2000's), is that rotational mass is what kills you; Roughly, if you can save 1 lb on the wheels, or 1.5 lbs on the frame, save on the wheels. It's mass that has to be accelerated/decelerated, versus (eg) the frame, which is 'static'. Edit: qualify "at all times", "late 80s, early 90s"

davidw 11y ago
http://thisoldbridgestone.com/tag/mb-1/ http://thisoldbridgestone.com/tag/mb-1/ - I had one of these from '92, I think, and it weighed 24 pounds, roughly. And that's a mass produced bike that was high end, but not top of the line by any means. Somehow I find it kind of sad that today, they weigh about the same because of all the stuff they've added to them.
- bch 11y ago
  Bridgestone was making highly regarded bikes, mass produced or not. Example, a state-of-the-art rig would be a Ritchey P-23 (c. ~1990), so named because it was a project to make a 23lb bike, which was a Big Enough Deal to name the bike after the project. I feel like the bikes[0] I[1] raced[2] at the time ($1800 - $2600, not adjusted) were in the 25-26lb range (19.5 - 20.5" frames). The very light bikes (like a P-23) were contraindicated for heavy, non-expert riding. Working at a high-end bike shop around that time, I saw them[3] come back in pieces. [0] http://www.retrobike.co.uk/forum/download/file.php?id=35724 http://www.retrobike.co.uk/forum/download/file.php?id=35724 [1] http://www.retrobike.co.uk/forum/download/file.php?id=258229 http://www.retrobike.co.uk/forum/download/file.php?id=258229 [2] http://i41.tinypic.com/j9y5ug.jpg http://i41.tinypic.com/j9y5ug.jpg [3] http://fcdn.mtbr.com/attachments/vintage-retro-classic/125402d1134938352-first-gen-rocky-mountain-wedge-89wedge.jpg http://fcdn.mtbr.com/attachments/vintage-retro-classic/12540...
- m0nty 11y ago
  > they weigh about the same because of all the stuff they've added to them Buy a decent frame and build your own bike. I have three bikes -- MTB, hybrid and one I made myself. The homemade one is easily my favourite, and I think it's the better bike. You get to decide what's important to you rather than the manufacturer. Road wheels with bullhorn bars and 3 cogs at the front? No problem, I can do what I like.
Nutmog 11y ago
Can you explain the physics of rotating mass savings being more important? The top of the wheel moves twice as fast as the bike, but the bottom of the wheel doesn't move at all so don't they balance out? The frame isn't static - you still have to accelerate it frame along with the wheels when you're speeding up. If your route has a lot of uphill, then I'd expect that 1.5:1 ratio to get closer to 1:1 where the work you do is more fighting gravity than inertia.
- adrianN 11y ago
  It takes energy to make things rotate: https://en.wikipedia.org/wiki/Rotational_energy https://en.wikipedia.org/wiki/Rotational_energy The wheels have a rather large diameter and go pretty quickly. Both diameter and angular velocity are quadratic terms. You could now do the math to see how much energy it takes to accelerate a bike to a given speed. But you're right, going uphill or at steady speed completely changes the picture.
- bch 11y ago
  Here are some articles[0][1] -- and to be clear, the tone of the first (bicycle) article is appropriately "fussy". One person who gets groceries on their bike may not notice, but a competitive racer might notice. So whether it matters (enough) depends on the situation. With suspended bikes, wheels are also never part of the "sprung" weight; minimizing unsprung weight in suspension is always beneficial. I don't have metrics for how many grams deliver $x performance, though. [0] http://velonews.competitor.com/2012/06/bikes-and-tech/technical-faq/technical-faq-does-wheel-weight-matter_223209 http://velonews.competitor.com/2012/06/bikes-and-tech/techni... [1] http://www.tuneruniversity.com/blog/2011/04/part-i-why-wheel-weight-slows-most-people-down/ http://www.tuneruniversity.com/blog/2011/04/part-i-why-wheel...
bigfudge 11y ago
Rotational mass is important if you're doing lots of accelerations, but for almost all riders the real killer is rolling resistance. The difference between good tyres and bad is light and day. And note, narrower+harder != better... tests have shown that wider tyres running low pressures but with supple side walls can be as fast or faster than narrower tyres, and are much more comfortable to boot.
- fulafel 11y ago
  > for almost all riders the real killer is rolling resistance Aerodynamic resistance becomes greater than rolling resistance very early. See eg. http://www.sheldonbrown.com/rinard/aero/formulas.htm http://www.sheldonbrown.com/rinard/aero/formulas.htm You may argue that people riding upright on city ("dutch") bikes make up the majority of bike riders, but their possibly heavy-rolling tires are made up for their aerodynamically pessimal riding posture! (Of course often it's easier to do something about rolling resistance than aerodynamics, despite being a smaller component)

by bch 11y ago

davidw 11y ago

http://thisoldbridgestone.com/tag/mb-1/ http://thisoldbridgestone.com/tag/mb-1/ - I had one of these from '92, I think, and it weighed 24 pounds, roughly. And that's a mass produced bike that was high end, but not top of the line by any means. Somehow I find it kind of sad that today, they weigh about the same because of all the stuff they've added to them.

bch 11y ago
Bridgestone was making highly regarded bikes, mass produced or not. Example, a state-of-the-art rig would be a Ritchey P-23 (c. ~1990), so named because it was a project to make a 23lb bike, which was a Big Enough Deal to name the bike after the project. I feel like the bikes[0] I[1] raced[2] at the time ($1800 - $2600, not adjusted) were in the 25-26lb range (19.5 - 20.5" frames). The very light bikes (like a P-23) were contraindicated for heavy, non-expert riding. Working at a high-end bike shop around that time, I saw them[3] come back in pieces. [0] http://www.retrobike.co.uk/forum/download/file.php?id=35724 http://www.retrobike.co.uk/forum/download/file.php?id=35724 [1] http://www.retrobike.co.uk/forum/download/file.php?id=258229 http://www.retrobike.co.uk/forum/download/file.php?id=258229 [2] http://i41.tinypic.com/j9y5ug.jpg http://i41.tinypic.com/j9y5ug.jpg [3] http://fcdn.mtbr.com/attachments/vintage-retro-classic/125402d1134938352-first-gen-rocky-mountain-wedge-89wedge.jpg http://fcdn.mtbr.com/attachments/vintage-retro-classic/12540...
m0nty 11y ago
> they weigh about the same because of all the stuff they've added to them Buy a decent frame and build your own bike. I have three bikes -- MTB, hybrid and one I made myself. The homemade one is easily my favourite, and I think it's the better bike. You get to decide what's important to you rather than the manufacturer. Road wheels with bullhorn bars and 3 cogs at the front? No problem, I can do what I like.

Nutmog 11y ago

Can you explain the physics of rotating mass savings being more important? The top of the wheel moves twice as fast as the bike, but the bottom of the wheel doesn't move at all so don't they balance out? The frame isn't static - you still have to accelerate it frame along with the wheels when you're speeding up. If your route has a lot of uphill, then I'd expect that 1.5:1 ratio to get closer to 1:1 where the work you do is more fighting gravity than inertia.

adrianN 11y ago
It takes energy to make things rotate: https://en.wikipedia.org/wiki/Rotational_energy https://en.wikipedia.org/wiki/Rotational_energy The wheels have a rather large diameter and go pretty quickly. Both diameter and angular velocity are quadratic terms. You could now do the math to see how much energy it takes to accelerate a bike to a given speed. But you're right, going uphill or at steady speed completely changes the picture.
bch 11y ago
Here are some articles[0][1] -- and to be clear, the tone of the first (bicycle) article is appropriately "fussy". One person who gets groceries on their bike may not notice, but a competitive racer might notice. So whether it matters (enough) depends on the situation. With suspended bikes, wheels are also never part of the "sprung" weight; minimizing unsprung weight in suspension is always beneficial. I don't have metrics for how many grams deliver $x performance, though. [0] http://velonews.competitor.com/2012/06/bikes-and-tech/technical-faq/technical-faq-does-wheel-weight-matter_223209 http://velonews.competitor.com/2012/06/bikes-and-tech/techni... [1] http://www.tuneruniversity.com/blog/2011/04/part-i-why-wheel-weight-slows-most-people-down/ http://www.tuneruniversity.com/blog/2011/04/part-i-why-wheel...

bigfudge 11y ago

Rotational mass is important if you're doing lots of accelerations, but for almost all riders the real killer is rolling resistance. The difference between good tyres and bad is light and day. And note, narrower+harder != better... tests have shown that wider tyres running low pressures but with supple side walls can be as fast or faster than narrower tyres, and are much more comfortable to boot.

fulafel 11y ago
> for almost all riders the real killer is rolling resistance Aerodynamic resistance becomes greater than rolling resistance very early. See eg. http://www.sheldonbrown.com/rinard/aero/formulas.htm http://www.sheldonbrown.com/rinard/aero/formulas.htm You may argue that people riding upright on city ("dutch") bikes make up the majority of bike riders, but their possibly heavy-rolling tires are made up for their aerodynamically pessimal riding posture! (Of course often it's easier to do something about rolling resistance than aerodynamics, despite being a smaller component)