13 ms·

Extra Mass on Bike Wheels Is Worse than on Frames

63 points by Fjolsvith 10y ago

gooseyard 10y ago
in racing I've heard this referred to as "unsprung weight" or mass. Makes it a little easier to find more information if you're interested.
- recursive 10y ago
  I think "unsprung weight" is a different idea, at least in bike racing. Unsprung weight represents the weight not supported by suspension. In road racing, the suspension is the rider, so the entire bike is unsprung weight.
- LeifCarrotson 10y ago
  Not quite. This is a direct relation to "rotating mass", which does include tires and rims but also includes stuff like driveshafts, which are made of shockingly thin tubes of steel or carbon fiber for this reason. Unsprung mass is relevant to vehicles with suspensions (including mountain bikes). The inertia of the vehicle is set against the inertia of the wheel when it's being pressed back down on the backside of a bump.
mikestew 10y ago
The article's conclusion isn't entirely correct. Mass on the wheels also affects braking (the reverse of acceleration), and handling (gyroscopes with less mass turn more easily). But otherwise, yeah, the standard line amongst racers is to upgrade your wheels before anything else (albeit racers do a lot more accelerating and braking that your average Sunday rider). Lighter wheels are like the SSDs of cycling: biggest bang-for-the-buck. As a sidenote, the picture looks to be a late-1880s Columbia of some sort. Yup, same Columbia from whom you can buy a bicycle today (well, at least something bicycle-shaped; they haven't made good bicycles in over 100 years).
- EarthIsHome 10y ago
  > (well, at least something bicycle-shaped; they haven't made good bicycles in over 100 years). At my bicycle co-op, we call these BSOs, bicycle shaped objects, to describe Huffys and other Walmart department store bikes :-)
- jackmott 10y ago
  "Lighter wheels are like the SSDs of cycling: biggest bang-for-the-buck." Completely wrong. Biggest bang for the buck is low CRR tires, then skinsuits, then, I don't know, maybe helmets. Then 100 other things, then light wheels.
  - mikeklaas 10y ago
    Completely agreed. Tires a neglected by most cyclist. It is shocking how many people buy a nice bike and keep the stock tires, or worse, slap on conti gator-skins.
    - panglott 10y ago
      Gator skins are heavy, but they do protect you from punctures on the road.
  - mikestew 10y ago
    Completely wrong. Biggest bang for the buck is low CRR tires, then skin suits, Skin suits? Who let the triathletes in? :-) Horses for courses, I guess. For a crit, road race, and generally just riding around, I'll take a nice set of wheels before squeezing myself into a sausage casing.
ars 10y ago
There is a similar concept with cars: https://en.wikipedia.org/wiki/Unsprung_mass https://en.wikipedia.org/wiki/Unsprung_mass The same conclusions about mass hurting acceleration also occur with the car, but the relative masses are so different, it's mostly irrelevant (cars are a lot heavier than bike frames). The main difference comes with the ability of a lighter wheel to be able to fully track the road, and not leave it on a bounce. This gives better traction. (But somewhat greater vibration in the cabin.)
- taneq 10y ago
  Unsprung mass is more about the effectiveness of suspension in keeping the wheel on the road. This is about rotating mass and the fact that you have to 'speed up the wheel twice', once in translation and once in rotation, and so rotating mass stores more kinetic energy than non-rotating mass.
davidw 10y ago
I'd be curious to see the math on 29 inch mtb wheels vs other sizes. Of course there are other things in play there like the ability to roll over obstacles (29ers do this well) and maneuver in tight spaces (not quite so good).
- niels_olson 10y ago
  http://hyperphysics.phy-astr.gsu.edu/hbase/ihoop.html http://hyperphysics.phy-astr.gsu.edu/hbase/ihoop.html
dahart 10y ago
> You will have double the increase in energy by adding mass to the wheel. Is this always true regardless of wheel radius? At first I was thinking it has to depend on radius, but then thought about how the ground contact point has a zero velocity, and the exact other side of the wheel is always double the velocity of the bike frame relative to the ground, regardless of wheel radius. I'm not sure if this is a reasonable intuition. Maybe it makes sense that a gram added to the rim is always double the difference in effort that a gram added to the axle or frame or rider is.
- brianwawok 10y ago
  Well for adult bikes you are pretty much fixed at 700C. If making a bike pedaled contraption not so much.
  - jean_claude 10y ago
    >Well for adult bikes you are pretty much fixed at 700C. If making a bike pedaled contraption not so much. For racing/road bikes, maybe. You're leaving out the 26" wheel adult bikes (which over time has encompassed 5 different rim diameters[1]) and 24" wheel bikes that are targeted at youth, but smaller adults sometimes prefer (well, those that have been give the option). My bike pedaled contraption is a rear suspension compact long wheelbase recumbent with two real 20" (406mm rim) tires and they're spectacular. [1] http://www.sheldonbrown.com/26.html http://www.sheldonbrown.com/26.html
    - brianwawok 10y ago
      I feel like less and less bikes are going for 26s. It used to be that the smallest bike or so from each manufacturer used 650C, then everything else used 700C. Seems like most manufactures just went to 700C for all adult bikes over the last few years...
  - ImprovedSilence 10y ago
    for road bikes yes, not so much true for mountain. (or bmx, or cruiser, or whatever...)
walrus01 10y ago
Road bike nerds have known this for a while. If you ride a lot you will immediately feel the acceleration difference in a wheelset that totals around 1450g front and rear with hubs, spokes, nipples and rims (example: White Industries road hubs, Sapim CX-Ray spokes, medium profile high quality aluminum rim) vs the same spoke count "cheap" wheelset that might weigh 1800g. That is all before you get into the category of exotic and expensive deep profile CF rim wheelsets that cost $1500+/pair...
- brianwawok 10y ago
  And us tri dorks don't care what we weigh because aero beats weight on most courses that we ride. The science of bikes is pretty great.
  - outericky 10y ago
    That's why we buy $3800 Zipps. Though they are both aero and light. That said, got mine used for $1800. Sold them 2 years later for.... $1850.
    - brianwawok 10y ago
      ya zips are spendy (but very nice). I am more of Flo fan for me $900 for a pair.. plenty aero.. fairly heavy.. but I can lose 1 pound from my belly for less than the $3000 nicer wheels would cost me to lose a pound.
  - eru 10y ago
    If you want to go even faster (on human power alone) lie even lower.
    - brianwawok 10y ago
      Recumbent? True for sure, but not so legal in triathlons.
      - 10y ago
shermozle 10y ago
Or to take the alternate view, if you want to get fit, get a heavy wheel. I'm having a super strong one built right now, and extra weight is fine by me.
- bluedino 10y ago
  >> if you want to get fit, get a heavy wheel Better yet, get a high resistance tire. Wide knobbies will do it.
  - LeifCarrotson 10y ago
    Or those trendy fat tire bikes. Yes, they are great on sand and snow, but pointless and even counterproductive on the asphalt where I am seeing them more lately.
    - farnsworth 10y ago
      Seriously, I keep passing these on the paved bike path on my way to work. Is that they only bike they own?
- adriand 10y ago
  Or take another alternate view: if you want to have a lighter bike and you don't want to pay for it, lose body weight instead. Then you'll be both lighter and fitter. Only once you've lost as much body weight as you can reasonably lose does investing heavily in a lighter bike make sense! Naturally this doesn't, of course, diminish the fact that lighter wheels give you more bang-for-the-buck than lighter anything-else, due to the physics described in the article. But if the difference between heavy, cheap wheels and light, expensive ones is a few hundred grams and a few thousand dollars, losing a pound of body fat is likely a better bet.
  - eru 10y ago
    Depends on how much body weight you start out with. There's such as thing as too skinny.
freehunter 10y ago
>Here’s The Thing With Ad Blockers Here's the thing with "I'm a print subscriber but hate having to log in on every device I might read your site on".
WalterBright 10y ago
Drag racers have known this forever :-)
- taneq 10y ago
  The rule-of-thumb I've always heard is that 1kg off your wheels is equivalent to 4kg off the weight of the car.
  - lostlogin 10y ago
    Wonder if you can apply the same theory that had me shaving the crank on an old car a bike...
dbg31415 10y ago
>Here’s The Thing With Ad Blockers Today I learned that a VPN counts as an ad blocker. Hooray.
3pt14159 10y ago
Last year I paid the $700 for custom made wheels. I fairly regularly go down short staircases (3 or 4 steps, or big curbs) and I used to blow through spokes like birthday cake candles. No longer. Screw minimizing wheel weight. I want my bike to be an extension of myself. I want to be able to push it and for it to deliver. If I need to spend some extra joules on angular momentum, fine. My thighs need the workout anyway.
- bbarn 10y ago
  And you're not racing :) Downhill bikes weight 40 pounds, BMX's have 36 spoke wheels for 20" rims, etc.. for good reason: they are built to be good at what they do. You want to go race faster, you get light wheels, with medium to deep section rims.
- collyw 10y ago
  How much do you weigh? I (used to) regularly drop off of stuff a foot or two and I never had any problems. My bike wheels can't have come close to that price. (I did need to move to downhill tubes as those kept getting pinches).
  - lostlogin 10y ago
    Tall guy who used to bmx here. Never broke a spoke but munted a few few wheels and one set of bearings. I dearly wish for a bmx scaled up by something like 1.3x or 1.5x. My neck has never recovered from the stupid head-tilted-up pose that bike forced me into. Loved the bike though!
    - eckza 10y ago
      How tall are you? We've got all kinds of stuff for tall people. Check out 24" BMX bikes (aka cruisers) - a cruiser with a long frame and 7" or 8" bars would probably suit you well.
      - lostlogin 10y ago
        1.95m. And thanks!
cellis 10y ago
Taken to the extreme, what is going to move faster, a thin strip of steel on 6 logs, or 6 logs on a thin strip of steel with, say cartwheels wheels under that?
thedufer 10y ago
I haven't taken the time to compare the sizes of the effects, but it doesn't sit well that they blow past seemingly obvious ways extra wheel mass would go in the opposite direction. I see at least two places they do this: Air Resistance: > However, this force will produce a greater change in speed on the bike with less mass. But the wheels act as (unsurprisingly) flywheels. Extra weight in the wheels adds both momentum and angular momentum, while frame mass adds only the former. This is exactly symmetric to their acceleration argument, so it's kind of shocking they skipped it. Internal Friction > More mass on a bike can increase the friction in the bearings—but again, this won’t matter where the mass is located. As an extreme example, a massful wheel with a massless frame clearly has no bearing friction. I'm pretty sure wheel weight does not contribute to bearing friction. Does anyone have any insight into why these matter less than the acceleration bit?
- davidw 10y ago
  In a road race, you have to attack to get away from the group, or win the race in a sprint. Either way, acceleration is critical.
  - thedufer 10y ago
    That seems like a very reasonable observation, and I would accept that as an answer if this were a discussion about road racing. However, the completely unqualified title (including the word "prove") implies something deeper. Road racing is never mentioned.
    - mikekchar 10y ago
      It's very common for bicycle enthusiasts to equate "better" with road racing. It's not just acceleration away from the group either. Almost all the effort you put into cycling at high speeds (say over 30 km/h) is overcoming wind resistance. You can save a huge portion of that effort by drafting behind someone. So in terms of saving effort (or making other people hurt) making and closing gaps is crucial. But of course most people riding a bike are not racing. Even still acceleration is quite important. When you are on a relatively uniform gradient you can judge your power easily and make sure you don't go anaerobic. It's when you have to push hard to get over a small bump, or sprint ahead to get out of traffic, etc that you get into the red zone. Making those situations easier will make your whole ride easier. But it is fair to point out that "good" bikes are really only "better" for certain situations. For example, my wife almost never travels faster than 20 km/h. Many of the things that are absolutely necessary on a "good" bike that is travelling at 40+ km/h make absolutely no difference for her. Lot's of people tootle around at 10-15 km/h. Any well maintained bicycle will be completely fine. In fact a "good" bicycle will be unsatisfactory because it will be hard to handle. It's all about context. And in the context of talking about which bicycle is "better", the convention is to assume you are talking about road racing unless otherwise stated.
jackmott 10y ago
This is one of the most persistent and silly myths in cycling. When biking at a steady speed, even when accounting for the fact that steady speed isn't entirely steady because humans pulse their power a bit, wheel weight is not worse than frame weight (the extra effort of each micro-acceleration is offset by the reduce slowdown between micro-accelerations and then some) When climbing a mountain, wheel weight is not worse than frame weight Yes, when accelerating, wheel mass is worse than frame weight, but only a tiny amount. source: physics: https://docs.google.com/spreadsheets/d/1N2aS3E0K4wrTa5jKqed7etJY_0XEyA6-23kUFR3KNmI/edit#gid=0 https://docs.google.com/spreadsheets/d/1N2aS3E0K4wrTa5jKqed7... That is my spreadsheet, it is very very basic physics and it drives me crazy that people spew pseduo physics and comment on this "without taking the time to comapre the sizes of the effects" take the time! TLDNR; don't worry about wheel weight any more than frame weight. Addendum: don't worry about frame weight much either.
- simonswords82 10y ago
  I went for a bike fitting today and the guy that did the fitting was incredibly knowledgeable about all things bikes. He told me that due to the "physics" involved that wheels were 2 to 3 times heavier at speed. Turns out he was talking nonsense! I wonder where this old wives tale about wheel weight comes from?
  - ben_bai 10y ago
    a 26inch wheel when spinning at 80 roations per minute (20km/h or 12mph) will have a Centripetal Acceleration of about 5g (G-Force) on the outermost spot. That does not make the wheel "heavier", but due to the gyroscopic effect and air resistance loose ever more energy, when spinning faster. Fun wheel videos: https://www.youtube.com/watch?v=GeyDf4ooPdo https://www.youtube.com/watch?v=GeyDf4ooPdo https://www.youtube.com/watch?v=ty9QSiVC2g0 https://www.youtube.com/watch?v=ty9QSiVC2g0
    - vlehto 10y ago
      The gyroscopic effect makes you lose energy only if you turn. Of course you turn a little all the time while cycling.
rawland 10y ago
Ex-Continental Tour Rider [1] & Computer Engineering Science PhD-student talking here. --- TL;DR Considering reasonable wheels: Wheel stiffness is more important than weight. A too light wheel, is not stable. --- Wired's physics are correct. However, neglect mechanical dynamics & handling. Probably the biggest downside of light (& aero even more) wheels is: When your wheels are very light, they are prone to cross winds and "jump around" a lot due to their low inertia. And, well, you always have cross winds and bumpy roads, because only very few of us are track riders. Considering the acceleration, you lose a lot of energy by "twisting" the wheel. That is: the hub starts to turn because the chain you pull with the crank arm in front is forcing it to do so. Then, all this tension is transferred to the spokes, rim and finally the tire. In that process most wheels lose a significant amount of energy by simply storing it via elastic torsion and releasing the energy without contributing to movement at all. As already said in another comment, we "pulse" the energy to the back wheel, as the maximum pulse comes due to our own biomechanics. And we have two pulses per revolution with a zero at almost vertical crank arm alignment! Therefore you want to have stiff wheels! Which stands in stark contrast to light wheels. The company Lightweight basically made its money by creating aerodynamic and very very stiff wheels for the weight they had. These wheels, however, are not maintainable any more & very expensive [2]. --- [1]: http://www.uci.ch/road/ucievents/continentalcircuits/ http://www.uci.ch/road/ucievents/continentalcircuits/ [2]: http://lightweight.info/us/en http://lightweight.info/us/en
- stinos 10y ago
  So we have Wired's physics are correct. However, neglect mechanical dynamics & handling. vs other comments denying that like This is one of the most persistent and silly myths in cycling. Which shall it be? A combination of the two?
  - rawland 10y ago
    When you read the latter, you'll find: Yes, when accelerating, wheel mass is worse than frame weight, but only a tiny amount. and Wired's physics are correct in the case of accelerating a wheel to the steady state of a spinning wheel. Edit: To expand on this a bit: This "tiny amount" is a lot when you are among people close to your performance. And I'm talking about stiffness vs. weight. Stiffness is just so much more important, because the sum of these infinitesimal losses is just huge: Modern riders rpm: 100 which equals to 200 energy pulses per minute, because each leg has a rest phase and a full force phase per revolution. In a 4h race: 240 * 200 which are 48000 pulses. Now imagine you have a super light but not very stiff wheel (because it's light, you know)... that's a lot of lost energy.
RP_Joe 10y ago
The comments here are better than the article.
slashdotdash 10y ago
Aerodynamics trumps weight for cyclists, even for wheels. "In summary, wheels account for almost 10% of the total power required to race your bike and the dominant factor in wheel performance is aerodynamics. Wheel mass is a second order effect (nearly 10 times less significant) and wheel inertia is a third order effect (nearly 100 times less significant)." http://www.biketechreview.com/reviews/wheels/63-wheel-performance http://www.biketechreview.com/reviews/wheels/63-wheel-perfor... http://www.slowtwitch.com/Tech/Why_Wheel_Aerodynamics_Can_Outweigh_Wheel_Weight_and_Inertia_2106.html http://www.slowtwitch.com/Tech/Why_Wheel_Aerodynamics_Can_Ou...
- rawland 10y ago
  Considering time trial or the last meters of a sprint, I completely agree. Riding in a bunch, race or the city. Not so much. In Crits (80 laps times 4 corners at least) or a city ride you don't move fast most of the time, but bike handle, accelerate & brake most of the time.
- slashdotdash 10y ago
  Some worthwhile further reading, including worked examples, comparing a wheelset with superior aerodynamics versus one that is lighter. "... the point of all this was to demonstrate the relative unimportance of wheel rim mass and why aerodynamics matters even when accelerating" [1] http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii.html http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii... [2] http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii.html http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii... [3] http://bicycles.stackexchange.com/questions/15047/are-aerodynamic-rims-worth-additional-weight http://bicycles.stackexchange.com/questions/15047/are-aerody...
Asooka 10y ago
Here's the thing with ad blockers: I will skip your article.
gerbilly 10y ago
I never was a weight weenie in my cycling. I never understood the obsession. Humblebrag: I could bunny hop my 28 pound trial bike 2 ft, and sidehop 30 inches too.
jdc0589 10y ago
This is pretty standard stuff in automobile land. Unsprung weight (includes slightly more stuff than this, but same basics) is known to have a disproportionate effect relative to, say, the driver gaining a couple lbs. People don't talk about it as much as other performance factors, but this is why magnesium wheels have existed for upper end cars for a while, and carbon-fiber more recently. On the flip side, this is also exactly the same reason why flywheels outside of automobile land, when used as energy storage devices, are hugely massive.
peterwwillis 10y ago
Increase in unsprung weight is also bad for suspension[1] and handling[2]. Here's something they don't mention in the article: the location of the mass in the wheel has a direct relationship to torque. The same mass located in the hub will take less torque to move than if the mass were located in the rim. So acceleration could in part be improved merely by relocating mass in the wheel. (But that's just wheel acceleration torque; you'll still need to do the same amount of work to move the same total mass of the bike at the same speed) Also, for the same weight tire rubber, wider tires would create increased friction and slow the tire down more. [1] https://en.wikipedia.org/wiki/Unsprung_mass#Effects_of_unsprung_weight https://en.wikipedia.org/wiki/Unsprung_mass#Effects_of_unspr... [2] http://www.formula1-dictionary.net/unsprung_weight.html http://www.formula1-dictionary.net/unsprung_weight.html
caycep 10y ago
is this something about unsprung weight? Similar rational for using carbon wheels on the new Mustang GT350R

63 points by Fjolsvith 10y ago

in racing I've heard this referred to as "unsprung weight" or mass. Makes it a little easier to find more information if you're interested.

recursive 10y ago
I think "unsprung weight" is a different idea, at least in bike racing. Unsprung weight represents the weight not supported by suspension. In road racing, the suspension is the rider, so the entire bike is unsprung weight.
LeifCarrotson 10y ago
Not quite. This is a direct relation to "rotating mass", which does include tires and rims but also includes stuff like driveshafts, which are made of shockingly thin tubes of steel or carbon fiber for this reason. Unsprung mass is relevant to vehicles with suspensions (including mountain bikes). The inertia of the vehicle is set against the inertia of the wheel when it's being pressed back down on the backside of a bump.

mikestew 10y ago

The article's conclusion isn't entirely correct. Mass on the wheels also affects braking (the reverse of acceleration), and handling (gyroscopes with less mass turn more easily). But otherwise, yeah, the standard line amongst racers is to upgrade your wheels before anything else (albeit racers do a lot more accelerating and braking that your average Sunday rider). Lighter wheels are like the SSDs of cycling: biggest bang-for-the-buck. As a sidenote, the picture looks to be a late-1880s Columbia of some sort. Yup, same Columbia from whom you can buy a bicycle today (well, at least something bicycle-shaped; they haven't made good bicycles in over 100 years).

EarthIsHome 10y ago
> (well, at least something bicycle-shaped; they haven't made good bicycles in over 100 years). At my bicycle co-op, we call these BSOs, bicycle shaped objects, to describe Huffys and other Walmart department store bikes :-)
jackmott 10y ago
"Lighter wheels are like the SSDs of cycling: biggest bang-for-the-buck." Completely wrong. Biggest bang for the buck is low CRR tires, then skinsuits, then, I don't know, maybe helmets. Then 100 other things, then light wheels.
- mikeklaas 10y ago
  Completely agreed. Tires a neglected by most cyclist. It is shocking how many people buy a nice bike and keep the stock tires, or worse, slap on conti gator-skins.
  - panglott 10y ago
    Gator skins are heavy, but they do protect you from punctures on the road.
- mikestew 10y ago
  Completely wrong. Biggest bang for the buck is low CRR tires, then skin suits, Skin suits? Who let the triathletes in? :-) Horses for courses, I guess. For a crit, road race, and generally just riding around, I'll take a nice set of wheels before squeezing myself into a sausage casing.

ars 10y ago

There is a similar concept with cars: https://en.wikipedia.org/wiki/Unsprung_mass https://en.wikipedia.org/wiki/Unsprung_mass The same conclusions about mass hurting acceleration also occur with the car, but the relative masses are so different, it's mostly irrelevant (cars are a lot heavier than bike frames). The main difference comes with the ability of a lighter wheel to be able to fully track the road, and not leave it on a bounce. This gives better traction. (But somewhat greater vibration in the cabin.)

taneq 10y ago
Unsprung mass is more about the effectiveness of suspension in keeping the wheel on the road. This is about rotating mass and the fact that you have to 'speed up the wheel twice', once in translation and once in rotation, and so rotating mass stores more kinetic energy than non-rotating mass.

davidw 10y ago

I'd be curious to see the math on 29 inch mtb wheels vs other sizes. Of course there are other things in play there like the ability to roll over obstacles (29ers do this well) and maneuver in tight spaces (not quite so good).

niels_olson 10y ago
http://hyperphysics.phy-astr.gsu.edu/hbase/ihoop.html http://hyperphysics.phy-astr.gsu.edu/hbase/ihoop.html

dahart 10y ago

> You will have double the increase in energy by adding mass to the wheel. Is this always true regardless of wheel radius? At first I was thinking it has to depend on radius, but then thought about how the ground contact point has a zero velocity, and the exact other side of the wheel is always double the velocity of the bike frame relative to the ground, regardless of wheel radius. I'm not sure if this is a reasonable intuition. Maybe it makes sense that a gram added to the rim is always double the difference in effort that a gram added to the axle or frame or rider is.

brianwawok 10y ago
Well for adult bikes you are pretty much fixed at 700C. If making a bike pedaled contraption not so much.
- jean_claude 10y ago
  >Well for adult bikes you are pretty much fixed at 700C. If making a bike pedaled contraption not so much. For racing/road bikes, maybe. You're leaving out the 26" wheel adult bikes (which over time has encompassed 5 different rim diameters[1]) and 24" wheel bikes that are targeted at youth, but smaller adults sometimes prefer (well, those that have been give the option). My bike pedaled contraption is a rear suspension compact long wheelbase recumbent with two real 20" (406mm rim) tires and they're spectacular. [1] http://www.sheldonbrown.com/26.html http://www.sheldonbrown.com/26.html
  - brianwawok 10y ago
    I feel like less and less bikes are going for 26s. It used to be that the smallest bike or so from each manufacturer used 650C, then everything else used 700C. Seems like most manufactures just went to 700C for all adult bikes over the last few years...
- ImprovedSilence 10y ago
  for road bikes yes, not so much true for mountain. (or bmx, or cruiser, or whatever...)

walrus01 10y ago

Road bike nerds have known this for a while. If you ride a lot you will immediately feel the acceleration difference in a wheelset that totals around 1450g front and rear with hubs, spokes, nipples and rims (example: White Industries road hubs, Sapim CX-Ray spokes, medium profile high quality aluminum rim) vs the same spoke count "cheap" wheelset that might weigh 1800g. That is all before you get into the category of exotic and expensive deep profile CF rim wheelsets that cost $1500+/pair...

brianwawok 10y ago
And us tri dorks don't care what we weigh because aero beats weight on most courses that we ride. The science of bikes is pretty great.
- outericky 10y ago
  That's why we buy $3800 Zipps. Though they are both aero and light. That said, got mine used for $1800. Sold them 2 years later for.... $1850.
  - brianwawok 10y ago
    ya zips are spendy (but very nice). I am more of Flo fan for me $900 for a pair.. plenty aero.. fairly heavy.. but I can lose 1 pound from my belly for less than the $3000 nicer wheels would cost me to lose a pound.
- eru 10y ago
  If you want to go even faster (on human power alone) lie even lower.
  - brianwawok 10y ago
    Recumbent? True for sure, but not so legal in triathlons.
    - 10y ago

shermozle 10y ago

Or to take the alternate view, if you want to get fit, get a heavy wheel. I'm having a super strong one built right now, and extra weight is fine by me.

bluedino 10y ago
>> if you want to get fit, get a heavy wheel Better yet, get a high resistance tire. Wide knobbies will do it.
- LeifCarrotson 10y ago
  Or those trendy fat tire bikes. Yes, they are great on sand and snow, but pointless and even counterproductive on the asphalt where I am seeing them more lately.
  - farnsworth 10y ago
    Seriously, I keep passing these on the paved bike path on my way to work. Is that they only bike they own?
adriand 10y ago
Or take another alternate view: if you want to have a lighter bike and you don't want to pay for it, lose body weight instead. Then you'll be both lighter and fitter. Only once you've lost as much body weight as you can reasonably lose does investing heavily in a lighter bike make sense! Naturally this doesn't, of course, diminish the fact that lighter wheels give you more bang-for-the-buck than lighter anything-else, due to the physics described in the article. But if the difference between heavy, cheap wheels and light, expensive ones is a few hundred grams and a few thousand dollars, losing a pound of body fat is likely a better bet.
- eru 10y ago
  Depends on how much body weight you start out with. There's such as thing as too skinny.

freehunter 10y ago

>Here’s The Thing With Ad Blockers Here's the thing with "I'm a print subscriber but hate having to log in on every device I might read your site on".

WalterBright 10y ago

Drag racers have known this forever :-)

taneq 10y ago
The rule-of-thumb I've always heard is that 1kg off your wheels is equivalent to 4kg off the weight of the car.
- lostlogin 10y ago
  Wonder if you can apply the same theory that had me shaving the crank on an old car a bike...

dbg31415 10y ago

>Here’s The Thing With Ad Blockers Today I learned that a VPN counts as an ad blocker. Hooray.

3pt14159 10y ago

Last year I paid the $700 for custom made wheels. I fairly regularly go down short staircases (3 or 4 steps, or big curbs) and I used to blow through spokes like birthday cake candles. No longer. Screw minimizing wheel weight. I want my bike to be an extension of myself. I want to be able to push it and for it to deliver. If I need to spend some extra joules on angular momentum, fine. My thighs need the workout anyway.

bbarn 10y ago
And you're not racing :) Downhill bikes weight 40 pounds, BMX's have 36 spoke wheels for 20" rims, etc.. for good reason: they are built to be good at what they do. You want to go race faster, you get light wheels, with medium to deep section rims.
collyw 10y ago
How much do you weigh? I (used to) regularly drop off of stuff a foot or two and I never had any problems. My bike wheels can't have come close to that price. (I did need to move to downhill tubes as those kept getting pinches).
- lostlogin 10y ago
  Tall guy who used to bmx here. Never broke a spoke but munted a few few wheels and one set of bearings. I dearly wish for a bmx scaled up by something like 1.3x or 1.5x. My neck has never recovered from the stupid head-tilted-up pose that bike forced me into. Loved the bike though!
  - eckza 10y ago
    How tall are you? We've got all kinds of stuff for tall people. Check out 24" BMX bikes (aka cruisers) - a cruiser with a long frame and 7" or 8" bars would probably suit you well.
    - lostlogin 10y ago
      1.95m. And thanks!

cellis 10y ago

Taken to the extreme, what is going to move faster, a thin strip of steel on 6 logs, or 6 logs on a thin strip of steel with, say cartwheels wheels under that?

thedufer 10y ago

I haven't taken the time to compare the sizes of the effects, but it doesn't sit well that they blow past seemingly obvious ways extra wheel mass would go in the opposite direction. I see at least two places they do this: Air Resistance: > However, this force will produce a greater change in speed on the bike with less mass. But the wheels act as (unsurprisingly) flywheels. Extra weight in the wheels adds both momentum and angular momentum, while frame mass adds only the former. This is exactly symmetric to their acceleration argument, so it's kind of shocking they skipped it. Internal Friction > More mass on a bike can increase the friction in the bearings—but again, this won’t matter where the mass is located. As an extreme example, a massful wheel with a massless frame clearly has no bearing friction. I'm pretty sure wheel weight does not contribute to bearing friction. Does anyone have any insight into why these matter less than the acceleration bit?

davidw 10y ago
In a road race, you have to attack to get away from the group, or win the race in a sprint. Either way, acceleration is critical.
- thedufer 10y ago
  That seems like a very reasonable observation, and I would accept that as an answer if this were a discussion about road racing. However, the completely unqualified title (including the word "prove") implies something deeper. Road racing is never mentioned.
  - mikekchar 10y ago
    It's very common for bicycle enthusiasts to equate "better" with road racing. It's not just acceleration away from the group either. Almost all the effort you put into cycling at high speeds (say over 30 km/h) is overcoming wind resistance. You can save a huge portion of that effort by drafting behind someone. So in terms of saving effort (or making other people hurt) making and closing gaps is crucial. But of course most people riding a bike are not racing. Even still acceleration is quite important. When you are on a relatively uniform gradient you can judge your power easily and make sure you don't go anaerobic. It's when you have to push hard to get over a small bump, or sprint ahead to get out of traffic, etc that you get into the red zone. Making those situations easier will make your whole ride easier. But it is fair to point out that "good" bikes are really only "better" for certain situations. For example, my wife almost never travels faster than 20 km/h. Many of the things that are absolutely necessary on a "good" bike that is travelling at 40+ km/h make absolutely no difference for her. Lot's of people tootle around at 10-15 km/h. Any well maintained bicycle will be completely fine. In fact a "good" bicycle will be unsatisfactory because it will be hard to handle. It's all about context. And in the context of talking about which bicycle is "better", the convention is to assume you are talking about road racing unless otherwise stated.

jackmott 10y ago

This is one of the most persistent and silly myths in cycling. When biking at a steady speed, even when accounting for the fact that steady speed isn't entirely steady because humans pulse their power a bit, wheel weight is not worse than frame weight (the extra effort of each micro-acceleration is offset by the reduce slowdown between micro-accelerations and then some) When climbing a mountain, wheel weight is not worse than frame weight Yes, when accelerating, wheel mass is worse than frame weight, but only a tiny amount. source: physics: https://docs.google.com/spreadsheets/d/1N2aS3E0K4wrTa5jKqed7etJY_0XEyA6-23kUFR3KNmI/edit#gid=0 https://docs.google.com/spreadsheets/d/1N2aS3E0K4wrTa5jKqed7... That is my spreadsheet, it is very very basic physics and it drives me crazy that people spew pseduo physics and comment on this "without taking the time to comapre the sizes of the effects" take the time! TLDNR; don't worry about wheel weight any more than frame weight. Addendum: don't worry about frame weight much either.

simonswords82 10y ago
I went for a bike fitting today and the guy that did the fitting was incredibly knowledgeable about all things bikes. He told me that due to the "physics" involved that wheels were 2 to 3 times heavier at speed. Turns out he was talking nonsense! I wonder where this old wives tale about wheel weight comes from?
- ben_bai 10y ago
  a 26inch wheel when spinning at 80 roations per minute (20km/h or 12mph) will have a Centripetal Acceleration of about 5g (G-Force) on the outermost spot. That does not make the wheel "heavier", but due to the gyroscopic effect and air resistance loose ever more energy, when spinning faster. Fun wheel videos: https://www.youtube.com/watch?v=GeyDf4ooPdo https://www.youtube.com/watch?v=GeyDf4ooPdo https://www.youtube.com/watch?v=ty9QSiVC2g0 https://www.youtube.com/watch?v=ty9QSiVC2g0
  - vlehto 10y ago
    The gyroscopic effect makes you lose energy only if you turn. Of course you turn a little all the time while cycling.

rawland 10y ago

Ex-Continental Tour Rider [1] & Computer Engineering Science PhD-student talking here. --- TL;DR Considering reasonable wheels: Wheel stiffness is more important than weight. A too light wheel, is not stable. --- Wired's physics are correct. However, neglect mechanical dynamics & handling. Probably the biggest downside of light (& aero even more) wheels is: When your wheels are very light, they are prone to cross winds and "jump around" a lot due to their low inertia. And, well, you always have cross winds and bumpy roads, because only very few of us are track riders. Considering the acceleration, you lose a lot of energy by "twisting" the wheel. That is: the hub starts to turn because the chain you pull with the crank arm in front is forcing it to do so. Then, all this tension is transferred to the spokes, rim and finally the tire. In that process most wheels lose a significant amount of energy by simply storing it via elastic torsion and releasing the energy without contributing to movement at all. As already said in another comment, we "pulse" the energy to the back wheel, as the maximum pulse comes due to our own biomechanics. And we have two pulses per revolution with a zero at almost vertical crank arm alignment! Therefore you want to have stiff wheels! Which stands in stark contrast to light wheels. The company Lightweight basically made its money by creating aerodynamic and very very stiff wheels for the weight they had. These wheels, however, are not maintainable any more & very expensive [2]. --- [1]: http://www.uci.ch/road/ucievents/continentalcircuits/ http://www.uci.ch/road/ucievents/continentalcircuits/ [2]: http://lightweight.info/us/en http://lightweight.info/us/en

stinos 10y ago
So we have Wired's physics are correct. However, neglect mechanical dynamics & handling. vs other comments denying that like This is one of the most persistent and silly myths in cycling. Which shall it be? A combination of the two?
- rawland 10y ago
  When you read the latter, you'll find: Yes, when accelerating, wheel mass is worse than frame weight, but only a tiny amount. and Wired's physics are correct in the case of accelerating a wheel to the steady state of a spinning wheel. Edit: To expand on this a bit: This "tiny amount" is a lot when you are among people close to your performance. And I'm talking about stiffness vs. weight. Stiffness is just so much more important, because the sum of these infinitesimal losses is just huge: Modern riders rpm: 100 which equals to 200 energy pulses per minute, because each leg has a rest phase and a full force phase per revolution. In a 4h race: 240 * 200 which are 48000 pulses. Now imagine you have a super light but not very stiff wheel (because it's light, you know)... that's a lot of lost energy.

RP_Joe 10y ago

The comments here are better than the article.

slashdotdash 10y ago

Aerodynamics trumps weight for cyclists, even for wheels. "In summary, wheels account for almost 10% of the total power required to race your bike and the dominant factor in wheel performance is aerodynamics. Wheel mass is a second order effect (nearly 10 times less significant) and wheel inertia is a third order effect (nearly 100 times less significant)." http://www.biketechreview.com/reviews/wheels/63-wheel-performance http://www.biketechreview.com/reviews/wheels/63-wheel-perfor... http://www.slowtwitch.com/Tech/Why_Wheel_Aerodynamics_Can_Outweigh_Wheel_Weight_and_Inertia_2106.html http://www.slowtwitch.com/Tech/Why_Wheel_Aerodynamics_Can_Ou...

rawland 10y ago
Considering time trial or the last meters of a sprint, I completely agree. Riding in a bunch, race or the city. Not so much. In Crits (80 laps times 4 corners at least) or a city ride you don't move fast most of the time, but bike handle, accelerate & brake most of the time.
slashdotdash 10y ago
Some worthwhile further reading, including worked examples, comparing a wheelset with superior aerodynamics versus one that is lighter. "... the point of all this was to demonstrate the relative unimportance of wheel rim mass and why aerodynamics matters even when accelerating" [1] http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii.html http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii... [2] http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii.html http://alex-cycle.blogspot.co.uk/2014/12/the-sum-of-parts-ii... [3] http://bicycles.stackexchange.com/questions/15047/are-aerodynamic-rims-worth-additional-weight http://bicycles.stackexchange.com/questions/15047/are-aerody...

Asooka 10y ago

Here's the thing with ad blockers: I will skip your article.

gerbilly 10y ago

I never was a weight weenie in my cycling. I never understood the obsession. Humblebrag: I could bunny hop my 28 pound trial bike 2 ft, and sidehop 30 inches too.

jdc0589 10y ago

This is pretty standard stuff in automobile land. Unsprung weight (includes slightly more stuff than this, but same basics) is known to have a disproportionate effect relative to, say, the driver gaining a couple lbs. People don't talk about it as much as other performance factors, but this is why magnesium wheels have existed for upper end cars for a while, and carbon-fiber more recently. On the flip side, this is also exactly the same reason why flywheels outside of automobile land, when used as energy storage devices, are hugely massive.

peterwwillis 10y ago

Increase in unsprung weight is also bad for suspension[1] and handling[2]. Here's something they don't mention in the article: the location of the mass in the wheel has a direct relationship to torque. The same mass located in the hub will take less torque to move than if the mass were located in the rim. So acceleration could in part be improved merely by relocating mass in the wheel. (But that's just wheel acceleration torque; you'll still need to do the same amount of work to move the same total mass of the bike at the same speed) Also, for the same weight tire rubber, wider tires would create increased friction and slow the tire down more. [1] https://en.wikipedia.org/wiki/Unsprung_mass#Effects_of_unsprung_weight https://en.wikipedia.org/wiki/Unsprung_mass#Effects_of_unspr... [2] http://www.formula1-dictionary.net/unsprung_weight.html http://www.formula1-dictionary.net/unsprung_weight.html

caycep 10y ago

is this something about unsprung weight? Similar rational for using carbon wheels on the new Mustang GT350R