Sampson produces an inexpensive fixed spindle with dual adjustable cup bottom bracket. The spindle for the Colorado is made of machined Ti 6Al-4V rod. The spindle's 2 degree tapered ends slope to become the 17mm diameter needed for the interior of the bearing cartridge. A flat shoulder, with a 21mm height, rises for the bearing to seat against.
The center of the spindle, between the two bearing cartridges has the diameter reduced to 17mm, for weight savings. The spindle has each end drilled to a depth of 23mm then tapped for the crank bolts. The bearing cups are machined from 2024 aluminum rod. Each of the cups are machined as a single piece and uses a lockring made from 3.04mm aluminum plate. Each cup has six 3mm diameter holes drilled in its exposed face for a B/B peg spanner (Park SPA-1 Green). The bearing cartridges are made in China (again, what was known as Mainland China) labeled "DF" and "6903-RS".
The sealed cartridge bearings rely on eleven 4mm diameter steel ball bearings in a steel retainer within the steel inner and outer races. A removable, rubberized steel seal is pressed into each side. The bearing cartridges fit tightly into the cups. Careful tightening of the cups presses them over the bearings and seats them around the cartridges. The outer face of both the cup and the lockring are given a mirror-like high polish. Crank arm bolts are not included.
The Colorado is available to fit a 68mm width B/B shell in these spindle lengths 103mm, 108mm, 112mm (172 grams), 116mm, 122.5mm, or 126mm. There are 108mm, 113mm, 122.5mm, 126mm made for 73mm wide shells. Also an Italian thread for a 70mm wide B/B shell is available in 112mm. The 108mm long version for the 68mm wide B/B shell weighs 160.5 g.