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Benefits of cycling

Dr Pooley’s Aero Bike Fit | How To Find Your Time Trial Position


– We often talk about
aero gains as free watts. Although, that’s not quite
true, because actually, you’re just going faster
for the same power rather than gaining more power. But anyway, a lot of people,
if they can afford it, will buy a time trial specific bike for time trials or triathlon even, assuming that it will be
faster, which it could be. But actually, it’s not
just about the bike, it’s more about your body position. You can get a really good
aero time trial position on your regular road bike with
a time trial handlebar. In this case, we’ve got the
Control Tech Time Zone Aero Bar. The reason for that, is they
asked us to use it in a video. In this instance, its range
and ease of adjustability makes it ideal for us to
demonstrate a time trial bike fit. For this video, I needed a
volunteer, because it’s a bit too complicated for me to both
talk and demo at the same time. So, I need, well, a
model cyclist (snapping). Simon, thanks for volunteering. – That’s all right. Not often I’m called a model cyclist. In fact, it’s far nicer than anything Lordy’s ever said about
me, so I’ll take it. – Well, anyway, I’m sorry
this is gonna be so boring for you, ’cause presumably
you’ve had hundreds of time trial bike set ups and
done loads of time trails. – You say that, Emma. I have never, in all my years
of racing bikes, had a time trial bike fit, so this is gonna
be very interesting indeed. – But, you have done time trials, though. You didn’t get through a
whole pro cycling career without doing a time trial, surely. – Yeah, no, I did five.
– Five? – I did five of them, yeah. Two of them were on a
proper time trial bike, but never one that had
ever been fitted to me. – Wow, this is incredible. It would have been even more
fun, to be honest with you– – Tell a lie, it’s seven. I’ve just remembered two more.
– Seven. Still, you can count on two hands the number of time trials you’ve done. Not a total beginner,
so it won’t be quite– – Eight, sorry. I’ve just remembered another one, Tour of King High Lake Pro Log. Sorry, anyway, that’s it now. I promise. – That’s still not very many. Although, like I say, it
would have been even more fun if you were a total
beginner, because I wanted revenge for the cyclocross
semi humiliation. But, you know. (bleep) Ugh. – It would hurt an awful
lot more falling off a time trial bike than a
cyclocross bike, I think, Emma. It’s certainly not quite (mumbles). – No, okay, but anyway. I think this is gonna
be super interesting. Maybe we could even shave a
few times off your local KOMs if there was anything you were chasing. – I’d be up for it. And yes, as it happens,
I am indeed chasing it. (upbeat music) – Now, I know you’re raring to hop on the bike and get training, Si. But, before you do, let’s
just ask the fundamental question of, what is the
point of a time trial bike? – Okay. It’s a bike that’s gonna be
faster than my road bike. – Yes. Riding on your own, specifically. There’s a few key things. I think there’s three key points about a time trial bike to consider. One is body position, one is the bike frame and one is the handlebars. – Okay.
– Right. – I don’t wanna seem ungrateful, Emma, but this is very clearly your bike and there’s a bit of height
difference between the two of us. It just looks a little bit small. – Yes and I grant you, it may
be a little on the small side, but the thing is, with a time trial bike, you are much better off
going for a slightly smaller frame than a frame that’s too big, because you have more degrees of movement. The key thing about time trial position is to get low at the front. If the bike’s too high at the
front, and I’ll be honest, for me, for time trial, this
frame, even though it’s the smallest frame I could
get, would be too high at the front for me to
get a low aero position. Whereas for you, it
might be a bit too low, but we can always go higher
by putting a longer stem, or a stem that slopes up. – Okay. – You have more degrees of movement and we can definitely
get you low and aero. – Sweet. (upbeat music) – Let’s start then with body position, which, as I said, is the
most important factor. This is where you will save the most drag. The most important thing is
to reduce your frontal area. Frontal area is your area
as seen from the front on. Fairly straight forward, really. – Yeah.
– So, you need to get low. – Okay. So, when we’re talking about fit then, is it gonna be this position here where I’m gonna be spending most of my time? This is the one we wanna get dialed? – Exactly, yeah. On the aero skis is the position
you want to work for you. You’re only really gonna
be on the break hoods when you’re breaking or
accelerating out of corners. And at that point, you’re
generally moving a lot slower, or trying to slow down, if you’re braking, so you don’t need to be so aero. Now, there are some
time trial courses where that might be different, but generally, that’s where you’re gonna
be when you’re going fast. This is the position we want to work on. – All right. – The most important thing,
like I said, body position. The most important part of your body position is your head position. It is very hard to tell for sure what’s fastest without a wind-tunnel test. But, without a wind-tunnel
test there is a rule of thumb and that is to try and get your head in line with your back and your bum. So, first of all, get your
back in line with your bum and then, get your head in line with that. Lovely. You want a flat line from
head to shoulders to bum. We’re almost there. You could actually go a
little bit lower at the front. – Could I? I’ve got a space under here? – You do have spaces, yeah, fantastic. The point of getting low at the front is just to reduce your frontal area. That’s not the only factor
in the drag of your body. There’s also the coefficient of drag. – [Simon] What actually is
your coefficient of drag, then? – The coefficient of drag is just a coefficient in the drag equation. It doesn’t any units as such. It’s hard to, it’s not a physical thing, but the way you can think about it is about the smoothness of a shape. Often, when we measure
drag, we measure CDA. That’s what we talk about. That has units of area. But, CD is the coefficient
of drag and A is your area. We measure them together. But, if you want to think
about separating them out, your front area, it’s
fairly clear what that is. CD, well, it’s about how
smooth the shape of you is. The more like a teardrop
shape you are, the better. Also, the smoother your
surfaces are, the better. That’s why we get super high-tech, funky, time trial skin suits at
the Olympics that people invest a lot of money into
making them slightly lower drag. That’s why your position is about more than just your frontal area. Sometimes people find that
they can get lower at the front and get a smaller frontal
area, but they’re not actually quicker in wind-tunnel
tests or on the road, because it might have changed their shape, such that their coefficient
of drag has actually gone up. – Okay, so actually,
you’ve got the hole that you’re punching through,
the wind, but actually a lot of your drag,
correct me if I’m wrong, is created from the
turbulence at the back? – Exactly, yeah. – Your coefficient of
drag is almost thinking about everything that
happens past here backwards. And that could be your skin suit, whether that’s causing micro-turbulence. It could be my bum, which causes massive amounts of turbulence. – [Emma] I doubt it causes, I think it’s gonna be a very tiny amount of turbulence. – [Simon] You’re too kind. – The second thing that
we think about with a time trial bike is often
having a time trial frame. You can tell what an aero
frame is by the way it looks. It does save a few watts, but actually, it’s not that much compared
to your body position. So, we’re gonna leave that for the moment. We do have an Orbea Orca Aero, but I think that’s gonna be far less important to you in your time trial gains
than your head position. Lastly, handlebars. We often think about the handlebars as being a way to get low in a time trial. That is, of course,
important, but the other thing about the aero bars is
not to get narrow and low, it’s also the fact that
it’s more comfortable for long periods pushing at a high wattage than holding yourself on
the drops, for most people, because you can essentially
use fewer of your arm muscles, which leaves you with more
energy for your leg muscles. (upbeat music) Now we know what we’re looking for. Let’s get stuck into the nitty gritty details of sorting out an aero position. First up is to get slammed,
get low at the front, because that’s the first
thing we’re gonna look for. That’s all about elbow
height, because your elbow height defines your shoulder height, defines your back height,
defines your head height. That looks actually pretty good. – Yeah? – Doesn’t look super comfortable, but it doesn’t have to be at this stage. Did it feel like you could pedal? – It did. It felt like I could pedal. My puny, little shoulders were starting to hurt a little bit. – Really?
– Yeah. They’re that weak. And I feel like I’m a little bit crammed. – Yes, so you’d like a bit
more space at the front? – I could go lower and
I think I could hold onto something other
than my gear shifters. (upbeat music) Whilst we’re adjusting
the height of the bars and the reach on the skis,
what about the angle? ‘Cause that changes obviously,
soon as you loosen the bolts. – Good point. These bars have a huge amount of adjustability, which is great. Angle of the skis is
mostly really about comfort and how you feel like
you can put power down. Some people find that changing
the angle will help them to move their shoulder
position and get more air into their lungs, give them more
space to breathe, basically. But, generally most people
go roughly horizontal. And it won’t really
change your frontal area and it probably won’t
change your drag that much. Changing your elbow position
outwards, so the width of your elbows, that can
make a bit of difference. We’ve got three bolt holes here. We could have actually gone quite a lot narrower with your elbows. However, there’s normally not
much point going a huge amount narrower than your hips,
because if you think about your shape from front on, if your
elbow’s in line with your hips, then that’s one shape for
the air to flow around. But again, that’s the
kind of detail that’s really hard to measure
without a wind tunnel. What your elbow really does affect is your stability and cross winds. I’ve found, we’ve found that
I was actually slightly more aero with my elbows really
close together in a wind tunnel. But, I couldn’t ride it on the
road, because the slightest gust of a cross wind and I
felt like I was gonna fall off. In fact, I probably almost did once. So, I start with slightly wider
elbows just because I could be safer and put the power
down without getting scared. There we go, we’ve taken out
this one-centimeter shim, which has got you slightly
lower at the front. We’ve also moved the aero skis forward, which gives you a bit more space in the chest region where you’re pedaling. How does it feel? To me, it looks really good. Your back’s really flat. I think if you wanted to keep
your head lower you could. Doesn’t feel great on the neck, I admit. But, just for first
impressions, how does it feel? – Good. It actually feels remarkably comfortable. A bit like you kind of
adopt that position on your road bike where you’re
balancing on the bars. It’s just, you’ve got
so much control and you actually feel quite secure
and you can really lean on it. – If you did want to go
further forward we have another stem, but if you
feel okay, we’ll probably leave that with the shorter
stem for the moment. – Yeah. I find it slightly weird that I’m riding a 47 with a 90-millimeter-long stem. – And you look pretty good. – And I feel remarkably comfortable. – One thing that’s worth noting
here, while we’re talking about elbow height, when
we’ve got you pretty low and I think you look pretty good from
a frontal-area perspective. We’re also thinking about
elbow position for aft. I always used to time trial with my upper arms roughly vertical. If I went any further
forward, which in some cases was more aero when we did wind
tunnel testing, I felt very unstable, because my arms were
quite extended then and it felt like I was gonna get
blown around in the cross wind. I would come to head position,
which is absolutely crucial. Of body position, head position
is the most important thing. How low you can keep you head is crucial. That’s to do with how long your neck is and how flexible, how big
your eyebrows are (chuckling). – Yes, I did notice actually
that I can’t really see, because my eyebrows
are getting in the way. – Yes, and being able to see
is really, really important. I can’t stress this enough, it’s one thing on a turbo, but safety is absolutely the most important thing out on the road. For most races the roads are not closes. You need to be able to
see where you’re going. No aero gain is as important
as making sure you’re safe. – Yes, yeah, no, I consider science to be of paramount importance when I’m cycling. – There’s a way of getting
the head low and being able to see where you’re going using
a sort of S-bend in your neck. It’s extremely uncomfortable.
– Yeah, it is. – Yeah, it’s horrible. You only need to look up just
enough to be able to see. I would find at the end of
a really hard time trial my eyeballs would hurt, because I’d be looking up so hard through my eyebrows. This sounds fun, doesn’t it?
– Yeah. I suppose I’ll have a
visor on my aero helmet, so the fact that my
forehead’s gone all crinkly doesn’t matter, ’cause
that’s actually not causing– – These wrinkles have not
come from nowhere (laughing). – Uh, right, okay. – Do you want to try
it with an aero helmet? – Yes, please.
– Perfect. (upbeat music) I know I keep going on and
on about head position, but really it is the single most important factor in your aero position. I know, because I’ve seen the
numbers in the wind tunnel. Just a centimeter can
make a huge difference in your drag compared to everything else. Now that Simon’s got the
aero helmet on we can see another point, which is
that if he even looks down, for example, the point
of the helmet sticks up. That is not optimal. Whereas, if he looks
up through his eyebrows in his carefully-trained position, that keeps the point of the helmet down. The tail of the aero helmet
effectively smooths the gap between his head and his back
and that’s what we want to do. That’s the point of the aero helmet. There’s no point in wearing an aero helmet if you don’t keep the tip low at the back. That’s something that you
should also go out and train. It’s not particularly comfortable. It’s not particularly fun. Nobody really likes wearing an aero helmet in training, but it is really important. I used to go out, for
example, with a magnet stuck under my jersey there and a 10-piece stuck in the tail of my aero helmet. I’d have to clip them together
and ride around like that. – Are you serious?
– Yep. It wasn’t very fun. – I’m starting to think time
trialing isn’t very fun. My eyeballs are hurting.
– Sorry. – I thought there’d be
different ones hurting, but no, it’s my eyeballs. (loudly laughing) – Now, have you noticed, Si, that because you’re on my bicycle you have 165 cranks? – I have, I have noticed. Not because of the way
they feel necessarily, because I haven’t pressed
on the pedals yet, but because with 165-mill
cranks, you’ve got quite a lot of extra crank at the end that
you’re not actually using. Haven’t you? – So I have. I hadn’t realized. I haven’t ridden longer
cranks for quite a long time. Now, this is a bit of a bodge
because you’re on my bike, but a lot of people do
actually find that it’s worth trying out a shorter crank
for time trials, because it keeps your knee lower at the
top of your pedal stroke. – [Simon] If at six-foot-one,
say 185 centimeters, I’d be considering 165s, what
would you consider then, 155s? – I’ve tried 155s. They didn’t go so well for me, actually. I don’t think I ever quite
got the coordination. But, I know lots of riders
taller than me who’ve gone for 155s and riders my
height who’ve gone for 150s. I think you could go longer, actually. Funnily enough, my first ever
World Championships time trial my team, who were fantastic,
they put my time trial bike together for the World
Championships and they put a longer crank on it, saying to me,
we’ve put a 175 crank on your bike, Emma, so that you get
more power for the time trial. I was totally confused,
because I thought, well, one, I’m pretty sure longer cranks
don’t give you more power, they give you more torque,
it’s not the same thing. And secondly, if they give you more power, why wouldn’t you use
them in a road race, too? Because, you want power
also in a road race. Anyway, it’s a myth that
longer cranks have more power. They have more torque. But, I think, for time
trialing the key thing is being able to hold the
position and pedal well. If you need a shorter crank,
don’t be scared to try one. (upbeat music) While we’re down in the
bottom-bracket region, let’s talk about Q factor, Simon. Not always discussed in bike fits, but it can make a significant difference for aero gains, because basically Q factor is about how far apart your feet are. When you think about frontal
area, that can make quite a big difference, especially as
your feet are spinning around, because they’re actually
creating even more turbulence. You can reduce your Q
factor by using cranks that have a smaller Q factor, that
are closer to the bike frame, by using pedals with a shorter spindle. – [Simon] You can move
your cleats in, I guess. – Exactly, yeah, you can
also move your cleats in. That is the simplest way of doing it. However, you don’t want
to end up with your shoe rubbing on the crank,
because that is generally a poor way to transfer power to the bike. – There’s also, presumably,
a (mumbles) on your actual bike fit from a comfort
perspective, because Q factor has a real bearing on knee
pain because of your IT Band. – Huge, yeah, exactly. A lot of people go as aero as they can in terms of narrowness Q factor and then find that they get knee pain, hip pain. You have to be very
careful with these things. Tiny adjustments around pedals and cleats can make quite a bit
difference to how you feel. – You could basically, for one big event, massively reduce your Q factor and then not walk for a couple
of months afterwards. – You could do. I wouldn’t take that risk, personally. I think you’re health’s
more important (chuckling). Well, I think you’re looking
pretty darn good there, Si. How does it feel? – Well, I’m quite positive
about how much power it feels like I could
put out on this position. So, that’s good. But I’m not gonna lie, even
in this short period of time, my shoulders are giving me a bit of jip. My eyeballs are definitely
giving me a bit of jip. Probably my neck as well. So, I think I’d need to
spend quite a bit of time in this position, actually
just getting used to it. Whatever. Thank you very much for
taking me through your bike. To be fair, I am genuinely quite motivated to do some time trialing. Partly, because you’ve
filled me with confidence, you said my position looks
all right, and partly because I’m still relatively competitive
and it seems like another– – I think you would absolutely nail it. I really want to see you do a time trial just so you can smash everyone. I think this is a GCN video in the making. – Well, there we go. Watch this space whilst
I train desperately. – Also, you could take a good 10 minutes off your commute, I reckon. – Well, that’s even more
appealing, isn’t it? – More time in bed.
– Nice. And, wouldn’t I look darn cool, as well, on a low-pro bike going to work? – So cool.
– Yeah, right. Well, thank you very much, Emma. Please use a big thumbs up. That’s some serious insight there. And also, if you are gonna
want to do some of those core exercises, Emma,
you took us through that. – Yep. – We have a video on that very subject.

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