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There are two videos on Youtube that have been regarded by bike fans as suspicous. I will let HN readers make their own minds up!

https://youtu.be/8Nd13ARuvVE?t=3m35s

and

https://www.youtube.com/watch?v=ideiS-6gBAc

I would love to hear smart people's thoughts!




Here's Cancellara winning Strade Bianche this past Sunday: https://youtu.be/X8YJH23dIAc

I think it looks pretty similar in terms of terrain, style, and effort, and it was a win over a tough field. With all the concern about mechanical doping, they checked his bike and there was no motor in it.

Of course there's no way to know what happened in 2010 for sure, but he has shown he doesn't need a motor.


I remember watching Miguel Indurain blow past great climbers without leaving the saddle during the 1990's. His resting heart rate was recorded at 28 beats per minute. The best cyclists are outliers among outliers.


surely indurain was doping, though.


As was every other cyclist back then. Look at the wiki, the guy was a horse.


Yes, Fabian is a beast. While those older videos seem intriguing, he is definitely very talented. But like Lance showed us, you never can tell.


Here's the thing. No one to date has actually been caught using one. The banned woman was caught having one, on a spare bike in the pit. She claims it's owned by a friend (who corroborated) and that her mechanics mistakenly put it in the pit, etc.. it's a pretty shaky story, but the fact remains they have never actually caught someone using one during a race.

There's a large number of people who think it just wouldn't help that much. While 100 watts extra would be a game changer, the forced cadence, inability to manipulate the pedals, etc makes it potentially no help at all.

As for those two videos.. Cancellara has been attacking like this for years. It's his style. He's also the 4 time world time trial (solo racing against the clock) champion, so he's exceptionally good at sustained high output power.

Hesjedal and the spinning wheel.. Why wouldn't you turn off your motor on a descent is the only thing I'd say? I wouldn't put it past him, he was one of the Lance era EPO doping crew, I just don't buy it on that video. I've seen plenty of crashes in person where bikes did all kinds of weird things.


> Here's the thing. No one to date has actually been caught using one.

Actually 6 weeks ago Femke Van den Driessche was caught with a motor in the Cyclocross World Championships.

The UCI are pushing for a lifetime ban and a very hefty fine for Van den Driessche, so there is a significant disincentive: http://cyclingtips.com/2016/03/uci-seeking-lifetime-ban-and-...


That's the same exact case GP is talking about. Femke's spare bike was found to have the motor, not the one she was riding during the race.


That isn't what Wikipedia says at all:

> During the race, the UCI checked the bicycles of Van den Driessche and found a motor in the bicycle she was riding.

And:

> “After one lap of the world championships, UCI took Femke’s bike in the pit area and tested it with some sort of tablet,” said Sporza journalist Maarten Vangramberen. “The bike was immediately sealed and taken. The UCI then called in the Belgian federation. When the saddle was removed, there were electrical cables in the seat tube. When they wanted to remove the bottom bracket, which is normally not difficult, they could not because the crank was stuck. Inside there was a motor.”

Several people in this thread are repeating the claim that it was a pit bike, the UCI seems to think otherwise. I am siding with the UCI on this one.

[0] https://en.wikipedia.org/wiki/Femke_Van_den_Driessche#Allega... [1] http://velonews.competitor.com/2016/01/news/uci_detains_bike...


In cyclocross your pit bike becomes the bike you are riding. They switch bikes out to clean mud buildup off of them. So she never used this bike but only because she didn't have a chance to. They discovered it on the first lap.


It literally says she was riding it. It doesn't say she is going to ride it.


I appreciate your quest for accuracy, but I think you are misinterpreting the material you quoted: "After one lap of the world championships, UCI took Femke’s bike in the pit area and tested it with some sort of tablet,” said Sporza journalist Maarten Vangramberen."

I think it means "they took Femke's bike [that was] in the pit area", and not "they took Femke's bike in[to] the pit area". As your first quote says, this was done during the race. Unless they stopped the race to do the check, they couldn't be referring to the bike she was riding at the time. And since this was during the first lap, she had not yet ridden the bike that was in the pit.

Here's the original quote in Dutch: "Na één ronde op het WK heeft de UCI de fiets van Femke in de materiaalpost gecontroleerd met een soort van tablet. De fiets werd meteen verzegeld en werd meegenomen." I don't speak Dutch, but I think "de UCI de fiets van Femke in de materiaalpost gecontroleerd" doesn't say they took the bike to the pit, rather that her bike "in de materiaalpost" was "gecontroleerd".

http://sporza.be/cm/sporza/wielrennen/veldrijden/1.2559848


I'm Belgian (Mother tongue Dutch) so for clatification here is the translation of that quote:

"After one lap on the WC, the UCI checked the bike of Femke at the pit area with a kind of tablet. The bike was immediately sealed and taken away"

While that source doesn't specifically say who took the bike into the pit area, other sources state that it was taken into the pit area by mistake (probably her entourage) and that it wasn't the UCI who took the bike into the ICU.

http://www.nieuwsblad.be/cnt/dmf20160130_02100012 [dutch]

So in short, it _isn't known_ if she used the bike in the WC, but the UCI _alleges_ that she did.


Thanks. Part of the issue is that there is a distinction between "ride" and "use". By the UCI's definition, putting the bike in the pit is "use" even though she may not have ridden it during that race. Do you interpret the UCI's claim to be that she started with the motorized bike, rode it part of the way through the lap, and then switched to a legal bike?


To reply to the following quoted message: "Thanks. Part of the issue is that there is a distinction between "ride" and "use". By the UCI's definition, putting the bike in the pit is "use" even though she may not have ridden it during that race. Do you interpret the UCI's claim to be that she started with the motorized bike, rode it part of the way through the lap, and then switched to a legal bike?"

The UCI never made any claim that she rode it, and I don't think they will do so either. My interpretation is that they find that a moot point and simply find the uncovering of a motorized bike to be unacceptable.


You realise Wikipedia isn't a source, right? Every news article about this incident (including the one you linked to) states that the tested bicycle was in the pits. The rider in question was out on course, riding a different bike.

That doesn't make it right of course. The whole incident stinks. But the UCI did not, and to date has not, caught someone racing with a motor.


> Actually 6 weeks ago Femke Van den Driessche was caught with a motor in the Cyclocross World Championships.

He discussed that: she was not caught using one.


That doesn't matter, the UCI code considers all equipment that a rider or team possesses within the confines of the race area as to be part of the equipment covered by the rules, and every rider and team knows this.

    The presence, within or on the margins of a cycling competition, of a bicycle
    that does not comply with the provisions of article 1.3.010. The use by a
    rider, within or on the margins of a cycling competition, of a bicycle
    that does not comply with the provisions of article 1.3.010. All teams must
    ensure that all their bicycles are in compliance with the provisions of article
    1.3.010. Any presence of a bicycle that does not comply with the provisions of
    article 1.3.010, within or on the margins of a cycling competition, constitutes
    a technological fraud by the team and the rider.
No rider brings into a competition area any equipment that they do not intimately know and they are fully aware that the UCI is going to have access to look at it all. Her excuse that it was a friend's is about as sound as Sharapova's excuse about doping yesterday. Possessing the bike, bringing it into a competition area, mixing it with competition equipment... it makes no difference whether or not anyone proves it was "used" (by any definition), the rules were explicitly clear.


My point isn't whether she broke a rule or not - she did, and deserves the ban. My point is no one has actually been caught taking advantage of the assistance from a motor during competition, and there are doubts as to it's true efficacy. It isn't just additive free watts, the type of "pedal assist" you get with top end bikes hasn't been miniaturized enough (to the known world) to be hidden, with a hidden battery. Look at the top end Bosch based e-bikes out there, it's a different world completely. These are more like if you can't put out X watts already, it will give it to you, not stack it on your existing high power. They can make a non-athlete get through a difficult section of terrain, but no one's seen anything that can augment a 1200+ watt attack enough to make it worth the risk in a ProTour race.

I firmly believe the tech WILL catch up that can do just that but it's not there, or if it is, it's being developed in relative secrecy. That just doesn't make any sense to me. Who is investing R&D money into this? For what return? They aren't getting prize money, sponsorship kickbacks.. the whole sport of pro cycling is dying financially without help from any external source. It's a very dated sponsorship model and races are drying up all over the world.


I'm not arguing she's not guilty of something, I'm saying that what the other guy wrote was technically correct.


good point, if a teacher catches you with a "cheat sheet" in school but you don't use it, is the student charged with cheating? yes, most likely.


Just like you're not driving if you're drunk, and only sit behind the wheel of your car. In some United States, you can be charged with DUI.


There is no forced cadence. The motor is not fixed at a particular RPM; if the motor were unloaded, it would spin a lot faster than it does. It supplies a certain amount of power, and the bike hits a certain ground speed, and through the gear ratio, that determines the motor's speed.

If you only want to go that fast, then you don't have to crank the pedals, and it's awkward. However, you can crank the pedals to go even faster.

That's the point of using the motor. You + motor is faster than you alone or motor alone. Or: you + motor requires a lot less effort on your part to maintain a certain speed than you alone. Suppose that you can go 30 mph, but with great difficulty and not for very long. Suppose that a given motor by itself can go 20 mph. If you use that motor and your own muscles together, you can go 30 mph with a lot less effort, and sustain it a lot longer. The cranking of your pedals and cadence will be natural; you're cranking 50% faster than what the motor can do by itself. It will be like cycling in the slip-stream of a truck, or down a slight downgrade. To the spectators, you will just look like a strong cyclist.

About the 100W, almost any amount of cheat torque can make the difference between placing N-th and N+1st. Every second counts.

Even a 2.5W power boost could be a game changer. If your muscles put out 250W, 2.5W is 1% more, which is significant. It's about 36 seconds shaved off a one hour haul. The game has changed from a neck-and-neck race to the front runner having a 36 second lead.

A tiny, light-weight motor of just a few watts that would be useless in a commuting bike used by someone who is out of shape and cannot climb hills could nevertheless win trophies for a cheater.

One minute you're racing just beyond your lactate threshold. Flip a concealed switch, and a tiny power boost drops you within your threshold.


This is what I call my "cheater bike": https://www.dropbox.com/s/nu2q0srtj62w3gl/cheater-bike.JPG?d...

It's a 250W rated bunch of Chinese-sourced parts on a $50 eBay steel framed budget mountain bike.

It's _so_ hilarious to ride, a friend says "it make you feel like Lance Armstrong!". It just makes everything too easy. I barely ever take it out of top gear - I just lazily pedal up hills, zoom along the flat, and have to brake to stop feeling suicidal down hills. I'm an almost 50 year old overweight and out of shape guy, and I commute to work on it keeping up easily with the lycra-clad mamils on what look like $10K+ carbon-everything bikes - I've been doing it for a few years and it's _still_ so much fun passing them going up hills.

I can _easily_ believe even a fraction of the power I've got there would turn a midfield racer into a winner.

(For the record, I've got a 7 cell LiPo battery powering mine, and off a full charge I see 470W or so coming out of the battery accelerating up a medium incline. It tops out at 25kmh, and pulls barely 100W to do that on the flat, but it's _so_ noticeable accelerating away form stationary or up hills. It's _ really_ fun :-)


Just curious: why not ride a regular bike to work? I've been doing it for a year now (16.5 miles round trip) and it has been great. I never could find the time to exercise before and now I commute and exercise at the same time. Parallelism!


Because lazy! At least mostly. Also we don't have shower facilities at work, so during summer (I'm in Sydney, so summer hasn't quite ended yet) I end up quite sweaty riding to work.

I do have a non-cheater bike as well, I ride it more when it's cooler (but I'm still lazy, so...) More exercise is the plan. Executing on that plan isn't always successful.


I'm looking at getting a similar setup for myself this summer. I hear "that's cheating" or similar from others, in which case my response is: Do you ever use a calculator? Why not work out everything with pencil and paper (or better yet, in your head)?

Of course, several years ago after I decided to get in shape, I tried cycle commuting and really enjoyed it (about 15 miles each way). But I could only pull it off about once a week or so (in order to make good time, it left me mostly worthless at work all day). Coming up, after I move in a month I'll be about 23 miles from work. Adding a hub motor will allow me to not only make the commute in just over an hour, but it will leave me less exhausted (I plan on still putting in some human power, but I won't have to over do it). The good thing though, is by adding electric power to a bicycle, it will get me on it much more often so I'll end up getting even more exercise than without power.


I built an ebike last year to do something similar to OP. I rode my bike (a full suspension mountain bike) a couple times, but found that 20 miles was just too far to cover for a commute. With the ebike, I am still pedaling and getting exercise, but it takes me 50 minutes instead of 90. Still a tad longer than it would take in my car, but I am definitely getting a decent workout (determined by how sweaty I am before I shower). Even if I only burn half the calories, I am getting nearly 2 hours of exercise a day I wouldn't have gotten otherwise, and am not adding much time to my commute.

Maybe someday I will be in good enough shape to make the 20 mile commute in around 1:15 without the assistance, but if it's between pedal assist and driving, pedal assist seems like the far better choice!

FWIW, I used to bike-commute to school when it was 8-10 miles, and that was great. But 20mi each way is just too much time for me when I need to get home to get kids to practice, or help with homework, etc.


This is a great description of why motors can make a big difference in racing. Even small differences in power output can make a big difference in an elite race where so little can mean the difference between winning and not. It's easy to imagine using a tiny motor (much smaller than the one mentioned in the article) could make the difference between winning and being an also ran.

However I have to nitpick on one point:

"Even a 2.5W power boost could be a game changer. If your muscles put out 250W, 2.5W is 1% more, which is significant. It's about 36 seconds shaved off a one hour haul."

Air resistance is one the most significant factor affecting riders at race speeds, and its force increases at a much greater than linear rate. You'd need about 3% more power in your example to save 36 seconds. In a flat time trial over one hour, 1% extra power would actually save you closer to 12 seconds. That said, the Tour de France has been won by less.


Also, a boost gives you a tactical advantage: an advantage of psychology.

Firstly, in a race, it is psychologically challenging to be the leader of the pack. Are you really faster than those behind you? Or are there opportunists nipping at your heels, wearing you down, who will surge by you when the goal is in sight? With a secret boost, you can overcome some of this uncertainty.

Likewise, you can use the boost to surge by opponents after tailing them for extended distances without the boost. When you surge by someone, it has a mentally devastating effect on them. You show that you have untapped reserves that they don't, which creates the belief that you cannot be beaten. In the absence of cheating, that belief is just a belief. The playing field is level: by trying to create the belief that you are stronger and faster, you're taking a risk (because it's not a given that you actually are; you're faking that out with a little surge that you could well pay for later.)

I believe that with a hidden motor, you can not only reduce your own race time, but make someone else's race time worse. You wear them down with an unrealistic pace, either as a leader or follower (pressure from the back) which you can then maintain yourself thanks to the motor, while they blow their race.

And then, here is the thing. If you win by tactics, that doesn't have to involve coming anywhere near the best time for that course or a world record etc. You get everyone to screw up, and then cross the finish first, but in some credible time that doesn't draw attention to your performance, seconds or minutes behind the best time that was ever observed on that course. That reduces the suspicion of any cheating, unless your splits over the course are scrutinized.


Yes, the math says so. Have a look at the video I posted above though. While E-assist bikes can do this, these hidden motor versions just don't in the real world, for racers. I do believe it will, at some point, I just don't think it's there yet. There's just no money in developing it right now.


The benefit provided by the output of the motor won't be linear, at least not for road races (cyclocross I'll grant is an entirely different beast).

The ratio of power output to speed follows a square law, so if you're going 20 mph and flip on a motor that doubles your power output, you won't even hit 30 mph, let alone 40mph (4x power = 2x speed). But this is an endurance sport and a huge part of your strategy involves dealing with wind resistance (by drafting) so even a little boost means that you might be able to pull off or prevent a breakaway at a critical moment of a race. For much of the race your goal isn't to go faster than the other guys, but merely to match speed without wearing yourself out.


On a long climb, timed right as part of an attack, it would definitely, definitely be a help. The difference between the top riders is so slim that it would without question make a difference, in my mind.

I think the Cancellara video looks odd, but he is super-human...

The Hesjedal video is just super weird. He could have knocked the motor on during the fall. He also gets up in a really suspicious manner IMO...


In the Cancellara video, the riders around and in-front ease up a bit just as he accelerates. It does look odd, but he's a freak of nature when it comes to long, solo efforts. And, he rarely looks "out of sorts" on the bike. The only time I recall seeing him look completely gassed was after winning Paris-Roubaix a few years ago. And that was after he won and collapsed in the in-field.


> The difference between the top riders is so slim that it would without question

Exactly.

In the first clip you posted, at the end in the tour of flanders when Cancellara attacks before the finish, neither his cadence nor his body position change as he accelerates. Further, the rider behind him who is undoubtedly an incredible athlete has to stand up just to keep his current pace.

At the very least it's not hard to see why this looks suspicious.


By the way, have you seen this? I think it just came out a week or two ago.. https://www.youtube.com/watch?v=Wv5F5N6mFf0


Regarding the first clip:

Cancellara is the greatest time triallist in the history of cycling. Putting out immense amounts of power from a seated position is his raison d'etre.

Regarding the second:

That section of road is steep and banked. After Hesjedal unclips his right foot, the only points of contact between the bicycle and the road are the rear tyre and the rubberised hood on his brake lever. The bicycle is pulled downhill by gravity, but rotates around the brake hood because the friction there is greater than the friction at the rear hub.


An even simpler explanation for the second clip is that a fast-rotating wheel has a decent amount of rotational inertia.

https://www.instagram.com/p/sh0fSPirPW/?modal=true


>The bicycle is pulled downhill by gravity, but rotates around the brake hood

Not convinced. The bike is close to stationary after the fall, then turns a full 180 and hits the next cyclist with quite a bit of force. Notice also that the back while is in constant contact with the road as it makes that 180 degree turn. Doesn't look gravity driven to me at all...


As I replied to the grandparent, rotating wheels carry enough rotational inertia to spin a lightweight bike.

https://www.instagram.com/p/sh0fSPirPW/?modal=true


I feel like this should be obvious to anyone who has ever fallen off a road bike. I know I have, and this is very frequently what happens. But of course if someone has no experience riding bikes and views the video it looks like cheating.


The Cancellara video looks a little odd just because of the dynamics of bike racing. If you interpret the video as Cancellara pulling away from other pros like that with everyone going full effort, it looks super human. In reality though, Cancellara pulls away from the group so quickly at 3:35 (the time you linked) because no one is trying to go with him at that moment.

He's attacking with ~50km left, which is far enough from the finish at a major one-day race (Paris-Roubaix here) that the chances of the main group reeling him back in are pretty high (he did go on to win that day). As another rider in that group, you have two options when you see someone attack: A) try to go with Cancellara's move and hope that you can beat him one on one (unlikely, Cancellara is one of the all time greats and 2010 was a year of peak form for him), or B) stay with the pack and hope that you can collectively haul him back later in the race (now you've saved your own energy and Cancellara has spent some of his).

Look at the lead rider in the pack (white jersey, blue shorts) at 3:46 as Cancellara goes past him. You can see him look back at the other riders in the group. He's checking to see if anyone else is deciding to do with Cancellara. No one else moves, so they maintain a steady pace, hoping to bring him back with option B.

In the other video, Hesjedal's bike spins because of the road gradient and momentum in his still spinning wheel hitting the road as he stands up. Hard to see the slope of the road from the camera angle but they are on a steep descent.

Mechanical doping is definitely a technological possibility and the UCI is starting to test bikes. That said, the "bike fans" who point to these videos out as evidence are conspiracy theorists. The explanations I wrote above are IMO pretty apparent to someone who has raced bikes before, but I can see how they look odd to a layman observer or a non-competitive cyclist (in the case of the Cancellara video especially).

Edit: the race I was referring to was actually Paris-Roubaix, not Flanders. This article has some pretty good post-race interview commentary from Boonen and Cancellara himself about how the effort to chase him down sputtered because of a lack of cooperation, not ability: http://www.telegraph.co.uk/sport/othersports/cycling/7578607...


I find his 2010 acceleration very unnatural. If you watch his win this past weekend and compare the effort made when accelerating it's like the difference between night and day. 2010 was too effortless even for someone of Cancellara's abilities. There was also the videos of him fumbling with something exactly where you would expect to hide a switch for the motor. All in all I reckon he did cheat with a motor in 2010 which is sad because initially I was amazed by his performance.


I believe Flandrian national feeling drove the Cancellara accusations. He just smoked home hero Boonen on the Muur. Nothing about that video is convincing. The hand movements look like shifts.



That second one is either a motor or a flywheel. No way a normal road racing wheelset could spin a fallen bike like that. Just my gut talking, though. I could be wrong...


All know motors for race bikes rotate the cranks when engaged, and his are stationary. You can also see another example here : https://www.youtube.com/watch?v=q7TWDNhWDlY#t=41


There's been a lot of buzz recently about inductive motors which drive the wheels directly. Maybe this is one in the wild?


Rotating a light bike like that takes a lot less energy than you might think. Kinetic energy is also V^2 and the out edge of that wheel is probably doing 30+mph as it's down hill, so IMO it's actually believable.

Granted, it would be much easier to get a motor to do the same thing.


Rotating a light wheel that takes less energy, too, but that means too that wheel isn't a big power store. A light weight wheel is precisely the opposite of a flywheel; it should stop nearly immediately because it's _not_ a heavy rotating mass with lots of stored energy. If we're talking about Ryder Hesjedals video, he's still attached (right foot) to his bike, everything appears to be static (he's not sliding anymore) and his rear wheel appears to be pressed into the ground. Then when he unclips his foot, his bike starts spinning around. Weird[0].

[0] Conclusion based on watching https://www.youtube.com/watch?v=ynLMfzLTc8M at 0.25 speed.


A light wheel with low resistance, like a highly tuned performance bike, can hold energy for a long time. My entry level road bike will spin for well over a minute with a light tug, maybe equivalent to 5-10 mph. He's going well over 30 mph in that video.

I'm not arguing whether this may or may not be an assisted bike, but what you're saying about a wheel is patently wrong.


Are you talking about light resistance in the bearings?

I think you are (forgive me if I'm wrong), but that doesn't matter. That is not an example of the wheel "doing work". That wheel in the video looked stopped at the end of the crash, and even if it wasn't stopped, the video looks really awkward. Sure, his crash started at 30mph, but ended at 0, and his wheel looks to be firmly placed on the ground, immobile. For sake of understanding though, it'd be interesting to know what power could be stored in a theoretical wheel that could stand in for Ryder's.

Eg. a pair of Mavic Cosmic Carbone Ultimate[0] apparently weight 1185g. The rear will weight a bit more (because hub/drive/gears), although that weight will be at the center of the spin, so I _guess_ not contribute significantly to the velocity of the wheel (angular momentum). So, how many watts are stored in a ~700g wheel that was moving at 30mph? That will determine the ability to do work (like spin a bicycle on the pavement).

[0] http://www.bikyle.com/MavicRoadWheels.asp

edit: expand point, suggest exercise


This is not my area of expertise, but to get things started, I went to a site[0] and looked up some formulas and specs, and came up with:

outside circumference of wheel ~2200mm (700c wheel w/ tire) 30 mph == 0.5 mpm (Miles per minute). 0.5 mile == 804500mm a 2200mm circumference will need to roll ~365.68 times to cover that distance. If that distance is covered in 1 minute, that means 365.68 rotations per minute.

This: Ef = 1/2 I ω2

wants I and ω.

I = m r squared.

m == 700g (this isn't properly distributed here, but it's a start)

r (at 2200mm circumference) == 350.14

0.7kg * ((350.14mm)(0.001m/mm))^2 == 0.7 * .122598019 == 0.085818613 kg/m2

1 rad/s = 9.55 r/min (rpm) 365rpm == 38.29 rad/s

so if this is at all correct:

Ef = 0.5 * 0.085818613 * 38.29^2 == 0.5 * 0.085818613 * 1466.1241 == 62.910368373 Joules

1J/s == 1watt. So with this fudgey math above (assuming it's even correct) we're working w/ ~60 watts(max, for an instance, then decreasing). I don't even know if that's enough to spin a bicycle around like was shown. I hope somebody that actually understands this field can chime in and fix my bad assumptions (which I think err to supporting this was strictly the spinning wheel (not a motor)) and what this means. I'll do practical tests later when I have my bike.

[0] http://www.engineeringtoolbox.com/flywheel-energy-d_945.html


Or simpler, you can just run the experiment yourself.

https://www.instagram.com/p/sh0fSPirPW/?modal=true


Yeah, good find.

I saw that earlier too, and forgot about it. So the question is less about whether its even possible, but whether or not it was likely in Ryder Hesjedal's circumstance. And the stakes, circumstances, etc aren't exceptional enough to warrant a commission.


60 watts is definitely sufficient to power a bike like that. I know I produce 50-80 pedaling at a "rest" pace, maybe 10-12 mph. Assuming your math is correct, it seems sensible that a wheel at 30 mph could move the bike. It seems like the biggest assumption here is that the wheel wasn't stopped in the crash and that it hovered above the ground, or sustained sufficient RPMs it was slowed.


Your assuming the wheel stopped rotating while it was lightly touching the side of the road. Visually you don't see the spokes on the low wheel, but you do on the vertical one, so it was still rotating.

If you think about it there was probably under 1 kg of force between the side of the wheel which has minimal grip and the road surface while he was attached for what 2-5 seconds?. Spin a wheel and try and slow it down from lightly touching the sides like that and it's going to spin for a while.

Further, while on the side the contact point of the wheel had a ~5 feet of leverage to the pivot point of the handlebars and the other contact point was a wheel. So, it would take very little force to get the bike rotating.

PS: I don't have a bike right now, but it should be easy to test if you do.


The second video is very suspicious. Cycle shoes attach to the pedal by a click system. When you fall, you usually detach from the pedal by one foot. The other one detaches very dependent on the situation, or not at all. You see this happening: Hesjedal falls, one foot clicks out. His second foot stays clicked in.

After Hesjedal falls, you clearly see the kinetic energy stopped of the back part of the bicycle at one moment. This is because his pedal is still attached to his right foot. After he "clicks out", the back wheel seems to bring the back part of the bicycle in motion. This is unexpected; the back part of the bicycle does not posses any kinetic energy.

Two other options exist for the bicycle movement to occur. 1) the left pedal is fixed to the connecting surface area (road) while the cranks still move. 2) the rear wheel still has kinetic energy (still turning).

The first option simply does not occur, as the right pedal keeps its position relative to the frame of the bicycle (see later frames in the video). The second option would never transfer enough energy to the bicycle as to display the observed bicycle movement. Hesjedal is already lowering speed substantially since he needs to maneuver into the left sharp corner. His speed is 20KMPH max, I'd say probably around 15KMPH. That is by far and large not enough to make the whole bicycle want to spin around hile on the ground.


I think what creates the confusion in the hesjedal video is that he is on a steep slope, but the angle of the video obscures that. That explains both the spinning wheel (caused by the bike slipping down the slope a bit while the wheel was touching the ground, causing the wheel to spin) and his somewhat awkward motion when he stands up.


What makes you say he was on a steep slope? Nothing about the background suggests that this is so (for example, all of the cars in the car park below). Also, if he was on a hill, the bike would have to have somehow had enough angular momentum to spin back up hill, as it appears to do in the later part of the clip.




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