deep carbon wheels look cool but there's also a host of other benefits to riding them seeing
as they're one of the most popular upgrades for people to make on their road bikes i wanted to do
a video on this topic and luckily i'm friends with an engineer who also makes carbon wheels so over
to dove first question is are they faster yes yeah but why so if you think about a bike wheel pushing
through the air the first thing that's going to hit the air as you're moving forward is the
front of the tire so the wind and the airflow comes in through the front hits the front of
the tire and is split what you want to be doing is trying to keep that airflow nice and smooth
so what we would call lamina which means moving in a straight line because that's nice and slippery
nice and aerodynamic the last thing that you want is turbulence so that's when air is moving around
what you think of as dirty air because that's what creates drag so we need to take the airflow
coming in from the tire and try and recapture it so you want a nice smooth surface to allow the
air to rejoin and flow off the back of it with a shallow rim you don't have much space or time in
which to do that so you'll get the airflow coming in hits the front of the tire comes off the back
of the rim it's still turbulent on a deep rim you see the airflow comes in through the front
hits the tire runs along the rim you've got a lot more time to recapture the air so this allows the
airflow to come together get nice and laminar rejoin at the back of the rim flows off the back
nice and smooth it's not so turbulent reduces drag okay but how fast do i actually need to ride
to benefit from them i think that's the million dollar question and it's there is a
little bit of a myth out there that says there is this magic number that you have to achieve
before an aero wheel really makes sense for you and i suppose the genesis of that is
the stat that people throw around that at 15 kilometers an hour or about nine miles an hour
that's the point at which half of the force that you're trying to overcome is aerodrag if you look
above that what's really important to remember is that of that force you're trying to overcome
things like rolling resistance so the friction between the tire and the ground that's linear so
by that i mean if you double your speed you double your rolling resistance aerodrag is not like that
that's actually a cubic relationship so if you double your speed you actually increase
the aero drag that you're trying to overcome by a factor of eight so above 15 kilometers an hour
it becomes almost exponentially more important to be reducing your drag
but then at the same time you've also got to remember that if you're talking about racing
over a fixed distance because let's face it most of us are thinking about this in a race context
or an event context you're trying to cover a fixed distance now if you're doing that at 15 kilometers
an hour you're going to be out there for a lot longer than somebody who's out there riding at
30 kilometers an hour and even though you might not be benefiting so much you're benefiting for
longer there is an argument and having run the numbers we can say this that if you're riding at
what we would think of as an average bike speed so say between 10 to 50 kilometers an hour
you can say that no matter what speed you're riding within that range
you're roughly speaking going to be saving the same amount of time over a fixed distance
so actually i would argue that it doesn't matter what speed you're riding at
you're still going to save time okay well how much would it actually save me in terms of power
and time so if you take a the most extreme comparison where we take a standard alloy rim
versus our deepest section wheel so this is actually a a new prototype that we're working on
going to sit in the lineup as a tt triathlon wheel the actual difference between these two
we've tested that and it's just under 16 watts and at 16 watts riding at 30 miles an hour but
if we flip that into time savings which is more broadly speaking the same regardless of your speed
you'd be saving 49 to 50 seconds so just under a minute over a 40 kilometer ride if you go for
a slightly shallower wheel the time savings will be slightly less but again it's worth remembering
that it's not just the case of a wheel half the depth saves you half the amount of time there is
a bit more nuance to it than that but we've got stats and data for every wheel in our particular
lineup on the website and we try to present it in a number of different ways both in terms of what
savings but also time savings because i think ultimately that's what people are interested in
and obviously it's worth remembering that that's numbers just for a single wheel um we're talking
about front wheels here so clearly you're most likely to be upgrading both front and rear wheels
it's not always as simple as your time savings for front and rear is one plus one equals two
uh your rear wheel is going to be in a slightly different air flow state and what i mean by that
is by the time the air hits the rear wheel it will have already come over the front wheel
your rider's legs the frame so it's going to be in a different state so when we're testing
for time savings for watt savings we have to consider that in terms of what type of
air conditions you're having at the rear broadly speaking if you're talking about saving in this
case 49 seconds over 40 kilometers for the front wheel if you add in a similar rear wheel then
you're probably talking about going from about a minute to 30 in terms of your overall savings so
over 40 kilometers that's not insignificant flipping around of course if you were going
to ride an alloy wheel set over the same 40 kilometers in order to ride at the same speed
you would have to be outputting 25 to 30 watts more that's a lot of watts imagine trying to
add that to your ftp yeah what about the extra weight compared to a shallow wheel because this
it's a big piece of carbon well it's a piece of carbon but that's the first thing to remember
so if you're thinking about upgrading from an alloy wheel set like i'm holding here to a deep
section carbon wheel actually carbon is a much lighter material so even though there's more of it
it won't necessarily weigh a whole lot more the difference in weight between these two wheels it's
less than 50 grams now obviously if we're talking about upgrading from a shallow carbon wheel to a
deeper carbon wheel then yes there's going to be a bigger weight difference you know up to something
like 200 grams as possible what you've really got to think about is what are you saving from a lower
weight versus what are you giving up in terms of the aerodynamics and it's important to remember
that think about the break point where it's worth being lighter versus being more aero for a trained
cyclist so call it a 300 watt ftp you're talking about a gradient of something like an outdoors
climb before weight becomes more important than aerodynamics whereas for us mere mortals
so if we call it an ftp around 200 the gradient goes down to more like a box hill type gradient
so still a not insignificant climb and of course you've got to remember that that's only for the
uphill section as much as you're saving a little bit on the uphill you're giving away huge amounts
on the downhill and even the flat the trade-off might make sense for a hill climb but in the vast
majority of situations aerodynamics is going to win out all right one last question is it really
worth it i mean i'm going to say it depends right um it depends entirely what you're looking to get
out of your riding so if you're racing then yes a hundred percent it's worth it if you're bike
packing and touring it's up to you it depends if you want to get there a little bit quicker or be
able to enjoy riding a little bit faster there are obviously other ways that you can get faster
that may be a little bit cheaper from where we're sitting in terms of an upgrade to your bike i
would argue that a performance wheel set is going to be one of the biggest changes that you can make
in terms of getting faster so i think it's fair to say like with a lot of tech in cycling
it all depends on what your goals are do you want to go faster in which case
yes generally speaking a set of deep wheels is going to make you faster compared to the
shallow equivalent bear in mind though there's some cheaper ways you can get faster on the bike
that you might want to look at first for example aero over socks there might be 20 or 30 pounds
skin suit makes a massive difference compared to a normal jersey and shorts even the tight-fitting
ones taping up vents in your helmet or wearing an aero helmet also goes a long way combining all of
these things together with deep wheels as well is really going to make a massive difference it
can be 60 70 watts if you're riding at race pace don't forget you can even do
things that don't cost anything at all like riding in an arrow position getting narrower
on the bike getting your head down and training in that position so you can still do the same power
all of these things add up to making you a faster rider big thanks to dog from parkours
for being involved in this video if you want to check out his website i'll put it in the link
down below he sponsors this channel i ride his brilliant wheels we've been friends for a long
time if you have any questions for him please put them in the comment section down below and
if you have any big questions that might be more appropriate for a video we'll be filming
some more stuff in the future so stay tuned for that thank you for watching and see you guys soon