XD-15 BB30 BOTTOM BRACKET, HIGH NITROGEN STEEL CERAMIC HYBRID, $198.00
FOR FRAMES WITH 42mm INSIDE DIAMETER
BOTTOM BRACKET SHELLS RUNNING BB30 CRANKSETS
Please note that this kit
is for the "classic" BB30 bottom bracket shell, which has an inside diameter of 42mm. The bearings press directly
into the shell (no cups of any kind are used). This kit is not suitable for replacing the bearings within a Press Fit
BB30 (which holds the bearings inside composite cups). We offer a complete Press Fit BB30 bottom bracket with Delrin® cups for press fit applications. BB30 bottom brackets are designed only for
use with BB30 cranksets, which have a spindle diameter of 30mm. This bottom bracket kit IS ALSO COMPATIBLE WITH THE
CERVELO "BBRIGHT®" (Non-Press Fit version).
bottom bracket is the fastest and toughest bottom bracket in the world.
XD-15 High Nitrogen Steel Alloy is 3.5 times more corrosion resistant than 440C Stainless Steel.
In the past, ceramic hybrid bearing manufacturers were faced with a choice in bearing race material: 1) The longer fatigue life of SAE52100 bearing steel when paired with the extremely hard ceramic balls,
or 2) The corrosion resistance
of 440C stainless steel for use in harsh environments. If they
opted for the longer fatigue life of 52100 bearing steel, the intrusion of water would always be a threat to the
races. If they opted for 440C Stainless, corrosion would become less of a threat at the expense of longevity.
The XD-15 steel not only combines the benefits of both, but EXCEEDS them on both counts. Yes, much greater
corrosion resistance than 440C and longer fatigue life than 52100 bearing steel.
XD-15 High Nitrogen Steel Alloy has
a 40 percent higher load rating than SAE52100 bearing steel. Ceramic hybrids made
with 52100 steel races, while having a longer fatigue life than stainless, were still subject to premature wear when
used with ceramic balls. Of course the main claim of ceramic hybrids was less rolling resistance, resulting in greater
speed and a more efficient transfer of the rider's output to actual forward momentum. Wouldn't it be great to
get this superior rolling quality while actually increasing longevity of the bearing? Now you can. XD-15 has an
extremely fine grain structure which dramatically reduces the risk of failure under mechanical loading, lowers noise
and vibration, and makes a perfect interface with ceramic balls. Weak spots in bearing races due to
grain structure flaws in traditional bearing metals are not present in XD-15, which has a homogeneous structure of finely
dispersed carbonitrides, as opposed to large carbides concentrated at grain boundaries (which are vulnerable to corrosion
and mechanical stressing).
Grade 3 pure silicon nitride (SI3N4) ceramic balls are the best available. These
made-in-USA balls are Hot Isostatically Pressed (HIP) for a pore-free microstructure with micron-sized grains.
Reduced bearing friction from ceramic balls is a function of smooth surface finish. The balls used in the XD-15
bottom bracket boast a surface finish of < 0.10 micro inch (< 0.003 micron).
contact bearings are a step forward in outboard bottom bracket design. Why? Deep groove radial
ball bearing cartridges are not designed to be "adjusted." Any inward or outward pressure on the inner races
put them out of alignment with the outer races, forcing the balls to ride up the side of the groove and exerting greater
pressure on the races. This results in increased friction and premature wear. Since almost all outboad
cranksets exert some inward pressure on the bearings when installed, it only makes sense to use a bearing designed specifically
for such loads. Likewise, the BB30 wave washer keeps pressure on the inner races of the bearings, making the angular
contact design of the XD-15 ideal.