I realized that one of the drag link dust covers on my RotoR crank had gone away, and some other maintaining was needed - so I took 'er apart. Left the BB in the shell, just took out the axle assembly, which exposes all but the spider bearing. I could take the spider off easily at this point, just push it off the eccentric of the BB - but its smooth as butter and no need.
Pic1: Here is the spider on its eccentric mount. The marks are for getting the eccentric clocked properly, but require the crank to be assembled. Note the two large posts that actually drive the spider.
Pic2: The axle assembly. The right crank arm (the one you see) rides on a bearing on the end of the axle - the removed left arm drives that other link behind the axle.
Pic3: The other side. That big tab is basically the end of the left crank.
Pic4: Here it is stuck back together - the left crank link is not on its drive pin, but the right is.
Clear as mud? As the spider moves around its eccentric mount, the links get different leverage on it. This is what speeds up/slows down the crank arms. Clocking the eccentric in the BB shell lets you line up the crank pulses with the power pulses of your legs. Get it right and it feels so smooooooth. You can see the 5 hash marks on the spider in Pic1 - that's the range of adjusment. The difference between one mark and the next is noticeable. Going to the longer marks gave more leverage, but made things "lumpy". And on my fixedgear drivetrain, it also took away from my resistance levearage. Going to the shorter marks improved resistance at the expense of power - and also got "lumpy". Just a little above the mid mark/arrow is perfect for me.
Results 1 to 5 of 5
Thread: RotoR Apart
Check out the hottest mountain bike products from these brands!
See All Interbike Coverage - Click Here »