unique pedal crank assembly

*as mounted on a diamond frame bike where the leg is coming down from above*

Have you ever seen anything like it? I didn’t think so. This technology is out of Japan as I understand it. It is said to be 35% more efficient than a conventional crankset and therefore able to propel a cycle faster for the same applied effort and energy expended. Since I know next to nothing about it myself and anything I could write about it would be that which I read online I will simply post a link HERE to an article about this revolutionary design where you can read about it. It is called “SDV drive with oval pedal motion”. According to their description “the SDV drive is comprised of two sprockets and a chain extended around the sprockets, thus forming an oval track of the chain. A pedal is attached to the chain directly.”

SDV drive

Borrowing from the article I linked to above this sentence somewhat sums up everything: “We think the geometry of SDV makes riders use larger muscles, giving lower cadences than we expected.” It makes sense that this system would work better than a conventional crankset. Of course, the positioning of the two sprockets would be different between a diamond frame bike/trike and a recumbent bike/trike since the legs are coming onto the pedals from different positioning … down from above on a diamond frame and forward from behind on a recumbent. In the image below I have drawn yellow lines showing the difference in the positioning of the sprockets between a DF bike and a recumbent. Both cycles are travelling in the same direction.

SDV drive on a recumbent and a DF bike comparison

I can’t find any online videos available to share here so if you want to see any you will have to download the files onto your computer like I did.  I am unable to post them here in this blog like I do other videos. HERE is a link to a webpage where you can download the videos. The webpage is all messed up and difficult to figure out what is there as there is text on top of other text. You will have to click on the British flag in order to open up the next page and then click on Movie Theater to get to the video links. You can try using this LINK  Using this link should start downloading the video unto your computer. It is a WMP (Windows Media Player) format. Personally I would not bother even looking at any of the other videos as they are either the same thing, but not as good of quality or not much to see.

unique pedal crank assembly on bike

HERE is a website page where you can read about the technical aspects of this drive. HERE is a .PDF file on this innovative design. It is quite technical so it probably isn’t of much interest to the average reader of this blog. And HERE is one of the better webpages I have found on this drive system.

It will be interesting to see what happens as time passes as to whether or not we start seeing this new technology put to common use. If I understand correctly this has been around since 2007 so it doesn’t look like it is getting rushed to market. Well, one thing for sure … with or without this innovative drive system my plan is to …


Author: Steve Newbauer

I have a few current blogs (tadpolerider1, navysight, truthtoponder and stevesmixedbag) so I am keeping busy. I hope you the reader will find these blogs interesting and enjoy your time here. Feel free to email me at tadpolerider2 at gmail dot com (


  1. My name is Noriyuki Oda of OTEC, Japan. Thank you for introducing our SDV technologies at this site. I am most grateful for your kind opinions.
    The web site is fully updated and the “Movie theater” page has been simplified a bit.

    1. I would like to use your drive system on my trike in exchange for promoting it. Please contact me at if you are interested. I believe this will be a big hit where I live.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.