GXP stands for Good Manufacturing Practices and is a collection of quality guidelines used to produce biopharmaceutical products. These guidelines ensure the safety and quality of biopharmaceutical products. GXP-certified bottom brackets adhere to these guidelines during manufacturing. They are threaded, external-cup units and compatible with SRAM cranksets.
Threaded, external cup unit
If your bike has SRAM or TruVativ GXP cranksets, you need an external bottom bracket. The external bottom bracket includes the left and right bottom bracket bearing cups, along with spacers. It also features an improved GutterSeal to improve sealing and reduce drag.
The external cup unit is designed to fit tightly and securely into the bottom bracket shell. Moreover, it is sized to accept a 24mm crank spindle. The threaded cup/collet system is compatible with Shimano, SRAM GXP, and Campy Ultra Torque frames. The entire bottom bracket lineup from Praxis uses this technology.
Threaded, external cup units for gxp bottom brackets come with a sealed bearing. This type of bearing has ball bearings inside a cage that is held in tension by an inner and outer race. This unit is designed to work with both a threaded and non-threaded bottom bracket.
While standardisation would make life easier for the consumer, it could also slow progress for the industry. There are still many aspects of bicycle design that need to be perfected. Threadless bottom bracket shells, for example, could benefit from improvement. Unlike threaded bottom brackets, threadless shells are not easy to install and remove. Moreover, repeated replacements can lead to damage to your frame.
In addition to the external cup unit, a threaded bottom bracket also has a bearing seat built in it. The cup is made of plastic or alloy and is either threaded or pressed into the shell. The external cup unit is better than the press fit version, but there are no foolproof alternatives in the industry.
The SRAM GXP bottom bracket supports SRAM’s road and mountain cranksets. It features smooth bearings to reduce drag. It also features seals to prevent debris from entering the bearing. The GXP bottom bracket is also designed for durability. It is compatible with both 68mm and 73mm bottom bracket shells.
The GXP bottom bracket is also lightweight. It uses CNC-machined aluminium, which not only makes it light but also increases the durability of the bike. This design also eliminates side-loading, which makes biking more comfortable and efficient. A 24mm crank is compatible with the GXP, but you’ll need a GXP adapter.
The GXP bottom bracket is the standard on many mountain bikes. It features a 92mm wide bearing. SRAM also offers a 29mm axle that solves the problem of oversized crank axles. It is also compatible with other bottom bracket shells. The 29mm spindle offers a greater selection of bearings and is lighter. The bearings are also just as durable as those matched to SRAM’s GXP axle.
Many manufactures have realized this and have introduced threaded cups. It is much easier to work with and less noisy than press fit BBs. The creaking of a press fit BB is a common complaint, particularly if you’re riding in wet or muddy terrain.
The BB30 was introduced at the Tour de France 2000. It was an oversized threadless shell that had bearings pressed into the frame. The company did not patent the design and offered it to all frame manufacturers. Eventually, the BB30 was adopted by Cannondale and many other frame manufacturers.
One of the main advantages of a stiffer GXP bottom bracket is its external bearing system. Its six-sealed design provides superior wear resistance and durability. In addition, it has an alloy cup and is compatible with 83mm bottom bracket shells. For installation, you’ll need a torque wrench and Park Tool BBT-9.
The SRAM GXP bottom bracket was originally a Truvativ design. SRAM bought Truvativ in the early 2000s and used the GXP as a drop-in competitor to the Shimano Hollowtech 2 standard. The GXP design moved bearings outward beyond the frame’s extremities, which reduced cantilever torque transfer.
Compatible with all SRAM cranksets
The SRAM GX 2x crankset offers consistent, reliable 2x shifting performance. With X-Glide chainrings, this crankset is designed to maximize your 2x shifting potential. It also features the most gear range of any 2x drivetrain, thanks to the narrow Q-factor and stronger crank construction.
With the new DUB system, SRAM cranks are more compatible with other cranksets. The new cranks have an improved bottom bracket axle, and improved bearing profiles. The new bottom brackets are assembled at SRAM’s own facilities. The DUB crankset is also SRAM’s lightest crankset to date. With an overall weight of 490 grams, the new XX1 Eagle DUB SL chainset is lighter than any other crankset currently available.
The DUB technology makes compatibility easier than ever. The DUB design simplifies the process of crankset and frame BB compatibility. In 2019, SRAM rolled out DUB cranksets for road bikes and started producing bottom brackets compatible with this new technology. These cranksets are compatible with all major bottom bracket standards.
Another issue that plagues GXP cranksets is the non-drive side taper. While many bicycle teams have opted to remove the inner clamp ring, they do so for several reasons. These factors include maintenance, longevity, and friction. Additionally, many SRAM products are not manufactured with the best tolerances. This can lead to substantial length variations.
Compatible with Shimano Hollowtech II
The Hollowtech II and Hollowtech cranks are not compatible. The former features separate left and right crank arms and an 8-spline spindle integrated into the bottom bracket, known as Octalink. The latter, on the other hand, integrates the spindle with the drive side crank arm and does not utilize an octalink.
The Hollowtech II form factor is used on road groupsets by Shimano, including the Tourney A070. This design features a hollow 24 mm steel spindle, splines for the non-drive side arm, and two pinch bolts to secure the non-drive-side arm.
BBs are also available for Hollowtech II. BB shells come in screw-in and press-fit styles. Press-fit BBs are compatible with 68mm and 73mm shells, but are slightly heavier. The SAINT BB-MT800 is a bit heavier than the SM-BB93, but offers the same specs.
Shimano HOLLOWTECH II cranksets are highly optimized to transfer power from the rider to the pedals. These cranksets also feature an optimum balance of weight distribution. The HOLLOWTECH II crankset’s 24mm axle has been carefully designed to ensure optimum balance.