customcranks.de
 i  n  d  i  v  i  d  u  e  l  l  e     K  u  r  b  e  l  n 


Initiative
Customcranks was created at the initiative of cyclists who found their ideas regarding ergonomics, biomechanics, and drive train efficiency not fully satisfied in the marketplace.
There are some aspects of  several relevant requirements that
the big brands in the bicycle industrie so far have not met. (There may be reasons for this or not.)
In order to 
better serve these specific requirements we manufacture some products that fall outside what is available in the general marketplace; and also strive to meet some individual customers specific needs and/or wishes.

Biomechanics & Ergonomics
Although crank length is a major ergonomic variable on all bicycles, petite 150cm ladies (4'11'') and 200cm tall giants (6'7'') all too often have the same crank length. Only rarely do you find crank length differences of more than 10%, even though the body and leg lengths vary by more than 20%.

With relatively longer crank arms, more of the available muscles in a rider's leg are used to produce power; consequently, throughout a normal pedaling circle with relatively short crank arms, some of the available leg muscles remain unused. Short riders will therefore experience the cycling more like mountain climbing instead spinning with higher frequencys (what smaller people usually can better do than the large).
Taller riders who cycle with relatively short crank arms limit their potential 
power during long or fast rides by not using all the available leg muscles. The problem would be alleviated by the use of crank arms proportionate to the length of the relevant bodyparts (leg, femur or inseam).

Drive Train and
Economy
There is a continuing trend in the bicycle industry toward reduction in size of the drive train used for MTB / ATB. Smaller sized chain rings increase forces on all sprockets, especially the smallest ones. The small chain link contact areas on a 10 or 11 tooth sprocket - combined with the raised chain tension on comparatively smaller chain rings - result in increased stress and wear on the drive train. Increasingly durable (and often more expensive) drive train materials are necessary to even hold the drive trains life time on smaller chainrings/spockets. This is not to everybody's advantage, since most cyclists are not involved in winning the Tour de France. Many cyclists will therefore value longevity of the drive train higher than small weight savings. For touring cyclists, who commonly use cross- or mtb-type bicycles laden with packing, this context becomes even more obvious. Avoidance the use of very small sprockets in combination with very small chainrings will increase the life of the drive train. Heavier and/or stronger cyclists need larger chain rings to overcome the problem of increased drive train wear.

We are making a selection of five-arm crank sets with 110/74mm Bolt Circle Diameter (often called 'Standard' bolt circle). The chain ring bolt angle of 72 on five-arm cranks, compared to 90 on four-arm cranks, allow for improved lateral stiffness with the largest selection of competitively priced chain rings from most manufacturers and fitting for different types of chains (for single speed or for 6,7,8,9.10 and 11 fold spockets).

Smallest chainrings on BCD 110mm have 34 (or even 33) teeth . The largest ring we have mounted on BCD110 so far is 70teeth.
Smallest chainrings for the BCD74mm have 24teeth (there *are* smaller chainrings [down to 20teeth] for other bolt circle patterns in the market - but with the mentioned disadvantages on drive wear - especially for heavier/stronger bikers).

Location
Customcranks are made according to customers wishes (and within our existing limitations)  in the
"United Crank Factories of Rennersdorf" in Stolpen, 30km in the East of Dresden.

Together with the cranks we can also deliver on wish: fitting chainrings, bottom brackets, crank bolts, chainring bolts and very precise spacers for the best chainring adjustment.