Found: Crank Tip Promises Less Fatigue & Greater Power w/ Unique Dual Swingarm Pedals

Sorry, but what exactly does this product do? Reminds me of this:

http://pardo.net/bike/pic/mobi/d.pmp-cranks/z-torque.html

Except that it only seems to displace the spindle down and forward by 12 & 16mm… meaning it might create some really difficult fitment issues. What exactly is the benefit?

Ok, by studying the diagrams a bit more and watching the video, I think I get the idea a little better. Doesn’t seem worth it by a longshot though.

Also, they would likely not be allowed in UCI (not that that matters much to us here), and it seems like it would create a disconcerting disconnect within the stroke, where you could move both feet independently in both directions while not pedaling. I’d try them out just for kicks, but it seems like it’d be strange. (deleted)

just in case you don’t understand the concept, this is basically making the lever arm longer on the down stroke. so more leverage on the down stroke, but there’s definitely compromises like no power at the top and bottom (transition periods) and decreased leverage on the up-stroke (which if your a triathlete trying to recruit all your muscles seems like a bad idea), and putting the seat lower when your TT bars can’t will likely increase drag.

that being said it’ll be noticeably feel easier to push a bigger gear.

Potentially a mechanical advantage, but 1.3 kg’s?! Need to compare these with the Dura-Ace pedals, same person, same bike

Dumb, if you want longer crank arms, just install longer crank arms.

Keep in mind, you get a mechanical advantage on the downstroke but you also have to move your leg that much further during that part of the stroke thanks to the larger circle you’re pedaling through at that point.

Riders who pull on the upstroke tend to ankle more, which would pull back on the pedals and give this an oval path. Seems to me the greater lever on the downstroke might be negated with the loss of efficiency from free play.

But giving the rider a greater lever on the power stroke is definitely a good idea.

yep, can do exactly the same with non-round chainrings, except with less weight, go figure.

Ok I am confused. I like the idea of a longer lever on the downstroke and a shorter return path. This would result in a smoother spin and potentially a smaller dead spot in the pedal stroke.

*However*, looking at the diagram if the resulting pedal stroke is indeed circular you can get the same benefit by moving the bottom bracket down and forward. If you already have a correct position this would decrease power.

*Correction* – moving the BB with regular cranks would result in the same pedal path, but the crank *leverage* would be less than the swinging pedal design.

For those talking about non-circular rings, these do not change the crank leverage like you are with this pedal design. Having a shorter return path and lower leverage during on the back stroke could be good as you cannot generate as much power on the back stroke (no matter who you are) and the shorter leverage would make it easier to turn the pedals over at a higher rate with a bigger gear.

@Andrew- the circle is not larger, it is displaced, and presumably not perfectly round…

I admire these guys for putting in the effort, and maybe it does feel good in a similar way to ovalized rings. Nonetheless I think it’s dumb… :-/

I would compare it to Rotor’s RS4x cranks. I had a chance to ride those cranks for several years (video here: http://www.youtube.com/watch?v=qwLLpd5c1M8)

Lengthening the time between the 1 to 4 position during the pedal stroke while simultaneously shortening the 7 to 12 position opens the hip angle, provides the benefits of shorter crank arms during latter half of the pedal stroke while increasing the length of the lever during the portion of the pedal stroke when there is the greatest ability to transfer the rider’s weight into the pedal stroke. There is very little power produced during the latter portion of the pedal stroke (see research and Shimano’s reason for it’s 4 arm crank). Mechanically eliminating the ‘dead spot’ of the pedal stroke is advantageous. The RS4x did test favorably, effectively reducing lactate levels…. but the weight of the crank was significant. That was not a factor on flat courses. I for welcome Oval chainrings, and welcome even more ways of using eccentric mechanisms to change the effective pedal stroke to be more efficient. http://www.ncbi.nlm.nih.gov/pubmed/11404667

Eccentric cranks have been used in locomotives forever…

@McClain, yeah, I was just trying to provide a good analogy for people. 🙂

My first thought was that Henk’s been in a good paddock.

Vista did something really pretty similar to this a few years ago with their Synchro cranks, whereby the pedal spindle was mounted eccentrically inside a large bearing at the end of the crankarm, which accomplished a pretty similar effect. Bearing wear on the crank-end bearing was supposed to be the ultimate flaw with them, from my understanding.

Still, this sort of thing, oval chainrings or eccentric pedals is really interesting, a pretty direct way to turn calories into more forward motion.

Why not, just use q-rings. They in theory do the same thing and don’t add has much weight.

“Still, this sort of thing, oval chainrings or eccentric pedals is really interesting, a pretty direct way to turn calories into more forward motion.”

This doesn’t say anything at all. Bicycles are a way of turing calories into forward motion. So is walking and it’s even more direct.

$500+1000g later and only minimally diferent from moving your saddle further back and up…

Like normal, mass skepticism. OK, fair enough. But these guys are not unknown riders. They’ve got pedigree, and Henk is nobody’s fool, in particular. If they think it works, I’m already interested. However, I’d like to see power meter output to know for sure. Biomechanically, the leg is not designed to work in circles (as per normal crank action), hence the interest in systems that emulate the leg’s natural action more closely (oval rings). No doubt, this design could be significantly reduced in weight and in price with mass production, so don’t even bother getting caught up in that. Let’s see if it works first – every innovation is greeted with similar negativity, and the bad ones go away, so time will tell…

I already use a variety of rotor rings which seem to do that same job this pedal does. However, with all the miles I put in on multiple bikes it may be less costly running these pedals and round chain rings. I’ll have to check them out.

I dont know what you guys are talking about, I have bought a set of these pedals and I know they feel better, why cause when I replaced them and return to my old pedals they felt like I had two left feet and i had to constantly check to make sure I was in the right gear at certain points in my ride as the bike felt harder to pedal, also they do not work in any way like roto rings. I dont know what you guys are saying cause the pedals cannot move back and forth independently that much that you can feel it, they cushion the rotating force at the bottom of stroke and at the top stroke your hip is better placed as its lower and less stressed. These are my experiences and I will not ride anymore without them.

@Stephen who wrote on 01/09/15 – 1:21pm
“Just imagine if Crank Tip were to team up with MagLOCK…those would be THE ULTIMATE BIKE PEDALS!!!”

You forgot to add Nikola, might as well have your foot flopping around all over the place and side to side too while you pedal. Now that combination is ULTIMATE!

“Biomechanically, the leg is not designed to work in circles (as per normal crank action), hence the interest in systems that emulate the leg’s natural action more closely (oval rings).”

This is complete nonsense and oval rings don’t change the foot path anyway. You still pedal in circles with oval rings and I’m amazed at the stupidity of this repeated claim.

“Let’s see if it works first…”

We already know it doesn’t because it’s based on a premise that have been disproven.

“I don’t know why everyone is equating this device with oval chainrings – it’s almost the complete opposite.”

mudrock is right about this. These have more in common with Biopace than with modern oval rings. They are, in fact, most like the Rotor RS4 crank mentioned earlier except that they are times opposite of those cranks and therefore work against you. If this kind of contraption worked at all, and it doesn’t, they have gotten it backwards.

I wonder what would happen if you mixed the Rotor RS4x crank, Osymetric chainrings, and crank tip pedals….
Would you even need to pedal? Do three wrongs make a right?

greg, you write that the “pedal threads down and forward”…. “FORWARD”

So, you recognize that the pedal moves forward of the pedal insert on the crank. How is that not creating a longer lever?

Also, why the negative reactions to a mechanical solution to the pedal stroke, one that creates a longer lever during the pedal position where the rider can put more of their body weight into the pedal stroke and minimizing the lever during the portion of the pedal stroke when there is little to no power contributing to forward movement while also minimizing ‘bunching up’ at the hip…., but no negative reactions to suspension designs like DW-link that mechanically change the path of swing arms through the use of parallelograms and eccentric pivots?

Great Idea! Congrats guys! Sound.