- [Daniel] Welcome again to GCN. And today I've got the pleasure of being
joined by Greg Foot of the Head Squeeze Channel.
- [Greg] Hey, guys.
- Today we're going to be answering the question, what is better?
A lighter bike or a leaner body? And that's why Greg's here to make sure we get
the science 100% accurate.
- I think I'm also here because here you've got a professional athlete,
a lean body, and I'm pretty much the opposite. That's probably my role.
But yes, we do want to make sure this is an accurate and an objective test.
So, we've come in, we're going to simulate the real world environment using this
incredible treadmill we've got here at the University of Bath.
Now, what we're going to do, what this allows, it allows us to strip out
traffic, rolling resistance, wind resistance, and all these other factors.
So, yes, it isn't a real world test but it's the best we can do and it's going to
be scientific.
- Yeah. It's controlled conditions and it allows us to go up to an 8% gradient,
which is just the sort of thing that the Tour de France riders are going
to be doing this year, twice in fact, when they take on the Alpe d'Huez
two times in one stage.
- We're going to be doing two different speeds. We're going to do 8 kilometers an
hour and 16 kilometers an hour. First one's kind of average club cyclist level.
Ssecond one's kind of average professional level. Neither of which really I tick the
box, as I found out earlier when I gave it a go.
Some professional cyclists actually use treadmills to train on.
Chris Boardman was one of those during his career and Bradley Wiggins now has one in
his shed. It's like the world's greatest turbo trainer, but it does take a while to
get the hang of. We're using my old race bike and we're going to add 2.6 kilograms
to bring it up to the weight of an entry-level bike. Then, we'll compare the
results with Greg riding. As you can see, he's got muscles, unlike me, and weighs
an extra 10 kilograms.
So, the first thing we want to look at is the effect of the bike's mass.
Now, the bike itself weighs 7.6 kilograms, but we've also added in the weight of the
harness as well, taking that up to 8.2 kilograms in total. So, that plus Dan's
lean, mean fighting machine weight, takes us up to 81 kilograms dead on.
So. first of all, we're going to go for the 8% incline, but at the 8 kilometers an
hour. We're going to have a look at the power required to tackle that.
So, we've got a PowerTap power meter on his back wheel there, and that's going to
give us a signal through to this and we're going to be able to see his current power
output. And also, once he's up to speed and that power's kind of settled,
I'm going to hit lap. We're going to measure for one minute and we're going to
take the average power over that one minute. Right, Dan. One minute starts now.
- So, what power are we holding now roughly?
- We're about kind of 150-ish, probably, on average.
- I'm having to concentrate on this treadmill as much as anything.
- Oh, yeah. When I tried it, I was all over the place. It just felt like it was
going to whip away from right underneath me. So, if the professional's struggling,
you'll see back there, right in the middle of the mat.
- It's because I struggle going this slow, Greg.
- Oh right, okay. That's fast for me that. Good work, just over 15 seconds left.
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Okay, five seconds left. Three, two, one. Average lap power: 146 watts.
Okay. So, now what we're going to do is we're going to add some mass onto Dan.
So, Jonathan, if you can just load him up, that'd be great. We're going to add 2.6
kilogram of mass, it's just sand and water in a drinks bottle,
and that's going to be the equivalent of him using an entry-level bike.
We'll have a look at the difference. So, he's going to get himself balanced up.
- Right, I think I'm there.
- All right. Once minute starts now.
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So remember, what we're looking at is the effect of what makes the biggest
difference? Is it a light bike compared to a normal bike? And is it a heavy guy
compared to a normal guy? Is it worth you really spending thousands of pounds on a
top-level bike? Does it make that much difference to the power?
Or perhaps you should just cut down a little bit on calories? This will show us.
So, that's 30 seconds through. Good work.
- And you can see much difference in power in this one?
- This is greater, and at about 155. So, that's an increase of about 7 watts,
roughly. Eight seconds left. Five, four, three, two, one, stopping it there.
Average power 155. So, that's a 9 watt increase with the additional mass
of 2.6 kilograms.
- What's that? It must be about 7%, is it? Greater?
- That takes a bit of maths.
- It must be around that.
- I can't just do it. I know I'm from Head Squeeze and everything but you know,
I need to some electronics to work that one out. Right, it's time to up the speed.
- Right. Whenever you're ready.
- Okay, and go.
- A little bit harder at 16 k's now.
- I'm just, I'm starting to sweat.
- Wait until you get on.
- Yeah, I know. That's the problem.
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- And how's the power looking at this speed?
- Yeah, so much higher. You're averaging about 280, over 280 watts,
so that doubles speed and the watts have jumped massively.
- This is bringing back some nightmares of laboratory testing
that I used to have to do.
- Have you done the Alpe d'Huez hill as well?
- I have done it, yeah.
- How did it feel?
- Safer.
- Okay, man. That's you done. Done, 279 watts I got as the average there, 279 at
the doubled speed. So, now it's time to put the mass in. Last push.
He's not even broken a sweat.
- I'm ready.
- Okay, lap starts now. One minute. So, this must be a weird experience because
you've probably, when you went up that big hill in Alpe d'Huez,
you know, the eight and a bit percent, you were probably on a good bike.
- Yeah, I was on a good bike. Well, you can start to understand why riders take
their bottles out before they get to the end of races. Not because they don't need
to drink anymore, because actually, just with water in the bottles, it weighs
quite a bit.
- This just shows you the difference. You're now up at about 325 watts,
so you're right up there again. A huge jump, you know, over 40 watts.
And that's just going from, you know, a really, really good bike to an entry-level
bike.
- Yeah. It makes a huge difference and I think that's exactly what we're going to
show in this experiment, why riders spend so much time losing weight from themselves
and also from the bike.
- And kudos as well, respect. Talking whilst also keeping the balance,
pretty impressive. Five seconds left, keep pushing it. Three, two, one,
stopping there, 319 watts was the average, 319. Good effort.
So, if you just hold there for one sec and keep going maybe.
We can crunch a little numbers, maybe I can chuck out a percentage increase.
Hi, man. I've punched the numbers a bit. Really interesting, actually.
So, for the slower speed, the 8 kph, the addition of the weight,
so basically what happens when you go from a really good bike to a kind of
entry-level bike, that was a 6.2% increase in power.
- Yeah.
- All right? And then, once we increase the speed to, what was it?
- Sixteen kph, yeah.
- Sixteen kph. That was a 14% increase.
- Oh, right. So...
- So, it just shows you...
- ...6 to 14. So, the faster you go and the better you are, the more beneficial
it is to have a lighter bike.
- Exactly. That showed it really nicely.
- Perfect. Your turn, then. I'm looking forward to seeing how you get on.
- I'm really not. I'm really not.
- Right. It's time now to see the difference that's some excess
body weight makes.
- Normal body weight, not scrawny body weight.
- Right. So, without the bike, just me on my own, I was 70.2 kilograms.
With the bike and the harness, that came up to 78.4. Greg, when he got on the
scales was 80.8 kilograms. With the bike and a harness, nice round figure of 89
kilograms. So, he's going to start as well with the 8 kilometers per hour,
8%, and then we're going to try and get him up to 16 kilometers per hour at the
same gradient of 8%. But first he needs to get his balance. So, let's see how he gets
on with that. Right, it's started, 55 seconds to go. So, we've already done the
experiment, and that's the extra 2.6 kilograms on the bike. The total
difference in weight between myself and Greg is 10.6 kilograms.
Let's see what change that makes and how that leads to an 8% gradient at 8
kilometers per hour. Five, two, one. One hundred and sixty nine watts average for
the minute over 8% gradient and 8 kilometers per hour. So, one test for you
left to do. Let's double the speed up and see what difference that makes.
- Great. Woah. How do you make your legs move so fast?
- You think you're going to be able to do that for a minute? So,
we're at the start of the minute. Go. Already 6 seconds in, 52 seconds to go.
Average power already significant higher than when he was doing 8 kilometres per
hour. Same gradient, remember, it's just double the speed. The faster you're going,
the more professional you are, the bigger difference the extra weight should make.
And we're going to see exactly how much difference in just a few moments,
when Greg's finished his one-minute effort. Twenty five seconds to go now,
over halfway there.
The greater the total weight of a rider and bike, the more power is required to
ride uphill at a given speed. This was shown as my power increased when we added
weight to my bike, and Greg's power was higher than mine because he weighs more.
In our experiment, weight was not added to the rotating parts of the bike.
An increase of one kilogram in the total weight meant that, to maintain a given
speed, Greg and I's respected power-to-weight ratios increased by 0.025
watts per kilo. We can see that being lighter helps you to go further and
faster, as you will use less energy at a given speed. So, where is best to lose
weight from? We think that most people could lose a kilo or two from their
bodyweight without much trouble or any expense. For the pros, there is a UCI
lower weight limit of 6.8 kilograms for race bikes, meaning that only so much
weight can be shaved from the bike. In fact, as you'll see from our pro bike
features, most bikes for races such as the Tour de France need to have weight added
to them in order to meet this limit.
Well done, Greg. Well, that was a great effort and there's some massive
differences in the power. And the reason we've got Head Squeeze along here today
is because they're used to doing these kind of number-crunching experiments on a
day-to-day basis. You're going to need to go over there now, just click on
Greg's hot, wheezing face and you're going to get there.
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