KrankUps, a new bicycle technology!

Yes? No? Maybe?
As seen on kickstarter...
https://www.kickstarter.com/projects/1790594728/krankups-a-new-bicycle-technology?ref=discovery

(Currently with "26 backers, $1,892 pledged of $45,000 goal and 14 hours to go.)

" if the pedals could swing on the crank arms, this would cause a push pull effect giving a longer power stroke. Having a longer power stroke gives you more pedaling power using the same effort."

What's the benefit over just using longer crank arms?

feels like a different way of doing elliptical chainrings to change where the most force can be applied in the power stroke. Would be interesting to see an actual test involving pistons that use the same force on with and without setup and putting the bike on a dyno to see whether the inventors claims are valid.

It also kind of makes the movement more treddle like, your feet will not go as far in front or behind the chainring but decrease the moment of turn as compared to longer cranks equalling this additions and original arm length.

could be useful in tadpole trike applications to reduce the height the feet reach like what bobc has achieved with his treddle drive. Feet appear to get in the way visually riding recumbent trikes from what i've been told.

danielrlee said:

What's the benefit over just using longer crank arms?

Click to expand...

Hehe... Somebuddy a little cranky today? I have no idea, `cept it occurs to me that the longer the crank arms the more likely they are to strike something on the ground perhaps? Back in the daze riding old-style classic/antique poop mobile bikes, with toes clipped in, used to power on the up strokes as well. Honestly, other than ground clearance, have no idea how this might service the EN (ebiker nation). So actually was just curious whether anybuddy else here could see some benefit to this. :wink:

(EDIT: There, ya see? Somebuddy else just posted. Now, back to reading...)

whereswally606 said:

feels like a different way of doing elliptical chainrings to change where the most force can be applied in the power stroke. ..

Click to expand...

I though it was true but in fact, it's not even the case

I spent about a decade researching alternative bicycle drive systems. This is not a new idea. Tried decades ago. I have personally used short and long cranks, elliptical chainrings, and Rotor cranks. Didn't see any change in performance. I did find adding arm power increased my endurance a bit...just by spreading the work over more muscles.

Adding a motor totally swamps any small effect changes in human power deliver may have.

In a sport worth billions per year, and every team having biomechanics paid hundreds of thousands a year, you would think if it increased power or endurance even 1% he would have teams throwing money at him just for a one season exclusive.

I'm deeply skeptical.

When you're clipped in, the down stroke is only about 40% of your power. the up stroke is another 30%, and kicking over the top, and pulling through the bottom of the strokes is another 15% each.
Also, while mechanically, a longer crank is a more powerful lever, the reality is that the human body isn't optimized to take advantage of long crank arms efficiently while pedaling. you can actualy produce more power per calorie with shorter crank arms.

Regarding elliptical/ovoid chainrings, I found that when I could still fully pedal my bikes that the Shimano version (Biopace?) helped my knee pain, vs round ones of the same tooth count and crank length.

Up to a point, shorter cranks also helped, but lower gearing did the same thing.

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amberwolf said:

Regarding elliptical/ovoid chainrings, I found that when I could still fully pedal my bikes that the Shimano version (Biopace?) helped my knee pain, vs round ones of the same tooth count and crank length.

Up to a point, shorter cranks also helped, but lower gearing did the same thing.

Click to expand...

I had a bike years ago with Biopace HG chainrings, really good system and I'm surprised they phased it out. It deffinitely made a difference.

Don't fancy the idea of two pedal pivots personally but I suppose you can't knock it till you've tried it?.

The bit where the guy rode with and without crankups in split screen was hilarious.