If you want an indestructible bottom bracket, the Phil Wood Crankbearing is among the most well known. The Crankbearing definitely is not the lightest, (weight at the B/B position is not that critical), but it is strong, smooth, and was the first to employ precision sealed cartridge bearings.
This bottom bracket is different. It is uses a thin stainless steel tube, into which are pressed, on each side, French made SKF, model #61903-RS1Z+37 precision sealed bearing cartridges. Through this bearing arrangement passes a precision ground and machined steel spindle, which is locked into place. The spindle ends are bored to a depth of 1 1/2 inches and then tapped for the crank bolts, leaving a solid, un-drilled center.
This entire cartridge unit is placed in your bottom bracket shell and a splined retaining ring is threaded from each side into the shell to hold the B/B in place. Because the rings are adjustable from each side, there is some lateral variation that is possible by adjusting the position of these rings.
The cartridge bearings will likely never need maintenance due to the special Phil Wood design. Mounting rings are made in aluminum with English or Italian threads. The spindle can be one of seven lengths, 108mm, 113mm, 119mm, 125mm, 130mm, 135mm and 140mm.
The Phil Crankbearing in the 113mm spindle, without rings, weighs 262 gram, the aluminum ring set weighs 11 grams. The aluminum ring set is available separately should you need to replace it later. Be sure when you order the Crankbearing, to specify the spindle length and English or Italian thread.
There is a second variation of the Crankbearing. It has the steel outer tubing shell replaced with a Metal Matrix version to reduce weight. The steel spindle has been replaced with one machined from Titanium 6Al-4V rod. The Ti spindle, like the steel one has each end bored to a 1 1/2" depth and then tapped for the crank arm bolts. The bearings used are still French SKF but the model is the slightly different #61903+42 PW903.
The Metal Matrix Crankbearing comes with a set Black anodized, machined aluminum mounting rings, which can be threaded for either English or Italian B/B shells. This Crankbearing is available in seven spindle lengths; 108mm, 113mm, 119mm, 123mm, 125mm, 130mm, and 135mm. The weight of the 119mm length with the included aluminum mounting rings is 164 grams.
Spin-08-13-19-23-25-30-35/Thread-E-I $Price in Catalog
As with many of the sealed bearing and "unit" type bottom brackets, the Phil Crankbearing has a unique spline system to thread and tighten the mounting rings into the B/B shell. This Phil tool is made to allow proper installation using a 12 inch adjustable wrench. The tool itself is made of exquisitely machined stainless steel and weighs 38.5 grams. $Price in Catalog