On the path of least resistance, Cook Bros. Bottom Brackets are lightweight and strong. Featuring quality sealed bearings and a precision ground heat-treated 4130 spindle (also available is a Titanium spindle version), this is a "set it and forget it" floating-type design. The bearing cups are machined from 7075 aluminum rod then anodized Black, into which Japanese KSK 6002RS precision sealed bearings cartridges are pressed from the outer side. The cups have the outer flange cut, creating parallel sides for a 35mm fixed cup wrench (Park HCW2 or equivalent), or less precisely an adjustable wrench, to grip. Both cups are threaded into place, then the spindle laterally slides through them and is adjusted to space the cranks properly.
An aluminum locking collar is used on outer side of each of the cups to hold the spindle in place. The locking collar slides down the spindle next to the bearing, and each one is cinched down with two recessed allen head set-screws. The spindle is machined from 4130 Cro-moly rod leaving a 5/8" outer diameter, with tapered ends. The spindle is drilled through to reduce weight, then tapped for the crank bolts. This B/B comes with steel crank bolts.
The Cook Bros. B/B with 120mm spindle weighs 273.5 grams (including the crank bolts and washers, which weigh 31 grams). The spindle is available in six lengths, 110, 115, 120mm, 124mm, 127mm, and 133mm. It will fit all aluminum crank arms, and is one of our most requested aftermarket replacement B/Bs. Cooks also make a press-in version for older Fat Chance or Klein frames, in fact Cooks is the only one to make a good aftermarket replacement for these. English only.