What difference does a light bike make?

you're right, it probably does come down to setup/position or stiffness under power, it's certain that if I was wearing a 2-3lb heavier bag last night riding the ASR I'd still have felt the extra acceleration & speed, definitely. And there probably is an element of psychological perception to it as well 🙂

No, I'm sure you're right Njee since humans don't produce power linearly but the effect of weight (certainly in the relatively small amounts most are talking about) are small compared to other effects that I mentioned which affect your speed far more. If you're a serious athlete doing everything else to ensure you're on absolute top form then it's worth worrying about but otherwise it's more psychological – there's no issue with wanting a light bike if that floats your boat (just as there's no issue with buying bling for the sake of it) but just don't be fooled into thinking that it'll turn you into a riding god 🙂

@ njee20

Agrre, not a scientific test but when I bought my first very high end road bike in 1990 and took it out over the same route I trained on nearly every day the climbing speed increased by a huge margin at a tad over 20%
Approx 9.5MPH average on a given climb yup to 11.5MPH. And when I saw the reading I went back and did it again and climbed at just under 12MPH.

Presumably that same high end road bike was a good bit stiffer too…

I had much the same experience when I changed a really nice but flexy steel road frame I had for an aluminium one which was stupidly stiff.

As I mentioned elsewhere, the changes brought about by making your bike lighter have a very small effect when considered in the context of the real world, which is where most of us seem to ride.

Drop 5kgs from a total weight of 100kgs, will you see a stunning performance improvement?

Or is it more likely that the idea of riding a lighter bike, the 'feel' of the bike act to make you over estimate the effect of the weight loss?

We can and have proved that reducing weight does have an impact on performance, but the size of the impact is only small. Especially when considered in the real world context of a standard STW rider doing a standard STW style ride.

Put it this way; I would spend more time stopping for a wee than I could gain by reducing the weight of my bike by 5 kgs.

Never mind the time spent suspension faffing, tyre pressure faffing, opening gates, closing gates, putting gloves on, taking gloves off, squinting at GPS, arguing about the best way down or up, putting waterproof on, taking waterproof off, unmisting glasses, putting glasses away, losing glasses, finding glasses again, laughing, swearing, falling off, getting back on, taking the mickey, taking a photo, and so on.

but fortunately, light almost always means expensive and boutique-ee, which also usually means exotic and high-tech along with aesthetically pleasing (bordering on industrial art in some cases!), so that's why we buy it really, 'cause it looks good and appeals to our shiny magpie nature… the light bit is just a way of 'justifying' it 😆

tbh I don't worry about the weight, I'm more interested in how it performs and how good it looks doing it 8)

Do you have evidence for that though crikey, or are you just theorising?

I wonder if I've still got the article, it was interesting the difference it made. Figures were more like 80kg for combined rider/bike weight, but dropping 0.5kg off the bike made a hell of a lot more than 0.6% difference, if you think otherwise then I wonder if you're a bit daft.

'A stunning performance improvement' is rather subjective, but I'll wager that you'll notice the difference if you drop 5kg, particularly if it comes off the bike.

I wonder if we can set up a scientific blind test for the magazine? settle this argument for good?

Light tyres and wheels can make a noticeable difference (and as Clubber suggests, not always a positive one – heavier wheels and tyres are a lot more stable over the rough stuff). It starts to get a bit murky after that IMO.

I'm sure a lighter bike feels noticably different under you, because it's a seperate entity.
But both rider & bike climb the hill, as a system, and the only power source is your legs.
How can the physics be any different?

We did the maths yesterday in a different thread.

http://www.analyticcycling.com/ForcesLessWeight_Page.html

Using the example figures here, a weight change of 0.5kgs gives a .88 secs advantage.

As for theorising, I can wee quite quickly, but I think I might dribble a bit if I tried to beat that time.

Play with the figures a bit, even a 5kgs weight loss up a climb like Minch Moor came out at a time advantage of a couple of minutes, which initially sounds impressive, but not when considered in the real world context of actual riding as above.

Folk saying "I climbed at 12 mph instead of 9mph when I got my light bike" are meaningless unless account was taken of heart rate etc, which I doubt.

There's no doubt the feeling of a light bike can spur you on a bit.

I'd like to see njee20's test undertaken with a few variables: blind testing using identical bikes with weight added invisibly, say in the seat tube; same but with the rider told which bike he is riding; same but the rider mislead as to which bike he is riding.

I had much the same experience when I changed a really nice but flexy steel road frame I had for an aluminium one which was stupidly stiff.

I agree with this, the difference between my old Peugeot crosser/roadie steel thing and now a proper stiff ali road bike was immense, and not just down to weight and I think my faster times are partly psychological because of it.

But I also agree with njee20 "but I'll wager that you'll notice the difference if you drop 5kg, particularly if it comes off the bike."
Undoubtedly anyone would be faster if this was the case, and nowadays I don't think lightweight necessarily means flaky performance either, friend has a Hummer that's not got race kit on it, but SX mavic wheels, 120mm rebas, and that weights 24lbs, handles he DH just fine.

The test was done by the a number of riders each riding each bike, using power output, I'm not saying there's no variables, if you've ever tried to ride at a constant power it's not easy, particularly outside. But the results were interesting, and it made more than 0.8 seconds difference!

They were fit guys, so maybe that's a factor, we're not talking about your average STWer, who seems to think 90kg is a healthy weight 😉

I'd like to see njee20's test undertaken with a few variables: blind testing using identical bikes with weight added invisibly, say in the seat tube; same but with the rider told which bike he is riding; same but the rider mislead as to which bike he is riding.

Would be a good experiment this… add in a power hub + Edge 705 to take telemetry?

The other thing worth considering is, unless you are actually racing is it worth bothering about?

If my bike was made considerably lighter, it wouldn't make climbing any easier, because I would put in the same effort anyway. 'It doesn't get easier, you just get faster' is the quote, I believe.

And if I went out riding on a £3k superlight bike with friends riding £1k 'normal' bikes and beat them on the climbs, it would actually reduce my bragging rights! Would I feel better than if I had a heavier bike?

Would be a good experiment this… add in a power hub + Edge 705 to take telemetry?

That's exactly how it was done… They used the Power Tap head though, not too sure what the relevance of the Edge is!

I'll do the wee part of the experiment, but I'll need some kind of liquid refreshment of a given standard to avoid any bias…

http://www.training4cyclists.com/how-much-time-does-extra-weight-cost-on-alpe-dhuez/

I can't really agree with the significance of the results though; it would be interesting to see him ride Alpe D'Huez four times on a normal bike and see what time differences he managed without any weight change at all, and more effort should be made to hide the weight change from the rider in an attempt to reduce the psychological factors…

I agree, I'm not so sure about that, still interesting to see. We don't know what rider weighs either, which could be relevant, although the comments suggest he's pretty fit.

The test I saw was a much larger sample, with more linear testing, was a few years back.

Maybe they should use one bike for all tests and add ballast down the seat-tube (i.e. lead weights) without the rider knowing. This would take frame quality out of the equation.

Surely all of us that race strive for lightness. However there is a point of diminishing returns, well for me anyway. I think I could now lighten my race bikes by up to 500g and it wouldn't make any difference to me.

Of course there is, and there's always a point where things are just too light, otherwise we'd all ride Furious Freds all the time!

Odd trial – 1.8kg in the tyres???

I think I need to lose about a stone before any of this is dignificant to me!

This is a classic STW thread, the sort that really puts people off this site.
For anyone that's ever wanted to go faster have they ever looked at making things heavier. And I don't mean things like swapping rigids for suss forks as they are two different things.

What's wrong with a bit of discussion?

Seems like quite a good discussion actually. Most un-STW – No personal insults (other than the brilliant 'dumb' comment), decent explanations of why people hold the view and so on.

I don't see why people taking on a popular view (that lightweight makes a big difference to how fast you ride) and explaining why they think it's not as important as many think is a bad thing. No one's suggested that heavier bikes make you inherently faster, have they?

It doesn't put me off the site 😆

I like discussion and questioning things – I'm not here for a circle jerk.

Just for the sake of reasoned argument….

The current Hour record holder did it on a bike that weighed 9.8 kilos.

Heavier than the previous 8 attempts.

…and we've not even touched on the idea that heavier things go downhill faster yet.

A lot of that weight was in the back wheel – IIRC it had a weighted rim weighing something like 3kg! (assuming we're talking about Sosenka)

This hour record… is that a track record?

If you are travelling at constant speed on flat terrain weight makes no difference.

Indeed, different reasoning for different purposes, I think we're talking about "average" riding here.

Didn't one of the mags recently (last couple of years at least) do some experiments with putting extra weights on the bike and the the rider? MBR I think, had rolls of soft metal wrapped around the top tube and all sorts of things. Mor or less came to the conclusion that more weight equals worse handling bike that was slower up the hills. Not exactly ground breaking…

…and we've not even touched on the idea that heavier things go downhill faster yet.

As do heavier riders! 😉 😆

I think it makes a difference my excuse is that I am very light and short so any advantage I get by dropping weight is welcome cause I can't grow longer legs for more leverage :p . Me combined with my bike should be below 70Kg so if I drop a couple of kg it has to make a difference :p

What I think is more interesting is the fact that aerodynamics has a greater effect than weight in terms of performance, and the skinsuit fiasco apart, I wonder how long it will be before we see deep section down hill rims appear?

Nothing at all.
Though I think there are too many variables in mountainbiking biking to answer this. I also think that some of the 'facts' that are linked to or pasted are to easilly taken as gospel, when nearly all of us are experienced enough to give real world answers based on solid learnt facts.
I always wish my bikes were heavier going downhill 😐
However with road lightness does count IMO
And I think it does with cross again IMO.

Like this crikey?

when nearly all of us are experienced enough to give real world answers based on solid learnt facts.

I would respectfully suggest that we are also all easily capable of fooling ourselves into thinking that some things are more important than they prove to be.

I've done the must get lightest stuff thing, buying the lightest road wheels I could afford, chopping the ends off drops and seatposts, and looking back realistically, it made a huge difference in one place; my head.

edit: Oooh, nice!

However with road lightness does count IMO
And I think it does with cross again IMO.

Yes, it does count but not to the extent that people think it does. Cross will be a bit different for the simple reason that a lighter bike is a lot easier to shoulder/etc!

I'll bet that for most riders, spending say £500 on a training camp in warm weather over winter would be much more beneficial than spending £500 saving weight yet what do most people do (and OK, I accept, not everyone can easily just get a week off work/away from the family/etc to do the training camp whereas you can buy stuff very easily 🙂 )