35mm Direct Mount Mountain Bike Stem - Adjustable 45-50mm Extension

In this review the RSX 35mm direct mount stem is judged as a focused choice for riders who run dual crown forks and want a sturdy, adjustable stem that does not add undue weight. The bottom line: this stem is for aggressive trail and downhill riders who need a precise fit and the ability to swap between a 45mm and 50mm effective extension without buying multiple stems. Build quality and clamp strength are the single biggest reasons to consider it.

Key Features

• 35mm bar clamp: The larger clamp diameter provides enhanced rigidity and better support for wider or heavier handlebars used in aggressive riding.
• Direct mount design: Made specifically for use with dual crown forks, it installs cleanly on downhill and freeride setups for a precise cockpit.
• 6061 aerospace alloy: CNC manufacturing from 6061 alloy gives a strong, lightweight platform that resists flex under hard braking and heavy landings.
• Adjustable extension: Built-in adjustment lets riders switch between 45mm and 50mm lengths with 20mm and 30mm rise for tailored fit without extra parts.
• Split two-piece design: The two-piece configuration eases installation and offers secure clamping while keeping service straightforward.
• Multiple colors: A range of finishes makes it possible to match the stem to a bike's aesthetic for a cohesive build.

Who It's For

This stem is aimed at downhill, freeride and aggressive trail riders who run dual crown forks and want a compact, robust direct mount option that reduces cockpit flex. Riders who value a mix of low weight and high clamp strength will appreciate the 35mm interface and 6061 alloy construction.

It is not the best choice for riders with 31.8mm handlebars, since this version is 35mm only, or for those who need a long or highly adjustable range beyond the supplied 45mm and 50mm extensions. Cross-country riders seeking ultralight parts with minimal rise should look elsewhere.

Pros & Cons

Pros

• High clamp strength and rigidity from the 35mm design and CNC 6061 alloy construction.
• Simple, practical adjustment between 45mm and 50mm extension for dialing fit on the trail.
• Direct mount form factor made specifically for dual crown forks, simplifying installation on downhill rigs.
• Available in several colors to match bike builds and components.

Cons

• Only available in 35mm for this variation, so riders with 31.8mm bars must choose a different version.
• Less suited to riders needing a wider range of extension or custom rise beyond the built-in options.

Specifications

Our Verdict

The RSX 35mm direct mount stem is a sturdy, well-made option for riders using dual crown forks who need a reliable, adjustable extension without extra weight. Its CNC 6061 construction and strong clamping make it good value for aggressive trail and downhill riders, provided you have a 35mm handlebar and do not need a wider adjustment range.

Frequently Asked Questions

Is this stem compatible with 31.8mm bars?
No. This variation is 35mm only; confirm your handlebar diameter before ordering.

Can I change the extension length in the field?
The stem offers built-in positions for 45mm and 50mm; switching requires basic tools but no additional parts.

What material is the stem made from?
It is CNC manufactured from 6061 aerospace grade alloy for a balance of strength and low weight.