Fast Company

CrankLock: A Revolution for Downhill Biking [UPDATED]

An invention that allows riders to easily shift their weight--and carve corners tighter than ever before.

Cranklock

Bicycle technology improves in teeny, tiny increments. So it's a once-in-ten-years thing when a device comes along that might reliably shave 20 seconds in just 3km. But that's exactly what the Cranklock purports to accomplish--and the invention makes obvious, intuitive sense.

A bit of background. If you're on a bike and you're cornering, you can't put any weight on your inside foot---if you do, the pedal obviously goes down, thus putting you in danger of scraping the ground. Wrecks often result--and that's why pro bikers put their weight on the outside pedal during tight cornering. (Watch the rider's pedals in this video if you're confused.)

But think about that for a second. Putting your weight on the outside means you're basically forcing the bike vertical--and, of course, straight. You're not carving as tight a corner as you otherwise might. By contrast, motorcycle riders lean into a corner. Pro racers nearly touch their inside knees to the ground doing so.

Okay, now that's out the way: Cranklock does just what the name suggests. At the push of a button, it locks the cranks in place, so that you can distribute your weight between inside and outside pedal any way you want. Thus, you can carve tighter corners, and slingshot around them--and that can be save 20 seconds in just 3km of aggressive descending. Which is truly a massive amount--in the Tour de France, for example, the entire race is sometimes won by just a few seconds.

The gadget was initially designed as a safety measure to eliminate speed wobbles. But it's proven useful in all kinds of settings, such as BMX, where rotating pedals can cause gruesome wipeouts.

[Update: There seems to be some controversy over the physics involved. Care to weigh in?]

[Via Gizmag]

Add New Comment

14 Comments

  • David-Henry Oliver

    Hi Chris,

    There's a whole lot of text above, so let me summarize.
    I've said your product may deliver on your claims of improved cornering. I don't say "may" to cast doubt. I will leave the testing to the reputable cycling magazine test crew of your choice.

    My primary issue is with your description of the physics involved. The engineers that worked on your product may have done a great job of designing the locking mechanism, but how the rider's COG moves around is a separate issue.

    The description of the physics, in my view, just isn't credible. While this is my view, the definition of COG is not a matter of opinion. That is
    precisely why I included a link to a definition. You are perfectly welcome to argue the definition with any number of dictionaries and mechanics textbooks. COG is a function of where you're body is and how it's positioned, not where you push.

    I've even said, I think there are reasons why it may work and briefly described them.

    It is clear from your last post that the press got a little ahead of your web site, placeholder images and all. This is why, when I found images that show you demonstrating your product that I amended my comments. Yes, your product does exist. The point of "Assuming your product exists*" was to illustrate that all we have to go on is what you've shared with us and our own knowledge of the subject matter.

    As for patents, they are more concerned with whether an invention is novel than whether it is effective. Locking the crank arms is certainly novel, as far as I know. This is why your patent should be granted.

    I will go further. As far as I know, the UCI is primarily concerned with whether or not a new product gives unfair advantage to the user. I don't think your product does. I think it simply gives racers more options for controlling and handling their bikes.

    So, product good. Description of physics, not so good.

    As I've said before, good luck with the product. It's novel, interesting and may be useful. That is more than can be said for many new products.

    Best,
    Dave

  • Juan Angulo

    Hello all,

    Im not sure if I understood correctly, but what I understand from this article is that this device locks your crack whenever you want. So far so good.

    Now, they claim to be able to reduce the center of gravity (CG) by pushing the pedals down!!! :O !!! Oh my god! I think this is one of those perpetual movement inventions. This people would make trillions selling this thing to F1 manufacturers, just tell your driver to push on the lever and you CG will go down!!!

    Now, I apologize for the sarcasm, but what I read here and in the manufacturer's website is wrong. The physics and mechanics behind the idea are wrong. I'm sorry.

    The manufacturer claims that its hard to corner in bicycles because you have to keep pedaling while cornerning.... mmm, they invented a way around that so many years ago, that Ive never riden a bicycle where you actually had to pedal to keep moving forward.

    Note that I'm not discussing if this device works or not. If it does it's because it gives the rider a little bit of extra confidence (which can never be underestimated), but the reasons why they say it works are very far from correct.

  • chris toal

    Hi David, firstly we have taken our time. We have had a working prototype for 18 months. We do have lots of low quality testing footage but decided to wait for the pros footage, however the story ran on the net before we were really ready. TV here are filming it and we have a photographer following that process, all that was supposed to be up on our site showing our product in use but the weather here has been atrocious so no filming or photography for the past two weeks. We had some pics in place to be replaced with the correct ones. Patent applications have been accepted so we know it is novel effective and the science is sound and the patent office agrees. Justin Grace 13 times NZ track champion and Commonwealth games rider has tested both our mountain bikes and road race bike and is an actual cycle engineer. he also agrees. He has no financial interest in the company and he stands by his opinion of the products effectiveness to the point that he is currently in Switzerland discussing with UCI getting race acceptance. Whilst you are certainly entitled to your opinion, comments such as "*Assuming your product works" and that "it's not really clear that your product exists" are unhelpful as others may view your comments as fact and may very well be found to be commercially damaging. Our prototypes were produced by leading engineering design company Buckley Systems which include some fabulous engineers who also agree that the product works and why that is so. Whilst you have "a few ideas of how to lock the cranks" we have already patented several versions both manual and electric and not at small cost. Re COG once effort is applied to the handle bars to push them downwards that mass causes the COG to move up the frame in direct proportion to the mass applied. With our system the mass stays at the pedals. Nowhere near the top tube, I'm unclear as to how you came to that conclusion. You will see some footage and pics in the next few days that will clear things up for you, it may be best if you wait till then before commenting further. Regards Chris

  • David-Henry Oliver

    Hi Chris,

    Let me say that I'm sure your product exists in some form. There are pictures over at Gizmag of you showing it to their crew. The pics don't really show the product, but the crew is looking at and filming something, they just didn't publish that footage. If you want it to remain proprietary for the moment, that's reasonable.

    As for the physics, I'd say consult with someone you trust about it. You can take or leave my critique if you're comfortable with the presentation. It would be a shame not to present your product in the best light.

    Again, best of luck with it.

  • David-Henry Oliver

    Hi Chris,

    Two things:
    1. Thanks for explaining the technique that you use to get the most out of Cranklock*. The good news is that I can see how use of the Cranklock* might yield the results you claim. This is, of course, important because cyclist trying to gain an advantage will probably care more about results than about why exactly they get them.*

    As I wrote in my first comment, I visited your site and have some issues with the description of how your product* allows the rider to shift his COG down around the bottom bracket (bottom of the first page of your "Why it Works" pdf(http://www.cranklock.com/whyit.... A quick look at the link I sent earlier should clarify COG, for anyone interested,and make it clear that unless you put both feet on the same side of the bike and, perhaps, squat down on one pedal your COG will not drop below the top tube. An alternative might be to wear lead boots.

    Your description of a force multiplier due to using the crank arm as a fulcrum is, again, inaccurate. A rider, using the technique you describe would be shifting their COG forward(but not lower on the frame), and distributing more of the resulting force to the front wheel. The difference is loading the bike through the bottom bracket and loading the frame/locked-crank combination the length of your cranks in front of the bottom bracket. The result would be the same if you were to clamp a peg to the downtube(around the same area as your forward pedal) and step on that. Similar results would come from putting more of your weight on the handlebars (I realize you think this is a bad idea).

    Assuming your product* works, your description just isn't doing it any favors.

    2) The reason for the asterisks above. I went back to your site to see if I had missed anything there. I did. What I didn't realize before is aside from a picture of what might be a handlebar mounted locking switch on a mountain bike, there are no pictures of your product.

    I thought, hey, there are pictures of guys cornering...30 of them, but all show riders with their outside pedals down. No need for Cranklock* there. Did they not get the memo to use your technique? There's a picture of a guy doing a BMX freestyle trick that is done with pegs, but no need to lock your cranks. There are a few pictures of someone standing on the pedals in the forward and back positions(forward could be done by locking your brakes, back by standing on the chainstay with your heel... I've done both).

    So the reason for the asterisk is that it's not really clear that your product exists. I'm not saying it doesn't, just that you haven't shared more than a description of the concept. If you are trying to determine if there is a demand for a product like this that's reasonable, but you've put hundreds of kilometers on it so let's see it. Better yet, take your time, get it right and send it to some of the cycling magazines for testing. If it works as claimed you may be in business and there may be a guy passing me with it sometime in the future. Maybe I'll even buy one.

    I'm quite familiar with proof of concept, prototyping and product development, it's what I do for a living. So if you're at an early stage of development, that's fine. Maybe it's just not ready for prime time yet.

    I really do wish you luck. I've even got a few ideas about how to lock the cranks.

  • chris toal

    Hi Cliff, You are welcome, we were just concerned that people were not thinking it all the way through jumping to conclusions and then stating those as facts. We've developed and patented a lot of revolutionary new technologies over the past decade and we find when we explain them, adding bit more information into the mix can often be required. By the way when Cranklock is locked you can pull off amazing (scary) slides get your back/front wheel down over jumps and pull, off lots of new BMX tricks (8 new extra pegs) Cheers Chris

  • Cliff Kuang

    @Chris--Thanks for taking the time to answer---Great information. Looking forward to seeing the Cranklock one day!

  • chris toal

    Hi All,

    Chris Toal the inventor of Cranklock.

    Thanks for all your insights, want to address a few questions.

    First we've done lost of testing. Initial testing to prove the principle was done with multiple riders with varying degrees of skills including some with Triathlon and no motorcycle experience right down to a novice cyclist non motorcyclist. All were faster, and the time reductions and cornering speed increases were almost identical.

    Second a bicycles COG or Point of Moment is directly affected by the distribution of the riders mass left and right and fore and aft and to a much greater scale that a motorcycle.

    Thirdly when cornering with Cranklock as weight is applied to the front / inside pedal that weight generates downforce that travels back to the crank which acts as a fulcrum then up the frame to the head stem. From there it travels down via the forks to the front wheel to the inside surface of the tyre and road. This results in minimal rider mass being required to be placed of the handlebars to ensure traction when turning. As this mass is now applied almost entirely inside of the frame and down at the crank and a riders upper body 'mass' is now almost entirely supported by the axle, the COG is lower on the frame and inside the frame in relation to the corner.

    Additionaly the effect is multiplied as the pedal arm uses the axle as a fulcrum it is possible to compress the front suspension and tyre with NO weight being applied to the handlebars at all.

    Hope that helps you to get your heads around it. When you first ride it the first few corners are terrifying but after a few hours you can feel the 'G' force pushing you down onto the seat.

    I'm sure that some of you will have to wait till bikes with Cranklocks are going past you before you will get it. We've riden it hundres of K's so we do have an advantage of those of you who are just hypothesizing.

    Cheers Chris

  • David-Henry Oliver

    Hmm... The force vector, line from the COG along the angle of attack should be going directly through the center of the tire. If not, you may be in for trouble. Once it gets there, tires and tire pressure are important. Tire designers have been for quite a while trying to maximize tire traction when the bike is leaned in a corner.

    I do not doubt that the guy who invented this has a feel for cornering. It looks like he raced motorcycles. My guess is that he was the guy who improved his time down a mountain pass because he may be more comfortable with motorcycling technique, where as a Tour de France rider would likely blow away his base line and Cranklock enabled times. Would a pro cyclist improve their time by employing moto technique. I'm not e traditionalist and think it would be cool if they could. Slap skates improved times in speedskating and are good example of gaining speed where no one else thought to look. That said, my feeling is no.

    The beginning of their description suggests that wobble is reduced(presumably for inexperienced riders) when the cranks are locked because otherwise they are free to move on "slippery bearings." So they remove a degree of freedom. This is kind of like saying it would be easier to stand if we didn't have knees.

    There are some other claims about handling that are also suspect. Again, these might be useful for freestyle BMX and for teach a kid to ride a bike (there are bikes without pedals for that). I just think they are overreaching with the claims.

  • Cliff Kuang

    @David-Henry---Please ignore first of the duplicate comments---I fixed a typo that would have affected what I meant!

  • Cliff Kuang

    @David-Henry---Do you think, as a mechanical engineer, that the traction issue is real? They seem to be arguing that the weight is ultimately distributed more evenly _at the tire_, which they claim allows you better grip and tighter cornering. Is that total bunk? I makes sense that if the traction were, say, weighted towards the outside edge of your bike, then functionally, the contact surface between the tire and road would be smaller/more prone to slips and wobbles. But then again, I'm having trouble seeing how being able to apple downforce on your inside pedal would fundamentally change your cornering angles--you'll still fall down if your virtual COG is closer to the inside pedal than the outside. Maybe the point of this is that you can apply just enough pressure on the inside to make your tires stick more? Forgive me--it's been a while since I took any course in mechanics! Your help is greatly appreciated...

  • Cliff Kuang

    @David-Henry---You make a great point, and one that was kind of gnawing at me after this post went up--I understand that the point about counterbalancing on your outside pedal is to change your own COG so you can effect a deeper lean. Curious if this thing really works---will see what I can dig up.

  • David-Henry Oliver

    Hi Cliff,

    When I first saw this entry I was intrigued, but I've raced bicycles and ridden motorcycles and thought the analogy between leaning a motorcycle and leaning a bicycle was a little suspect. Yes, the skills I learned racing bicycles transfered when I started riding motorcycles, but the weight of a motorcycle makes handling quite different. Your moving the COG of the motorcycle which is much heavier than you are, as opposed to shifting your own COG on a much lighter bicycle.

    I'm also a mechanical engineer and the real problem came when I visited the Cranklock site and read the "Why it works" pdf. They make some basic errors in their description of the physics involved and movement of the riders Center of Gravity.

    They've passed this misunderstanding on to Gizmag and to you.

    You can see an illustrated explanation of Center of Gravity at
    http://www.answers.com/topic/c.... If you take a look at the diagram you will see how the COG moves as a man bends to touch his toes. Imagine him on a bike trying to get his COG down around his feet.

    Maybe they found a cyclist that shaved time off a descent using this. If so, the cyclist did it in a way that the guys at Cranklock don't seem understand.

    In any case, I would suggest they pull that pdf off their site and consult with someone who can help them unlock the mysteries of how their product might work. On the plus side, I can see how locking the cranks might allow freestyle BMXers to do some new tricks.

    Dave

  • Todd Singleton

    As with any bicycle racing part the big question is: how much does it weight? For downhill mountain biking I suppose it's not that big of an issue.