Plan B Forum

Tiny Motor Powers a New Threat to Cycling Races
Ian Austen

A grueling cycling race is somewhat less grueling if your bike is a motorcycle. Understanding this, some cunning cyclists may be turning the sport into Nascar on two wheels by surreptitiously giving their bikes a motorized boost.

The first confirmed case of mechanical doping surfaced this year when a tiny motor and battery were found inside a Belgian cyclist’s bike, but that involved cyclocross, a comparatively minor branch of the sport. The latest accusations emerged Sunday on Stade 2, a sports program on the French television network that is also the host broadcaster of the Tour de France. The report suggested that motor doping is also at the highest levels of the sport.

rubato wrote:Is it worth the weight penalty?

At the Cyclocross World Championships earlier this month, Belgian cyclist Femke Van den Driessche had her bike confiscated by the UCI—the governing body of pro cycling—and a motor was found hidden in the seat tube of the frame. Believe it or not, hidden motors, or "mechanical doping," has been on the UCI's radar for some time, though this is the first time that a motor was actually discovered in competition.

These motors are nifty if dubious little contraptions. The Vivax Assist is one of the most popular models, though the UCI has not specified what motor was found in Dressche's bike. The 22-cm (8.7-inch), 750-gram motor is slotted into the top of a bike frame seat tube and pushed down to the bottom bracket. The motor kit comes with a gear ring that is positioned over the crankshaft and connects to the bottom of the motor.

The button to turn on this motor connects to an electronic control unit that is housed in a special seat post (provided with the motor kit) and routes to the motor via the seat tube. The standard kit comes with a battery bag that can be tucked under the saddle, though Vivax Assist offers an Invisible Performance Package that hides the battery and activation button in a water bottle to "invisibly transform your racing bike into an e-racing cycle" (see video below). The setup weighs between 1.8 and 2.2 kilograms (4 to 5 pounds), depending on battery options, but it provides an additional 100 to 150 watts of power to the driveshaft.

Ostensibly, motors like the Vivax Assist were created to give commuters a greater range and allow older or less proficient cyclists to ride with faster friends, and the Invisible Performance Package was developed to retain the aesthetics of your bike. But clearly the design has made its way into professional competition.

rubato wrote:Ye gods moron can't you even discuss a simple technical question without being a dick?

You apparently never followed bike racing. Otherwise you would know how important weight is in uphill contests. Riders often had specially lightened bikes for alpine stages like the famous alpe d'huez or the mt ventoux time trial.

A rider who was 5 lbs overweight would be at a significant disadvantage and larger and more muscular riders don't do well going uphill in the mountains anyway.

So the question is whether the significant weight disadvantage is actually offset by the power avail. Before the battery runs out.

On the flats weight is less important and air resistance is more important.


To put it another way, people spend a lot of money getting a bike that's 5lbs lighter.

yrs,
Rubato

Bicycle Bill wrote:I wouldn't worry so much about the elite pros using this technology and getting away with it.  Now that the cat is out of the bag and the officials know that it is out there — and has already been attempted — they will do things like x-raying the bikes or using infra-red scanners to detect the heat signature of the little motor.  And events like the UCI World Championships, the Olympics, or major events like the Tour de France have the funds, the ability, and the motivation to do something like this in order to protect their reputations.

It's the lesser events, the club rides, the recreational events, or even "personal bests" set through the STRAVA app, often unsanctioned with the USCF or any other 'official' body and run on a shoestring where they cannot afford the cutting-edge tech necessary to detect this new form of cheating, where we will see this technology come into its own.  Questionable techniques and tactics are already being employed and I have seen many examples of it already.  People like myself are already willing to spend five thousand dollars or more on a 'race-ready' bike made with all the latest frame materials, aerodynamic design technology, and bleeding-edge componentry; as soon as these in-frame hidden motors become a little less expensive and thus more common — in fact, I fully expect they will eventually be able to be retro-fitted within an existing bicycle to even further mask the assist — a 'friendly' bicycle race between friends will become a 'friendly' moped race instead.
 
-"BB"-

Jarlaxle wrote:

rubato wrote:Ye gods moron can't you even discuss a simple technical question without being a dick?

You apparently never followed bike racing. Otherwise you would know how important weight is in uphill contests. Riders often had specially lightened bikes for alpine stages like the famous alpe d'huez or the mt ventoux time trial.

A rider who was 5 lbs overweight would be at a significant disadvantage and larger and more muscular riders don't do well going uphill in the mountains anyway.

So the question is whether the significant weight disadvantage is actually offset by the power avail. Before the battery runs out.

On the flats weight is less important and air resistance is more important.


To put it another way, people spend a lot of money getting a bike that's 5lbs lighter.

yrs,
Rubato

I forgot, I'm dealing with Ozzie here...not sure I can explain this on the level of a 3-year-old, but I'll try. The weight added is not significant, because (use your reading finger here) when climbing, the rider can simply engage the electric motor on steep grades!

Jarlaxle wrote:"...

I forgot, I'm dealing with Ozzie here...not sure I can explain this on the level of a 3-year-old, but I'll try. The weight added is not significant, because (use your reading finger here) when climbing, the rider can simply engage the electric motor on steep grades!

But is that weight worth it? It depends. In a hidden system like this, the battery isn’t large enough to provide power for an entire road race, although it could for most of a cyclocross race, which runs an hour for elite men and 45 minutes for elite women. Most of the time, it would be up to the rider to decide when to turn the system on and off—for crucial climbs or attacks, for instance. The systems are said to be very quiet—possibly undetectable against crowd noise or even nearby cars and motorcycles in the race caravan.

Vivax claims its stock system provides 200 watts of additional power to the crankshaft, but due to efficiency losses, actual power at the wheel is anywhere from 40 to 100 additional watts depending on the rider’s own cadence. Burn time is 40 to 100 minutes, according to Vivax’s charts. At slower cadences, the motor helps more than it does at faster RPMs. Depending on the version, once above 75 or 90 RPM, the power assist drops dramatically because the rider’s own pedaling rate is faster than the motor’s.

That’s for the stock system; a custom system could be tuned to work at higher cadences, or to provide power over a shorter period of time. Even a modest boost of 20 to 30 watts could make a significant difference on a long climb in a stage race like the Tour de France.