General Cycling Discussion - Rotor Cranks

This looks like a really great idea to eliminate the major dead spot in the pedaling motion (12-6 o'clock). Basically introduces cams to variably offset cranks, so when your bottom pedal is at 6 o'clock your top pedal is already at 1 o'clock. Cranks are then back to normal at 3 and 9 o'clock. Anybody see any major downsides to this idea? A description and review from cycling news is below.


http://www.cyclingnews.com/tech/?id=2002/reviews/rotor_cranks

Weight, and more to go wrong.

The bicycle is a wonderful piece of equipment because it is so simple. I don't see why people try to make it more complicated. Even Campag have an electronic shift on test now.

Anyone remember Biopace rings?

Looks like another solution looking for a problem. I used Biopace for a while and it worked mostly (didn't work well with high cadences). This looks like a complicated mechanical solution to the same problem.

I've never regretted dumping the Biopace stuff.

From the photos that I have seen I don't believe the upper
crank get as far as 1 o'clock. That probably explains why you only
get an extra 3 mins. of pedaling per hour. That extra pedaling
is not all done in your maximum power application pedal area,
you have extra weight, more friction, a most unbalanced
pedaling style and very expensive pieces of equipment.

The present chainwheel and cranks are perfect for eliminating
the dead spot area but you can never get perfection by
completely eliminating it because of the slight loss of effective
pedal power at moderate cadence when the pedal power
application changeover is being made one foot to the other.
When you eliminate any of the upper dead spot area, you
automatically eliminate the equivalent area below.

Anquetil's invincible time trialling technique eliminates the
area from 12 to 1 o'clock when cruising in time trials and when
max power needs to be turned can also eliminate half of the
11 to 12 o'clock area. This gives extra value mins. per hour of
5 and 7 1/2 resp. This is very effective pedal power applied directly in the dead spot area with the smoothest possible
pedaling style. The additional advantages of this technique
are it enables you to combine arm and leg power when riding
at speed in the saddle. This combined power technique together
with the method and direction in which the power is applied to
the pedals greatly reduces the workload on the knees and
build up of lactic acid in the legs. But most important of all, it
eliminates all the lower back strain associated with the recommended round pedaling style and by doing so, it
completely eliminates even the worst cases of persistant
cycling related lower back pain. It also prevents you from
sliding forward on the saddle even if tilted down at the extreme
angle of 45 degrees, taking all pressure off the hands.

The experts have always frowned on the style of Anquetil and
the only explanation I can give for this is, they did not have and
still do not have the brains to discover how he did it. It is so
simple and soon becomes an additional natural pedaling style
and unlike rotor cranks it's free.

ncr - Can you elaborate on Anquetil's technique and how it differed from others? thanks.

Another solution to a nearly nonexistant problem.

The engineers of the world can't leave well enough alone! I'm surprised Shimano HASN'T jumped on this as the author mentioned.

The solution is a non-solution because it teaches the rider to pedal in an erratic pattern. If you pedal in circles, there is no dead spot. This crank teaches you to pedal in ovals!

Time will tell, I'm sure there will be some improvement over time and it will appear on more bikes, but the additional expense and weight will turn off too many cyclist who are concerned with both. This will cause this to be a "botique" component.

L8R

When you pedal circles your brain has to send 8 signals to the
legs for every complete revolution of the chainwheel and as the
cadence increases the brain cannot cope and you are only
tickling the pedals instead of applying effective power. How much
effective power can you apply as you scrape the mud of your shoe
in the lower dead spot area at a cadence of 100+ or in the upper
dead area at that cadence.
Anquetil's pedaling is linear, direct downward pressure on the
pedals is never used, the line through which the power is applied to the pedals feels parallel to the pulling line of the arms and it
is this important fact together with the special method of applying
the power from shoe to pedal that makes the combination of
arm and leg power possible. Just as rowers use combined arm
and leg power, cyclists can also makes use of the much more
powerful combined arm/leg technique. With this technique the
brain has only to send one signal to each leg during one
chainwheel rotation and that enables you to continue applying
the continuous power in exactly the same manner regardless of
whether the cadence is 50 or 150.