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Your body is the biggest source of aerodynamic drag on the bike. Join us as we use cutting-edge real-world aero testing technology to measure the difference between riding on the hoods, in the drops, and in an aggressive breakaway position.
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00:07as cyclists we spend an absolute tonne of time and money trying to go faster on the bike i'm
00:14talking about deep carbon wheels wax chains oversized pulley wheel systems and every new
00:20bike that claims to be the fastest in the world but what if the biggest difference that you can
00:25make to your speed is your body position i'm not even talking about changing the width of your
00:30handlebars or slamming your stem i'm talking about just how you hold the bars well today with the help
00:36of some aero experts and some fancy new cda measuring tech we're going to try and find out
00:41this is cycling weekly let's go do some aero testing
00:59right so for today's testing i'm joined by manuel the founder of aeroscale so manuel just how important
01:07are aerodynamics to begin with i mean it's about 85 percent of your uh poor lost on the flat road
01:15it's about aerodynamics so it's about everything on the flat road so everything the wheels the bike
01:22the handlebar 15 percent and people spend a fortune on that stuff we've done outside testing before
01:28we've used uh the chung method and we've done many many laps to try and get some accurate results but
01:34today we've got the help of of this device so can you explain this to us yeah so actually we
01:39used
01:39also a lot of chung method and we decided that it was very frustrating to have to wait a lot
01:46of run
01:46and the repeatability was not correct so we really wanted to have something simpler and more accurate
01:52so for that we needed to switch to another level of uh sensor so to implement uh very accurate testing
02:00with a very uh few seconds so we speak about seven seconds so we leverage a gps rtk so it's
02:07a gps
02:08capable of positioning you with centimeter level of accuracy okay and this is what it's showing on
02:13the screen right now so this is exactly the elevation and if i just go like that then we can
02:19see the
02:19graph go up look at that it's only 10 centimeters or 15 centimeters but the graph uh it's got a
02:26little
02:26wave in it now exactly so actually the basic principle is that we collect the poor from your
02:32pedal and we need to subtract everything that does not relate at all to aerodynamics so we speak about
02:39energy to accelerate or energy to uh to overcome a short climb even few centimeters is really important
02:47yeah so if we want to cancel that energy which is not a wasted energy which is not linked to
02:52aerodynamics
02:52we need very precise sensor we need gps rtk and a very precise speed sensor so once we have this
03:00uh
03:00what we call the wasted watt we're able to infer what is your aerodynamic drag in real time so today
03:06what i want to do is i want to test three positions ideally i want to test a upright in
03:11the hoods like
03:12i'm out on a sunday cafe ride i want to test in the drops because well i sometimes sprint in
03:19the drops
03:19and then i want to test i don't know what we're calling this people seem to be agreeing that this
03:24is a a breakaway position or whatever you want to call it with sort of a right angle in your
03:30elbow
03:30you want to minimize your uh your arms aerodynamic drive and with those three positions what sort of
03:36accuracy are we going to be able to get today actually the system is designed to be two percent
03:41accurate with seven second timing window okay and less than one percent 0.5 percent on 60 seconds but what
03:48you
03:48will see is maybe a little bit more viability because you will be the most uh source of degradation
03:55of the because it's impossible to have a perfect stable position on different trails so most probably
04:02we'll have one two percent difference between the baseline yeah and one other question i wanted to ask
04:09is a wind tunnel still the gold standard of aero testing or is there a place for both the two
04:14have
04:15their place but now this kind of device gets more and more important in the bike industry because
04:21wind tunnel is a special environment closed environment it's a lab and now people what they
04:27want is to prove outdoor in real race condition that their uh equipment is is getting faster yeah so we
04:34need we want to prove that it's fast outside not just in theory exactly cool right let's get into it
04:40you may have seen aero testing before but because wind tunnel time is very expensive it's often only
04:46pro teams that can justify it and therefore most aero testing inevitably ends up being done at pro
04:52level speeds aero does matter for us amateurs as well though and so for this testing we decided to
04:58use a more amateur friendly speed of 30 kilometers per hour the plan was to complete one lap in each
05:04of
05:04the body positions which was more than enough time to capture the recommended 60 seconds of data at our
05:10target speed i had just one job hold the position and don't break not whilst the devices were working
05:16out how many watts were propelling me forwards i did then want to repeat a few runs just to double
05:21check
05:21the reliability of our results some of which are rather surprising right well i've completed my uh my
05:28laps and uh we've got some results so i've got run minus five so this was my first one right
05:34and so i did this
05:36in the upright hoods position and according to this i had a cda of 0.318 is is is that
05:42good i mean
05:46that's a no i did do another run in the same position so the same upright hoods position i wanted
05:54to see how repeatable our testing was today and i had a fairly similar cda of 0.313 but then
06:02things get
06:02interesting as i changed position so i then went into the drops and i was expecting a much bigger
06:09difference uh my cda only dropped to 0.308 now this is something very usual i mean the difference
06:18between this one and this one it's not that much so because when you do on the drops actually you
06:25increase your frontal area with your uh with your arm so actually it's not really improving that much
06:31i was expecting a much bigger difference there and i'm someone who doesn't ride in the drops very
06:37much and i always thought i probably should ride in the drops more even if it's a sprinting position
06:43people always think maybe it's fast but actually not this one is not that different maybe the position
06:50i really need to be focusing on is this breakaway position the one with my my elbows at 90 degrees
06:56because on this run my cda dropped to 0.262 so significantly less how much difference is that
07:04going to make out in the real world yeah that's the problem of cda so this is why we uh
07:10cda is good
07:12metric but it's always we need to do some math to extrapolate cda doesn't mean as much to me as
07:18it
07:18probably does to you so if we go to the next screen then we can see the the wasted watts
07:23yeah and here we
07:25can see that when i was in the upright hoods position uh my number was 128 watts yeah 128 wasted
07:35watts
07:35because so can you just explain to us wasted watts are the watts you would be wasting at exactly 30
07:41kilometers per hour so it's an extrapolation and it's a good metric because yeah you can say that okay
07:48if i would be on a very uh still calm day riding at 30 kilometers per hour you would be
07:54losing uh 128 watts
07:57that's worth mentioning that we tested at 30 kilometers an hour air speed yeah not ground speed
08:02and then uh yeah on this on the second run same position 127 so just one watt difference yeah pretty
08:10similar so with one back one watt difference between two baseline we're super happy one watt is like the
08:16golden metric there's less than one watt difference between two baseline we're super happy and then
08:21when i went on to the drops 125 watts so only two maybe three watts difference yeah that's not a
08:29lot at
08:29all no no no the problem is that when you're on the drops you increase the frontal area yeah so
08:35actually you are lower on the bike but more frontal area so at the end no much gain and is
08:41this why
08:41we're seeing a lot of pro riders they're no longer actually slamming their stems and going for as low
08:48as possible i mean the lower is better in terms of aero was a myth of 10 years ago now
08:55it's we see
08:56completely different number when we look at the reality we see that uh it's not always lower that is
09:02the best and and sometimes it's it's better to be a little bit higher comfortable for the the most of
09:09the
09:09ride and and then being able to grab a very aggressive position uh when it's in the critical
09:15phase of the race this is a good one in the breakaway position 110 watts so 15 to 17 watts
09:23less
09:24just from holding that different position yeah at 30 kilometers per hour as well yeah yeah so it
09:29it would be much more at 45 kilometers per hour so that that's big big difference it's more than uh
09:35almost 20 percent efficiency gain just on the position so so we've seen that your body position
09:41can make an absolutely huge difference on the bike we haven't got time today to go and test every
09:47different wheel bike frame saddle handlebar width clothing etc but in your experience if you could give
09:56five things that amateurs like me that go out and average 30 kilometers an hour on their rides should be
10:03paying attention to should be considering when it comes to aerodynamics what would those five things be
10:08so first i would uh be concerned about the handlebar width because it's really affect the
10:13your position and your drag so short handlebar so now it's limited with the uci but yeah as short as
10:20possible
10:21then i would care a lot about the helmet because the helmet has a strong impact
10:27uh and uh and it's really i mean one helmet does not fit all everybody so you really need to
10:35cherry
10:35pick your helmet depending on the aero efficiency so for that you need a tool to measure that i would
10:42put a lot of care also on the skin suit so we've seen some crazy difference like 30 watts at
10:4845 kilometers
10:49per hour so that's huge huge difference um i would care also a lot about yeah globally what we call
10:57the attitude so it means really how how do you uh uh achieve your aero position especially how you
11:04roll the uh the the shoulder uh and and put your head within your your shoulder okay so yeah tuck
11:12your
11:12head sort of in yeah yeah yeah that that that's really important and and yeah the the most obvious
11:18thing is what we've seen is really caring a lot about your position trying to to uh to be on
11:24this
11:24breakaway position as uh as much as you can sometimes it's really amazing to see that even pro they do
11:30not adapt the most efficient position in the breakaway so they are losing like maybe 20 30 watts for
11:37nothing so that's amazing so we really need to care and to uh to have concern about uh position all
11:43the
11:43time yep yep and as as we've seen today there really is some big gains to be had and uh
11:50a lot of people
11:52obsess over weight and not necessarily over aerodynamics yeah and honestly on the flat road
11:58white you don't do not care really i mean it's almost an issue in cycling on the flat road cool
12:06well thank you very much thank you yeah if you've enjoyed this sort of content then please do give it
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