Run your favorite 31.8mm clamping diameter handlebar on a bike with Knock Block with the Rhythm Comp 31.8. It adds Knock Block compatibility to a durable stem with multiple lengths to let you fine-tune the fit to your ride. Get 31.8mm handlebar compatibility with your Knock Block system;Also compatible with standard headsets and spacers;Knock Block system protects frame from impacts by fork and handlebars by eliminating over-rotation of bars;Available in a wide range of sizes for today's mountain rider;See Service Parts for other Knock Block parts;

On today's road bikes, silver stands out amid the sea of stealthy black color schemes. This time-honored color is available on the Zipp Service Course stem. Since the introduction of our line of Service Course and Service Course SL components, we've had amazing success with our pro-level athletes in all disciplines. While the successes have reinforced our design decisions, we have also drawn from their feedback. We not only learned how and why athletes make their equipment choices, but how our manufacturing methods and materials affect product performance. With new knowledge as well as new engineering methods, we are proud to introduce our completely redesigned line of Service Course and Service Course SL stems. - Class-leading stiffness-to-weight ratio - More options for a better fit - New faceplate and geometry for greater stiffness and easier installation - Distinctive silver finish

The perfect fit The Bontrager Elite Blendr Stem provides easy solutions for accessory integration. This alloy stem is light and strong, and it gives you endless options to integrate lights, a computer and more with Blendr accessory integration. Product details - Blendr Elite allows seamless accessory integration - 4-bolt dual band clamp retains stiffness and reduces weight - Opposing 2-bolt steerer tube clamp - Uses M5 countersunk, corrosion-resistant steel bolts with 5.2Nm torque spec - Approved for carbon bars and steerer tubes - Suitable for both MTB or road use - Includes Blendr mono base and accessory mounts

Dimension 25.4 Stem is a fully forged 6061-T6 aluminum stem with 4-bolt handlebar clamp. - 2-D forged AL-6061-T6 - Four-bolt handlebar clamp - 41mm height - Dimension stems are not intended for use with carbon handlebars or carbon steerer tubes - Weight: 130g-180g

Stiff and light with the cleanest accessory solutions available When all you need is the right position, the Elite stem gets it done and more. The strong and light alloy stem is your bike's best workhorse and also features Blendr accessory integration for a sleek setup. Key features - Seamless accessory integration with Blendr Elite - 6061-T6, 3D, forged alloy construction - 4-bolt dual band clamp retains stiffness and reduces weight - Opposing 2-bolt steerer tube clamp - Uses M5 countersunk, corrosion-resistant steel bolts with 5.2Nm torque spec - Safe for use on carbon steerer tubes and handlebars - Includes one Blendr base to integrate Ion lights and Trip computers.

Electra's Cruiser Aluminum Stem is a stable, solid replacement for your original equipment. Designed to work with a 1-inch headset, the Cruiser Stem is made from no-frills aluminum that keeps off the weight while maintaining strength where you need it.

Features a wide range of adjustment to dial in your fit. Ensure a proper fit for the best ride experience. Product details - High-quality alloy adjustable stem is quill-style, for use with threaded forks - Seamless integration with Bontrager's Elite Blendr mount kit, sold separately - Features 64 degrees of angular adjustment - 50mm stack height adjustment allows for a wide-range of fit options - Quill stem length is 180mm

Zipp's Service Course SL Stem, crafted from 7075 aluminum, features a shape that's strong and lightweight, resulting in a best-in-class 1.85 grams per newton meter of stiffness. That results in no-flex sprints and accelerations. This stem is a favorite of Zipp ambassadors and pro athletes. - Distinctive Zipp cosmetics - Zipp Quickview integrated computer mount available separately - Lifetime warranty

Promax's DA-1 XC mountain bike stem is 3D cold-forged, then CNC-machined from 6061-T6 aluminum to create a lightweight and strong stem. The two-piece faceplate features their bar-gripping DWT (Dynalock Web Technology), which increases the bar/stem interface.

The Impact is Promax's top-load BMX stem. They come in 48-, 53-, and 60-millimeter extensions and are cold-forged from the highest quality 6061-T6 aluminum then CNC-machined to refine the shape and further reduce weight. The “open” design keeps weight low while maintaining plenty of strength and ensuring your bars stay put. - Weight: 9.8oz. - Stack height: 30.5mm

The Atmos 7k stem is a lightweight performance stem designed for trail and cross-country use and is the lightest stem in the Atmos range. Featuring a rise or drop of 6° depending on your preference, all fasteners are adjustable via a T25 tool for easy, quick adjustments. The Atmos 7k also features an integrated GoPro mount. - ±6° angle - Integrated GoPro mount - T25 fasteners for 1 tool across the cockpit SPECIFICATIONS - Stem Angle/Rise: 6 degrees - Clamp diameter: 31.8mm - Steerer clamp diameter: 1-1/8 in - Hardware: Steel

FSA's K-Force OS-99 CSI is 3-D forged and CNC machined from AL2014 before a uni-directional (UD) carbon weave skin is applied through the Carbon Structural Integration (CSI) process. To further reduce weight the OS-99 uses a 4-bolt sculpted AL2014 alloy/carbon faceplate and titanium hardware. CSI is a process that permanently bonds carbon to alloy, to create a true hybrid product, with many of the benefits of aluminum and carbon. - Stack Height: 41mm - Weight: 126g (100mm)

Whisky's No.7 Stem is a lightweight stem with a clean aesthetic. Stems only have a few jobs to do: hold the bars, provide stable support, and look good. Ours does all three admirably. Paired with any of our handlebars, it rounds out the perfect Whisky cockpit. Available in a wide range of lengths to perfect your bike's fit and performance.

Zipp's Service Course Stem is strong, light, and reliable. Forged of 7075 aluminum with stainless steel bolts, the Service Course is stiff enough to harness the power of your burliest sprints and withstand the jarring forces of the meanest potholes. It keeps the front end completely rigid, providing control no matter the condition.

- Available in a variety of lengths, angles, and bar bores for the perfect fit - Road or Mountain compatible - 3D forged AL6061-T6 alloy construction - 40mm stack height - 4-bolt front loading one-piece faceplate design - ISO-Mountain safety certified

Kalloy's 822 Adjustable Stem lets you set up your handlebars exactly where you want them using just an allen wrench! With a 0-60° rise, you're sure to find a position that puts you comfortably in control. Its 4-bolt handlebar clamp makes bar changes easy and secure. - For quill-style steerers

• Forged aluminum • 2-bolt clamp • 250mm tall (extra tall)

Sunlite's Adjustable Quill Stem puts your bars right where you want them. This wonderfully easy-to-use stem adjusts from 0 to +50 degrees—more than enough to help you find your ideal position. And, the 2-bolt clamp holds securely holds your bars.

Developed for longer-travel trail bikes, Promax's S-29 stem offers the perfect configuration to set you up for maximum comfort and control. Featuring an oversize extension tube and faceplate with massive clamping area, it’s sure to keep your bars stylishly in place through the most demanding terrain. These stems are cold-forged and CNC-machined from 6061-T6 aluminum for strength, low weight, and durability.

Strong, light, and capable The Kovee Pro 35 stem is the perfect centerpiece for cross country race bike. This lightweight stem is optimized for the latest XC mountain bike standard, with a 35mm clamp diameter that combines with a 35mm handlebar to provide a stronger, lighter system. An oversized 35mm clamp diameter MTB stem that offers increased strength and minimal weight - Oversized 35mm clamp diameter offers increased strength and minimal weight - 7075 T73, 3D, forged alloy construction - Laser-etched calibration marks make dialing in the perfect angle simple and repeatable - Compatible with both Knock Block and standard headsets and spacers - Blendr compatible for an elegant, integrated accessory mounting solution - Available in a wide range of sizes for today's mountain rider - High-strength, corrosion-resistant steel bolts - Approved for carbon bars

When stiffness and weight are the top on your list, you want Ritchey's SuperLogic C-260 Carbon Stem. This revolutionary design starts with a bar clamp that wraps a full 260-degrees around the handlebar to distribute clamping stress evenly through the handlebar, faceplate, hardware and stem body. Ritchey's first full-carbon stem, the C-260 features high-modulus carbon for stellar strength-to-weight ratio that translates into a solid but forgiving ride. And, the steer tube clamp uses three bolts and a curved slot to reduce clamp stress on the steer tube, so you can run carbon bars and a carbon steerer with no problem.

- CNC machined 2014 aluminum body and 7075 aluminum clamps - 240 degree wrap-around, twin plate clamping system - External webbing to maximize structural strength - 118-158g including stainless steel bolts

The WCS C220 stem is easy to install and remove thanks to a press-fit handlebar clamp interface and forward-facing hardware. - The handlebar clamp design creates a more secure interface by wrapping a full 220 degrees over the handlebar - Bolt forces are aligned with the clamp so that the stem body embraces the handlebar which is less prone to damaging lightweight bars - Clamp design allows for a lighter faceplate and stem body with no sacrifice in strength or stiffness

Proven time after time to be a reliable, easily adjustable system that continues to outperform the competition, the 4-Axis stem is a surefire go-to for an entry level stem that has world-class performance. - Bar Clamp Diameter: 31.8mm - Material: Alloy - Stem Angle: 30 degrees - S.H.I.S. Stem Clamp Diameter: 28.6

Oversized diameter 35 mm stem accessible to all mountain riders. Oversized and in control Equip your whip with this 35mm Line stem and give yourself the oversized advantage. Forged from 6061-T6 3D aluminum, this 0-degree stem provides the increased strength of the latest mountain-specific bar diameter. Product details - Oversized 35mm clamp diameter provides a new level of strength and weight savings - Forged from 6061-T6 3D aluminum - Laser etched calibration marks make dialing in the perfect angle simple and repeatable - Compatible with both Knock Block and standard headsets and spacers - Knock Block system protects the frame from impacts by fork and handlebars by eliminating over-rotation of bars - Available in a wide range of sizes for today's mountain rider - Safe for carbon bars

A light, durable 35mm MTB stem that adds Blendr capability for clean, integrated mounting of lights or computer. Equip your whip with this 35mm Line Pro stem and give yourself the oversized advantage. Forged from light and strong 7075-T73 3D aluminum, the oversized 35mm design offers increased strength and a lighter overall bar and stem system weight. Use with included Blendr base and mount for integrated mounting options for light or computer. Product details - Oversized 35mm clamp diameter offers increased strength and minimal weight - 7075 T73, 3D, forged alloy construction - Laser-etched calibration marks make dialing in the perfect angle simple and repeatable - Compatible with both Knock Block and standard headsets and spacers - Blendr compatible for an elegant, integrated accessory mounting solution - High-strength, corrosion-resistant steel bolts - Includes Blendr mono base, Garmin Mount, and Ion Light Mount - Approved for carbon bars

FSA ACR (Aerodynamic Cable Routing) Stems have a low-profile frontal area that is suitable for road and gravel riding. - Aerodynamic Cable Routing (ACR) - Low-profile frontal area - No rotation limit - Body and faceplate - 6061 T6 - Chromoly hardware - Specific frame and headset required - 31.8mm handlebar clamp diameter - 30mm fork clamp stack height - Compatible with: K-Force Light ACR Compact, SL-K ACR Compact, Energy ACR Compact, K-Wing AGX and K-Wing AGX handlebars

The Cavity stem was developed with pain staking focus on strength, function and attention to detail. Tapered body for cleaner lines and weight reduction, multiple internal and external machining processes to reduce every gram possible and chamfered edges throughout for stunning detail. - Machined from 6061 T6 aluminum - Wide 55mm faceplate for increased stiffness with wide handlebars - Rounded edges at all sides, corners, and angles - Reverse cross bolt system for increased clamping power - Flip flop design for increased range of height adjustment - Pro Installation Tip: Always run the steerer tube all of the way through the stem with a small spacer on top - Bar Clamp Diameter (mm): 31.8 mm - Material: Aluminum - Stem Angle (deg): 0 deg - S.H.I.S. Stem Clamp Diameter: 28.6 - Stack Height: 33 - Weight: 150 g

Zipp's Service Course SL OS Stem, crafted from 7075 aluminum, features a shape that's strong and lightweight, resulting in a best-in-class 1.85 grams per newton meter of stiffness. That results in no-flex sprints and accelerations. This stem is a favorite of Zipp ambassadors and pro athletes. - Distinctive Zipp cosmetics - Wide range of sizes and angles. - Service Course SL OS stem made for 1-1/4" steerer tube bikes. Ships with shims for 1-1/8" steerer tubes - Zipp Quickview integrated computer mount available separately - Lifetime warranty

Make sure your fit is dialed in your race against the clock! Bontrager's Speed Concept Stem allows you to set up your Speed Concept bike for proper ergonomics and aerodynamics. Plus, the precisely integrated design keeps your super aero bike fast and looking pro! - Low-Near = 17° rise / 77mm length - Low-Far = 100° rise / 110mm length - Mid-Near = 50° rise / 67mm length - Mid-Far = 45° rise / 110mm length - High-Near = 80° rise / 67mm length - High-Far = 75° rise / 110mm length