Our Bead Socket Technology rim design is the foundation of modern tubeless.

Bead Socket Technology rims are designed to match the shape of your tire's bead to create a safer and more secure air tight interface.

Unlike the secure “socket” of a BST design, conventional rim shapes drive the bead of the tire down deeper into the rim, putting pressure on sidewalls that causes friction, restricts tire volume, and keeps the interface from forming a sufficient seal for tubeless use. BST rims secure the bead of the tire, not the sidewall, creating an air tight seal while allowing the tire's sidewall to expand to its true, rounder, more effective profile.

The result is more traction and less rolling resistance. With lower-profile, less vulnerable sidewalls, our BST rims are also lighter and stronger by design, and accelerate more quickly.


BST-Asymmetric combines the benefits of Stan's BST with more balanced spoke tension to create a stronger wheel.

BST-Asymmetric rims combine Stan's patented Bead Socket Technology--the original and still most reliable tubeless-ready rim design--with an asymmetric shape that allows for offset spokes, creating a stronger overall wheel.

Most asymmetric rims struggle to inflate easily and maintain a reliable seal on both sides of the rim, but Stan's BST-Asymmetric rims equalize tire retention and dent resistance on each side of the rim, allowing for easy inflation and total ride confidence under even the hardest cornering.

Stan's BST Asymmetric rims feature distinct spoke hole offsets based on rim width. At 25mm wide, Crest MK4 rims have 1.5mm of spoke offset. The 28mm Arch MK4 rims use an offset of 2.5mm. The 30mm wide Flow MK4 rims use a 3mm offset. This level of precision optimizes spoke tension balance and allows for the strongest and most effective tubeless rim shape. The Crest MK4 asymmetric rim, for instance, has a near perfect 92% balance between drive side and non-drive side spoke tension, versus the 58% spoke tension balance of previous symmetric Crest MK3 rims. When used with M-pulse or E-sync hubs, Stan's MK4 BST-Asymmetric allows a single spoke length to be used for all matching sets.

Whether you choose a MK4 wheelset with M-pulse hub or S2 wheelset with E-sync hub, a complete set of Stan's Crest, Arch, or Flow wheels will each use only a single common and readily available spoke length that works front or rear, either drive side or non-drive side, making maintenance and service easier than ever.


Balancing rim width and tire width leads to faster cornering and improved control.

The most important piece to the bicycle-terrain interaction is the contact patch between the tire and terrain, so tire profile and tire pressure play huge roles in bicycle performance and overall handling. But many rims just don't work well with the tires we're all using.

Rims that are too narrow fail to offer sufficient sidewall support and protection to your tires and create a less stable shape. The result is less control in the corners, less traction on climbs, and more rolling resistance.

Rims that are too wide also distort the tire profile, decreasing traction and control and driving impacts directly into the rim, negating the impact absorbing advantages of a tire's volume. Our WideRight rim widths are designed to strike the perfect balance between tire volume and sidewall function.

WideRight rim profiles allow the tire to achieve its proper shape, and that's the foundation for a great handling, fast-rolling, and responsive bike.


Too narrow. Tire is constricted, robbing traction and cornering stability.


The perfect width. Tire expands to full volume without distortion. Tread pattern and side knobs are in the correct position for cornering, maximum traction and control with minimum rolling resistance.


Too wide. Tire beads are pushed wide, deforming intended tire shape and tread design. Tire has less ability to absorb impacts and less cornering control, and sidewalls are exposed to cuts.


WideRight Recommended Tire Size Ranges graphic Our WideRight system makes it easy to find the perfect rim width for the tire size and volume you ride. Too narrow of an internal rim mixed with a high sidewall design gives you a "light bulb" tire profile while an ultra wide rim on a narrower tire will give you a flat to "bell shaped" tire profile. Neither of these scenarios give optimal tire profiles nor allows the tire to perform as intended.

WideRight profiles provide the optimal volume without distorting the tread pattern or the side knobs so each part of the tire is in the correct position for rolling and cornering, allowing for maximum traction and control as well as offering minimal rolling resistance.

The WideRight profile advantages don't stop there. Proper tire profiles not only allow for optimal tire performance but also allow the tire to do its secondary job of protecting the rim as well as the tire's sidewall. A flat or bell-shaped tire profile leaves the tire exposed to sidewall cuts and creates undue chances for rim damage.

  • Optimizes tire profiles
  • Maximizes traction
  • Properly distributes tire volume
  • Promotes the design intent of the tire profile and overall tire performance
  • Reduces tire pinch flats and sidewall damage
  • Allows tire to protect rim


Innovative hubs designed for durability, fast and positive engagement, and low drag.

Combining the best materials and construction with a smarter engagement system, M-pulse hubs are built to roll smoother longer.

The heart of M-pulse hubs is the magnetic locking engagement system based on the innovative Project321 design and manufactured in their small-batch, high-precision facility in Bend, Oregon.

M-pulse freehubs feature six pawls equipped with Neodymium magnets engaging every 1.66° with more force than traditional spring-based pawl designs and less resistance when coasting. With less friction and drag, M-pulse hubs spin more freely to roll further faster, and with less effort.


All hubs suffer from momentum-robbing drag as you coast, but when it comes to creating the most efficient and reliable ratchet system, pulling is better than pushing.

Conventional mechanical pawl springs are constantly attempting to push the pawls into the ratchet ring. Those push springs are weakest when fully extended, as the teeth of the pawl engage with the teeth of the ratchet ring, but as you coast and the teeth of the pawl disengage and move down out of the teeth of the ratchet ring, push springs compress and exert even more pushing force. This creates significant drag and friction.

Unlike these inefficient mechanical push spring systems, M-pulse hubs use the pull force of Neodymium magnets to reduce drag to the absolute minimum, while still being able to engage with reliable precision the instant you push on a pedal. Magnetic pull springs are at their strongest when the pawl is engaged and are weakest during coasting, the ideal scenario to reduce drag.

Project321’s patent pending placement of the powerful but small rare earth magnets let the pawls self-align quickly and consistently during engagement while creating a hub with almost no rotational resistance when coasting.

The M-pulse hub's six magnetic pawls and hardened steel ratchet ring are also built to outlast conventional mechanical springs, which can fatigue, lose tension, and become misaligned over time. With better durability, stronger engagement, and less drag, the M-pulse design is a better way to build a hub.

  • Neodymium rare earth magnetic spring provides stronger engagement with less drag
  • 7075-T6 hub shells and axles can withstand years of high torque use
  • Fully shielded Enduro bearings with custom grease fill for long life and low resistance
  • U.S. machined and assembled precision 6-pawl freehub with extremely fast 1.66° engagement
  • Adjustable preload allows longer bearing life and lower friction to roll smoother
  • Available in Shimano Micro Spline, HG, and SRAM XDR, 6-bolt and Centerlock, with options to fit most axle widths


Because an innovative design is only as good as its materials and construction, each detail of the M-pulse hub has been engineered to systematically eliminate weaknesses found in traditional pawl and ratchet style hubs.

The new M-pulse hub starts with the most simple and durable version of Project321’s magnetic pawls, and features an all new freehub body and main seal design for outstanding protection from the elements.

The hub rolls on Enduro bearings with a custom grease fill optimized for low resistance, and every bearing on the M-pulse hub is shielded, meaning no bearing seal is directly exposed, for smooth rolling in all conditions and increased bearing life.

The 17mm axles are made of 7075 aluminum and roll on long-lasting Enduro brand bearings that feature custom-tuned grease fills that reduce resistance. A double-row main freehub bearing was chosen after tests proved it to be more durable than two individual, separate bearings. Multiple teeth on each pawl provide a greater surface area to distribute load to improve engagement, and the angle of the pawls was optimized to distribute stress away from the rotating bearings for added durability under high torque.

Beyond the strength and speed of engagement, M-pulse hubs feature adjustable preload that decreases drag and resistance for less effort and more speed.

Adjustable preload also prolongs bearing life by allowing the hub's bearing tension to be tuned with greater precision in contrast with most hubs that tension unevenly by relying solely on how much the bike’s axle has been tightened.

A precision piece of equipment deserves the option of precise tuning, and the M-pulse hub's adjustable preload, available on both the front and the rear hub, delivers that level of tuning precision.

With their quality materials and construction, M-pulse hubs are backed by a 5-year warranty.

M-pulse hubs are available on MK4, CB7, and Podium series wheelsets, and are offered with Shimano Micro Spline, HG, or SRAM XDR freehubs, 6-bolt or Centerlock brake style, and options to fit all popular axle configurations.

Oh, and how does it sound? Here's the M-pulse hub compared to some other popular hubs.


Hubs built to handle the stress of eBikes and adverse conditions.

Strength and durability were the main priority in designing E-sync hubs. Designed for more aggressive riders, wet environments, and the added torque and weight stresses of eBikes, E-sync hubs are built to last.

The cromoly axle and Enduro sealed bearings of the E-sync can handle high loads and harsh conditions, and the double row Enduro bearing at the heart of the E-sync's freehub lasts longer than simply pairing two standard cartridge bearings side-by-side. The 6066 alloy shell and heat-treated steel ratchet ring add further durability, allowing the E-sync to boast a 47% higher max torque capacity than previous Neo hubs.

Beyond materials, the E-sync's durability and reliable engagement relies on smart details like a pawl angle and new longer pawl shape that channels stress away from the bearings and into the strongest, most reinforced areas to drastically improve both bearing life and overall hub durability. The E-sync's flange spacing and design also balances spoke tension between each side of the rim better. It all works together to make the E-sync hub stronger and more durable. And with 8.18° engagement, the E-sync hub is as fast as it is strong.

Available with Shimano Micro Spline, HG, or SRAM XDR freehub, and 6-bolt or Centerlock brake style, with options to fit all popular axle configurations.

  • Cromoly axle and full Enduro bearings with double-row freehub bearing for years of trouble-free performance and eBike compatibility
  • Fast 8.18° engagement with reinforced high-torque capable pawls
  • Matched wheelsets use traditional J-bend lacing and share a single spoke length for easy serviceability
  • Backwards-compatible to accept Neo end caps, offering options to fit every popular axle style


Radial Impact Absorbing Carbon Tech creates a smoother, faster, and more comfortable carbon rim.

Everyone knows carbon fiber can create a stiff wheel. We knew it could do much more. The carbon fiber rims on our CB7 series wheelsets are 30% stiffer laterally than our legendary aluminum rims, but the key to their outstanding ride quality is Radial Impact Absorbing Carbon Technology.

Obsessive attention to the shape of the rim and a proprietary carbon fiber lay-up process lets us create carbon rims that absorb radial vibrations and impacts while maintaining lateral stiffness, keeping your wheels driving constantly forward with less energy loss than other carbon rims.

Originally developed for or highly successful Valor rim, RiACT offers added strength, less rolling resistance, and the best ride of any carbon rim. On our Podium SRD wheelset, RiACT lets us create a rim that's lighter than the competition while also being stronger. Our carbon rims can deflect 7-10mm without damage or pinch flatting.

If there's one thing the overwhelming success of our tubeless technology has demonstrated, that's it.

The more forward momentum your wheel and tire can maintain without deflecting off the ground and sending your energy upward and backward, the faster you roll. Our RiACT rims allow the wheel system to absorb more, offering levels of vibration damping and impact absorption never possible before.

RiACT lets Stan's Podium SRD, Crest CB7, and Arch CB7 rims and wheelsets roll faster and last longer.