Last word on Aero Riding Positions

Ok one last post on the Super-Tuck. There’s some mis-information out there. I think everyone agree’s that it’s empirically faster, however great caution must be exercised when using it. Trying it out mid-race will endanger you and people around you. As with most things cycling related: practice first.

OK, warnings aside, onto some practical information.

Thanks to Hincapie Rider Mac Brennan for the following information from the A2 wind tunnel in Charlotte. 31.02a Left Side 33.0 Left Side35.0 Left Side 37.0 Left Side

As you can see there’s 4 positions: Drops, Hoods, Elbow’s on Bars, and finally ‘Super-Tuck’. One other note is that all positions were done while pedaling except the Super-Tuck….which is usually pretty appropriate.

Recalling the Drag equation,  CdA is a measure of how ‘aero’ something is and is directly proportional to the amount of drag generated by an object.

Power to overcome drag (30mph) CdA (m^2)
Drops 415w 0.28
Aero on Hoods 409w 0.276
Aero Postion tops 383w 0.259
Super tuck 279w 0.188

Recall, that CFD report that came out mid-TdF busting the Aero benefits of the ‘super-tuck’ claimed that the super-tuck was 0.6% LESS aero than a standard drops position. However Mac’s wind tunnel results show that Mac’s position in the Super-Tuck is 32% MORE aerodynamic than his position in the drops. I’m sure this delta is exacerbated by the fact that he’s pedaling in the drops…but still. Even if it’s only 25% without pedaling in the drops that difference is HUGE.

The answer to what to do with regards to the super-tuck is…….it’s complicated.

For instance We just did a Time Trial this weekend as part of the River Gorge Omnium. If you’re not familiar with the courses there are several relatively long downhills during the course of the 4 mile TT. We don’t have specific time trial bikes since we don’t really do many during the course of the year. Riding a standard road bike changes the type of ride you’ll have to do for a TT. On the main downhill that occurs mid-way through the race:


I mean yeah I’m 6 seconds slower than the eventual winner from this year’s TT: Aaron Beebe, but I’m also fairly certain I did less pedaling and probably recovered a bit thanks to coasting for a whole minute.

More specifically you can compare it like this: given the CdA values supplied by Mac above you get the following picture. SuperTuck Drag Profile at -5 gradient

This kinda paints a picture of what kinda gains you’re getting in the Super-Tuck. At 25 mph, for instance, the difference is pretty small and you probably should be pedaling. However the faster you go the more benefit you get. Hypothetically on a smooth, straight road going down a 5% gradient mac could do ~45 mph in the super tuck without pedaling, while the Aero Tops position (which is BASICALLY a TT position) he’d have to pedal at 340 watts, and in the Drops 445.

Bang for your buck wise, when I’m racing, I’m not pedaling over 35 mph. If you’re on a TT bike and strong enough to win a TT it’s a different story, but most crit racers are rarely in that situation.

However, if you’re mid-pack and you’re super tucked…..YOU ARE A MORON

**cough** looking at several riders at River Gorge Omnium, especially the kid with his jersey unzipped while he was super-tucking **cough**


The problems with the ‘Super-Tuck’

In the last post I did I outlined the benefits of the ‘Super-Tuck’. Now onto it’s problems. Like I said earlier looking at the benefits only takes into account one side of the dynamic bicycle system: Aerodynamics/Power. The second type of system you have to look at, which is the reason why you’re a freaking idiot if you use this position a lot, is control systems.

Every engineer is familiar with the following (unless you’re an Industrial Engineer *cough* *black sheep* *cough*)

This is a mass/spring/damper system. It’s a simplified version of A LOT of real world applications. Enginineers use this simplified model to figure out how to make cruise control, autopilots, heaters, generally anything where you’re trying to help control the behavior of a physical/electrical system. It’s essentially a mass connected by a spring and damper to some either stationary or moving anchor point.

If you apply this system to a bike/rider and your chubby ass is the block (mass – m), then your legs and arms act as both the spring and damper. When you go through a turn/rough patch of road, your arms and legs act to smooth out any bumps you ride over and the diagram becomes something more closely resembling this:

An Inverted Mass/Spring/Damper system with variable displacement

An Inverted Mass/Spring/Damper system with variable displacement

You can obviously get infinitely more complicated than this but the math and physics of the simple mass/spring/damper system remains. This type of modeling is very familiar to mechanical engineers due to its obvious applications to motor vehicles.

Now the problem with the top tube surfing position is that since you’re resting your ass on the top tube you completely you not only increase your spring stiffness by eliminating any bump absorption of your arms and legs, but you also GREATLY under-damp the system.

The example below shows a block with gravity acting on it with a starting position, the blocks are dropped and eventually achieve equilibrium.



The thing to notice about the under-damped system is how dramatic the OVERSHOOT is (that is the amount the blue block overshoots it’s equilibrium point). Anyone who’s tuned MTB suspension will begin to see the correlation now. When you setup a MTB fork and don’t have any damping, the fork will absorb the bump…..but then translate that displacement further up to your hands. This is great if you’re doing dirt jumps or something….not so great in the ‘Super-Tuck’.

In short, if you hit an unexpected bump in the road (cuz your foolishly super-tucking in the pack) not just your wheel/tire but everything will now go flying in the air.

This same effect will be seen in your steering system, albeit in a much more complected manner. However the end result will be the same: no ability to quickly turn to avoid hazard and any outside input to your steering will send you wildly off course due to your inability to correct the course.

Just watch the dudes at Rio tackle the technical descent into the finish:

No super-tuck-ing there.


Are you a Froome Dog?

So if you’ve done any races with hills (aka outside the midwest) you’ve probably noticed a lot of people doing their best Chris Froome impression:

The reason why I hate people using this position is actually a great example of system analysis. There are a lot of physics going into why this type 0f riding is both great….and awful. I will get into both.

This history of super tuck is pretty short, I think widespread is first spoted in Kwiakowski at the 2014 world championship.

Since then it’s been used by Sagan to great effect and a lot of dudes going for that ‘Local Strava KOM Descent’. Needless to say it’s permeated to the point that dudes are super-tucking mid-pack during races…..which is INCREDIBLY STUPID. I don’t care who you are, or what race you’re doing, it’s foolish.

The problem is that the ‘super-tuck’ really does work….IMHO.

Recently, Bert Blocken posted an article on Froome’s position. Blocken used to have a course on on Sports and Building Aerodynamics which was pretty good. In the paper his main postulation is that just simply riding in the drops is only 1% less aero than a TT position while the “super-tuck” is 1.6% less than the TT position. So there’s really no point to ‘super-tuck’ since it’s worse than just riding downhill in your drops.

CFD of body bike positions

Fluent SUCKS!!!!

I’m REALLY skeptical of these results even though the modeling practice he uses are “wind tunnel verified”

NUMEROUS sources indicate that the differences between positions is MUCH greater than 1% as indicated by their CdA (the non-dimensionalized correlation to compare the ‘slipperiness’ of various aero shapes). CdA is a much more important metric than simple Cd. For instance, the reason why a TT position is necessarily more aerodynamic than a standard road position is that the ‘A’ in you ‘Cd * A’ term is reduced by tucking your arms in in-front of your body. Cd by itself is simply the slipperiness of a given shape irregardless of size.

If you want to see some comparison’s see the tables listed below, but the bottom line from these other tests is that the difference between your vanilla in-the-drops-road-position vs Full Aero position is REALLY around 13%-15%. Which, anecdotally seems right.

It has seemed to be successful for at least TWO world championships and for Froome’s daredevil descent in the TdF.

MORE anecdotal evidence can be found pretty much anywhere. Go descend with anyone, once they get into a super tuck, you’re really pedaling to keep up. The article feels very much like it’s safety driven, and wrong(despite the fact that I agree with the sentiment). I mean, it WAS written on LinkedIn.

I’ll break this post up into two parts since it’s getting a little long. So far I’ve established that the ONE cfd  report done on the issue is definitely missing something, and that ANECDOTALLY the ‘super -tuck’ seems a whole Hell of a lot faster.

3 HPV performance aero and drag chart

Other sources (from

Source Test Format Scenario CdA
High Performance Cycling (Jeukendrup, 2002) Wind Tunnel Tops .4080
Hoods .3240
Drops .3070
Aerobars (Clip on) .2914
Aerobars (Optimised) .2680
Bikeradar Article “How Aero Is Aero” (2008) Wind Tunnel Road Bike, Road Helmet, Drops .3019
Road Bike, Road Helmet, Aerobars .2662
Road Bike, TT Helmet, Aerobars .2547
TT Bike, Road helmet, Aerobars .2427
TT Bike, TT Helmet, Aerobars .2323
Scientific approach to the 1-h cycling world record: a case study (Padilla et
al, 2000)
Complex Estimation Mercx 1972 (Road bike, Std. Helmet, Drops) .2618
Moser 1984 (TT bike ex. Aero bars) .2481
Obree 1994 (Obree position) .1720
Indurain 1994 (TT Bike, TT Helmet, Aero bars) .2441
Rominger 1994 (Superman position) .1932
Boardman 1996 (Superman position) .1838



The “safe” neutral lap

This past week was the USACycling Winston Salem smorgasbord of races, where probably 100 races were hosted and my teammates and I were only eligible to do one: the Crit. I didn’t see any of the masters racing but apparently their crit, run on a different course, was a total mess. You can read the great write up here:

It’s simultaneously pretty infuriating and indicative of why races are losing riders in droves. The biggest event of the year for many non-pro riders which is also VERY expensive, is essentially ruined.

I remember the first time I did an Elite Nationals Crit in Augusta Georgia. I registered day of, the woman running registration did not have a cash box and stuck my $120 in her bra, not sure what was more believable: that I didn’t get a dance out of it, or that a crit cost $120.

One thing that stuck out to me in Koontz’ article was the incident with the race stopping and the officials attempting to re-start with a neutral lap.

A similar thing happened at the USA Crits Spartainburg Criterium. There was a crash a few laps into the race due to poorly placed barriers on the inside of a corner. The crash was pretty nasty and the officials were forced to stop the race, which was a good call. However things went down from there.

The officials stopped the race right at the crash corner. Ideally everyone should stop behind the chief judge. But, since this is a very technical race where your relative position in the field matters quite a bit, riders are inclined to “sneak” past the moto ref. Obviously not every bike rider is a callous jerk, but it becomes a bit of a prisoners dilemma, if you’re the ONE guy following the rules you get stuck at the back and your race is significantly more difficult now. What resulted were riders slowly leap frogging each other until the crashed rider and EMT people were literally in the middle of the field.

The officials decided to re-set and bring the field back to the start finish line for a restart……a NEUTRAL restart.

Anyone who’s raced probably has the experience of a “neutral” start. They’re either REALLY hard because the lead car is doing 30mph and they think that’s normal. Or they are the sketchyist things you’ve ever done. You have 100 guys bumping elbows, bumping barriers, and in the worst case, bumping the lead car or moto (with potential of someone getting run over). Now I’m not sure where the idea of a neutral start being a good idea comes from, is it a USA Cycling officials thing? Do officials think we’ll all stay in line like a NASCAR re-start (heck no!).  After much yelling by pretty much every single rider in the field they settled for a 1/2 lap neutral start which was about as useless as it sounds, but at least not super super dangerous.

I don’t understand the need for neutral re-starts in crits. Typically for criterium racing the faster and more strung out the race is, the safer it is. Plus when the race actually starts, there’s no neutral start and everyone seems to do just fine with it.

My 2-cents, for what it’s worth, is that officials need to be more strict with some of these safety issues (which is a fine line I realize). The riders really don’t have a lot of fear of breaking some of these rules during races so you have situations like the one in Spartainburg.

Oh well.

In other news here’s the crit course for the upcoming Elite crit nationals:

Norton Commons Criterium Course



No defense of the snake

I sadly will not be able to defend my title at Snake Alley this year and instead will be racing the Crit at Winston Salem.

It just could not work out with work. The 12 hour drive made it impossible to get there without taking a BUNCH of time off work. Flying was out due to the pretty remote nature of Burlington Iowa….surprise, there’s not a lot of flights going into Iowa.

Great shot attacking up #snakealley with @isaaclneff @pocsports @raleighbicycles @stansnotubes @guenergylabs

A photo posted by Chris Uberti (@cuberti) on


I’m SUPER bummed. It not only goes down as my favorite race on planet freaking EARTH, but probably the closest Snake Alley win in history:Chris Uberti winning 2015 Snake Alley Criterium

The #snakealley bike throw. Just a hair #cycling #sprinting #winning great racing with @Chris_winn

A video posted by Chris Uberti (@cuberti) on

So best of luck to everyone racing in Iowa this weekend.

My only real hope this weekend is that it ends up raining for the PCT race in Winston Salem.