Wilderness Trail Bottom Brackets

WTB CLASSIC CRO-MO & TITANIUM SPINDLE BOTTOM BRACKET

Wilderness Trail Bikes produces an unusual B/B that implements their famous Grease Guard principle. Designed by Mark Slate, it uses SKF 6003-RS1 sealed bearing cartridges with the inner seal removed. Behind each bearing cartridge is aluminum ring, cut on the edge, with a specially created rubber ring that forces grease injected into the cut area into the open ended sealed cartridge.

The outer seal on the cartridge is made so the inner lip of the seal moves away temporarily under pressure, permitting old grease to be purged from each bearing cartridge. To prohibit grease from migrating back into the center of the B/B, there is an aluminum tube that slides over the spindle, making a tight seal with both the rubber ring and the inner bearing race, leaving the spindle to revolve freely. The aluminum ring is cut on edge to create a 2mm wide gap, that is nearly an inch long that permits a wide target to inject the grease into. This B/B doesn't come with standard threaded bearing cups. Instead, the user reams their B/B shell with a 1 3/8" (1.375") reamer, to give the interior a smooth surface. The aluminum ring is pushed in with the cut edge facing the direction you intend to inject the grease from. The bearing cartridge is then pressed in, with the seal out. On the other side, the aluminum sleeve is inserted, the spindle is carefully pressed through, then the other aluminum ring, and the remaining bearing.

The outer diameter of the bearing and the alloy ring is 35.0mm, and they fit tightly within a round properly reamed B/B shell. If the shell is slightly oval Loc-Tite adhesive may be required. The cut edge of the alloy rings should face the same direction, to meet a 1mm hole that will have to have been previously drilled 11mm from each end of the B/B to pump the grease into the assembly, (there wasn't a way to explain their need earlier). The holes on a aluminum frame can be Zerk fittings, for steel, it is suggested that electrical tape be used to close them off between grease applications.

The WTB bottom bracket is available with either a Cro-Moly spindle, (made for them by Chris King), or Titanium spindle, (made for them by Doug White at White). Both spindles have the required two degree taper to fit all aluminum crank arms, and both are drilled through to reduce weight. The Cro-moly spindle is made in either 116mm or 122mm lengths. The Titanium spindle comes with matching Titanium crank arm bolts, and is available in 108mm, (for XTR), 115mm, or 122mm. The weight of a WTB Cro-Moly B/B with a 122mm spindle is 267 grams. A Titanium version wasn't at hand for weight at the time of writing.

Cro-Moly Spindle Length-16-22 $Price in Catalog
Titanium Spindle Length-08-15-22 $Price in Catalog

WTB PARADIGM GREASE GUARD B/B

Although Wilderness Trail Bikes has had Suntour be the maker and seller of mass produced Grease Guard B/B's, Suntour has left the bike industry for good and WTB has come up with version based closely on the Suntour implementation. WTB has this bottom bracket made in Japan by the Tange company in Osaka. (Our understanding is that Marui Ltd. is the sole export agent for Tange. WTB's relationship with Marui probably came from when they were designing parts for Specialized. It si well known that Rio Marui offered unusla assistance and support to Specialized in their formative years, ages 1 to 12)

The Paradigm employs what we call "Standard" design, having Fixed drive cups with an adjustable non-drive cup and fixed bearing width. Grease Guard is a name that WTB uses to describe their grease injection system. Grease is squirted into a hole in the crank arm cap and pushes its way through the spindle to emerge on the inner side of a sealed bearing cartridge that has its inner seal removed, allowing the grease to pass through the bearing near the spindle. When the older grease emerges outside around the spindle it can be wiped away.

The spindle is made of forged steel that is machined after forging to perfect its surface. The ends are bored to a 37mm depth and tapped with 8mm x 1mm crank bolt threads. Ateach end, a small hole is drilled into the spindle that ends in the crank bolt hole. When the bearing cup is in place these holes will fill the bearing cavity with grease. The drive cup is made of machined aluminum and has the 1 way purge bearing machine pressed in place. A rubber seal held in place by a steel cap forces injected grease toward the outward direction. This fixed cup has two sides cut parallel at a 36mm distance for a B/B spanner (Park HCW4, or Sugino B/B tools) to tighten. The non-drive cup, also machined of aluminum threads into the left side of the B/B shell. It has six equi-distant square notches in its face so a Park SPA4 pin spanner can be used to tighten it. A steel lockring with six square notches on its perimeter is used to cinch the cup in place. Any hook spanner will work on the lockring.

The included set of crank arm bolts and washers are made of nickel finished steel. The Paradigm B/B is available in a 113mm or 122mm spindle to fit a 68mm wide shell. The 113 x 68mm B/B weighs 241 grams, the steel bolts add another 29 1/2 grams for a total weight of 270 1/2 grams. The 122mm version has a total weight of 282 grams.

Spindle Length - 13 - 22 $Price in Catalog

WTB Ti PARADIGM GREASE GUARD B/B

WTB also has the Paradigm available in a Titanium spindle model. It uses the same Japanese bearing cups and crank bolts. The spindle spindle is machined from 6 AL 4V Titanium rod to be mechanically the same as the Japanese steel one, but is probably made in the United States. The Japanese have an absolutely unblemished record of failing to make a Titanium bicycle that succeeds in the world market, so we believe that this spindle to made by Paragon Machine Works for WTB.

The steel version in the 113mm length weighs 159 grams, while the Ti replacement is just 90 1/2 grams. The Ti Paradigm B/B is available in a 113mm toor 122mm spindle to fit a 68mm wide shell. The 113 x 68mm B/B weighs 172 grams, the steel bolts add another 29 1/2 grams for a total weight of 201 1/2 grams.

Spindle Length - 13 - 22 / T $Price in Catalog