- 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.