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GRAFTON JOYSTIX MOUNTAIN CRANK ARM SET
The Grafton Joystix are CNC machined from 7075-T6 aluminum alloy. Each of the arms is machined from a single piece of billet aluminum, so the right arm and its spider are one piece. At the pedal spindle the arm is 1" (25.34mm) wide, it narrows slightly above it to 19.3mm, then gradually widens to 36.81mm at the B/B spindle hole. Both arms share these dimensions. At the pedal, the arm is 15mm thick, adding thickness gradually up the arm to the B/B spindle. On the left arm it's 25.81mm thick at the B/B, the right arm, at 26.08mm has slightly more material to support the arm on the spindle. A cut is made by the milling machine at approximately 45 degrees around the entire upper perimeter,cutting the corner away giving it an angled edge. This same angled cut my the milling machine is made on the reverse around the length of the arm, omitting the B/B spindle area.
The spider has a swept arm to the right design. Each spider arm has a 6.7mm thickness, but is 13.81mm thick to make the drilled and tapped post for the inner fixing to thread into. The end of each arm is machined to a 3.6mm thickness to properly hold the middle and outer chainring.
Around the B/B spindle, on the back side, the aluminum is milled away reducing the 6.7mm thickness in these areas to 3.50mm You will notice that many of these dimensions, measurements, and style of construction are rather similar to those used on the Sims cranks, this is because Benson Sim was once Mr. Grafton's sub-contractor making the Grafton arms (Grafton has no machine shop of his own), and began making and selling cranks under their own name when Mr. Grafton was unable to meet his commitments, (also, see the Topline story).
The pedal spindle hole is drilled and tapped with 9/16" by 20 TPI threads. The crank arm dust cap holes are bored and tapped with 22mm by 1mm threads. The square tapered hole for the B/B spindle is milled to shape as a part of cutting the rear of the arm. Each of the arms is polished, then anodized, if it to be colored, or left un-anodized yet high polished if it is to be Silver.
Joystix crank arms come anodized in Blue, Black, Lavender, Red, or Silver. They are made in 170mm, 172.5mm, 175mm, 177.5mm, or 181mm lengths. Grafton Joystix cranks come as right arm, with integrated spider, left arm, a set of five steel outer bolts and nuts, and a set of five steel inner fixing bolts. Chainrings, crank arm bolts, and crank arm dust caps will be needed separately. We found Joystix Mountain cranks had a Bike-Pro Q measurement of 154mm. The weight of the 175mm long Joystix Mountain crank arms is 439.5 grams, the nut and bolts sets weigh an added 38.5 grams. Made in USA. Specify length and color.
Size-70-72-75-77-80 Color-B-BK-L-R-S $ Price in Catalog
GRAFTON HYPER-C MOUNTAIN CRANK ARMS
There is also a Hyper-C compatible version of the Joystix Mountain cranks. All other aspects of the arms are the same, except the single piece right arm has its swept back spider arms made slightly shorter. The shorter arms bring the outer chainring bolt holes to the 94mm center diameter of the Hyper-C cranks. The inner chainring posts are spaced inward to the 58mm Shimano standard. Nothing much else is different, even the weight is very close. The Hyper-C Joystix crank arms come anodized in Blue, Black, Lavender, Red, or Silver. They are made in 170mm, 172.5mm, 175mm, 177.5mm, or 180mm lengths. Hyper-C Joystix cranks also come as right arm, with integrated spider, left arm, five steel outer fixing bolts and nuts, and a set of five steel inner fixing bolts. Chainrings, crank arm bolts, and crank arm dust caps will be needed separately. We found Hyper-C Joystix Mountain cranks had a Bike-Pro Q measurement of 155mm. The weight of the 175mm long Joystix Mountain crank arms is 438 grams. The nut and bolts set weighs an added 38.5 grams. Made in USA specify length and color.
Size-70-72-75-77-80 - Color-B-BK-L-R-S $ Price in Catalog
GRAFTON SPEEDSTIX ROAD CRANK ARMS
Another variation of the Grafton arms yields a Road racing arm set. Again the arm set is CNC machined from billet 7075-T6 aluminum alloy. The Speedstix 175mm left arm weighs 165 grams, while the Joystix 175mm version is 200 grams. Each of the Speedstix arms weighs less than their Joystix arm equivalent because they are a little more slender in width and thickness. At the pedal spindle they are 23.97mm wide, narrow to 18mm then gradually widen to just 32.33mm at the B/B spindle. For thickness the arms are 13.62 at the pedal spindle, thickening to 15mm. The last 100mm (4") from the B/B end have the arm gradually thickening from 15mm to a final 23.13mm at the B/B spindle. The Speedstix 175mm right arm weighs 201 grams, down from the Joystix 175mm right arm weight of 240 grams. The Speedstix right arm again has an integrated spider cut with the arm.
This Road arm uses a 130mm bolt center diameter. The swept back arms on the spider give the impression of forward motion. The spider has a nominal material thickness of 6.35mm but has most of the back of it milled away leaving a 2.45mm thickness throughout all but the edges and the support area for the B/B spindle. The pedal and crank arm cap holes are made like those on the Joystix. Speedstix will work on any bottom bracket using a two degree tapered spindle. We found Speedstix had a Bike- Pro Q measurement of 146mm. Speedstix crank arms come anodized only in very HIgh Polished, un-anodized Silver. The finish on these arms is more mirror-like than a glass mirror. They are made in 170mm, 172.5mm, 175mm, 177.5mm, or 180mm lengths. Speedstix cranks come as right arm, with integrated spider, left arm, and a set of five steel outer fixing bolts and nuts. Chainrings, crank arm bolts, and crank arm dust caps will be needed separately. The weight of the 175mm long Speedstix Road crank arms is 366 grams, the fixing bolt set weighs an added 25 grams. Made in USA. Specify length. These are not as available as they once were. There may be delays
Size-70-72-75-77-80 / S $ Price in Catalog