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Today I was at a bike shop looking at single speed bikes. I rode one, but didn't buy it because I like to bike fast, and this bike must have weighed 2x more than my aluminum road bike (the bike was steel).

The store owner told me that the bike weight will not have as great of an effect on my top speed as many other things both on the bike and things I could change about how I ride.

Is he right or wrong? Does bike weight make a big difference or is it just very good marketing?

mkoryak
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  • He's right, in general. The total weight you need to push is the weight of the bike plus the weight of your body. Most people would do just as well to reduce the weight of their body, rather than the weight of the bike. Of course there will be exceptions to this rule, and these are the people who will benefit from a lighter bike. – PeteH Apr 01 '15 at 20:17
  • He's kind of right. On flat surfaces, the weight of the bike doesn't make a huge difference. However the point of a single speed bike is that it has a lot fewer parts than a regular road bike, and therefore should weigh less. A single speed has the disadvantage that you'll almost never be in an optimum gear, so it should make up for that in other areas, such as being lighter. They are also easier to maintain, however I would still be wary of a single speed bike that is heavy, as they probably use low quality components. – Kibbee Apr 01 '15 at 20:41
  • I am not buying any SS weighs 2x more than your aluminum road bike. If you are looking for top speed then don't look at SS. – paparazzo Apr 01 '15 at 21:39
  • @Blam: I believe it if he's looking at something close to a BSO and comparing it to something of much higher quality, and not seeing the other differences. – whatsisname Apr 01 '15 at 22:30
  • @whatsisname If he has a high quality bike then just why is he looking at a BSO level SS. And what "bike shop" even carries BSOs? And what SS BSO weighs twice as much? – paparazzo Apr 01 '15 at 22:38
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    @Blam: It's a strange world out there. – whatsisname Apr 01 '15 at 22:42
  • I would rather not buy a BSO, I know nothing about single speeds but would like to know more, and what better way than owning one! The price that was quoted for this bike was about 1/3 of my road bike - I need to do more research before asking them to make it more expensive :) – mkoryak Apr 02 '15 at 02:04
  • @mkoryak: if you specify the make/model of your road bike and the SS you were looking at, we can provide you a more useful information – whatsisname Apr 02 '15 at 03:39
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    Elementary physics: On the flat at constant speed* the weight has no influence. Uphill the lighter the better, downhill it's the opposite! (* if you want to accelerate the lighter bike will have an advantage!) – Carel Apr 02 '15 at 11:49
  • Figure out what the difference in weight is. Likely it's on the order of 5 pounds, maybe 10 in the extreme case. What fraction of total bike+rider weight is that? 5 pounds for a 150 pound rider is about 3%. This is the amount that your acceleration and hill-climbing will be affected. Your flatland top speed will not be affected. Other effects -- riding stance, bike geometry, tire efficiency, etc -- will be far more significant in most cases. – Daniel R Hicks Apr 02 '15 at 12:00

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The weight of a bike has virtually no effect top speed. It takes very nearly the same amount of effort to maintain a speed of 30 mph on a 20 lb bike and a 30 lb bike on flat ground. The biggest factors that come into play at high speeds are aerodynamics and rolling resistance ( slick, efficient tires ).

http://velonews.competitor.com/2012/05/bikes-and-tech/technical-faq/tech-faq-does-bike-weight-matter_220429

That said, is top speed what you're really worried about? Probably not. Even if you like to bike fast, I truly, truly doubt you should be concerned with top speed. You'll probably enjoy a bike that accelerates quickly and feels nimble. Unless you live in a flat, remote area, in which case you probably wouldn't want a single speed, you're probably going to be accelerating and maneuvering more than you are achieving top speed. And again, these factors don't necessarily correlate with the weight of the bike.

Scott Hillson
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  • Weight does actually matter when accelerating and maneuvering. It's easier to accelerate a lighter bike, which is particularly felt on the uphills. I agree though that the difference is only felt at low speeds. At higher speeds the air drag is a couple times higher than any other resistive force. – Slovakov Apr 01 '15 at 20:26
  • Its impossible in the cycling world to separate weight from quality. As no one makes good quality heavy components, lighter bikes are generally faster - because they are better quality. – mattnz Apr 01 '15 at 23:38
  • Quality is not synonymous with weight or top speed. A counterfeit Chinese carbon frame may be faster than a well made steel frame and built up to be a rugged commuter with wide puncture resistant tires and stainless steel fenders. You're probably going to pay more for lighter components, but that's not a guarantee of quality, not on its own. – Scott Hillson Apr 02 '15 at 18:07
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Well, the usual argument is that an average person can easily lose one or two kilos of body weight, and that would cost good money if you take it from the bike.

On my experience, weight is more noticeable when riding uphill, but then, if you usually ride uphill I don't think you would want a single speed. Other issue would be speeding from a stop, or starting a sprint from a lower pace, but again, on a single speed you already have a problem with that, specially speeding from stop (or if your single gear is short, maintaining high speed for a good stretch, the eternal tradeoffs)

I rather start in a short gear with 5 kilos more and then switch to longer gear if we were to race 100 meters, or from a light stop to another, than on a single gear. I don't know, if you want speed, gearing seems to me a lot more important. On long stretches you could use longer gear.

Then, if we are comparing same gear ratio on same frame geaometries and handlebars, for the same cyclist, of course you want less weight, but is it worth the money? I don't think so.

All in all, if you were to magically create a clone of yourself, and race against him in the same magic bike, but one is 15 kilo and the other 7.5, and all conditions are magically the same, wind, body placement, whatever, physics of this planet will make the lesser weight bike faster.

Is it worth it? that's up to you, and more specially to your cash availability. If you want an opinion, it is not, I ride a road bike and a mountain bike, the mountain bike must be 3x the weight of the road, and still, I ride a lot of Strava segments that I did faster on the mountain bike (it's got no suspension though). So, yep, hunching like an egg and saying to yourself I'm going to pass that guy on the scooter or die trying, that can be more relevant to speed than triple weight. And of course, having bottom bracket destroying hams is #1 in the speed equation... sometimes I wheelie from the sheer power, in a 52-13 ratio :D

Really, diss weight and get some bike you fancy, and ride it fast if that's what you like. But don't put yourself or others in danger knowingly.

edit: only top speed?: enter image description here

gaurwraith
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I love this question, and the answers are solid, but let me add that the weight of moving parts on a bike is more important than the weight of non-moving parts. So for my money, a heavier (read: steel) frame and lighter wheels is optimal. In addition, stopping an object with greater mass takes more energy, so if you've got those light wheels and some good weight on them, you can go faster, farther, with less effort.

That being said, and this is a personal tragedy for me, I especially like the point about the economics of losing weight versus buying a lighter bike. Very good but inconvenient point in my opinion.

Charlie Wheeler
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    http://bicycles.stackexchange.com/questions/7428/what-is-the-effect-of-adding-weight-to-a-wheel-vs-adding-it-to-the-frame – Daniel R Hicks Apr 02 '15 at 12:04
  • Okay, I think my answer is congruent with what you reference - although my wording is not nearly as precise since by "moving", I mean the rim weight. Do you mean that it being only 2x makes it not as important? Or are you pointing out that weight is just weight and that what I'm saying about acceleration/deceleration is false? – Charlie Wheeler Aug 03 '16 at 00:44
  • Okay, I reread the original post, so now I understand, it's that the effect of rim weight is negligible. It's a bummer to be down-voted, but better to learn the truth. – Charlie Wheeler Aug 03 '16 at 00:53