impact of rider weight in cycling

shaungil

Folks (Beasty and Lumen you probably might have some good insights) what effect does weight loss of a cyclist have on speed for a cyclist if he can maintain the same power output.

Obviously downhill it's probably not beneficial ??? but on the flat and uphill. I was told something about uphill needing 8 times harder for twice the weight (2 cubed) but am dubious on this.

To giuve examples let's use theoretical cyclist A 100 kg what would a 5kg decrease or 10kg decrease impact.

Wow I just realised I'm 100 kg so that's really handy;)

Bluefoam

Weight of the rider doesn't have any effect once you have the most expensive components, accessories and bike. As much carbon as possible. This way you can eat all the pies/cake you want

ROK ON

I was 100k now 88.
Main impact has been on the flat for me.
24kmph spins have become 27kmph spins on average ceteris paribus.

On the climbs I am still slow but now my HR isn't all over the place while climbing, which tells me that I have more pace if I can put more effort in.

Main thing is that on similar distance spins versus last year my recovery time is significantly shorter. Maybe that in itself is worth everything.

roc_racer

The fatter you are the slower you go.

How many porkers do you see on the podium ?

IM0

simplest way to figure this out is to put 5kg in a bag and put it on your back and go for a ride, then do the same without the bag and look at the times.
or you could just go to analyticcycling.com and imput the numbers.

Lumen

Shaun,

Weight doesn't matter much on the flat, and arguably you get back on the descents some of what you lose on the climbs, but I'm convinced that even on a slightly rolling course the energy savings from being lighter make a big difference.

The toughest climbs in A4 races I've done have been at about 300W, and that was in Stamullen when you dropped me (on the climb).

I weigh 68kg, so you weigh 40% more than me (including bike weight). So you can put out in excess of 400W for a few minutes. That's a lot.

Maybe you just have loads more anaerobic capacity than me, but I reckon if I had your power and my weight I'd win everything.

Certainly if I had to carry 30kg on my bike I'd get dropped within minutes.

Bluefoam

roc_racer wrote: »

The fatter you are the slower you go.

How many porkers do you see on the podium ?

It doesn't matter how fat or unfit you are, once you have a lightweight bike... Anyone can win a race, once they have the latest euro gear...

niceonetom

The bike calculator gives you the option to play with some numbers. It's wildly optimistic when calculating aero advantages, but maybe it's better with mass.

On a 5% gradient
100kgs @300w -> 16.2kph
70kgs @300w -> 18.9kph

On a 10% gradient
100kgs @300w -> 9kph
70kgs @300w -> 11kph

Or, to put it another way, if you want to go uphill as fast as Raam you need to put out ~420w for his 300w.

niceonetom

roc_racer wrote: »

The fatter you are the slower you go.

How many porkers do you see on the podium ?

Quite a few at the level most of us race at actually. The Clonard GP that blorg won was dominated by fat blokes. The winner was probably the only man in the top 10 who was under 90kgs...

In a flat race (and they're nearly all flat in Ireland) the ability to hide in the bunch and then push out 800w for a few seconds to get to the front will get results.

DirkVoodoo

niceonetom wrote: »

On a 10% gradient
100kgs @300w -> 11kph
70kgs @300w -> 9kph.

Hmmm....something not quite right, or maybe I need to hit the fridge!

dario28

You are forgetting the body fat to muscle factor , where does that stand ?

Would a 80 kg person with 10% body fat smoke a 70kg 20% body fat for example

niceonetom

DirkVoodoo wrote: »

Hmmm....something not quite right, or maybe I need to hit the fridge!

Fixed now. As you were.

ROK ON

@NOT. Surely as the racing category increases the weight falls. I saw 2 stages of Ras Mumhan - there were no 90kg blokes riding it from what I saw.

Lumen

niceonetom wrote: »

In a flat race (and they're nearly all flat in Ireland) the ability to hide in the bunch and then push out 800w for a few seconds to get to the front will get results.

They're not nearly all flat, in my experience.

Of the ten A4 races I've done this year, only four have been flat.

Unfortunately some of the heavies can climb too, or at least hang on long enough not to get dropped.

mloc123

dario28 wrote: »

You are forgetting the body fat to muscle factor , where does that stand ?

Would a 80 kg person with 10% body fat smoke a 70kg 20% body fat for example

not at the same power, chances are the 10% @ 70kg will be stronger then the 20% @ 70kg and would produce more power

niceonetom

Lumen wrote: »

They're not nearly all flat, in my experience.

Of the ten A4 races I've done this year, only four have been flat.

Unfortunately some of the heavies can climb too, or at least hang on long enough not to get dropped.

I guess were differing in our use of the word "flat". Any race where the undulations are not long enough or steep enough to cause a split between the featherweights and the lardies is flat to me. So that's most of them. Stamullen would be "lumpy" but even that wasn't enough to really punish the bigger guys (as shown by the OP's placing there). I guess I don't count anything that is short or shallow enough for the heavies to hang on as a real climb. I didn't ride it but the Orwell race from Roundwood sounded like it had enough in it to count as "hilly".

ROK ON wrote: »

@NOT. Surely as the racing category increases the weight falls. I saw 2 stages of Ras Mumhan - there were no 90kg blokes riding it from what I saw.

At that level, yes, no more fatties. Those guys just don't slow down for the hills. At A3 and A4 though it's very different - it's very hard to judge a rider by looking at them.

Chips Lovell

Shaungil was pretty much the exception to the rule at Stamullen. There was a lot of us RPOBs shelled out the back on that climb.

ROK ON

I am hoping to do a little racing next year. On the basis of what I know thus far I would say the following.
As I have lost weight I have become fitter. As I have become fitter I have gotten a little faster with better recovery after intense efforts.

Thus if I lose some more weight I will get fitter thus faster. There is an optimal level here which I guess is what the OP wants.

What level of weight loss for a bloke of his size gives best bang for buck.

Lumen

niceonetom wrote: »

I guess were differing in our use of the word "flat". Any race where the undulations are not long enough or steep enough to cause a split between the featherweights and the lardies is flat to me. So that's most of them. Stamullen would be "lumpy" but even that wasn't enough to really punish the bigger guys (as shown by the OP's placing there). I guess I don't count anything that is short or shallow enough for the heavies to hang on as a real climb. I didn't ride it but the Orwell race from Roundwood sounded like it had enough in it to count as "hilly".

In the context of this discussion, my definition of flat is anywhere I wouldn't mind carrying 30kg on my bike.

Stamullen did punish some of the bigger guys, you just didn't see them fall off the back because you were at the front.

The reason Shaun didn't get dropped in Stamullen is because he's got loads of power.

I think the real question here is: for a given 100kg rider, will dropping 15kg make a difference in most races. I think the answer is a definite yes.

Beasty

The issue to me is simple in principle - how much weight can you lose before you lose a disproportionate amount of power. Without doubt you do not make up on the downslope what you lose on the climb. But if an extra 10% weight allows you to pump out an extra 10% power (which is unlikely), you do not lose anything on the hills, and gain speed on the flat and downslope

In my own case, I reckon I probably have up to 5kg of totally inefficient weight - I reckon I could lose this amount without losing much power at all - this would mean I gain nothing on the flat or downslope, but would definitely climb faster (it would mean, for the first time in nearly 35 years, that I would no longer be technically "overweight":)

Shaungil, you really do need to get your power output measured;). I reckon you could easily lose 5kg without losing much power at all. You would still be heavier than me. Once you get that far (definitely do it over time) you may find you could let go of another few kg

niceonetom

Lumen wrote: »

In the context of this discussion, my definition of flat is anywhere I wouldn't mind carrying 30kg on my bike.

So for you flat = downhill then? 30kgs with no extra power would see you instantly dropped on anything else I think. Accelerating out of a corner would be enough to open a gap that would grow.

Lumen wrote: »

Stamullen did punish some of the bigger guys, you just didn't see them fall off the back because you were at the front.

I didn't see them fall off the back of the bunch. I did see them bridge back on on the descent and undulating back of the course though (hence my "attack") so I still wouldn't see that course as really favouring a climber per se. I'm sure some were shelled for good though.

I'm not sure if there's any real point in trying to come up with a magic weight for the OP or for some notional ideal rider. It wold probably make more sense to talk about what w/kg is necessary for x minutes... and that I haven't a clue about.

So, in summary, eat less cake. And, um, do more intervals...

@ROK - I think you'd be well able to start league racing next year without any real need to go crazy on the diet or training front. You're easily fast enough I bet. It's very good environment to find your legs and get the skills before open races too.

IM0

niceonetom wrote: »

I guess were differing in our use of the word "flat". Any race where the undulations are not long enough or steep enough to cause a split between the featherweights and the lardies is flat to me. So that's most of them.

that might be the case for the lower cats, but what about the a1 a2's? you cant use the same argument for them [no fatties]. Practically ALL races here are hilly/ undulating, except those around the midlands?

It sounds like your getting your view of irish amateur racing mixed up with
the Pro Tour events, those races have distinct catagories :flat: :hilly: :mountainous:

we dont, even our 'mtn' stages in the ras are more like hilly stages.

niceonetom

me@ucd wrote: »

that might be the case for the lower cats, but what about the a1 a2's? you cant use the same argument for them [no fatties]. Practically ALL races here are hilly/ undulating, except those around the midlands?

It sounds like your getting your view of irish amateur racing mixed up with
the Pro Tour events, those races have distinct catagories :flat: :hilly: :mountainous:

we dont, even our 'mtn' stages in the ras are more like hilly stages.

I don't understand the thrust of this post at all. I'm guessing you've completely failed to grasp anything I've said up to this point. What to do, what to do...

Lumen

niceonetom wrote: »

So for you flat = downhill then? 30kgs with no extra power would see you instantly dropped on anything else I think. Accelerating out of a corner would be enough to open a gap that would grow.

You're confusing me. Which bits are you disagreeing with?

My point is that on a rolling course power/weight matters to performance, even to actual results. Even if you manage to hang on with the bunch over the climbs you have to have something in reserve for the sprint.

I can put out 800W for 20 seconds in a single fresh interval, but in Sunday's race in Wexford my final (unimpeded) sprint didn't top 500W, and I was really trying. I placed precisely nowhere.

This is because in the preceeding gallop (up a bit of a drag) I was using up some of my anerobic capacity. If I'd had more aerobic power (or less weight) I'd have gone less into the red and had more in reserve for the sprint.

Obviously having greater anaerobic capacity is also good. You want more of everything, except weight.

kennyb3

el tonto wrote: »

Shaungil was pretty much the exception to the rule at Stamullen. There was a lot of us RPOBs shelled out the back on that climb.

prob scary to think what he could do if he trimmed down and kept the power up.

niceonetom

Lumen wrote: »

You're confusing me. Which bits are you disagreeing with?

This bit:

Lumen wrote: »

In the context of this discussion, my definition of flat is anywhere I wouldn't mind carrying 30kg on my bike.

If that is a definition of "flat" then flat would have to mean entirely downhill. 30kgs with no extra power would end you on any other course, even one across a salt pan - throw in some tiny undulations and a few corners and it's over.

I guess I'm using flat to mean a course where an average 100kg rider has no significant disadvantage over an average 75kg rider. On that basis, given our results, Stamullen qualifies (though it's a stretching it a bit I suppose). Basically, most courses even out.

My more general point is that, at the level we race, outright power is a much better indicator of results than simple w/kg. Most races do not have any climbs big enough to root out the sprinters. Most races end in a bunch gallop. Most sprints are won by bigger guys.

Again, at our level.

GlennaMaddy

niceonetom wrote: »

I didn't see them fall off the back of the bunch. I did see them bridge back on on the descent and undulating back of the course though.

Stamullen was a straight descent, ideal for the heavier rider, but on other descents where brakes have to be applied the heavier riders advantage is lost completely (in otherwords no gain for the pain).

mloc123

ROK ON wrote: »

I am hoping to do a little racing next year. On the basis of what I know thus far I would say the following.
As I have lost weight I have become fitter. As I have become fitter I have gotten a little faster with better recovery after intense efforts.

Thus if I lose some more weight I will get fitter thus faster. There is an optimal level here which I guess is what the OP wants.

What level of weight loss for a bloke of his size gives best bang for buck.

You can get fitter without losing weight. The two are not linked however people do tend to lose weight as they get fitter mainly due to more cals out than in.

shaungil

I know this is a somewhat spurious argument (isn't that why boards was invented) but I was hoping you would just say that I'd win x amount of races if I lost x kg. It does not appear to be that simple unfortunately:)

Perhaps I should have equated directly to a 40km TT for example as this is more quantifiable. Racing has too many variables but the calculator does give you a good idea.

@Beasty we'll sort out the power calc in the next few weeks and then maybe test again later next year to see if it's changed (or if I've lost weight how it impacts)

I know I am somewhat sceptical re the science of cycling as there is so much to just holding a wheel when all science and your body says it's just not possible but adrenalin and stubborness disagree.

So lose weight keep power is good. Lose weight gain power is even better. Maybe hit the gym in the winter?

Bluefoam

shaungil wrote: »

So lose weight keep power is good. Lose weight gain power is even better. Maybe hit the gym in the winter?

or else just buy a new group set or some carbon handlebars.

ednwireland

i'm fat and slow
i'd never win a race

shaungil

new TT bike is being built up as we speak.

Bluefoam

shaungil wrote: »

new TT bike is being built up as we speak.

Good man, now eat some cake

Lumen

niceonetom wrote: »

My more general point is that, at the level we race, outright power is a much better indicator of results than simple w/kg. Most races do not have any climbs big enough to root out the sprinters. Most races end in a bunch gallop. Most sprints are won by bigger guys.

Most sprints are won by people with more power. They also happen to have more weight.

There is some survivor bias here.

The powerful light riders have been promoted into the higher cats.

The weak heavy riders (if any exist) do not bother turning up as they'd get dropped on the first drag.

So what's left are the heavy powerful riders and the lighter weaker riders. No contest there once it gets to a flat sprint, hence it's often the heavies that get placed and presumably promoted to the point where they are forced to step away from the chips or get dropped.

What matters is: for a given rider, what can they do to be more successful? And aside from race tactics and bike handling (which are hugely important) and training to increase power (which everyone does), dropping excess weight is a sure way to expend less energy during a race and therefore be more successful.

ROK ON

Lumen wrote: »

Most sprints are won by people with more power. They also happen to have more weight.

There is some survivor bias here.

The powerful light riders have been promoted into the higher cats.

The weak heavy riders (if any exist) do not bother turning up as they'd get dropped on the first drag.

So what's left are the heavy powerful riders and the lighter weaker riders. No contest there once it gets to a flat sprint, hence it's often the heavies that get placed and presumably promoted to the point where they are forced to step away from the chips or get dropped.

What matters is: for a given rider, what can they do to be more successful? And aside from race tactics and bike handling (which are hugely important) and training to increase power (which everyone does), dropping excess weight is a sure way to expend less energy during a race and therefore be more successful.

@lumen. IIRC Cavendish is pretty light particularly for a sprinter.

Diarmuid

It's easy. Lose weight. At the worst(*), you won't go any slower

* = within reason

shaungil

Bluefoam wrote: »

Good man, now eat some cake

Can't afford cake money going on bike.

Lumen

shaungil wrote: »

I know I am somewhat sceptical re the science of cycling as there is so much to just holding a wheel when all science and your body says it's just not possible but adrenalin and stubborness disagree.

I think the mind plays very subtle tricks. You cannot defeat biochemistry with willpower but you can convince yourself that you did.

That said, there is one race this year where my power stats were so high that I thought my power meter was miscalibrated, but my HR averaged 176bpm over the whole race (<170bpm is more normal) so they seem correct. That was the only race my kids were watching.

So the answer is clearly to forget about your weight and get some cheering fans.