Hershey Racing Cranks

The Hershey cranks have a simple appearance that doesn't betray the complexity in their machining. Each arm numerically control machine cut from a single piece of billet 7075-T6 aluminum. Unlike many of the other arms reviewed in this article, the right arm and its spider of this crank set is a single piece. The two piece spider and arm used by many other crank makers occasionally brings problems. Our service department has tried to install two piece drive arm cranks and discovered the spider to have been permanently installed not in the proper line of travel. Sometimes the two piece arm is prone to bending or minor separation at the joint when in use. One piece construction avoids this, and it also avoids the most common problem with two piece construction, which is "creaking." Under full weight the spider and arm flex at a slightly different rate and the rider hears a loud creaking noise coming from what is at first thought to be the B/B.

The arm is 1" (25.4mm) wide at the pedal spindle and narrows to 3/4" (22.2mm). For the final 3" to the top of the B/B spindle the arm gradually widens again to 1.3" (33.22mm). The arm is 16.4mm thick except in the last 3" to the top of the B/B spindle. The rear of the arm has much of the aluminum milled away, leaving 2.4mm walls as supporting trusses, while reducing the thickness from 16.44mm to just 5.575mm. Added mill work near the B/B spindle reduces weight still more, bringing the left arm to just 179 grams. The spider arms are 6.63mm thick reducing to the needed 3.5mm where the double fixing bolt set passes through.

Each of the spider arms is joined by an aluminum ring after the cutting process that is 3mm wide by 6.3mm thick. This left in place ring adds extra rigidity to each of the spider arms making bending of any difficult. The inner fixing bolts anchor into 13.5mm tall posts tapped with threads left after cutting. The Hershey crank uses the standard mountain bike bolt pattern of 110mm for the middle and outer chainrings and 74mm as the bolt center diameter for the inner. The pedal spindle hole is drilled and tapped with 9/16" by 20 TPI threads. The crank dust cap hole is bored and tapped with 22mm by 1mm threads. The 2¡ tapered square hole for the B/B spindle is cut as a part is the milling of the back of each crank arm. The Hershey crank arms come anodized in Blue, Black, Lavender, or Silver. We can also special order them in Pewter Grey, Gold, Green, or Red. They are made in 170mm, 175mm, or 180mm lengths. Hershey cranks come as right arm and left arm only. Chainrings, the fixing bolts and nuts, the inner bolt set and crank arm dust caps will be needed separately.

We found the Hershey cranks had a Bike-Pro Q measurement of 164mm. The weight of the 175mm long Hershey crank arm set is 412 grams. Made in California, USA, specify length and color.

Size-70-75-80 - Color-B-BK-G-GN-GY-L-R-S   $ Price in Catalog