Anyone out there have an honest explanation of what happened here? Sure looks to me like the bicycle accelerates itself. Here’s a link to a sport director from Garmin’s explanation. Slick road. The only explanation I can come up with is that he kicks his bike forward when he releases his right foot. The only problem with that is you need to twist to release. Here is a link to an experiment that “explains” the bikes motion. The problem with this is that Ryder’s rear wheel is on the ground when he is sliding, thus there should be no rotational stored energy. I think it is just a weird continuation of momentum thing, but it really looks screwy.
Steve Tilford
Blog
That has to be a motor; is there any other possibility?
It certainly looks odd, but consider some items – the cranks are not turning, so no power assist in the bottom bracket. This video doesn’t allow a view of the back wheel hub, but electric-assist bikes have wheel hubs that are obviously larger than those usual on a Mavic wheel. Garmin uses power meters in the crankset, not a powertap hub, so it would be tough to disguise it there. Personally, I’m going to chalk this up to a freak circumstance of momentum, pavement surface and wheel spin momentum rather than chase down that Cancellara electric-bike hole again.
That is tough to say. It sure looks like that rear wheel is powered. I want to believe that the “slick road” or “angle in the road” lends to the bike spinning like that. The front wheel is upright and could indeed make it easier for the bike to roll like that (as opposed to the side of the handlebars being in contact with the road). But, it appears to me, that the bike and the rider lose momentum (at the point just before Ryder starts to get up) and then the bike actually gains momentum again as it starts to spin. I suppose that doesn’t have to mean it has a motor, maybe there is some acceleration of the bike after it initially starts to spin do to centrifugal force (I am not sure at what spin speed this would come into play) or the angle of the front wheel against the pavement could be “pushing” the bike through the spin (maybe the cable housing is providing some resistance and spring into the front wheel trying to straighten itself back out). It does look suspect though. It is the slight pause in the bike’s momentum and subsequent acceleration that makes be wonder. Again, if the front wheel wasn’t upright, providing a little more ease of movement and an axis for the rest of the bike to rotate on I would say it would be even more likely that a motor was involved. This clip is in slow motion too; maybe at full speed, we would see that there is actually a little more momentum than it appears to have in slow motion?
ok but if there is a motor… why do his results still suck?
Oh, come on you guys. You can see that Ryder and his bike are still moving forward (in a relatively straight line) when his right foot (and whole body) disengages from the pedal (0:05 in the video). At that point the left STI lever is dragging on the pavement creating a pivot, while the majority of the weight (and momentum) of the bike is outboard to the right…and it is resting on a friction point that has a lower friction level than the STI lever (either the rear wheel (which itself is spinning in a direction that would add to the motion you’re seeing) or the left pedal). Simple physics that can be recreated by taking a metal pipe on the ground. If the pipe is evenly weighted it will roll straight…however, if you weight one side and/or increase friction on the other, it will turn circles.
I’d have to say yeah, something very fishy is going on here. Perhaps the UCI minimum bike weight limit allows the companies / teams to build super light bikes and then get them back up to the limit with questionable ah, ‘equipment.’
Perfect example of the perils of today’s bike set-up (tiny frame, raise the saddle and slam the stem to the head tube) that is perfect for wind tunnels and and going straight. Not so good for cornering due to the ridiculous weight distribution. Every pro race sees a few crashes like this and idiot commentators question why this is happening. Look, the answer is right before your eyes! Take a photo of Bernard Hinault’s bike, Greg Lemond’s or Freddy Maertens’ and overlay a photo of a climber’s bike of today….duh! Wonder if the wind tunnel speeds give the rider an advantage after a couple hard tumbles for the day.
L, I disagree. It looks as thought they come to a complete stop, then as he moves from the bike (unclips), it takes off again, almost getting faster as it rotates. Very strange. I don’t know where the motor would be if there was one. Probably just some freak event….I hope.
All I can say is that bike is spinning/sliding like it’s on ice, although Ryder’s ass seems to stop his slide pretty quickly.
Once a cheat always a cheat! I wouldn’t put it past him or his “clean” team.
You are right. It looks like it stops and then accelerates as it rotates across the road. Hybrid drive with regenerative braking.
Looks innocent enough just physics but would make a good party piece for sharp Garmin as they would never never never ever cheat & are totally clean if completely dull…
He’s on a descent, so if there’s nothing odd about the rear wheel, then it should continue to slide downhill, slow down, and then come to a stop as the rubber contacts the pavement, no motive force being applied through the pedals. Instead, the rear of the bike when the tire hits the pavement accelerates visibly uphill, against the force of gravity, using the stopped front wheel – which lost its momentum when it hit the pavement with no motive force applied – as a pivot point. Conclusion – there’s something funny going on here, the rear wheel somehow has energy stored in it like a flywheel – similar to a gyroscope…
Looks like maybe the wheel never really lost rpms and was barely touching the ground. That would cause it to spin around like that, although Ryder probably is cheating with a bike motor too!
It has been a long time since statics and forces in college physics, but here goes…
The bike was still sliding when he unclipped and never lost force of inertia – it never came to rest. That energy still had to dissipate for the bike to stop, and I suspect the road is steeper than it appears.
The contact points with the road were the front wheel, STI lever, and side of the rear wheel, with the balance point of friction forces being somewhere in between the STI lever and rear wheel briefly while the direction of force was in the almost the same direction as the front wheel was oriented, hence the short period where the bike slides in roughly a straight line – think of the inertial force as an arrow in direction down the hill, and a line drawn across the contact points (front wheel, STI lever, and rear wheel). The force line is close to perpendicular to the line through the contact points, which have similar and somewhat balanced drag across the three contact points – hence the period of the bike sliding in a straight line. If the axis of the drag forces was perfectly perpendicular to the inertial forces with no changes, the bike would have slid to a stop in a straight line.
However, as the front wheel starts to rotate off axis compared to the direction of inertial force, the drag forces between the front wheel and the road begins to increasingly move from an on axis rotation where the wheel rolls, to off axis and begins to scrub increasingly more than it rolls, causing the front wheel to have an increasing drag force, relative to the contact points of STI lever and rear wheel, which maintain a similar level of drag. This moves the line through the contact points from perpendicular to the inertial force to an rapidly decreasing angle.
In effect, the front wheel became an anchor and since the inertial force contained by the bike still has to dissipate, the rear wheel of the bike rotates around that anchor point and gains velocity as it dissipates energy. Think about playing crack the whip on ice skates as a kid – when the big kid on one end digs into the ice, the other end of the chain with the skinny kid whips around – and at a much faster velocity than they previously were going.
So all of the remaining energy dissipated when the motorcycle ran over the frame?
Here’s the latest –
http://www.cyclingweekly.co.uk/news/latest-news/ryder-hesjedals-clockwork-cervelo-uci-checks-garmin-sharp-bikes-134803
Everyone was laughing except the UCI Commissaires on the race. “Apparently they got a lot of messages from the public, so they had to come and investigate,” said Fernandez, “they came this morning and said that they had to look at the bikes. I think they were almost embarrassed, but they came along and had a look anyway.” And they found nothing.
Read more at http://www.cyclingweekly.co.uk/news/latest-news/ryder-hesjedals-clockwork-cervelo-uci-checks-garmin-sharp-bikes-134803#tvev3IbRD8Ys3vbt.99
That road looks slick, and may be WAY steeper to the inside than it looks on camera. You know how cameras flatten surfaces out big time… but it does look funky…
SB
Watch the vid closely. I’m convinced the front wheel is still spinning. Look at the spokes.
Back & to the left?
https://m.youtube.com/watch?v=9MLc0udf_74
It’s really funny to read all you wanna be physics professors try to explain this. He crashed and his bike moved weird. End of story. That and he is doping just as 95% of the euro boys are still doping, only with new -and-yet-undetected drugs.
Stop the motion and think for a minute. If the rear wheel was in sustained forward motion and responsible for any continued spin on the overall bike, the rotational spin would HAVE to be in the other direction.
It’s really funny to read all you wanna be physics professors try to explain this. He crashed and his bike moved weird. End of story. That and he is doping just as 95% of the euro boys are still doping, only with new -and-yet-undetected drugs.”
And then there are the wannabe MDs who don’t understand biological passport.
Today’s drugs change how fat is burned in muscle cells. They transform power output just like EPO and transfusions did. Look for riders who have super-low body fat and hardly any muscle, those are your cutting-edge dopers. Since the testers don’t know what to look for it’s not even doping. The doctors are always ten years ahead of the testers and always will be.
drugs the past 50 years, now bikes with motors… who cares…
Honestly Steve, why would you stoop so low with that teaser of a headline? It is comical reading all the conspiracy theories hear. Just say its weird and move on folks.
If the free hub locked up it would be easy for the bike to spin this way.
So now, according to Shumi, watch out for the skinny dudes, there be the dopers. And super fat burning is as good as epo. Sure thing, and 92 vs 87 octane is like going from normally aspirated to supercharged?
Franz.. In that video that guys keeps that wheel off the ground then drops in down. Ryder’s rear wheel was dragging on the ground and came to a complete stop then started back up again… 🙂
Exactly. This is the way a bike moves when the rear wheel is in sustained motion and then establishes contact with the ground. Exactly what happened to Ryder’s bike.
You guys are funny…great fun to speculate, but seen this so many times with bikes hitting the ground.
The weight of the bike is on the front wheel…the back wheel is spinning and as it makes contact causes the bike to spin….pretty simple. Everything “L” said in a sentence.
Also when UCI went to check because of all the speculation…they were embarrassed, but there is a fraction of a fraction of a fraction of a chance since no one was there watching it and can only speculate.
http://www.theguardian.com/sport/2014/sep/04/ryder-hesjedal-motorised-bike-vuelta-espana
Not sure how anyone can say the wheel did not come to a complete stop. I watched several times and could not see this at all. Even if the bike itself came to a stop, which it doesn’t appear to do either, that wouldn’t mean the wheel would have to stop spinning. It was spinning fast when he went down and likely continued spin and skip on the pavement until it was crunched by the moto. Wheel spinning that fast is not going to come to complete stop in a second or two unless you put a lot of force directly on the tire, which isn’t happening here at all. Think skipping stone across a pond, or a driveway.
Franz video isn’t a perfect demonstration but it demonstrates the forces at action.
Did anyone notice the bike handling skills of the trailing rider? Locks up the rear wheel, skids, and then starts pedaling again.
As for Ryder’s bike…once his rear tire sidewall hit the ground it would be like hitting a giant brake pad and would quickly stop…unless he lifted the bike up by the handlebar while he was sliding to effectively remove almost all downward force and friction points like the guy in the video.
Very unnatural! Now, someone needs to get a motorized bike and try to replicate the bike position and forces and video it for us to evaluate.
that’s not the way it happened on the video, no hand!
He is riding down a steep ass mountain on a road bike. Why on earth would he want a motor engaged on his rear hub?
I’ve unconvinced myself – not the front wheel.
I’ve seen motorcycles do that same move- when the throttle got twisted into the ground! And I did the same thing Ryder is doing- dive for the kill switch! He is the biggest cheater in a sport of cheaters on a cheating team, but no surprises there really…
This could be a preview of future Tour bike crashes!
Why is this even a discussion? Ridiculous…..Newton would be laughing at this
http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Inertia-and-Mass
Michael Rasmussen was the first with these new drugs. Half the body fat percentage of Lance and no muscle. WADA has banned the first generation of these drugs but riders are now using the third generation. Once the testers have caught on to the new drugs and created tests the riders are already on to something else, they are chasing ghosts. This is why the average speed in Grand Tours never drops even though all the riders say they aren’t doping. It’s true, they aren’t doping, what they are using is not banned.
Looks like Froomey.
I cannot believe how many physics experts out there missed that the wheel is rotating BACKWARDS! It is hilarious. Yes, he was using anti-power assist because being in the breakaway was too easy and he needed some hard training. Haha!
Intel Inside.
The wheel is rotating *BACKWARDS* *BACKWARDS* *BACKWARDS* *BACKWARDS* *BACKWARDS*. This is an embarrassing demonstration of the state of science education in this world. Please stop with these ridiculous “discussions”!
This bike is doing exactly what it is supposed to do. Momentum at work.
• If there was some kind of motor within the frame, it would be connected to the C R A N K S, not the rear hub, so it would be the cranks that would continue to spin if a motor had somehow refused to go idle.
• If there was a motor connected to the cranks (and it was still engaged on a downhill), Ryder would not have laid it down. He’d have gone straight over the edge (without falling first). Law of physics: “An object in motion, tends to stay in motion.”
The handlebars created a pivot-point, just like in the Rasmussen demo. The continued perpetual motion of the C O A S T I N G rear wheel, combined with traction (caused by slight contact with the road) and the pivot-point of the bars, caused what you see. Physics at work.
He is in 37th place and 30 minutes down in the GC. What’s this about a motorized bike?
Bingo. The pedals and bars acted as pivot-points. The momentum of the wheel created the centrifugal force that allowed it to rotate on one of those two axis.
That bike skids back tire first, which should scrub some of the momentum from the spinning wheel. then as soon as he unclips the bike seems to spin at a constant rate. No deceleration as the spinning wheel slows. It just looks odd. How easy would it be to hide a switchable electric motor within DI2? Could it be triggered with a shifter button that was damaged in the shifter down fall of Ryder’s accident. A late season race, with a Ryder nobody would be looking at would be a good test mule. I don’t know how it would be powered.
Except that with Ryder’s bike it spins in the opposite direction of the wheel’s spin, from what I can see…
Here’s the motor: http://www.bikeradar.com/us/gear/category/bikes/electric/product/review-gruber-assist-conversion-kit-42720/
I want one, just to keep up with my buddies!
The wheel is spinning backwards? Wow, Not only do they have motorized drive trains they even have reverse!
I don’t see the wheel spinning backwards; looks to me to be forward and pulling the bike in the wrong direction that natural spin would.
Shouldn’t his cranks be turning backwards, then?
Nope, check again, it spins in exactly the same direction as in the movie shot by Alex Rasmussen.
The rear wheel never stopped rotating. When the wheel wasn’t touching the ground immediately after the crash there was just a little sliding motion, but then it regained contact with the ground, and the bike started spinning. Just like in the video Alex made. You can test it yourself at home. Case closed.
no, it goes in the direction it should, assuming the pivot point is at the handlebars somewhere. Just watch Rasmussen video, it is exactly the same case. Wheel rotating FORWARD (as it normally would) and bike spinning just the way Hesjedal’s bike was spinning.
I have to say that it is a very simple case of his speed modulation control being damaged and stuck in the “go” position. Don’t believe me? Look it up, man, look it up.
John Puffer A lot of comments elsewhere on this. It looks to me like the Cannondale Rider gets a slight bit loose and Ryder over corrects bringing him down. His left foot is immediately un clipped. His rear wheel comes up then comes back in contact with the ground. Most people assume that this stops the rear wheel, in my opinion (and Newton’s) it wouldn’t. The video is in slo motion so it distorts how fast he is going when his rear wheel is in contact with the ground. Ryder’s hands are also not on the brakes when he is on the ground, Thus the rear wheel is going to “spin” as fast as it is going down the road, just like when you are riding. As Ryder slows down he starts trying to get his right foot out, which means he is lifting his heel and probably the rear of the bike ever so slightly. The rear wheel then would likely have keep spinning. When he finally gets his foot free, the rear wheel comes back into full contact with the ground. At that point the bike would accelerate as it began to “hook up” with the road surface again.
John-I think you’re close. I think another contributing factor is that I believe the pedal must be in such a position that it allows the bike to pivot around with very little resistance. The left brake lever is touching the ground, but his crank needs to be in a perfect location, to position the pedal, to allow the bicycle to spin around it.
And he won the stage today. Lets roll this to a hundy…or start making that entry equation algebraic?
The motor was for recovery day. The onto the win without the motor. *Wile E Coyote… Genius…”
What people are missing here is that more than one thing at a time can have momentum. The wheels had momentum before (and after the) crash. The bike “as a unit” had momentum. The wheels in combination with a static surface can change momentum. Ryder had momentum. The cranks had momentum. Anything that can pivot can (and will) pivot.