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Does he have an engine tucked into his bike frame? Clue: no.

Heads up conspiracy fans! First it was Cancellara, and then Hesjedal... New video footage has come to light that proves* road riders are using cheeky motors in their down tubes to help them up the climbs! Don't believe us? the vid is below...

As you can see from the video, Hesjedal's bike continues to move after he's flung clear of it, and then the moto runs it over. That's enough for some salacious headlines, such as Dirt's Is this video proof that roadies really are the biggest cheating bastards ever?

And is it? Well, no. It isn't. And here's why.

Firstly, Hesjedal goes down on a downhill, and he's going quickly, so the bike is carrying plenty of momentum. It slides while he's still in contact with it. When he's clear the bike is still moving but most of the mass has been removed, and the only parts of the bike contacting the road are the front tyre, one shifter and the rear tyre. The front tyre starts to roll down the hill, and because the rear wheel is in angular contact with the surface it moves in an arc, turning the bike round.

Secondly, the system we're talking about is something like the Vivax Assist, which is hidden in the down tube of the bike and drives the bottom bracket. Here's a helpful video explaining how it works. and here's another one in full conspiracy mode. The main thing to note is that it's a bottom bracket system. It drives the pedals. Do Hesjedal's pedals go round? No.

Thirdly, come on. Motors in bikes? Plausible deniability? You can't claim it was a dodgy steak or an 11-pint bender.

So, any questions?

*it doesn't really prove it

Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.

26 comments

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rggfddne [217 posts] 2 years ago
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I call it gravity doping myself. Turns even the fattest - infact especially the fattest - into speed demons.

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andybwhite [250 posts] 2 years ago
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even if he did have a sneaky motor he wouldn't have it engaged going downhill !

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andycoventry [110 posts] 2 years ago
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The crank isn't moving so it would have to be rear axle driven, and that would be one small motor...

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Mr Agreeable [178 posts] 2 years ago
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I wish you were as classy as Dirt. I'd be able to look forward to clickbait posts like "Are downhillers the fattest pie-sucking knobheads in cycling?", or "Enduro - for when you're too old and frightened to win a proper race ".

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Malaconotus [100 posts] 2 years ago
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I watched this nonsense gather momentum over at Cycling News's 'The Clinic' subforum. The sheer number of people prepared to propose, defend and floridly embellish the ridiculous was staggering. Put me off the whole forum and put their lurid allegations of doping by just about the entire peloton in perspective.

When it was pointed out that a motor that drives the wheel in the direction it moves would not be much of a help it was suggested that the motor going into reverse and malfunctioning was what caused the crash?!?!?

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Jimmy Ray Will [529 posts] 2 years ago
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I'm fascinated by the continuing movement of the bike... if you look, its actually accelerating its movement right up until the motorbike runs over it.

Not saying its a motor, but interesting... I would assume its in relation to the camber on the road or something.

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aslongasicycle [385 posts] 2 years ago
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YorkshireMike [91 posts] 2 years ago
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RIDERS SHOULD BE TESTED FOR GRAVITY.

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Simmo72 [618 posts] 2 years ago
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hampsters in the downtube. I use 2 off the buggers, 3 if its a headwind.

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triplettravel [25 posts] 2 years ago
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It is a compressed gas system powered by the ultra high pressure tyre and rim. You can see the gas escaping in the video past the grassy knoll. This is why they keep changing wheels when the gas runs out.

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stenmeister [320 posts] 2 years ago
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triplettravel wrote:

It is a compressed gas system powered by the ultra high pressure tyre and rim. You can see the gas escaping in the video past the grassy knoll. This is why they keep changing wheels when the gas runs out.

Where's Zapruder when you need him to make a film from the Grassy Knoll?

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SteppenHerring [330 posts] 2 years ago
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Motor doping is pretty easy to rule out.

Look at your phone battery - the size, the weight. A lot of research goes into making them as small and energy-dense as possible. Now that battery is maybe capable of delivering 3Wh - 3 watts for an hour. So if you want an extra 100 watts for an hour you haul around 33 of the buggers for the rest of the ride - plus the motor, gears and control system.

That's without factoring in the mechanical and electronic losses in the system.

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Paul J [908 posts] 2 years ago
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Steppenhering: Wh is a unit of energy (power = rate of energy use, 1 Watt is 1 Joule per second, so 1 Wh is 3600 Joules). 3 Wh is enough energy for 1 kW for 10 seconds, or 108 W for 100s.  3

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Paul J [908 posts] 2 years ago
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SteppenHerring: Yes I know that. However, 3 Wh doesn't mean a battery is limited to 3 W. A Wh doesn't have anything to do with power (least not directly), rather it's the total energy capacity. That energy could be put out slowly (i.e. at a low power) or very quickly (high power). Anyway...

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SteppenHerring [330 posts] 2 years ago
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Paul J wrote:

SteppenHerring: Yes I know that. However, 3 Wh doesn't mean a battery is limited to 3 W. A Wh doesn't have anything to do with power (least not directly), rather it's the total energy capacity. That energy could be put out slowly (i.e. at a low power) or very quickly (high power). Anyway...

I'm well aware of that. I just made the calculation simple - want 100 extra watts for an hour, need 33 batteries. Not sure what the max discharge current/internal resistance is for a modern Lithium Ion battery but not a lot I suspect (compared to a lead-acid one).

A boost for a few seconds would be worth sod-all in a long, hilly stage. My original point was that, in order to make a motor assist system useful, the combined size and weight of batteries and motor would be impractical.

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SteppenHerring [330 posts] 2 years ago
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Paul J wrote:

Steppenhering: Wh is a unit of energy (power = rate of energy use, 1 Watt is 1 Joule per second, so 1 Wh is 3600 Joules). 3 Wh is enough energy for 1 kW for 10 seconds, or 108 W for 100s.  3

The abbreviation for Watt is W. Batteries are rated in Wh - Watt-Hours (or mWh often).

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Paul J [908 posts] 2 years ago
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Ah, if you were aware, fair enough.

Note that for a race you don't need 100 extra Watts for an hour, you just need that boost at certain critical times. 100 extra Watt for a minute and a half could be quite valuable. E.g. a 100 W boost to make an attack, or to let you recover after an effort while others can't, or for a sprint - could make quite a difference.

You don't need a big capacity energy wise. 3 Wh would be enough, in a competitive setting. Even if it wouldn't be that useful in a consumer eBike context.

Course, there's all the other extra weight, the motors and cabling, that'd make it not worth it.  1 Oh, and the Ryder ebike allegations are total guff of course.  1

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ratherbeintobago [29 posts] 2 years ago
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Dirt's Is this video proof that roadies really are the biggest cheating bastards ever?

Never passing up a chance to have a pop at Dirt, I'd have to suggest that a major qualification for being a journalist is the ability to write something that can at least be sub-edited into intelligible English.

The Dirt staff, and Steve Jones in particular, seem utterly incapable of this, not helped by 'interesting' formatting, e.g. blue type on a yellow page.

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Must be Mad [574 posts] 2 years ago
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Could I throw in my own conspiracy theory??

Its well known that many tour bikes are underweight, and have to add ballast to bring them up to the minimum weight limit. Could this bike have the balast in the chain stays? that might explain how the back of the bike has more momentum than the front?
From the pictures, it looks like the rear wheel touches the ground (which should have the effect of stalling its spin) - but could the pedals be keeping the wheel off the ground?

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BikeJon [162 posts] 2 years ago
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The Vivax system is just under 2kgs (with a standard battery) and it gives you around 150W assistance. It probably only has around 30 mins runtime. As the article says, the pedals need to be turning (between 30-90 rpm) and the motor stops if you suddenly stop pedalling. But 75W per kilo isn't to be sniffed at!

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J90 [375 posts] 2 years ago
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What the fuck is Dirt? Sounds like a bunch of knuckle draggers to me.

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fpollero [4 posts] 2 years ago
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andyp [1473 posts] 2 years ago
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it certainly looks comedy at first glance, until you *think* for a second.

Also. Why the hell would you engage your secret motor on a *descent*

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aIex [5 posts] 2 years ago
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nuclear coffee wrote:

I call it gravity doping myself. Turns even the fattest - infact especially the fattest - into speed demons.

Actually not. At least law of conservation of energy says so.

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Wooliferkins [50 posts] 2 years ago
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I'd forgotten about Tom Boonens mechanic perfecting the old "Wheel in the Face" routine in Jimmy Ray Will's video

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don simon [796 posts] 2 years ago
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I'd heard that there is a motor available that is driven by the magnets that the TV helicopters carrry. Discreet and lightweight but only works when the helicopters are close.
That's what a bloke in the pub said anyway.