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Naturally, carrying a light bike up the stairs is much more enjoyable compared to a heavier bike. Are there any other aspects of a bike which are affected by its weight?

For example, would the weight affect handling at low speeds? Higher speeds? Turning? Stability in strong crosswinds, heavy rain or other adverse weather conditions?

What does the weight say about a modern bike's components? About its durability or dependability? Maintenance? Wear and tear?

Are lighter bikes always better? What would be a reasonable weight threshold below which gains are diminishing?

As an inexperienced cyclist looking for a new bike, I'm unsure how much I should be paying attention to its weight.

UPDATE: what specific weight ranges should I be looking for these days? What would be considered very heavy, reasonable, and at what weight do we enter the multi-thousand-dollar pro racing bikes?

I found a cheap made-in-China fixie in Singapore (where I live); when I learned it weighs 17kg I realized why it's so cheap!

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If you're an inexperienced cyclist, there's no reason to shell out buckets of cash for a bike that's marginally lighter. It's a lot easier and cheaper to shave 1lb off yourself than to shave it off the bike. And the difference in performance is going to be largely negligible. –  Stephen Touset Dec 1 '11 at 15:04
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Given that it's the sum of your weight and the bike's that matters, I think if you look at price and weight you can see the diminishing returns for yourself. How much are you willing to pay to shave a hundredth of your weight off the bike? –  Jefromi Dec 2 '11 at 19:28
    
Depends a lot on the type of bike you're looking at -- mountain bikes are heavier, touring bikes are heavier. Eg, Novara is a decent brand sold by REI outdoor equipment stores in the US. A Novara Randonee (mid-range steel touring bike) weighs 28 pounds and costs $1200 USD. A Novara Divano (mid-range aluminum road bike with carbon fork) weighs 24 pounds and sells for $850. Novara's entry-level mountain bike (suspension, aluminum frame) weighs 31 pounds and sells for $400. By comparison, a Cannondale Flash carbon frame mountain bike weighs 23 pounds and sells for $2700. –  Daniel R Hicks Dec 4 '11 at 14:31
    
It should be noted that many of the anecdotes reporting that folks could ride much faster/easier with a lighter bike are (when not due to wishful thinking) because the lighter bike was simply a better quality one that fit better. –  Daniel R Hicks Jul 10 at 11:50
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You can go downhill a bit faster with a heavier bike, and that is one of the best parts of cycling!(bicycles.stackexchange.com/questions/21330/…) –  George H Jul 10 at 21:51

9 Answers 9

up vote 21 down vote accepted

Other than the obvious fact that your better quality (and better handling) bikes tend to be lighter, there's no real correlation between weight and performance (other than a modest effect on acceleration and the obvious effect on hill climbing).

But you can generally (with some exceptions) assume that a bike that is quite a bit (like 2x) heavier than others of the same basic style is poorly made, with poorer quality components. Eg, hubs and rims are apt to be stamped steel rather than machined aluminum, the crank is likely a solid steel one (with large, crude bearings) vs a 3-piece one with alloy arms and better quality bearings. The spokes are probably just plated steel rather than stainless. The pedals are probably stamped steel, and when you spin them you can hear the bearings rattle. And the tubes in the frame will be so thick and heavy that the bike will feel stiff and "dead".

That said, there's no need for a beginning cyclist to find the lightest possible bike. Eg, a good quality steel frame will be maybe five pounds heavier than the equivalent aluminum one, but the steel frame will be cheaper and more durable. Other components may be heaver or lighter as well, making possibly a 10-15 pound difference between two essentially identical bikes, but beyond a certain point lighter, more expensive components (eg, drilled brake levers, ultra-thin tires) are less durable than their slightly heavier counterparts.

Finally, if you're still tempted to spend an extra $300-3000 to get that ultralight bike, ask yourself how much you weigh, and whether you couldn't afford to lose a pound or two. The heaviest thing, by far, on a bike is the rider.

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"no real correlation" - I'd say it depends. Sure, it's small if you don't ride too hard and you're in a flat area. But if you ride somewhere with a lot of hills, or on a commuting route with a lot of stopping and starting at lights, the obvious effects on performance can be pretty big. –  Jefromi Dec 2 '11 at 19:23
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I said (other than a modest effect on acceleration and the obvious effect on hill climbing), and I stand by that. Between a good quality bike and a super-light one of the same style we're talking 5-10 pounds. Maybe if you weight 110 pounds you'd notice the difference, but the average 180 pound male would not. And if you commute you probably add on 10-15 pounds of racks, bags, lights, fenders, et al. –  Daniel R Hicks Dec 2 '11 at 23:35
    
+1 All right, fair enough. I just think it feels pretty significant (not modest) to me when I'm riding with a heavier load than normal, and consider that a real part of performance. –  Jefromi Dec 3 '11 at 0:00
    
@Blam - Double the weight of bike and rider and you'll be lucky to get acceleration at all. And given my infirmities it's a trick to just keep the bike upright. –  Daniel R Hicks Jul 10 at 11:59

It's something that should be experienced. Go grab an old school beater bike (like my old MTB that weighs 35lbs), ride it for awhile. Then, stop by a bike shope and see if they'll let you test drive a nice lightweight bike (usually on the order of 16-20lbs). You'll be astonished at how much more FUN it is to ride the light bike due to the responsiveness (handling, accel, braking)!

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+1 Don't underestimate the power of fun to keep you motivated and keep you riding! –  Mac Dec 1 '11 at 18:59
    
I can totally see how weight can factor into the fun of riding the bike. Thanks for bringing that up :-) –  Mike Mazur Dec 4 '11 at 13:56

For commuting, a heavier bike might actually get you overburned if you ride everyday. I have a 18kg bike (full-fledged mtb converted to city bike) and a 10.5kg bike (steel 10 speed converted to fixed). I use both for commuting, depending on weather and mood.

Specifically when I carry some stuff on the rear rack (then the bike is even heavier), compared when I ride light with the fixie, the difference in how I get tired is huge. Not only because of hills (there are some on my way), but also because of traffic lights which demand me to stop-and-go all the time in heavy traffic (when it's go, I actualy HAVE to GO!).

Now if I ride on a lighter scenario (open road), the difference is the heavier bike is more comfortable, since it has more mass to absorb road irregularities.

All in all, it's worth having a heavy bike, specially if you have a lighter one to seize the extra-training earned from riding heavy.

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I forgot to ask for specific weights in my question, so thanks for providing some hard data! I'm going to update my question. –  Mike Mazur Dec 4 '11 at 13:54

I will say this much. When I switched from a youth MTB years ago (I think it was a Mongoose? Nothing great, just a whole lot of unnecessary metal on the frame that made it heavy) to a Specialized Hardrock that was still 10 years old, the change was amazing and it did make a world of a difference. The combination of a lighter bike, and overall better construction and components was like night and day. Even then, riding my Hardrock, and taking my dad's Bianchi for a test ride was even then a bigger difference.

Really, you can get a bike with a decent weight for not that much, and it is worth it-or you can go really cheap and get something heavy and clunky. I think if you went to a bike shop, and gave a few decent bikes a test ride, you would be able to feel the difference in the handling right away. It's easier to experience if for yourself, than have someone explain it to you.

I think another important thing to note is the lighter the bike, typically the more expensive and therefore higher end the bike will be. If you look at pro bikes in the TDF, they're in the 16 pound range. Not that everyone needs a carbon racing bike. Plus, it's only at that top pro level that the ounces start to matter. However if you're looking at a 10 pound difference, it is worth it.

If you're curious, this is the specs list of second placed TDF rider Andy Schleck's bike from the 2011 TDF: http://www.bikeradar.com/gear/article/pro-bike-andy-schlecks-leopard-trek-madone-69-ssl-28915

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What weight would you consider a "decent weight?" –  Mike Mazur Dec 4 '11 at 13:53

The answers that point out handling might also be weighed against some other practical qualities, like how you use and store the bike. As cyclists, we spend a lot of time picking the thing up, sometimes shouldering it, sometimes loading it down, sometimes carrying it up stairs or high curbs.

I have a long recumbent, an Xtracycle, and a Trek 7200 road bike. I commute on all of these as my needs require. By far the lightest of my bikes is the long recumbent because it has smaller wheels, simple alumnium frame with a sparse number of weld points, and puny handlebars.

Luckily I have a shed to store them in, and I hang them up on the wall by their front wheels. The recumbent is easy to rack. The Trek is surprising difficult because often I have light system batteries, wet tires and fenders and a robust pannier rack on it. The Xtracycle takes something more like a weighlifters belt in preparation to lift it the four inches to get to the hook.

None of these bikes would be friendly for an apartment dweller that wanted to store their bike inside, had to deal with stairs or narrow doorways, or wanted to rack their bike on the bus. If I have to push the Xtracycle up a wet grassy slope, I'm praying my feet keep traction.

And to conclude, more than once I've often considered retiring my domestic fleet for a single Brompton and utility trailer.

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Yeah, as primarily a commuter/tourist, I have fenders, rack, light and battery, and a pannier or two. (Finally removed the front rack about 3 years back since I no longer do loaded touring and it makes it harder to park it.) –  Daniel R Hicks Dec 2 '11 at 12:24

Rotational weight very important. So light wheels make bigger than difference than slightly lighter frame.

Accelerating the weight of the wheel hard work. Same for crank.

From what I've heard, adding one pound of rotational weight is about the same as adding 3 pounds of stationary weight.

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When you work out the numbers, this is balderdash. In particular, the moment of inertia of the crank is rounding error. The wheels contribute only slightly more. –  Daniel R Hicks Dec 4 '11 at 21:59
    
+1 Not 3:1. Rotation weight is 2:1. –  Blam Jul 10 at 3:59

When I select a new bike setup i don't tend to look at the weight of the bike complete. If you want a faster bike for less money get a cheap 2nd hand frame and group set then swap out the "heavy" wheels that came with it and get some lightweight wheels.

There are a number of reasons for this.

1st, the heavier the wheel specifically the rim and the stuff at the outside of the wheel the harder its is to accelerate. The same conversely true of stopping

2nd, when spinning each wheel has a gyroscopic effect, this means that a heavy wheel is stable, but hard to change direction, which makes the wheel sluggish to respond and makes the bike feel "heavy". Remember.....

Centripetal force = Mass x (Velcocity^2/Radius)

3rd, If you choose your wheels your wheel, or have them built for you you can really focus on the right balance of strength and weight for the type of riding you do (road, city, touring etc etc)

I would expect to pay at least as much for wheels as i have for a frame, second to the frame they ARE the most important two items on your bike.

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A "light" bike these days is around 16 lbs. Getting down to that kind of light weight involves a lot of optimizations-- it is not just the frame, but also the wheels, cranks, handlebars and everything else. The end result is something that is very nice but quite expensive. You won't want to leave a bike like that alone on a public street even with a good lock.

To really take advantage of a bike that light you also have to be light. If you aren't at sub 10 percent body fat, it doesn't make much sense to shell out 1000+ dollars for a pair of wheels. In other words, it is much cheaper and more logical to just drop your own weight first to a minimal level before thinking about a seriously light bike.

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I am continuously amazed at the overemphasis placed on the weight of bikes. Yes it is important, but relative to other factors in deciding which bike to buy it is not that significant.

Lets compare a 20lb bike to a 24lb bike. If your budget is $1000 for a new bike, would you choose a 20lb bike with very good components and a so-so feel/fit, or a 24lb bike with the correct feel/fit and superior components. The heavier bike is 20% heavier...but lets ask more questions.

  1. On your typical ride, how many long steep climbs are there?
  2. How often do you need to do long/hard accelerations? I ask these because the only time weight is a significant factor is while climbing or accelerating. In flat or nearly flat sections of a ride weight is virtually insignificant. And, BTW for all the climbs you do there is presumably equal descents, during which time more weight works to your advantage.
  3. What (other than weight) can quickly sap your energy?
    • Rough gear changes due to less effective derailleurs (even small jolts can break your rhythm and stroke)
    • Poor body position due to improper fit.
    • Poor technique. (My 80 yr old mother regularly swims 1-1.5 miles, and can only do so because of a lifetime of swimming distances which require excellent breathing and stroke techniques. I can bike 40 miles NP but can only swim a few laps, because my technique sucks.

How much do you weigh?

If you weigh 165lb then the difference between the two bikes, including rider weight, is 2%!!! Would you trade that for better components? If you're buying a new bike and are more than 10lb overweight, which is the vast majority of us, you can expect to save more in weight by riding than you can buying a lighter bike.

Lastly, unless you are competing, an additional 5% on your ride time is not nearly as important as how much you enjoy the ride, which comes from (among other things) overall bike quality and fit, not weight.

Spend your money on overall bike feel/fit and quality of components. Save weight by riding more. Do not worry unnecessarily about 1MPH or 3 minutes during a 1 hr ride. We are riding to enjoy life and the experience.

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