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Exclusive: Cranklock system delivers massive corner speed advantages for racing cyclists

By

July 22, 2009

The Cranklock in action

The Cranklock in action

Image Gallery (8 images)

Seconds are everything in cycle racing. A 10-second gap on the nearest guy behind you means he's got to work his butt off just to stay in touch. So a device that can reliably give you an effort-free 20-second advantage on a 3km twisty downhill stage is clearly going to be dynamite in the racing market. It's called the Cranklock, and it allows cyclists to enjoy motorcycle-style lean angles and massively improved cornering speeds by putting your center of gravity low and to the inside of the corner, like you can on a motorcycle. And if initial reactions from pro racers in New Zealand are any indication, it's going to revolutionize the world of competitive cylcing. Oh - and there's safety and security benefits for your average road rider, too. This is a sensational idea.

The cornering problem

Motorcycles and bicycles are very similar from a dynamic point of view - inline two wheelers, with a seat for the rider and steered through a handlebar. And yet riding them downhill through a set of corners is a very different experience.

If you're on a motorcycle, you can achieve huge corner speeds using massive lean angles that let your knees (and sometimes elbows) drag along the road. But on a bicycle, with essentially the same setup, you're forced to brake a lot earlier and go much slower, with a greatly reduced lean angle. But why?

The answer jumped out at New Zealand-based inventor Chris Toal as he remembered his Superbike racing days. "I was taught by a world champion, and he taught me that you've gotta get your weight on the inside of the bike, as low as you can, and that's where all your cornering comes from. So you push down with that inside foot, and then you just gently adjust with your handlebars."

But on a bicycle, it's impossible to get that weight down low onto your feet, because your feet are resting on moving pedals. Instead, you support yourself between the seat and handlebars, which moves the bike's center of gravity right up - and causes the bicycle's handling instability.

Finding a solution

This set Toal's creative mind off on whether a solution could be found - obviously, you can't put a set of motorcycle-style footpegs on a pushbike, because they'd foul the motion of the crank. But what if you could temporarily lock the crank in place like a temporary set of footpegs as you went into a corner? You can't pedal in a tight corner anyway - could a locking crank be an answer to allow motorcycle-style cornering on a pushbike?

Toal built a crude prototype, welding washers to his bicycle's front sprocket and simply firing a pin in to lock it. To test the pure cornering theory, he got a few riders together and ran a series of timed trials on the twisty downhilll section of road leading to New Zealand's Piha surf beach. The riders coasted all the way down the hill, so there was no advantage for the stronger pedallers, and the tests were repeated many times with the crank locked and unlocked.

By the end of the day, the advantage was becoming very clear. With the crank locked, riders were covering the 3km downhill twisty stretch an average of 20 seconds faster, purely because of how late they could brake and how much extra speed and lean angle they were carrying through the turns. The bicycle was handling like a small motorcycle.

"You ride past the 'I am going to crash' point, and you lock it, and put your weight on it," says Toal. "And as soon as you put your weight on it, the bike does this weird thing. It feels like you've stepped off your bike onto some sort of scooter - 'cause it stops wobbling. Because all your weight goes from up high in the bike, and balancing between your arms and the wobbly pedals, straight down to your feet. So exactly when you need it, in the middle of the corner, your center of gravity drops down around your feet."

Riders' reactions

Junior downhil MTB racer Brook Macdonald (1st Junior DH, 2008 MTB world cup, Australia, 1st Junior U19, 2009 NZ Raboplus National Championships) simply says "It's sick." Sick meaning "really, really good," we understand.

"Within a minute and a half, he was trying to ride it around in a circle in the carpark and get the inside handlebar to touch the ground," Toal says.

Likewise, NZ motocross and BMX champ Blake Gillard simply said: "It's awesome."

Thirteen time NZ national speed cycling champion and two time Commonwealth games team member - and bicycle engineer - Justin Grace was a little more forthcoming. "Cornering speed can be dramatically increased. Turning circles can be tighter. This will likely revolutionize the cycling world, from BMX stunts, Downhill and Road."

The Cranklock system

The Cranklock system works by simply giving the rider a lever to press to lock the crank. The crank will lock at any 90-degree increment from vertical - so you can lock it with the pedals straight up and down, or with them horizontal.

Toal recommends you lock it just as you are about to enter a corner, with the inside foot leading. You then put your bodyweight on that inside forward peg and turn the bicycle like a motorcycle, enjoying the additional lean angle and corner speed, before releasing the lock and pedalling out on the exit.

Using the system, he says it's not just a speed advantage - you've got a much better body position and centre of gravity to correct the bike if it loses traction, and because you're slowing down so much less for the corner, you don't have to put in as much effort to get your bike back up to pace on the exits.

There's also an in-built security device - you can lock the crank with a key when you leave the bike unattended, making it useless to bike thieves even after they've cut your bike lock.

Toal estimates that if the Cranklock is built into the manufacturing process for new bikes, it should cost around NZ$40 to add in, and is unlikely to raise the retail price by more than NZ$100. He's also working on a retrofit system to sell as an aftermarket add-on into the enormous cycling market.

It's currently illegal in road racing and certain triathlons, but Toal is working on having the technology evaluated and approved for road racing by UCI Switzerland.

Certainly, if it's as effective as Toal says it is, crank-locking systems are going to be a massive force in races like the Tour de France, where there are numerous hair-raising, high speed downhill sections featuring treacherously tight corners. If it gains roadracing approval, and the results back it up, you'll see a Cranklock on pretty much every competitive racing bike - and the system's very effective on a sliding or jumping MTB or BMX as well.

A business opportunity

We reckon Mr. Toal is on to a winner - and, being big motorcycle fans, we'd love to try it out! If it really does deliver a motorcycle-style cornering experience, then it could have quite a serious flow-on development effect - will bicycle road tyre technology have to improve to give the extra levels of side-grip you'll need for these huge corner speeds? Will tyre profiles need to change to allow you to put rubber on the road at angles you never needed before? It'll be fascinating to see.

Chris Toal is looking for business partners to start working on licensing the technology throughout the cycling industry, as well as setting up the manufacture of aftermarket Cranklock systems. If you know of anyone who might be interested, he can be contacted through the Cranklock website. He's also working on some other very exciting technologies too, that we hope to bring to you within the next few weeks. We wish him the very best of luck.

About the Author
Loz Blain Loz has been one of Gizmag's most versatile contributors since 2007. Joining the team as a motorcycle specialist, he has since covered everything from medical and military technology to aeronautics, music gear and historical artefacts. Since 2010 he's branched out into photography, video and audio production, and he remains the only Gizmag contributor willing to put his name to a sex toy review. A singer by night, he's often on the road with his a cappella band Suade.   All articles by Loz Blain
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8 Comments

Of course, you could just ride a recumbent. A low centre of gravity all the time, and a high bottom bracket so you can safely pedal through the corners rather than coasting. But the somewhat luddite UCD tend to ban everything that's been invented since the 1920s, including recumbents, so Cranklock will probably go the same way.

Ian

gadgetmind
22nd July, 2009 @ 01:28 am PDT

Im not sure if I understood correctly, but what I understand from this article is that this device locks your crack when ever 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!!!

Its been a long day in the office and Im a bit tired, so if I misunderstood the article, I apologize, but what I just read is the most ridiculous invension in the world. Not only that, they claim that its hard to corner in bicycles because you have to keep pedaling while cornerning... wow, 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.

ps: mmm.... where exactly would you CG if you push down hard with your legs?... mmmmm

getsmart1
22nd July, 2009 @ 08:20 am PDT

Ian,

I think the keeping uprights and recumbents seperated for competition purposes is perfectly reasonable, (even if the UCD is motivated in part by ludditetry) given that they really are vastly different designs to the point of barely being the same vehicle. This system is merely an addition to an existing design, more akin to steering improvements, and may get a favoruable ruling. In anycase, while it is true that recumbents already have a low centre of gravity and therefore corner better than uprights at high speeds, this same low centre of gravity means they tend to have less fine manaueverability at low speeds (for tricks, sharp turns and in crowded situations) where a higher centre of gravity is more advantages. The above system seems to give the rider the benefit of both worlds and would therefor be more suitable for a wider-variety of situations (I mean, people dont go dirtbiking on recumbents, do they?)

getsmart, yes, I think you did misread the article.

earlleonard
23rd July, 2009 @ 05:10 pm PDT

Recumbents are three-wheelers - that's a pretty fundamental difference! This jigger doesn't fundamentally alter the dynamics of the bicycle.

Getsmart - I've seen this argument at motorcycle forums before - I think it gets sketchy when physics terms come into it. Centre of gravity or otherwise, I think we can agree that a bicycle feels different to ride and steer when you place your weight on your feet, and take as much as possible off your hands and butt.

I think we can also agree that cornering feels very different on a motorcycle with fixed pegs than on a bicycle with moving pedals - and that motorcycles can lean a lot further without feeling nearly as sketchy as a bicycle.

Ultimately you'd have to ride a cranklocked bicycle to make your mind up - perhaps you can find a way to bodge something up on your pushbike? Chris reckons that all sorts of riders of different ability levels are jumping on and working it out within a couple of minutes - all they have to do is coast down a hill, weaving back and forth, with the pedals free and then with the crank locked - and nobody who's tried it is disputing it.

Then again, our information is coming straight from the inventor - that could be seen as an unreliable source until we've tried it ourselves. Does anyone wanna step up and bodge up a test version to stop this argument before it gets started?

Loz
23rd July, 2009 @ 10:34 pm PDT

Loz: What gives you the idea that recumbents are three wheelers? Some are but the vast majority aren't. Mine is a two-wheeler but I do actually fancy a three wheeler - you can go even lower/faster and it would come in handy in the snow/ice when anything else is a bit of a handful.

Earlleonard: Regards recumbents in tight situations, I'm actually very pleased and surprised by how things improve with practice. I didn't expect to use mine for commuting in dense traffic but it handles it really well. I'm not as nifty as on my Brompton folding bike (which is very narrow and can turn on a sixpence) but the difference isn't as large as I expected.

Regards dirtbiking, I don't really know what this is and wikipedia didn't really enlighten me. But it's true that while recumbents are great for travelling around (work, shops, pub, seeing the countryside, etc.) there are specialist areas where they might be less than ideal, but that's why most cyclists have a selection of bikes in the garage.

But what I don't currently have in my garage is a 1920s style diamond framed bike that the UCI would approve of!

Ian

gadgetmind
24th July, 2009 @ 01:02 am PDT

You have to wonder if the extra speed is just through the added feeling of confidence/security by standing on a solid (non-moving) pedal.

The big question is - what happens when you're mid-corner and going faster than you normally would and need to pedal out of a situation..?

Facebook User
24th July, 2009 @ 01:24 am PDT

I think getsmart needs to have a quick think about it. lol.

Fixed pedals would be MINT! I used to road cycle and I'm into MTBing now. (MX bike in garage for the time being)

Standing up (as you should) gets your CG lower but you have to have it even (balance the pedals) if it was locked you can have it on one side (more through 1 leg) without that pedal going to 6 o'clock (where the ground is) which is a BAD thing.

Would be nice heading into a jump and knowing where your pedals are going to be if things get a little sketchy and you lose them.

Very cool, must be a million easy (i.e: simple) ways for this to work.

Drill some holes into the small main crank, trigger for your finger off your regular gears for your index finger (not a main grip finger) and a spring return.

hold down trigger = locked crank

let go = operation as usual :)

Craig Jennings
26th July, 2009 @ 03:15 am PDT

Ian,

Oops, I meant MTBing (off-road); dirt-biking is more a motorcycle term. But anyway, I think you get my point where there is a range of other biking activities where a recumbent (even if you are getting good at commuter handling personally!) has other unsuitability issues that still makes working on improving the upright a worthwhile task.

Craig,

If all your intested in is private activity then, yeah, people will eb able to design their own systems; but if the tech is ever aloud into comps (be in racing or trick) they'll be some standard bought in that this guy Toal could have the headstart on.

earlleonard
27th July, 2009 @ 05:22 pm PDT
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