Kooka Cranks


Kooka arrived at the bike industry trade show for the first time in September of 1993. One of our staff, namely your beloved author, noticed immediately that these people were comers because they incorporated a feature into their crank arms that seemed both natural and obvious. The Kooka Kranks are Computer Numeric Control machined from billet 7075-T6 aluminum alloy. The arm has a 24mm width at the pedal spindle widening gradually to 36.65mm at the bottom bracket spindle. Through the middle of the front and back of each crank arm a square trough is milled away. This milled trough is 14mm wide at the pedal and widens to 18.5mm at the B/B. This same cut is made on both the front and rear to reduce equally from both sides the thickness of the arm from about 15mm to just 2.7mm, this reduces tremendously the arms weight. A small amount of weight cut from the pedal spindle area by cutting a 9mm wide to a depth of 1.8mm around the lower 1 1/4." This same type of trough is cut around the B/B spindle, extending 1 3/4" from the top of the arm.

This B/B cut is 1/2" wide to a depth of 4.58mm (1/5"). The pedal spindle holes are drilled and tapped with 9/16" by 20 TPI threads. Each arm is bored for the arm dust cap which has 22mm x 1mm threads tapped for the cap. This process reduces the weight of the left arm to a startling 156.5 grams. Now on to the spider, which is machined from 6.60mm aluminum plate, and held on a 21mm square protrusion, that is hollow for the B/B spindle to pass through, and fixed in place on the protrusion by a bonded steel bolt.

The spider has a swept arm shape with each arm moving visually clockwise. The unique feature of this crankset is the spider, which has three bolt center diameter hole patterns to hold the three chainrings. It has the 110mm needed for the middle and outer chainrings. It has the 74mm used commonly for the inner chainring, but also has another set of holes drilled and tapped nearer the B/B spindle. This nearer set of holes is the 56mm bolt\ center diameter which the inner chainring size is you were using the Suntour Micro Drive standard. This gives you the option of using for your inner chainring, the 20 tooth stainless steel chainring for an ultra-low "Granny" gear while using a standard mid and outer. The 20 tooth inner with a 28 tooth freewheel cog provides you with a gear ratio of 0.7 to 1 without the need of an added device like the Limbo spider or Avid Micro adapter. You can certainly use any of the more common inner chainrings on the 74mm BCD holes instead.

The Kooka Kranks will work on any 2 degree tapered spindle bottom bracket. The Kooka crank arm come anodized in Blue, Black, Gold, Green, Pewter Grey, Lavender, Red, or Silver. They are made in 170mm, 175mm, or 181mm lengths. Kooka Kranks cranks come as right arm, with spider, left arm and a set of five inner fixing bolts and five aluminum spacers to use with the inner chainring (wherever mounted). Chainrings, the fixing bolts and nuts, and crank arm dust caps will be needed separately. We found the Kranks had a Bike-Pro Q measurement of 151mm. The weight of the 175mm long Kranks crank arm set with five spacers is 384.5 grams. Made in Nevada, USA. Specify length and color.

Size-70-75-81 - Color-B-BK-G-GN-GY-L-R-S   $ Price in Catalog 

Kooka Micro D Crank Arm Set
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