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Am I the only cyclist here? I can't imagine voluntarily putting batteries in my bike on a long, mountainous stage. There's no way the batteries will last, and t

Am I the only cyclist here? I can't imagine voluntarily putting batteries in my bike on a long, mountainous stage. There's no way the batteries will last, and then I'm stuck with dead weight. And, looking through the actual documentary, I didn't see any incontrovertable thermal proof of a battery in any racer. In the guy posing for a shot, yes, but not in the cyclists laboring up the hill.

samatman 11y ago
Modern race bikes are already deadweighted to make it to the minimum weight, so it's not a question of making the bike heavier.
- hughw 11y ago
  Not deadweighted in the amounts a battery with enough energy has to weigh.
  - bwilliams18 11y ago
    But it's conceivable they've found ways to shave the bikes weight down even lower to accommodate the battery and motor.
hooloovoo_zoo 11y ago
It will obviously pay for itself in terms of energy... in the limiting case, you could just hop in a Tesla and win the race.
- erikpukinskis 11y ago
  Hm. I love the idea of a logic proof, but is this correct? In the limit the Tesla runs out of battery and you can't push it up the hills.
  - bigiain 11y ago
    Interestingly, they race electric motorcycles at the Isle of Mann TT, and the riders all talk about how it's a different game to racing fuel-powered bikes - the bikes are capable of using up all their energy much more quickly that a fuel powered bike, so it becomes as much an efficiency trial as a race, they need to manage their energy consumption to ensure they make it to the finish line (all while still averaging over 100mph around the 40-odd mile mountain racecourse...)
    - aaronbeekay 11y ago
      I work on a team that designed two electric motorcycles for the IOM TT Zero. Yes, it's a very different game from the gas races. Aero and energy storage on board are the primary concerns - the top team for the past several years has been successful primarily by packing on ~20-30% more energy than their competitors, so that they can go faster, for longer. The TT is really an edge case, though, since it is such a long (38mi) and high speed course.
      - bigiain 11y ago
        If you've been there a while, I probably met you, or at least your colleagues - a few years back at Maker Faire (where you were showing off a yellow motorcycle, from memory R6 based?), and again at Sears Point for the first US TTxGp back in maybe 2010? One of your guys (Richard?) offered to get me good prices on Agni motors and packs of A123 cells for $300-ish per kWHr. (I should have taken him up on that... My current ride is a probably-illegal-in-CA 125cc two stroke Cagiva Mito - which is a barrel of fun! I could easily see myself looking for 30 or 40kW of electric motor/controller/battery to jam inside it next time it needs a complete engine rebuild...)
        aaronbeekay 11y ago
        Hmm, not us! We were there in '13 and '14, and our bike was built on a CBR1000RR chassis. I can't remember who had a yellow bike, although it sounds familiar... it may have been a bit before my time if they were talking about Agni motors. Small world :)
hughw 11y ago
Although I strongly agree with you, and I strongly doubt this report, the story is that they change bikes during the stage. There's no limitation on changing bikes for mechanicals or any other reason. So the hypothesis is, they don't carry the dead weight. They change to the electric bike just for the Muur von Geerardsbergen or whatever.
crispyambulance 11y ago
The key thing is being able to respond to attacks and keep a gap from forming. Often all this takes is a well-timed burst of power for a few seconds at a time. Easier said than done, but juice from a battery could easily make the difference.
nordsieck 11y ago
The thing to understand is that often times the bikes that pros ride are below the minimum weight as set by the race. They'd be carrying dead weight either way.
aidenn0 11y ago
Have you ever used an electric assist? a 50Wh battery weighs very little[1], the motors are similarly light, even by road-bike standards. Remember that there is a minimum weight, so you have a small amount of deadweight to play around with as well. That would give a pro biker a 10%[2] increase in power usable over 1 hour of the stage. It would make the uphill parts way better while negligibly affecting flat terrain and downhill. 1: Maybe 300g for such a battery were it lithium polymer. Lithium primary cells can be even lighter. 2: Or 5% increase in power for 2h, &ct.
- peter303 11y ago
  Ive some of these tube-size assists are 100 watts. That could be as much 30% in sustained riding. They were designed to provide half the power for commuters.
  - aidenn0 11y ago
    indeed; my point was that even a modest amount of power would clearly be a net-advantage versus no assist, despite the weight.
bigiain 11y ago
I've got about 150 Watt Hours from a ~900g battery on my cheater bike. (link below) I dunno how much ballast a really lightly built race bike has to carry these days, but even a quarter of that energy would likely make a dramatic difference - at 25W of assistance (which is something like 10% of a rider's total long-term output) a battery 1/4 the size/weight of mine would provide 90mins of assistance. Would that be "worth" 250 odd grams (plus motor and controller as well...) http://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Compact_5800mAh_7S_25C_Lipo_Pack.html http://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Comp...
- wobbleblob 11y ago
  Why do you need a cheater bike?
  - bigiain 11y ago
    To clarify, my cheater bike" is a $50 eBay 2nd hand mountain bike that I use to commute to work - not something I ride dressed in lycra pretending to be faster than other people... I call it my "cheater bike", 'cause that what it _feels_ like riding it up hills... It makes me laugh everytime I ride it. (I do _occasionally_ enjoy passing mamils on bikes that weigh less then their brekfast going uphill on my way to work.)
    - rhizome 11y ago
      Every spandex rider you pass is pretending?
      - bigiain 11y ago
        Nope - that was aimed at me not them - but I'm happy to let the stereotype burn stand ;-) I will say to a first approximation, 100% of the RadioShack lycra liveried carbon fibre Trek riders I see riding through Sydney traffic on a weekday morning are _not_ Lance Armstrong class riders. (Not any more than I'm a Carl Fogarty or Troy Bayliss class motorcycle racer when I put my racing leathers on and fire up my Ducati Monster...). It's mostly posing and toys, with an unhealthy dose of brand snobbery and wealth signalling (and being brutally honest, I'm guilty of a little bit of both of those myself - no matter how much I protest that "My Ducati is just a fun toy! I;m not a brand conscious poser! Not like those _other_ Ducati riders...")
InclinedPlane 11y ago
The dude who was cruising up the hill without standing on his pedals seemed pretty obviously using an assist.
- dingaling 11y ago
  Standing on pedals is actually less efficient than remaining on the saddle. You break out of the optimum cadence. However it does shift the work to different muscles which is why some riders stand for particular stretches of hill prior to a seated sprint.
crawdog 11y ago
With the minimum weight requirements in bikes they are having to add weight inside the frame to meet the minimum. Adding a battery + motor that provides even 20W of assist is a huge gain for a bike that still only hits the minimum weight.
deleted 11y ago
[deleted]
benbou09 11y ago
They can easily switch bikes pretending that they have a flat tire, or any other issue. IIRC suspects of using batteries have also been seen to switch bikes at suspicious moments.
IshKebab 11y ago
The maths doesn't work like that. Weight is actually not a huge factor in cycling performance because you mostly go horizontally. Top athletes only go for super-light bikes because they need every tiny advantage they can get. Adding a battery will increase the weight a bit, but the extra power from the battery more than makes up for it. Let's do some massively oversimplified maths: A lithium ion battery might have an energy density of 0.5 MJ/kg. A typical insane Tour de France climb might be 2000m. To lift itself that high, the battery-motor system needs to only be (20009.81/500000) ~= 4% efficient! The actual efficiency will be a lot* higher than that. Usually over 50%, so adding a battery is definitely worth it. (I haven't mentioned the weight of the motor, which is usually more than the battery - at least on conventional e-bikes, but it still works out as being definitely worth adding.)
madaxe_again 11y ago
IMR 18650s are very light, will fit in pretty any much tube on a bike, potentially even inside a tyre on a tubeless job, and will push 80A for 120 seconds, which is a crap-tonne of power. Having a battery assist is the difference between working hard for an entire hill climb, or being able to do 30 seconds on 30 seconds off and fartlek your way up the hill - which is the difference between winning and losing. For the mass of 10 cells (500g) you can get 25aH - which works out as about 60W for an hour at 2.5v - which is enough to save you 10% of your energy expenditure over a one hour race if you're going hell for leather - which is still the difference between winning and losing.

samatman 11y ago

Modern race bikes are already deadweighted to make it to the minimum weight, so it's not a question of making the bike heavier.

hughw 11y ago
Not deadweighted in the amounts a battery with enough energy has to weigh.
- bwilliams18 11y ago
  But it's conceivable they've found ways to shave the bikes weight down even lower to accommodate the battery and motor.

hooloovoo_zoo 11y ago

It will obviously pay for itself in terms of energy... in the limiting case, you could just hop in a Tesla and win the race.

erikpukinskis 11y ago
Hm. I love the idea of a logic proof, but is this correct? In the limit the Tesla runs out of battery and you can't push it up the hills.
- bigiain 11y ago
  Interestingly, they race electric motorcycles at the Isle of Mann TT, and the riders all talk about how it's a different game to racing fuel-powered bikes - the bikes are capable of using up all their energy much more quickly that a fuel powered bike, so it becomes as much an efficiency trial as a race, they need to manage their energy consumption to ensure they make it to the finish line (all while still averaging over 100mph around the 40-odd mile mountain racecourse...)
  - aaronbeekay 11y ago
    I work on a team that designed two electric motorcycles for the IOM TT Zero. Yes, it's a very different game from the gas races. Aero and energy storage on board are the primary concerns - the top team for the past several years has been successful primarily by packing on ~20-30% more energy than their competitors, so that they can go faster, for longer. The TT is really an edge case, though, since it is such a long (38mi) and high speed course.
    - bigiain 11y ago
      If you've been there a while, I probably met you, or at least your colleagues - a few years back at Maker Faire (where you were showing off a yellow motorcycle, from memory R6 based?), and again at Sears Point for the first US TTxGp back in maybe 2010? One of your guys (Richard?) offered to get me good prices on Agni motors and packs of A123 cells for $300-ish per kWHr. (I should have taken him up on that... My current ride is a probably-illegal-in-CA 125cc two stroke Cagiva Mito - which is a barrel of fun! I could easily see myself looking for 30 or 40kW of electric motor/controller/battery to jam inside it next time it needs a complete engine rebuild...)
      - aaronbeekay 11y ago
        Hmm, not us! We were there in '13 and '14, and our bike was built on a CBR1000RR chassis. I can't remember who had a yellow bike, although it sounds familiar... it may have been a bit before my time if they were talking about Agni motors. Small world :)

hughw 11y ago

Although I strongly agree with you, and I strongly doubt this report, the story is that they change bikes during the stage. There's no limitation on changing bikes for mechanicals or any other reason. So the hypothesis is, they don't carry the dead weight. They change to the electric bike just for the Muur von Geerardsbergen or whatever.

crispyambulance 11y ago

The key thing is being able to respond to attacks and keep a gap from forming. Often all this takes is a well-timed burst of power for a few seconds at a time. Easier said than done, but juice from a battery could easily make the difference.

nordsieck 11y ago

The thing to understand is that often times the bikes that pros ride are below the minimum weight as set by the race. They'd be carrying dead weight either way.

aidenn0 11y ago

Have you ever used an electric assist? a 50Wh battery weighs very little[1], the motors are similarly light, even by road-bike standards. Remember that there is a minimum weight, so you have a small amount of deadweight to play around with as well. That would give a pro biker a 10%[2] increase in power usable over 1 hour of the stage. It would make the uphill parts way better while negligibly affecting flat terrain and downhill. 1: Maybe 300g for such a battery were it lithium polymer. Lithium primary cells can be even lighter. 2: Or 5% increase in power for 2h, &ct.

peter303 11y ago
Ive some of these tube-size assists are 100 watts. That could be as much 30% in sustained riding. They were designed to provide half the power for commuters.
- aidenn0 11y ago
  indeed; my point was that even a modest amount of power would clearly be a net-advantage versus no assist, despite the weight.

bigiain 11y ago

I've got about 150 Watt Hours from a ~900g battery on my cheater bike. (link below) I dunno how much ballast a really lightly built race bike has to carry these days, but even a quarter of that energy would likely make a dramatic difference - at 25W of assistance (which is something like 10% of a rider's total long-term output) a battery 1/4 the size/weight of mine would provide 90mins of assistance. Would that be "worth" 250 odd grams (plus motor and controller as well...) http://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Compact_5800mAh_7S_25C_Lipo_Pack.html http://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Comp...

wobbleblob 11y ago
Why do you need a cheater bike?
- bigiain 11y ago
  To clarify, my cheater bike" is a $50 eBay 2nd hand mountain bike that I use to commute to work - not something I ride dressed in lycra pretending to be faster than other people... I call it my "cheater bike", 'cause that what it _feels_ like riding it up hills... It makes me laugh everytime I ride it. (I do _occasionally_ enjoy passing mamils on bikes that weigh less then their brekfast going uphill on my way to work.)
  - rhizome 11y ago
    Every spandex rider you pass is pretending?
    - bigiain 11y ago
      Nope - that was aimed at me not them - but I'm happy to let the stereotype burn stand ;-) I will say to a first approximation, 100% of the RadioShack lycra liveried carbon fibre Trek riders I see riding through Sydney traffic on a weekday morning are _not_ Lance Armstrong class riders. (Not any more than I'm a Carl Fogarty or Troy Bayliss class motorcycle racer when I put my racing leathers on and fire up my Ducati Monster...). It's mostly posing and toys, with an unhealthy dose of brand snobbery and wealth signalling (and being brutally honest, I'm guilty of a little bit of both of those myself - no matter how much I protest that "My Ducati is just a fun toy! I;m not a brand conscious poser! Not like those _other_ Ducati riders...")

InclinedPlane 11y ago

The dude who was cruising up the hill without standing on his pedals seemed pretty obviously using an assist.

dingaling 11y ago
Standing on pedals is actually less efficient than remaining on the saddle. You break out of the optimum cadence. However it does shift the work to different muscles which is why some riders stand for particular stretches of hill prior to a seated sprint.

crawdog 11y ago

With the minimum weight requirements in bikes they are having to add weight inside the frame to meet the minimum. Adding a battery + motor that provides even 20W of assist is a huge gain for a bike that still only hits the minimum weight.

deleted 11y ago

[deleted]

benbou09 11y ago

They can easily switch bikes pretending that they have a flat tire, or any other issue. IIRC suspects of using batteries have also been seen to switch bikes at suspicious moments.

IshKebab 11y ago

The maths doesn't work like that. Weight is actually not a huge factor in cycling performance because you mostly go horizontally. Top athletes only go for super-light bikes because they need every tiny advantage they can get. Adding a battery will increase the weight a bit, but the extra power from the battery more than makes up for it. Let's do some massively oversimplified maths: A lithium ion battery might have an energy density of 0.5 MJ/kg. A typical insane Tour de France climb might be 2000m. To lift itself that high, the battery-motor system needs to only be (20009.81/500000) ~= 4% efficient! The actual efficiency will be a lot* higher than that. Usually over 50%, so adding a battery is definitely worth it. (I haven't mentioned the weight of the motor, which is usually more than the battery - at least on conventional e-bikes, but it still works out as being definitely worth adding.)

madaxe_again 11y ago

IMR 18650s are very light, will fit in pretty any much tube on a bike, potentially even inside a tyre on a tubeless job, and will push 80A for 120 seconds, which is a crap-tonne of power. Having a battery assist is the difference between working hard for an entire hill climb, or being able to do 30 seconds on 30 seconds off and fartlek your way up the hill - which is the difference between winning and losing. For the mass of 10 cells (500g) you can get 25aH - which works out as about 60W for an hour at 2.5v - which is enough to save you 10% of your energy expenditure over a one hour race if you're going hell for leather - which is still the difference between winning and losing.