GCN’s DIY Aero Road Bike – It’s Free, But Is It Faster?

GCN’s DIY Aero Road Bike – It’s Free, But Is It Faster?


– We can all get aero for free. I mean dropping your head,
tucking in your elbows, minimising your frontal area. It means you can actually go
faster for the same power. But taking it to the next
level involves spending money. – Yeah and the trouble is aero equipment can tend to be quite expensive, so it can take a lot of money. However, the question is
can we do it for free? – Can we modify a bike to
make it more aerodynamic? – How much faster will it go? (calm music) – So here we are and
the plan is to transform Si’s commuter bike into a
super-duper aero-machine so that he can shave five
minutes off his commute and sleep in a bit longer. So here we are, we have
this beautiful Orbea. Stefano, talk us through what you think is the best option for
speeding up the bike. – Well, as a first idea, let’s
try to close all the frame, to avoid any gaps between tubes and so on, to avoid air passing on the frame. So, all the air outside the frame. – So keep the air outside the frame. So every gap is slowing
you down basically. – Yeah, we try this way. So a fairing covering all the frame. – One big fairing, that’s
the way we’re going. (calm music) – [Emma Voiceover] So what
does our experiment involve? Well, we’re going to try to
use cardboard and duct tape to try to improve the
aerodynamics of the bike. Since we can’t reduce
the frontal surface area, after all, we’re not going to
chop anything off this bike, the way to minimise drag is
to make the shape of the frame such that turbulence in a work is reduced. How? Reduce air disturbance by
encouraging more skin friction. Air disturbance creates turbulence and covering gaps in the frame will reduce this air
disturbance, in theory at least. – And red is actually faster
they’ve shown, haven’t they? I mean someone has
shown everything really. Here Si is cutting out
a gap for the front mech because it’s always handy if a bike works as well as being super aero. – [Emma Voiceover] This also includes filling in the gaps behind wheels, and frame, and seatpost, making cardboard fairings basically. (calm music) – That’s actually pretty
good frictionwise. That could be a ceramic
bottom bucket for all I know. Smooth out those wrinkles. Oh, the size on the case. – That’s good, yeah, look at that. – That is looking sleek. – Okay, Emma, do you
wanna do the honours and– – I’ll do one side. – christen our bike. – Wow! Now we’re going fast. So, shall I get suited up then? And we’ll give this a run
before we tackle the wheels. Let’s do it. – Yeah, let’s do that. ♪ You got me down again ♪ (energetic music) – And we’ve reached 40
kilometres an hour, wind speed. So here, on this screen
in the control room we can see, top number on the right is cadence in rotations per minute. The next number down is the wind speed in kilometres per hour, 40 in this case. And the third number down is
the drag force in newtons. And that is literally the
backwards force on Si, thanks to his aerodynamic resistance. And when it’s green that
means that it is lower, as in better, less drag
than on the previous run which was the controlled situation of Si without the fairing. If it’s red, it means it’s
higher than the last run. Now obviously you can see it’s varying between red and green here. That’s because we gonna run this test for at least two minutes
and take the average from those two minutes to see
what the real comparison is. – Well, I’m not gonna lie Emma, that was a pleasure to ride actually. There were a few moments earlier on where I was frankly petrified
that bits were gonna fly off. – We were worried too, but
we didn’t want to tell you. – Terrible paper cuts, and then ruin the priceless wind tunnel. But once I got over this fact that the duct tape was
holding, I just enjoyed it. – And how was the
handling, did it feel good? – Well, I’m glad we didn’t
investigate your angles, let’s put it that way.
(Emma laughing) The results of that first run
were not terribly positive. I’m not gonna lie. So, we’re bringing out the big guns. We’re making a disc wheel. But we’re making it for the front wheel, which may not do much for
the handling of this bike but we’re hoping it’s
gonna ace the wind tunnel. (upbeat music) – [Emma Voiceover] A
disc wheel is, of course, not usually made of cardboard. But the principle I the same as filling in the gaps on
the frame: reduce turbulence. We just have to hope it stays together whilst rotating once the wind gets going. Because it might be a bit hazardous if it detaches and blows away at speed. Please be assured that
we’ve all been trained in the safe use of both
scissors and screwdrivers to chop up cardboard. – Safety first. Gotta put a rotor back on. – [Emma Voiceover] There is a slight problem here, of course. Even if this monster is more
aerodynamic into a headwind, when you turn it so the
wind hits it at an angle, known as a yaw angle, it would
not necessarily be faster. That’s why frame and wheel companies test their equipment at
various different yaw angles. Because in real life,
there’s often a crosswind. There’s also the question
of whether a bike like this, with a front disc wheel
would be rideable at all in any kind of crosswind. – It’s not often I get
nervous on an indoor trainer. A mighty relief to have
got through that run with a homemade front disc wheel, which incidentally we do not
recommend that you try at home. But the good news, at least I think, is that I saw a lot of green
on the real time screen which I think means that we
may have become more aero. I just don’t know what went wrong. I mean, we invested so much
time, effort, duct tape. We’ve converted a beautiful Orbea Terra into what is effectively
an unrideable monster and we haven’t saved any watts. What’s gone wrong, Stefano? What have we done wrong? – It’s hard to reply. Maybe cardboard is not the
best to make an aero bike. – Okay. I take your point. – [Stefano] You should have
a more aerodynamic rider. (Si laughing) – Well there was that. I could have maybe bent my elbows and we’d have saved 20 watts. But, all jokes aside, it’s
obviously very difficult and time consuming and
incredibly expensive to make an aerodynamic bike. But, would we expect to
save that many watts anyway if we had managed to do something? – [Stefano] The research is going on so we can save some watts. We should find out how. – You said that I could be more aero, we could have a more aerodynamic rider. What can I do to save watts? – Okay, you have to
reduce your frontal area. So, try to be as small
as possible on your bike. So, head down, narrow your elbow, as narrow as possible. And to reduce your frontal
area, this is the best. – Okay, so drop head, pull
shoulders in, elbows in, and I can save, how
many watts could I save, do you think, at 40km/h? – [Stefano] Difficult to say but also up to 10% drag reduction– – [Si] 10%. – [Stefano] Yeah. – Okay, maybe we’ll do that
next time instead of duct tape. Well, I think it’s fair to say
we have failed spectacularly to make any kind of
modifications whatsoever to that lovely Orbea Terra other than to effectively make it
completely unrideable. – I guess it just goes
to show that aerodynamics is quite a complicated subject and making a bike fast is
really quite difficult. You can see why a lot of bike companies and teams spend a lot of money
trying to make it happen. – Right, now we have to give a huge thanks to Politecnico Milano for having us, allowing us to use their wind tunnel. And also providing us
with so much expertise even if ultimately it was
quite a futile effort. But, they were absolutely brilliant. – They were also very, very
good at sticking cardboard down. – Yeah, they were. Multi-talented guys. Right. And all that’s left to be said now is please give this video
a big thumbs up as well if you’ve enjoyed it. And if you wanna watch another video from right here in the wind tunnel, not quite so left field perhaps, we tested to see which is the fastest way of carrying luggage on a bike. – Check it out.