[Closed] Interesting article on how weight affects speed

The focus appears to be on touring rather than someone trying to take 6 seconds off their PR for a 2 minute climb.

Also just some charlie ont web so not really conclusive.

Interesting never the less.

Cycling Weekly did a video of the time differences extra weight makes when hill climbing - http://www.cyclingweekly.co.uk/videos/cycling-tech/how-does-weight-affect-your-climbing-speed-video

Bikepacking bags are faster than panniers too. Damn those new-fangled ideas.....

(he does make the point that weight matters when you have lots of climbing and/or longer rides.)

What I learned from that -

Weight does matter about as much as you'd think.
Existing calculations on that are about right.
Its all irrelevant for mountain bikes.

Its all irrelevant for mountain bikes.

I'll remember that for the next "how much does your bike weigh?" thread 😀

What I find very interesting following adding circa 750g to my Orange Five with my CCDB Coil is this...20kg slows you down by circa 10%, 10kg by circa 5% so 750g is seeker FA.

And with tyre choice, set up, line choice an other variables it mean virtually nothing!

Why irrelevant for mountain bikes? Even Swinley has a little elevation?

Over the past year I have become a convert to the idea that weight is relatively unimportant but surely it's the same calc on or off road?

Its all irrelevant for mountain bikes.

Both the original link and the one I posted came at it from the wrong direction - they are maintaining power and then measuring time, what they should have done is keep the time constant and measure the power required. This would be harder to do consistently in a test though.

The reason to do it that way is that maintaining the speed of the lighter test when loaded up might push the rider into the red and they'd then have to recover from that whereas the lighter rider/bike setup could just keep going. Obviously that's in a race type situation but it also applies when trying to keep up with your mates - the lighter ones can just keep pushing on whereas the heavier ones need to ease up.

Box Hill - does 5% even count as a gradient?

I've just straight-swapped all my components (except stem) from a cheap steel frame to an old but expensive aluminium frame - significantly faster uphill offroad. Less to do with weight, more down to stiffness, I think.

On outright speed I have always thought weight makes little or no difference.

Accelerating or decelerating though, and therefore average speed, it possibly makes more difference on a mtb than on a road ride with long periods of consistent speed.

Weight will always make a difference, especially at the sharp end. Maybe not so much for recreactional riders.
Set up, geometry, length of travel, tyre choice will always help to compensate but all things being equal if you had two bikes the same but sand bagged one of them, it will be the slower bike. You cannot change the laws of physics.

Weight definitely makes a difference descending too. A road bike will tend to be faster downhill when heavier (or with a heavier rider) so might overcome some of the climbing disadvantage. It's less clear cut on a mountain bike where the additional weight could compromise handling and result in it being slower both uphill and down.

In 2014 I was racing hill climbs and managing to top 10. I weight 75kg and rode an 8kg bike.

In 2015 I weighed 69kg and rode a 7kg bike. I was on the podium in all but one event, won two and took the series over all along with a course record. I knocked chunks out of PBs on 5-8minute climbs and minutes out of the big ones like hartside at <18minutes.

It matters a lot on uphills provided you are going hard and the difference is large enough. Buying Ti bolts will to F all but dropping significant bodyweight will help.

Weight matters in relation to effort/fatigue... I definitely get more fatigued riding a heavier bike at the same pace as a lighter bike.

For me tyre choice is an important factor in the reduction of fatigue, a fast rear tyre works for me.

Im not saying weight doesn't matter, it does. Just that weight matters in way more important ways on MTBs than the relative total mass of rider and bike (which is what is tested in this post).

another variant here. This time adding 2kg to a road bike. Similar conclusion. But they also did a no power meter run. Just using similar perceived effort. In this case it made more odds.

Of if you are in a race then as we know loosing 30 seconds on every climb due 2kg extra is GC leader to no one cares, in Tour terms

The other factors are.

"I like a light bike so its up to me if I'm happy to pay £800 for a rim."

and

"Its alot easier to lift onto my car, onto the train over a mountain"

Jonba are you telling us your fitness was the same for those 2 seasons?

Lots of you are stating the frikkin obvious - of course weight will slow you down, the point is its a tiny factor when you look at changes you canake in eg fitness and aero.

🙂

I'm in no doubt that fitness matters most.

(Oh, Jo has the tyre. No slat hoofing was done)

Hill climbs are a bit of a special case. Most HCs are steep enough that you can pretty much ignore aero and rolling resistance, and there's no downhill that would benefit from the extra weight. It doesn't surprise me that losing 10% of your weight is the difference between podiums and not. All your power is being used to overcome gravitational force which is proportional to your weight.

To a first approximation, the time taken to complete a HC at a given power is proportional to your weight. Lop 10% off your weight, and you should ride it 10% faster at the same power. You might even do a bit better because you can hold a higher power for the 10% shorter time you'll be riding.

Buying Ti bolts will to F all but dropping significant bodyweight will help

Isn't that kind of the point? Work on your fitness rather than spending money on your bike? I've just come back from bashing out the local 25% hill climb on my £400 road bike, while the MAMILS are hanging out sipping lattes in Cheddar Gorge Costa admiring each other's carbon wonderbikes...

Work on your fitness rather than spending money on your bike?

Are they mutually exclusive?

There can be a bit of both, but to put things into perspective, an average guitar player will still sound average playing a fender strat.. But if you give Eric Clapton a £150 squire strat.. He'll make it sing!

I've just come back from bashing out the local 25% hill climb on my £400 road bike, while the MAMILS are hanging out sipping lattes in Cheddar Gorge Costa admiring each other's carbon wonderbikes...

And??

Maybe they are out for a social ride, and they do their hill-reps during the week? And why are you doing this - what is the point of your masochism? To make yourself quicker up that 25% climb, or are you actually training for an event. If that's the case then you'll be better trained if you choose a variety of hills to beast yourself over.

Btw it's no secret that expensive bikes are better. Not necessarily lighter, but stiffer, components work better, forks absorb more. Telling us the cost of your road bike - very much entry level - shows inverted snobbery that's hard to get past.

[quote=IdleJon ]And why are you doing this - what is the point of your masochism? To make yourself quicker up that 25% climb, or are you actually training for an event.People do just train to get fitter you know. To cycle further/faster. There doesn't have to be an event of some sort involved.

That's true scotroutes, but repeating a 25% hillclimb just for the sake of it is as pointless as a 50km ride with coffee and cake at the end. The sort of ride he was mocking.

repeating a 25% hillclimb just for the sake of it is as pointless as a 50km ride with coffee and cake at the end

The difference being, I can do both. I'm always trying to improve my fitness on climbs. It's an entirely personal, almost meditative process.

Road bikes - simple, simple tech. No point spending lots for anything other than cutting edge racing level - it's all down to the engine in the saddle, which constitutes by far the biggest proportion of the total weight, even with a cheap bike.

Mountain bikes, now, are different...

I bet a lot of the mamils do both.
They've just chosen to spend more on the bike. And TBH life is to short to ride shit bikes.

And it's not a particularly interesting article, it's nothing that's not been documented several times before.

The difference being, I can do both. I'm always trying to improve my fitness on climbs. It's an entirely personal, almost meditative process.

the "difference being" to what? Anyone who goes to a cafe stop on an expensive carbon bike can't ride steep hills? For somebody with a Zen-like approach to climbing you seem to have a very sneery attitude to other riders?

It takes a certain amount of power to push a certain weight up a hill. More weight requires more power, more power will fatique you more quickly or be beyond what you can produce at all.

Its not personal or subjective its maths.

For somebody with a Zen-like approach to climbing you seem to have a very sneery attitude to other riders?

And also rather disingenuous. Montgomery seems to have bought a Cannondale CAAD8 Sora two months ago. £750 reduced to £400 (and a very sweet choice, if I may say!) Certainly not the £400 bike he suggested. 😉

Tee hee. But I DID pay £400 for it.

Anyone who goes to a cafe stop on an expensive carbon bike can't ride steep hills?

Of course they can, some of them - and I have respect for that. Fat knackers on expensive bikes, though? Lose 10 kilos, climb some hills then come back and ask for my respect. Why is that even controversial?

Lose 10 kilos, climb some hills then come back and ask for my respect. Why is that even controversial?

There are many ways to enjoy riding a bike, just don't be dick about it.

I am unsure as to why your respect is so important Montgomery?

Of course they can, some of them - and I have respect for that. Fat knackers on expensive bikes, though? Lose 10 kilos, climb some hills then come back and ask for my respect. Why is that even controversial?

Do you compete in Sportives?

No. I don't consider myself a road cyclist, I just knock out road miles to keep fit. Switch off, look at the view, avoid getting hit by cars. I look at the current roadie scene and it has no interest for me. Golftastic.

Switch off, look at the view,

You clearly don't switch off your sense of superiority, or your need to judge other people.

Nothing wrong with having a nice bike. Just toys at the end of the day. It's funny how much people buy into the weight thing though. Bumped into a guy a while back, freezing cold, waiting to be picked up because he didn't have a spare tube. His reasoning for not having one, was that he needed all the help he could get given his extra body weight.

Now, to be fair, I think he was referring to lugging an entire saddle bag about, which I can understand. It's nice to not have it. But it really is not going to make any difference to anyone even slightly overweight. It's something that's only going to be noticed by a bona fide racing snake.

The last thing you need to lose weight on is the bike. Because to an already heavy rider the returns are massively diminished. It's a drop in the ocean. And a light rider will be fast on a heavy bike.

I ride a lot of hilly terrain. It's up and down as far as the eye can see. And I go between 8kg road bike, and 12kg road bike (probably closer to 14kg when laden with bags, bottles, lights, etc). Do I notice the difference? Yes. There's very much a perceived difference on steep climbs, 12% and above. Actual times are not massively different. And in relatively tame rolling terrain, it's barely noticeable. In a 100 mile sportive, you might be talking a difference of 5 minutes. I still choose to ride the heavy bike for some sportives, even if I plan on going flat out. It's only a game change if you plan on taking it very seriously!

I also dropped about 3 stone from my bodyweight. Went from a fit fatty who could keep up on the flat, only to get dropped on every climb, to right on the line on my BMI, and the difference is night and day. Massive. I was beating PRs on Strava well under my threshold. And smashing them while on it. It's only now that I feel small fluctuations in weight. A few years back I could've towed a trailer full of bricks and not noticed it.

+1 to that butcher, my summer and winter bikes are similar weights to the two you mention. The 13Kg winter bike is definitely slower but that's probably as much to do with the heavier wheel/tyre combination as the complete weight. I reckon it's about 10% slower than the 8Kg summer bike.

A couple of years ago I lost just under 20Kg in bodyweight, a huge difference in how climbs felt before and after that loss. Once you are close to your ideal weight then an extra Kg feels a lot.

No. I don't consider myself a road cyclist, I just knock out road miles to keep fit. Switch off, look at the view, avoid getting hit by cars. I look at the current [s]roadie[/s] [i]MTB[/i] scene and it has no interest for me. Golftastic.

FTFY

That's true scotroutes, but repeating a 25% hillclimb just for the sake of it is as pointless as a 50km ride with coffee and cake at the end. The sort of ride he was mocking.

You think there is a point to any of this? Unless your getting paid then surely its all pointless. Do the rides you enjoy end of story. I accept that training for an event might be more specific. But in end the event and its training are without purpose other than you own enjoyment.

Unless your getting paid then surely its all pointless.

This. It amazes me how snotty people get about other folk being on the wrong bike.
Too fat, thin, expensive, cheap, 29ery, slack, racy, rigid. Especially the genuine vitriol dished out to fatbikes from some 'I'm moar enduro than you' types I know 🙄

We're all riding round in circles for fun, it shouldn't cause you stress to see someone doing it a bit different to you.

ampthill - Member
That's true scotroutes, but repeating a 25% hillclimb just for the sake of it is as pointless as a 50km ride with coffee and cake at the end. The sort of ride he was mocking.
You think there is a point to any of this? Unless your getting paid then surely its all pointless. Do the rides you enjoy end of story. I accept that training for an event might be more specific. But in end the event and its training are without purpose other than you own enjoyment

Yeah, you've repeated my point using different words. 😆

Yeah, you've repeated my point using different words.

But I was to dim to realise that was what I was doing