I am a six foot four inch tall recumbent and mountain bike rider.
When I bought a new long wheelbase RANS recumbent to replace my old
BikeE I loved it but noticed somthing wasn't quite the same.
I focused in on the fact that the new bike came with a 170mm crank
where the old one had a 175mm.
Looking around at the raging debates on the internet about optimum
crank lengths I saw lots of opinions. Everything from "forget about
it" to "shorter the better" to "longer legs need longer cranks".
The final argument made the most sense to me. I read where champion
riders chose to ride cranks that where roughly proportional to their
leg length. I also noted that not many champions where on the very
tall end of the human scale. If you extrapolated the numbers a rider
my size might want a 190mm or longer size for a match between the
crankset and their anatomy.

I found few cranks available even at 185mm.
So I invented Crank Clockers.
There were a few crank length adjusters out there but they were
either extremely expensive and required replacing the crank anyway or
they are big clunky looking things that only allow relatively huge
steps in adjustment of 15mm at a pop. I wanted to be able to shorten
or length the crank to any length with in reason.

What I came up with is a set small links with two holes. One hole for
a bolt that goes into the pedal and one hole to screw the pedal
into. It is 25mm between holes which meant I could set the crank on
my new recumbents 170mm pedal anywhere from 195mm to 145mm increments
as small as I was willing or able to measure. The two bar linkage
formed by the pedal and the links in my Crank Clockers allows you to
set any length by clocking the small link. Obviuosly you need to
clock them both the same way to maintain 180 degrees between the
pedals. The trick to making it work on any bike is a row of M5 set
screws pressing against a washer that locks the link from turning.
It holds under the heaviest and strongest rider without budging and
can be reoved without marring the crankset in the least.

Any added benefit to me is that the Crank Clockers also set out the
pedal 1/2" which helps with my wider body size. This of course does
not optimize the Q factor but I think getting your pedal spacing and
especially your crank length just right is WAY more important.


I now ride 190mm crank lengths on my recumbent and 200mm crank
lengths on my mountain bike. My average time has gone up at least 1
mph, the hills are easier, sprints are more powerful and the sore
spot in my quads after a hard ride has moved. The big muscle gets
sore more in the center rather than out toward the knee. I feel like
I am making much better use of my quads.

I am offering these things for sale and paying the machinist to make
them. I only have 5 sets right now and they are price at $149.95.

I hope to get a patent. I imagine one day that lots of bicycle crank
arms will be made as adjustable two piece linkages and you all can
say you knew me when I was just an obscure guy from Stone Mountain
pedalling his life away.

Anyway email me or watch the website www.dcmchenry.com for info as it
is made available. Grab a set you will be glad you did.

David