Motor doping thread

[sniper]

Re: Re:

If 50 guys say the car is yellow, and two guys say it's green., well, it's probably yellow.

Oh boy, think again about this argument.

It's not an argument. It's a metaphor meant to clarify an argument.

It's as stupid as it possibly gets.

Whilst it surely wasn't the best choice of metaphor, your response quite neatly demonstrates that in fact it can get stupider. But lets move away from calling each other stupid. It's stupid.

I'm not even claiming anything. But you have to acknowledge that it's very hard to tell. We have moving camera angles that are from the front mostly. And reference points to compare to that are not steady themselves. Very bad circumstances to reliably detect small unnatural changes in momentum.

Agreed.

I have seen many people so far who have expressed their conviction that a motor has to be in play. But nobody of them has actually made a convincing argument for it.

Don't hold your breath. It looked unnatural to a bunch of people, and not so unnatural to another bunch of people. I don't think anybody claims it would stand up as evidence in a court room.

In the end it doesn't change much about the reality of motors and the need for journos to start/continue digging. Like the Stade 2 guys, whom (iirc) you remarkably accused of bad/sloppy journalism.

After all these 'incidents' concerning Van Aert, it's pretty sad to think that the UCI probably still won't check his bike at the next race he enters.

 

[Tienus]

I see your point. It's really not easy to see but I feel that (when watching it frame-by-frame) the front wheel kinda falling into a small hole or hitting a small bump leads to this impulse and it therefore is not a clean highsider. I don't think that it's the rear wheel re-gaining traction or anything like it that initiates this jump. But hard to tell.

CX size wheels have the tendancy to roll over bumps and holes. If the hole or bump is too big the front wheel will get airborne hitting it and not the rear.

Why should the wheel stop turning when he stops pedalling? Traction on this mud is small and angular momentum can't suddenly vanish into nowhere.

Stop is not the right word, I would expect it to slow down significant. In the slip he stops putting energy in the rear wheel before his right foot reaches bottom dead point. After this his tire still spits out dirt and judging by the shape of the tire its making good ground contact. You can also see the question mark shape skid. I would expect a pro cyclocross wheel to be very light which means it does not need much friction to get rid of the kinitec energy.
Here is a good tool to watch frame by frame:
http://rowvid.com/?v=2VGrJ6M6VGY

Don't get me wrong: A hub motor would help a lot to lose the rear wheel in this situation, no doubt about it. I just look at this footage and ask myself: Do we really need a motor to explain what we're seeing? The underground at this spot is very slippery, he chooses a line that is not very smart given the angles of the terrain and he tries to overtake and therefore pushes hard. I feel that, combined, this is enough to lose the rear wheel like he does without external "assistance". But open for debate for sure.
(As a matter of fact I have a considerable scar on my elbow from having done the same mistake on my mountainbike once. Lost the rear wheel after having attacked the terrain on the same bad angles. But that doesn't add any value to this discussion.. :lol: )

We dont need a motor for power oversteer, it could be achieved by pedalling only. I have actually never seen it before in cycling in an allmost straight line. I disagree that the angles of the terrain are bad, there seems to be a bit of camber but looking at the metal fence its not too bad. It sure is slippery but thats normal for cyclocross, the reason the riders all choose the same line is the compactness / less rolling resistance. If there was less rolling resistance on the slippery part they would all ride there since there is no turning involved.

Do you agree its most likely power oversteer? Thats the first response I posted to this incident because it is very rare to happen when you cycle in a straight line.

Thanks for clarifying the Varjas interview.

LaFlorecita wrote:
People still don't get it.
Three times his rear wheel seemed to have a mind of its own. I call BS.

I absolutely do get it but I call BS on this argument as well.

I disagree. I know the human brain could easily be fooled. But if van Aert's wheel is fooling the brain of many people often one has to wonder if its not van Aert who is fooling us.

 

[Nicko.]

Re:

To me and to a whole bunch of other folks it looks as if he is propelled forward after his wheel hits the bump. It looks like an increase in momentum. It looks like a motor.

You didn't adress my points. You come with "it looks like"...

I'll tell you why it can't be a motor from the observation "it looks as if he is propelled forward after his wheel hits the bump. It looks like an increase in momentum."

Assume the hub motor has 200W (=overestimate by 2-4x)
Apply 200W for 0.5sec (the time between last pedal stroke to 'catapult')
Now your motor put 100J in to the 80kg body, traveling at say 10m/s.

Velocity after motor 'bump': 10.12 m/s.
1.2%

Physics. Sniff test...?

 

[Tom the Engine]

We owe the developmment of our knowledge in that period [world ain't flat afterall] to a minority of people capable of critical thinking.

I agree on this but, you know, "critical thinking" has nothing to do with "to criticise" or "to be critical of". The fact that these expressions are so similar is very unfortunate as it leads to many people thinking of themselves as "critical thinkers" just because they proudly disagree with the mainstream. While in fact they're often hardly capable of constructing or deconstructing even the simplest sound and consistent argument. And have spectacular track records of falling for all sorts of different logical fallacies.
To critically evaluate an argument is independent of the position behind it. Could be mainstream or not. Doesn't matter. It's about the methodology used in the reasoning process and not about the result.

If it looks unnatural to a shitload of people who ve watched a lot of cycling in their lives, well that's probably because it was unnatural.

Oh no, here it is again, the yellow-car-argument in a different flavor.
Maybe you all got fooled by the deceptive front view? Estimating distances and speeds from front view are a tricky business. As said, I'm not sure myself.

With all due respect, I might be a rookie-poster in the forum but I've followed this for a long time now. And what has become very evident is that a ton of people in the online communities have their judgement dominated by wishful thinking. The natural enemy of critical thinking. So I couldn't care less how many of them believe this or that.

And here is a prediction: At some point in time we will have more proof for motors. I would be surprised if not. And then all the people who just screamed "motor" whenever they saw a video of somebody riding a bike will take this as a personal victory and run around with a told-you-so attitude. Independent of whether they made any sensible statements on the way or not.

It's not an argument. It's a metaphor meant to clarify an argument.

You can call it whatever you want. The implication that an argument carries more truth simply because more people believe in it is stupid. And calling it out as stupid is not more stupid. (And for the record: I didn't call you stupid, just this sentence.)

Like the Stade 2 guys, whom (iirc) you remarkably accused of bad/sloppy journalism.

Yes I did. But there is a differentiation very much in the spirit of "critical thinking" vs. "to criticise".
I applaud them for taking on this spicy topic and trying to uncover something that many of us think is there in some way but some authorities would not like to have revealed.
But I indeed did not like their documentary ver much and I think it's flawed on many levels (and I added a whole list of arguments as to why).
So full credit for the intentions but their end-product is not good journalism. Got it?

 

[Sciatic]

Re: Moto-fraud: first rider caught

Sorry about the double posting

 

[Sciatic]

Re: Moto-fraud: first rider caught

Someone posted the wiki link earlier, which includes this statement:
"Once a tire slips in a curve, it will move outwards under the motorcycle. What happens from there depends on how well the rider is able to restore balance and control. If the tire regains traction after the rider starts to skid while the motorcycle is moving sideways, the tire will stop its sideways movement causing the motorcycle to suddenly jerk into an upright position (and beyond). This movement can easily cause the rider to be thrown off."

Note in the video that the moment the bike starts to straighten and seems to accelerate is when the spinning tire leaves a patch of blackish colored mud and enters a different colored (sandy colored) soil. Is that enough to partially explain this?

BTW, I haven't ridden cross and thus not much in dirt or sand, so I'm not trying to speak from personnel experience.
But I do think motors are out there.
Thanks[/quote]

 

[Sciatic]

Re: Moto-fraud: first rider caught

Someone posted the wiki link earlier, which includes this statement:
"Once a tire slips in a curve, it will move outwards under the motorcycle. What happens from there depends on how well the rider is able to restore balance and control. If the tire regains traction after the rider starts to skid while the motorcycle is moving sideways, the tire will stop its sideways movement causing the motorcycle to suddenly jerk into an upright position (and beyond). This movement can easily cause the rider to be thrown off."

Of course, maybe this is the point people have been trying to make: the behavior in the wiki-description occurs in a vehicle with . . . A motor

 

[hrotha]

Hey guys can we please stop saying that anybody thought the earth was flat, much less implying that anyone who claimed it was round would get in trouble with what passed for a scientific community at the time? K thanks.

 

[sniper]

Nicko, I owe you a response but it's well above my paygrade. Maybe someone better versed in physics than me can address it.

 

[muddyarse]

Is this the time to revisit Wout's rear wheel spinner at Hoogerhide 2015-16 WC?
4th rider through the corner at 10:50:

https://youtu.be/TUOS8v6QlCM?t=10m50s

 

[Tom the Engine]

After this his tire still spits out dirt and judging by the shape of the tire its making good ground contact. You can also see the question mark shape skid. I would expect a pro cyclocross wheel to be very light which means it does not need much friction to get rid of the kinitec energy.

At this point I simply have to admit that I can't see anything conclusive in the video. Neither way.
But we can do indirect arguments about momentum and loss of it. Speeds and distances are hard to judge in front view. Just imagine for a second how this situation might have looked from side view. The fact how quickly van Aert passes the other riders indicates that he was much faster than them to start with. And the first rider starts slow-pedalling and then stops altogether to prepare for the upcoming turn while van Aert goes full gas on his rather reckless maneuver to overtake him.
After his sliding and saving happend the two riders end up side-by-side, going at more or less the same speed (that's where we first see a side view). And van Aert is not accelerating away there, he just got the inner line in the turn. And if anything, then the other rider lost momentum, too, in this process, as he may have touched the barriers or he may have hit the brakes but we don't really see.
And then also take the third rider into account. He also stops pedalling before the turn. When the camera goes into side view we first see that this third rider first is at quite a distance from the other two. But he comes much closer in very short time, which is also an indication that van Aert might have lost a substantial amount of momentum in this incident as is to be expected.

I disagree that the angles of the terrain are bad, there seems to be a bit of camber but looking at the metal fence its not too bad. It sure is slippery but thats normal for cyclocross, the reason the riders all choose the same line is the compactness / less rolling resistance.

No, the angles are not bad in general. What I'm saying is: The angles of the line he takes are bad.
There are two good lines to take in my view, the one on the right and one on the left. And I agree with you on why all riders choose the same line. But the one thing that you shouldn't do as a rider there is to change from one line to the other in-between as van Aert does. That's where the bad angle is.
If you choose a line like this you expose your bike to those dangerous lateral forces that may result in loss of wheels. And the slippery ground at this point and the fact that he goes full gas just adds to that. And if you watch the video carefully, right before the wheel starts sliding away he's leaning slightly to his left (the bike is visibly tilted from the front), which also adds to this lateral force.
And heck, a hub motor would make it even much worse but as said I feel that the other factors are enough already. I consider his decision to overtake there the way he does a bad tactical mistake and he almost paid for it.

Do you agree its most likely power oversteer?

This really depends on your exact definition of power oversteer.
I'll keep it general: The lateral force on the rear wheel was bigger than the lateral traction that the ground could provide at this point. And the fact that he was driving his rear wheel hard (by pedalling for sure and probably a motor) certainly was an important factor for it.

I disagree. I know the human brain could easily be fooled. But if van Aert's wheel is fooling the brain of many people often one has to wonder if its not van Aert who is fooling us.

There is an assumption in there that we've seen all spinning wheels in cyclocross races so far and it's exclusively van Aert who is affected by it. I don't believe this for a second. Every rider who carries his bike with a pedal in vertical position that hits the ground ends up with a spinning wheel.
The reason we're discussing van Aert could also be plain selection bias. First he's on camera a lot more than other riders and secondly people who are looking for motors to post clips about it on social media might focus on him specifically since there are rumours about him.
In addition the first two examples are really not that convincing in my view if you look closely at them.
Honestly I'm not willing to watch hours of cyclocross footage. But I'd hypothesize that more wheel spins in the mud and such stuff would be found if you'd focus on it.

 

[Huapango]

Re:

I guess Van Aert needs a bit more traction than the rest of the bunch, with the extra horsepower under the hood: http://www.cyclingweekly.co.uk/news...sed-win-cyclocross-world-championships-309215.

 

[Tom the Engine]

Re:

Is this the time to revisit Wout's rear wheel spinner at Hoogerhide 2015-16 WC?
4th rider through the corner at 10:50:

https://youtu.be/TUOS8v6QlCM?t=10m50s

Thanks for the video. I've only seen the short clip before and not the whole race so this was enlightening for sure.
(Disclaimer: I'm not very familiar with cyclocross. In fact this is the only race so far that I've watched in its entirety.)

I don't consider this clip by can Aert to be very suspicious - even less so than before.
In my view this is a simple but extreme wheel spin because of lack of traction and the following points are the reason why it's so pronounced:

1) The inner line in this left turn seems to be extremely slippery. Many riders struggle mightily on it (and as the race goes on it turns out that taking the outer line might be the better strategy if you want to ride through).

2) While taking this turn he slows down and almost comes to a standstill. That's a mistake. When struggling with bad traction (be it on a bike in mud or with a car on a steep snowy uphill road) you have to keep going no matter what - as soon as you're standing still or getting too slow it's game over.

3) Then he's leaning forward quite considerably. Therefore reducing the weight on the rear wheel, which is bad for traction of the rear wheel.

4) He not only slows down but in addition he also stops pedalling completely. And then all of a sudden he starts pedalling again very forcefully. This cannot possibly work well under the given circumstances! When traction is bad you have to apply your force as smoothly and regularly as possible. Abrupt changes like this power spike he tries to produce here necessarily lead to massive or next to complete loss of traction. And therefore to an almost comic-like spinning wheel like we're seeing here.

5) One aspect of why it looks so strange is that he actually makes it through and completes several full rotations with the pedals before he regains traction. When you're pushing the pedal hard but you don't feel the resistance that is expected (since the wheel is slipping) it might throw you off-balance as it's like stepping into a hole. And you can see other riders in the video who have the same strong kind of wheel spin but who get off the bike after one half or one full pedal rotation because of it. Van Aert probably was prepared for this to happen and showed good balance - otherwise he would have had to put a foot on the ground quickly and there wouldn't be anything to discuss.

Such wheel spins really happen all the time in this race. Just look a bit a the race footage how bikes slide around and wheels lose traction constantly. The scene from Van Aert is among the more extreme for sure. But I don't see why we would need a motor to explain it. There are a couple of reasons why he has next to no traction (as discussed above) and the rest just follows from this.

 

[sniper]

I haven't seen the worlds, but hearing about Van der Poel's four or five mechanicals made me raise an eyebrow or two.
Did his motor jam?

Van der Poel won in Zeven last year beating Van Aert after an impressive comeback following a mechanical:

“In the sandpit, someone touched my rear wheel and some spokes went out. I couldn’t get in my light gear anymore and it was a lot of time before I could change my bike.”
...
Despite the early setback, he remained calm and trusted his training as he slowly worked his way back up through the field. His comeback could have easily been derailed by trying to make up too much ground too quickly or railing it too fast through some of the technical sections. Instead he worked his way up spot by spot and left enough in his legs to launch his impressive performance on the definitive seventh lap

http://www.cxmagazine.com/2016-zeven-world-cup-mathieu-van-der-poel-wins-overcomes-mechanical-results

 

[sniper]

as we're (re-)analyzing more or less dodgy footage, there was this one from Adrien Costa:
https://www.youtube.com/watch?v=tZerARsCqAE
The dodgy thing, imo is *not* the spinning of his rear wheel (which may have been induced by the impact of the pedal on the ground), but how quickly he picks up his bike *after* he sees his wheel spinning.
He just crashed on the ground to catch a breath, then sees his wheel spinning and remarkably decides to stand up, pick up his bike and rest on it.

Looks to me, as soon as he sees his wheel spinning he has a brief heart attack thinking "christ on a bike didnt I switch of the engine?"

 

[Tienus]

@Tom
It sounds like we agree in general.

But he comes much closer in very short time, which is also an indication that van Aert might have lost a substantial amount of momentum in this incident as is to be expected.

I agree and I think he lost that momentum by friction during that slide and the torque when his rear wheel finds grip again.

But the one thing that you shouldn't do as a rider there is to change from one line to the other in-between as van Aert does. That's where the bad angle is.
If you choose a line like this you expose your bike to those dangerous lateral forces that may result in loss of wheels. And the slippery ground at this point and the fact that he goes full gas just adds to that. And if you watch the video carefully, right before the wheel starts sliding away he's leaning slightly to his left (the bike is visibly tilted from the front), which also adds to this lateral force.
And heck, a hub motor would make it even much worse but as said I feel that the other factors are enough already. I consider his decision to overtake there the way he does a bad tactical mistake and he almost paid for it.

The initial rear wheel losing grip is due to lateral force, the big powerslide is due to his wheel spining fast in my opinion.
Its got nothing to do with the motor discussion but I dont see him making a tactical mistake. Its the last lap iirc and overtaking just before a turn can give you a huge advantage. If he would not be riding close to the limit he would not be that good.

There is an assumption in there that we've seen all spinning wheels in cyclocross races so far and it's exclusively van Aert who is affected by it

I did not make that assumption. I write van Aert because 3 clips of him have ended up in social media and I dont know of any other examples. I could have written pro cyclocross rider instead of van Aert. I know there are much more wheel spins if you only look at the Hoogerheide alone race like you did. The question is why people think it looks odd and post it. You have given plausible explanations for that. I also thought all three clips looked strange the first time I looked at it. That on its own does not mean much but what if there is one or more clips posted of him every week? Many riders have white text on the side of the rims so I dont think that makes a difference. If van Aert or other riders trick our brains often we have to wonder why did this not happen before and it could ofcourse just be the aftermath of the Femke incident.

In general:
Van Aert and van der Poel are both also good road racers and I think motordoping is done by all teams who get results. Lars Boom is riding cyclocross this season and I have seen many suspiscious road bike changes of him since 2008.

 

[Tienus]

I haven't seen the worlds, but hearing about Van der Poel's four or five mechanicals made me raise an eyebrow or two.
Did his motor jam?

I havent seen the race either but all riders where having a lot of punctures. Some had to forfait after all there spar tires where flat.

 

[Tienus]

Looks to me, as soon as he sees his wheel spinning he has a brief heart attack thinking "christ on a bike didnt I switch of the engine?"

I agree. The spinning looks normal his reaction a bit suspiscious.
From the video his rear wheel looks the same as the one van Aerts is using.

 

[Valv.Piti]

Re:

I haven't seen the worlds, but hearing about Van der Poel's four or five mechanicals made me raise an eyebrow or two.
Did his motor jam?

Van der Poel won in Zeven last year beating Van Aert after an impressive comeback following a mechanical:

“In the sandpit, someone touched my rear wheel and some spokes went out. I couldn’t get in my light gear anymore and it was a lot of time before I could change my bike.”
...
Despite the early setback, he remained calm and trusted his training as he slowly worked his way back up through the field. His comeback could have easily been derailed by trying to make up too much ground too quickly or railing it too fast through some of the technical sections. Instead he worked his way up spot by spot and left enough in his legs to launch his impressive performance on the definitive seventh lap

http://www.cxmagazine.com/2016-zeven-world-cup-mathieu-van-der-poel-wins-overcomes-mechanical-results

Thats just clueless. Everybody punctured everywhere in that race.

 

[sniper]

Re: Re:

Fair enough of course.

 

[sniper]

Lol, Vayers own "Wout Van Aert motorbike compilation"
https://youtu.be/rUGNKwcbbDw
Tweet: https://twitter.com/festinaboy/status/828564395387187202

Nota bene: the first one in that clip is new to me and looks extremely weird.
Thoughts?

 

[King Boonen]

Re:

Lol, Vayers own "Wout Van Aert motorbike compilation"
https://youtu.be/rUGNKwcbbDw
Tweet: https://twitter.com/festinaboy/status/828564395387187202

Nota bene: the first one in that clip is new to me and looks extremely weird.
Thoughts?

He pushes the pedal down and the wheel turns. How does that look extremely weird?

 

[Nicko.]

Ok, listen up all non-engineer-types:
before you think/say/decide "motor" when you see a wheel spin up in a CX race, you need to decide whether this 'motor' sits in the hub or the crank.
I'm leaving the rim-based wheels out out of this one (for obvious, physical reasons).

Crank motor:
high power (>200W) AND high wheel torque/traction force is possible, depending on gearing
rear wheel can spin/slip even when loaded
cranks MUST rotate in synchronicity with the rear wheel

Hub motor:
with the hub diameter limited to ~40mm, power is limited (<50W?) by the size constraints and the necessity of a gear box, axle and electrical stuff.
But the wheel torque/traction force is VERY limited since the peak RPM of the motor must be geared for peak wheel speed (50kph?).
That means that during acceleration after the turn at 15kph there might, maybe, be 20W available, or ~0.5 kgf of traction force.
Rear wheel CAN be driven without cranks moving
Rear wheel will NEVER spin/slip when loaded, only when lifted off the ground

If you want to call "MOTOR!", decide which motor type and check with the properties above before you go public.

Carry on.

 

[veganrob]

Re: Re:

Is this the time to revisit Wout's rear wheel spinner at Hoogerhide 2015-16 WC?
4th rider through the corner at 10:50:

https://youtu.be/TUOS8v6QlCM?t=10m50s

Thanks for the video. I've only seen the short clip before and not the whole race so this was enlightening for sure.
(Disclaimer: I'm not very familiar with cyclocross. In fact this is the only race so far that I've watched in its entirety.)

I don't consider this clip by can Aert to be very suspicious - even less so than before.
In my view this is a simple but extreme wheel spin because of lack of traction and the following points are the reason why it's so pronounced:

1) The inner line in this left turn seems to be extremely slippery. Many riders struggle mightily on it (and as the race goes on it turns out that taking the outer line might be the better strategy if you want to ride through).

2) While taking this turn he slows down and almost comes to a standstill. That's a mistake. When struggling with bad traction (be it on a bike in mud or with a car on a steep snowy uphill road) you have to keep going no matter what - as soon as you're standing still or getting too slow it's game over.

3) Then he's leaning forward quite considerably. Therefore reducing the weight on the rear wheel, which is bad for traction of the rear wheel.

4) He not only slows down but in addition he also stops pedalling completely. And then all of a sudden he starts pedalling again very forcefully. This cannot possibly work well under the given circumstances! When traction is bad you have to apply your force as smoothly and regularly as possible. Abrupt changes like this power spike he tries to produce here necessarily lead to massive or next to complete loss of traction. And therefore to an almost comic-like spinning wheel like we're seeing here.

5) One aspect of why it looks so strange is that he actually makes it through and completes several full rotations with the pedals before he regains traction. When you're pushing the pedal hard but you don't feel the resistance that is expected (since the wheel is slipping) it might throw you off-balance as it's like stepping into a hole. And you can see other riders in the video who have the same strong kind of wheel spin but who get off the bike after one half or one full pedal rotation because of it. Van Aert probably was prepared for this to happen and showed good balance - otherwise he would have had to put a foot on the ground quickly and there wouldn't be anything to discuss.

Such wheel spins really happen all the time in this race. Just look a bit a the race footage how bikes slide around and wheels lose traction constantly. The scene from Van Aert is among the more extreme for sure. But I don't see why we would need a motor to explain it. There are a couple of reasons why he has next to no traction (as discussed above) and the rest just follows from this.

So the guy who is not familiar at all with cyclocross and watched his first race ever just recently is telling the World Champion how to ride his bike?

 

[sniper]

Very fair points Nicko.

@kb, u may be right. I think I am seeing ghosts now.