How important is the weight of the bike

[rogerzilla]

Weight on the bike makes much more difference than flab on the rider, IME.  It's partly about lugging dead weight up a hill (as opposed to weight that moves and can be used to turn the pedals) but also about handling -  the whole bike is basically unsprung weight and your legs are the springs.

[LittleWheelsandBig]

So your bike goes faster when you take 2 full bidons from their cages and put them in your pockets?

[rogerzilla]

Of course 

[giropaul]

My take on this is this:

There are loose categories of road bike (leaving aside BSOs) - hefty, reliable, long-lasting tourers, "sporty" audax and all-year -round bikes, and "pure" racing bikes.

Within each group, any variations in weight will be almost insignificant. However, there is always a psychological effect of having a newer, nicer, more shiny etc bike, or a new bit of kit.

IF you are at peak (Wiggins standard) fitness then some weight reduction on the bike MAY have a "marginal gain". As I don't think Bradley and his mates come on here very often, then it's probably pretty academic. This is the area where you have individual bikes for different days in a Grand Tour, and have domies to carry your spare bidons.

However, in my years with teams, people were often suprised at the heftiness of the average team rider's bike. Reliability and strength are important. Ultimately, in say the Tour of Flanders, if you need a bike change, then the break could have flown.

Most of us can make a bike ride "faster" (whatever that means), with a pair of really good wheels. However, do we want to risk £1,500+ wheels and £80+ tyres on a ride that isn't a race - and have a following car in case of failure?

[Hot Flatus]

Lightness matters going up hill, but then so does stiffness. I go up hills far more easily when I remove the saddle bag full of crap.

Do I care?

Yes, anything that makes going up hill easier usually translates to an overall faster speed on long rides and an earlier finish and less likelihood of meeting mattc. However, what would really slow the speed would be mechanical breakdowns and punctures, so by and large equipment is chosen that will be reliable for a number of years in order to equate to value for money.  I really like my Kysrium SSC wheels, they are light and fast but only come out on good weather rides on good roads for special events.

[Asterix, the former Gaul.]

Over the last 9 years I have kept a record of the time it takes me to get round my "lunch-time loop".

I do it a lot and occasionally I'll go into TT mode to see how quick I still am (or how slow I am if we're being more honest).

I won't tell you the length of that route, it's too embarrassing, but here are the best times I achieved by bike.

50mins 0secs - British Eagle Touristique (531 frame)

That's a lovely restore job.  I have a Touristique that I picked up off ebay for £50 a few years ago.  It was such a nice bike to ride I have completely renovated it but it's a workaday effort compared to that.

Despite it being 531st and heavy I find it pretty quick even up hills.  When I went out with a bunch of roadies I kept up very nicely on a ride into the N. York Moors.  They seemed surprised having originally suggested I might be better suited to CTC rides!

Have done the Raid Pyrenean twice on steelies.  There's no doubt that I am quite slow up them mountains compared to the featherweights but I think it's more due to my weight than the bikes.  The group I did it with (the first effort was solo) were all 10 or 20 kg lighter than me.  I finished each day around the middle of the pack mostly thanks to insane descending. 

So I don't care about bike weight, it's what it is like to ride that matters.

[velosam]

Well I.thought I would update with.a recent experience.  Today I did a short ride in crappy conditions on a genesis Croix de fer.  For something on cx tires and apparently heavier, it rolled really.well compared to my genesis equilibrium, which does have m+ tires.  It fell just as spritely and comfortable on crappy roads despite the steel fork.

[Toady]

If you have a bit of time on your hands you could play around with the calculator on this page.
http://analyticcycling.com/ForcesLessWeight_Page.html

Suppose one is considering buying a new, light-weight frame or going on a diet. What is the benefit from having less weight? How much time would be saved over a given distance on a specified slope? How much more distance would be covered in a given time? 

[LEE]

Over the last 9 years I have kept a record of the time it takes me to get round my "lunch-time loop".

I do it a lot and occasionally I'll go into TT mode to see how quick I still am (or how slow I am if we're being more honest).

I won't tell you the length of that route, it's too embarrassing, but here are the best times I achieved by bike.

50mins 0secs - British Eagle Touristique (531 frame)

That's a lovely restore job.  I have a Touristique that I picked up off ebay for £50 a few years ago.  It was such a nice bike to ride I have completely renovated it but it's a workaday effort compared to that.

Thank you.



Shame about the frame snapping.

[Asterix, the former Gaul.]

That is so sad.

I don't rely on my own expertise in these matters and had the frame stripped and checked by a frame builder as part of the re-enamel process.  I'd a previous 531 frame snap in 18 months after a t-bone.  The damage to the down tube was quite unnoticeable and the radial crack appeared some distance from it by the dt band-ons.   Being emotionally involved with the beast I had it professionally repaired (new tube, etc)  and rode it for several years (including some 80 km/h descents ) before it got nicked.

[uphillbothways]

Bike weight is utterly irrelevant to non-racers. The difference between a superlight carbon confection and a classic steel tourer might be 7kg or so - a 100% difference in the weight of the bike, but only a small difference in the weight of the bike and rider combined.

Let's imagine an approximate Ventoux - a brutal 22km climb at a constant 9% grade. Let's also imagine an approximate rider - he weighs 80kg and puts out a constant 160w. Using the (very accurate) calculator at kreuzotter.de, we can see that on a 6.8kg UCI-minimum racer, he would expect to complete the climb in approximately 3 hours and 8 minutes. On a 9kg winter trainer, he would take another 6 minutes. A 14kg tourer would be 9 minutes slower again. Obviously that's an eternity to a racer, but to a tourist or a recreational rider it's a sandwich stop. On normal routes, this time difference shrinks considerably - over a typical 200km audax, a kilo of weight is worth less than a minute to most riders.

This seems totally counter-intuitive, but it's not hard to understand the underlying physics. Very lightweight bikes feel fast because they're easy to handle and accelerate from a standing stop, but that represents only a tiny proportion of the energy that goes into propelling a bicycle. The vast majority of pedalling effort is lost to aerodynamic drag, which is largely a product of rider position.

[L CC]

Psychologically the effect is greater. I go much faster on a light bike, despite being a Lardy lardarse, perhaps because I feel better and work harder. It's a much larger effect than mere physics would explain, as the 5kg difference is  about a week's weight variance in me. Part of it is gearing, a lighter bike trends not to have touring gears, and because there's no spinny bail-out, you MTFU and push harder.

[Asterix, the former Gaul.]

Psychologically the effect is greater. I go much faster on a light bike, despite being a Lardy lardarse, perhaps because I feel better and work harder. It's a much larger effect than mere physics would explain, as the 5kg difference is  about a week's weight variance in me. Part of it is gearing, a lighter bike trends not to have touring gears, and because there's no spinny bail-out, you MTFU and push harder.

Ergonomics could have the same effect.  I've been trying to work out why a particular bike just makes me  'feel better and work harder' even tho' it's no lighter.  The handling is very sharp too and yet I have it set up the same as my other machines.  A project I'd like to do is ask a frame builder to copy it in a lighter material with the same stiffness, if possible, just to see what happens. 

[DrMekon]

Psychologically the effect is greater. I go much faster on a light bike, despite being a Lardy lardarse, perhaps because I feel better and work harder. It's a much larger effect than mere physics would explain, as the 5kg difference is  about a week's weight variance in me. Part of it is gearing, a lighter bike trends not to have touring gears, and because there's no spinny bail-out, you MTFU and push harder.

This, except my HR suggests I'm not working harder than I do on my commute on my ali FG CX bike. I did the Delightful Dales (3.5aa) on carbon in almost exactly the same time as I did the Burford Bumble (0aa, doesn't get much flatter) on my steel tourer, despite worse conditions. My carbon bike weighs about 8kg my tourer weighs about 15kg. The main difference for me is not going into the red so much on climbs and accelerations. At the end of the Delightful Dales, I didn't feel like I'd spent the day lugging scaffolding about. I have to admit, I happily resort to 34-28 on my carbon bike, so maybe I'm not doing the "work harder" thing.

Going from heavy steel to light carbon has been a revelation for me. I feel so much fresher at the end, it feels like cheating. I'll still use my steel and aluminium bikes for audax, but only when I want to make it harder for myself.

[Toady]

Going from heavy steel to light carbon has been a revelation for me. I feel so much fresher at the end, it feels like cheating. I'll still use my steel and aluminium bikes for audax, but only when I want to make it harder for myself.

I think that for many recreational non-competitive riders - well for this one anyway - that's THE key criterion.  Not how fast you go, but how you feel after a given distance: when do you go from enjoying a ride into the grim zone, just churning the pedals round wanting it to end.   I find that  point is also strongly influenced by weather conditions, the grim zone is never too far away in the rain.

One day I'll try a lighter bike and see if that affects it, but actually acquiring one that I want is way too much hassle for me to face at the moment, and I have soooo much room for improvement just by riding more.

[mrcharly-YHT]

Psychologically the effect is greater. I go much faster on a light bike, despite being a Lardy lardarse, perhaps because I feel better and work harder. It's a much larger effect than mere physics would explain, as the 5kg difference is  about a week's weight variance in me. Part of it is gearing, a lighter bike trends not to have touring gears, and because there's no spinny bail-out, you MTFU and push harder.

Ergonomics could have the same effect.  I've been trying to work out why a particular bike just makes me  'feel better and work harder' even tho' it's no lighter.  The handling is very sharp too and yet I have it set up the same as my other machines.  A project I'd like to do is ask a frame builder to copy it in a lighter material with the same stiffness, if possible, just to see what happens.

Or you could securely fasten 2kg of weights to the frame (evenly distributed) and see if that makes a measurable difference.

[contango]

I've currently got a very lightweight racing bike in my kitchen that a friend lent me so I could see how it compares to my cross bike (Specialized Tricross, with rear rack permanently attached). The difference in weight between the two bikes is significant - just lifting the bikes it's clear one is much lighter than the other. I could easily believe one bike is 30% lighter than the other. As soon as I sit on the bike I'd hazard a guess the difference in rider+bike weight drops to under 5%.

On an initial run (just a couple of miles to get the saddle and handlebars adjusted) I got it into just under 25mph for a fairly short sprint. It felt subjectively like it took less effort to get to speed than the Tricross does, but holding the speed is another matter. I'm planning a slightly longer run today to see how I get on, although I overdid it a little yesterday (too high a gear up a hill) and my knees are a little sore today, so it might not be as long as originally planned.

[velosam]

I've currently got a very lightweight racing bike in my kitchen that a friend lent me so I could see how it compares to my cross bike (Specialized Tricross, with rear rack permanently attached). The difference in weight between the two bikes is significant - just lifting the bikes it's clear one is much lighter than the other. I could easily believe one bike is 30% lighter than the other. As soon as I sit on the bike I'd hazard a guess the difference in rider+bike weight drops to under 5%.

On an initial run (just a couple of miles to get the saddle and handlebars adjusted) I got it into just under 25mph for a fairly short sprint. It felt subjectively like it took less effort to get to speed than the Tricross does, but holding the speed is another matter. I'm planning a slightly longer run today to see how I get on, although I overdid it a little yesterday (too high a gear up a hill) and my knees are a little sore today, so it might not be as long as originally planned.

I would be interested in an update.  When I commute and get home I am exhausted on  my steel ride.  I really need to borrow a carbon jobby for a day to see how it feels.

[caerau]

Is a carbon jobby what you get if you eat too much burnt toast?

[MacB]

When I commute and get home I am exhausted on  my steel ride.  I really need to borrow a carbon jobby for a day to see how it feels.

That's interesting, and I've posted this info before, because I have a sort of comparison which would be relevant here. I used to do a lengthy commute, 40 miles per day, and I began doing it seriously on a light carbon/alu combi frame with carbon forks. It was a really nice ride but not so good when laden and a low spoke count rear wheel didn't like the rougher sections very much. After much research and many questions on the forums I bought a dedicated bike for commuting. At the time this was a Surly Crosscheck and kitted out with 9 speed hub gear, Brooks saddle, guards, rack, etc.

Both bikes had identical cockpits but the commuter had much bigger tyres(M+) and weighed a lot more, approx 50% more actually. The light bike felt a lot faster but my averages told me that was never more than 2mph max and more like 1mph or less a lot of the time.

What I did notice more than anything else was that as I tired towards the end of the commuting week the big heavy bike was comfier. I tended to sit heavier and wasn't as adept at avoiding road imperfections and the big tyres and Brooks saddle really helped. A few times it almost felt like the bike just knew its way home. Now I fully accept that the heavier bike would have contributed to my level or accumulated fatigue but my gut instinct was that it more than offset this by increased comfort levels.

I believe that enough that the various incarnations since haven't lost those core factors. The Brooks saddle is still there, hub gear is now a Rohloff, the steel frame is now titanium though still with steel forks. As punctures are no longer an avoidance priority the tyres aren't M+ but they are Marathon Supremes and have gone up to a 700x40. The rack and guards are still there and are now complimented by dynamo lighting. The biggest change is that the latest incarnation is staggeringly more expensive but that pricetag hasn't brought about any weight savings. We're still talking about 33lbs or thereabouts.
 

[Biggsy]

This seems totally counter-intuitive, but it's not hard to understand the underlying physics. Very lightweight bikes feel fast because they're easy to handle and accelerate from a standing stop, but that represents only a tiny proportion of the energy that goes into propelling a bicycle. The vast majority of pedalling effort is lost to aerodynamic drag, which is largely a product of rider position.

It's true, of course, that the majority of pedalling effort is lost to aerodynamic drag, but that doesn't mean the ease of accelerating from stopped/slow is utterly irrelevant for non-racers, especially, but not only, for those in an urban environment with loads of stops and starts.  And for hill climbing, it's not time that the non-racer cares about, but effort and enjoyment.  I enjoy the benefits of a light bike, and I've never done a proper race in my life.  I accept, though, that it's less of an issue for heavier riders, as the weight of the bike diminishes in proportion to your paunch.

[Kim]

It's true, of course, that the majority of pedalling effort is lost to aerodynamic drag, but that doesn't mean the ease of accelerating from stopped/slow is utterly irrelevant for non-racers, especially, but not only, for those in an urban environment with loads of stops and starts.

I think there a lot of truth to this, though I'm sure it's as much ergonomics/handling as weight.

My experience of properly lightweight bikes is minimal, but I know that heavy touring recumbents (even the kind where you never have to put a foot down), while reasonably aerodynamic, are tedious and energy-sapping in a start-stop hilly environment.  A heavy DF tourer is measurably faster and seems less tiring, even when ridden with a recumbentist's aversion to filtering.  But I reckon a small-wheeled upright bike (a 20" Dahon or something Moultonesque) is even nicer - they accelerate quickly, steer nimbly and stop securely.

[velosam]

When I commute and get home I am exhausted on  my steel ride.  I really need to borrow a carbon jobby for a day to see how it feels.

That's interesting, and I've posted this info before, because I have a sort of comparison which would be relevant here. I used to do a lengthy commute, 40 miles per day, and I began doing it seriously on a light carbon/alu combi frame with carbon forks. It was a really nice ride but not so good when laden and a low spoke count rear wheel didn't like the rougher sections very much. After much research and many questions on the forums I bought a dedicated bike for commuting. At the time this was a Surly Crosscheck and kitted out with 9 speed hub gear, Brooks saddle, guards, rack, etc.

Both bikes had identical cockpits but the commuter had much bigger tyres(M+) and weighed a lot more, approx 50% more actually. The light bike felt a lot faster but my averages told me that was never more than 2mph max and more like 1mph or less a lot of the time.

What I did notice more than anything else was that as I tired towards the end of the commuting week the big heavy bike was comfier. I tended to sit heavier and wasn't as adept at avoiding road imperfections and the big tyres and Brooks saddle really helped. A few times it almost felt like the bike just knew its way home. Now I fully accept that the heavier bike would have contributed to my level or accumulated fatigue but my gut instinct was that it more than offset this by increased comfort levels.

I believe that enough that the various incarnations since haven't lost those core factors. The Brooks saddle is still there, hub gear is now a Rohloff, the steel frame is now titanium though still with steel forks. As punctures are no longer an avoidance priority the tyres aren't M+ but they are Marathon Supremes and have gone up to a 700x40. The rack and guards are still there and are now complimented by dynamo lighting. The biggest change is that the latest incarnation is staggeringly more expensive but that pricetag hasn't brought about any weight savings. We're still talking about 33lbs or thereabouts.

thanks, that is useful. Over three quarters of my route is canal/ cycle path, which is rubbish.  I am contemplating getting a croix de fer, as I can then run 700x32 tires and have discs.  I don't really need the latter but when I commute I tend to hang up the season ticket and therefore end up riding in rubbish weather.  Its the weight of the cdf that is bothering me, although I don't know how much heavier it is than my genesis equilibrium running M+.  The CDF will run M+ as well maybe. I was wondering if wider tires had less punctures?

[marcusjb]

I've never really owned a light bike.  The audax bike weighs something like 12Kg with lights, pump and bagman on it (but even more once bidons and barley go on).

I'm pretty slight of build (5 foot 8 and 60Kg).  So I'd guess I'd benefit more from a lighter bike than someone heavier (in terms of percentage gains, a couple of kilos loss on my all-up weight is going to make more of a difference than it would to someone of a bigger build). 

When I go and do laps of Richmond Park (my local park where 3 laps is just about bang on 20 miles with a few reasonable lumps and bumps to climb), I'll take as much weight off as I can.  Does it make any difference?  Probably a small one. 

What has made a difference to lap times is different wheels and tyres.  I've recently built up a set of lighter wheels with Vittoria Open Pave tyres on - compared to my usual 36 spoke wheels with Conti 4-Seasons on, I'm finding about 60 seconds difference over the 3 laps (so somewhere around 1.5% faster).  Now having changed two things at once, that is fairly meaningless data.  But overall the bike feels much quicker to climb with (and this is backed up by strava on the hills).

I'd always been of the understanding that rotating weight matters - but I run hefty wheels for the reliability of 36 holes etc. - but it seems that this does make a difference. 

[zigzag]

it's true that the weight of the wheels matters a lot, especially towards the outer edge i.e. rims/inner tubes/tyres/nipples. small wheeled bikes can provide fast acceleration even with heavier wheels as the outer edge of the wheel is close to the hub and carries less momentum (the analogy of a sledge hammer with long and short handles).
i can't wait to test out my newly built wheels weighing in just over 1.4kg (with 32/32 spokes) - combined with the efficient drive of single speed the acceleration should be pretty good