Sims Cranks

It's our belief that Sim's learned what they needed to know about making crank arm sets from John Grafton, after Grafton and Topline parted ways. It seems that Grafton and Sims have now parted ways and Sims is selling cranks under their own name. The Aluminum Lite-Ning arm set has a single piece right arm. Each arm is CNC machined from a single piece of 7075-T6 billet aluminum. The arm is 1" (25.35mm) wide at the pedal spindle, narrows just slightly over the pedal and gradually widens to 1.47" (37.5mm) at the B/B spindle. The elegantly flowing shape to the arm is 15.5mm thick at the pedal spindle gradually becoming 20.5mm thick near the B/B spindle on both arms. The outer corners of the front and the back of each arm are cut with a 10mm quarter round flute which run around the B/B spindle.

These cuts give the arm a much more finished appearance than their predecessor. On the right arm, the spider is left as a part of the arm, after the cutting is finished. Large circular cuts separate each of the spider arms. The 6.42mm thick arms have the back side milled away leaving just a 3.03mm thickness. The posts left for the inner fixing bolts are 12.3mm thick with tapped holes for the inner bolts to anchor into. At the arm ends, where the middle and outer chainrings bolt to them, they are milled to a 3.75mm thickness. The Sims cranks use the standard 110mm bolt center diameter for the mid and outer chainring, and 74mm for the inner. 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 B/B spindle hole has its tapered sides made in the milling of the back of each arm.

Sims also includes a nifty set of crank arm caps. The caps are machined from aluminum rod and look just like the ones that Grafton marketed for the past couple of years. Weighing three grams a pair, a slot on the face is used to turn them into place. The caps come anodized to match the arms. We found the Sims Aluminum Lite-Ning crank arms has a Bike-Pro Q measurement of 154mm. The cranks come anodized in Blue, Black, Pewter Grey, Lavender, or Silver. They are made only in 170mm, 172.5mm, 175mm, 177.5mm or 180mm lengths. Lite-Ning Aluminum Mountain cranks come as right arm, with integrated spider, left arm and a set crank arm dust caps. Chainrings, the double chainring fixing bolt set, and the inner fixing bolt set, will be needed separately. We found the 175mm arm set weighs 404.5 grams, the caps add another 3 grams. Made in Santa Ana, California, please specify length and color

Size-70-72-75-77-80 - Color-B-BK-GY-L-S  $ Price in Catalog 








 

Sims uses nearly the same numerics in controlling their lathe to have the CNC station turn out Titanium 6Al-4V versions of their aluminum arms. But first, a reality check! If you read our metals section you know that the 7075-T6 aluminum alloy most of the numeric controlled arms are made of, is as strong as about anyone needs. Also in the Metals section you are told that Titanium is 60% heavier by volume than aluminum. Titanium's real virtue for crank purposes is enhanced stiffness, not weight reduction as a substitute for the already lighter aluminum. Now, that being said, we know that are people who want expensive and exotic, and very stiff un-yielding crank arms, these cranks are for them. The left arm is made with the same style as the aluminum version. The width at the pedal spindle end isn't quite as wide, just 21.81mm and gradually widens to 36.7mm at the B/B spindle. The Ti arm is only 24.67mm thick at the B/B spindle. The right arm uses two piece construction, with the spider madeas a separate piece from aluminum. To machine the arm and spider from a single piece of Titanium would have wasted a great deal of expensive metal because the piece it would be cut from would have to be at least 125mm wide and 25mm thick and 250mm long. By making the arm and spider separately, the arm can be cut from a piece that is 40mm x 25mm x 210mm less than a quarter by volume of the single piece size. The spider is made of 7075-T6 aluminum alloy, made exactly like as the one on the aluminum arm. Added weight reduction on each of the spider arms is achieved from 9.5mm holes drilled through each near the arm.

The spider has a 22.62mm hole which fits over a fitted square protrusion on the back of the arm. The spider is pressed into place and further held by three small steel bolts. This spider uses the same 110mm and 74mm Bolt pattern of the aluminum model. Crank arm dust caps are also provided with the Ti cranks. The caps are again made of aluminum but have a 5mm hex fitting to tighten them in place instead of the single straight slot of the aluminum arms. The Ti arms are polished after being machined, and are discernible by the hex fitting on the cap, the two piece right arm construction, and the Silver aluminum spider is slightly brighter than the polished Ti arm, giving the right arm a two tone appearance. They are made only in a 175mm length. The Lite-Ning Ti Mountain cranks come as right arm, with spider, left arm and a set crank arm dust caps. Chainrings, the double chainring fixing bolt set, and the inner fixing bolt set, will be needed separately. We found the 175mm arm set weighs 476 grams, the caps add another 3.5 grams. Made in Santa Ana, California.

Mountain arm set $ Price in Catalog 

Sims also make the Titanium crank arms with a 130mm BCD spider. The Road version comes in two lengths, 172.5mm or 175mm.

Length-72-75  $ Price in Catalog