The X4 is absolutely the best combination of strength and weight available. Enduro and downhill riders can run Thomson confidently. X4 offers precise steering and tracking for the ultimate in control while riding. 32mm, 40mm, and 50mm stems are available in block style only.
Too many modern mountain bike stems sacrifice strength and torsional stiffness for a few grams of saved weight. The Thomson X4 is the leader in strength and stiffness.
The Thomson 35mm X4 stem allows you to realize the benefits of stiffer forks and stiffer 35mm bars. X4 offers precise steering, tracking, and more control while riding, all wrapped up in a beautiful design.
Certified to: CEN ISO 4210-5
The Thomson 35mm X4 is based on proven design. It features a traditional steerer clamp that is shaped to save weight and to be knee friendly. X4 is absolutely the best combination of strength and weight available. Thomson stems are the strongest in the industry, meaning enduro and downhill riders can run Thomson confidently.
This stem body is forged AL7050 where every surface is machined. The faceplate is forged from AL6066 and 100% machined. It’s built and tested to the same standards as our aerospace parts, and it’s the best stem for all-around mountain biking.
Is X4 safe for carbon fiber?
X4 is engineered to work very well with both carbon handlebars and carbon steerer tubes. All torque requirements in our instructions must be strictly followed for carbon components.
Why did you change steerer clamps on X4? Were there problems with the old clamp?
We changed to save weight. There were no problems with the old clamp but it did add about 20 grams.