This is a story more about materials and design than products, specifically, but it ends with an addition to their lineup. Enduro’s XD-15 material is considered a “super stainless” because it has a much higher nitrogen content, which helps make the metal more homogenous. So you end up with far less pitting and much more even wear regardless of the type of bearings rolling around in there.
They’ve used that material for years and years, but only in the angular contact bottom brackets that have a 45° angle, which require proper bearing preload to work properly. That means they’re really aimed at the rider that’s willing to spend the extra time setting up their gear, because without the right preload tension, they won’t work as well or last as long.
Now, they’ve added the XD-15 race material to their 15° Angular Contact and true radial contact bearing bottom brackets. Yes, that means there’s an XD-15 15º, which can be confusing, so just remember that the XD-15 BB’s mean you’re getting the better metal inside.
Both the new 15º and radial bearings offer much easier set up since they don’t require preloading to work properly. During installation of the cranks, most of us like to crank them down pretty tight so they won’t come loose during riding. So, most every bottom bracket ends up with some side load, even if it’s one with radial bearings that don’t need any preload. Enduro says, because of this, their 15° bearing BBs will offer a little smoother performance than using a true radial bearing since they can handle that side load better and will last longer when run under such tension. As such, they’ll only offering complete bottom brackets with the 45º and 15º angular contact bearings. The radial bearings will be available separately if that’s what you really want, and you can pop them into the BB shell yourself.
Enduro Bearings’ XD-15 bottom brackets will be available for pretty much any crank and frame standard you have, check their website for a complete list to find the fit you need. Retail pricing depends on the model – The Enduro Bearings Corsa BB is 45° and runs $299, and the Pro BB is 15° for $249.