Stan’s NoTubes introduces MK4 and S2 rims and wheels

Stan’s NoTubes has introduced the new Crest, Arch, and Flow MK4 and S2 series aluminium rims and wheelsets.

Building on its experience making asymmetric carbon rims that incorporate its patented Bead Socket Technology (BST), Stan’s developed the MK4s, its first asymmetric aluminium rims. The BST-Asymmetric design allows for an improved bracing angle and nearly equal spoke tension balance, while also maintaining easy inflation and a reliable airtight seal.

The new MK4 series rims are available in three updated widths. Each Crest, Arch, and Flow model has its own purpose-built, wider rim shape and spoke hole offset.

“Stan’s obsessive dedication to tubeless performance led to a total rethink of asymmetric rim design and resulted in wheels that are stronger overall,” said a statement. “In creating the new MK4s, Stan’s addressed the issues that most traditional asymmetric wheel designs have – such as being more difficult to inflate, being more prone to air loss due to unequal bead retention, and being more likely to be dented by impacts.

“As a result, the new MK4 design gives a balanced pressure along the drive and non-drive-side tyre beads and a consistent impact resistance on both sides of each rim.”

Crest, Arch, and Flow MK4 rims are made of 6069 aluminium with a welded seam, have a reinforced spoke bed and walls and feature a matte-blasted finish.

Built for gravel and cross country riding, Crest MK4 rims have an internal width of 25mm with a spoke hole offset of 1.5mm and are optimised for 40mm gravel tyres up to 2.3in mountain tyres. Offered in 20in, 24in, 26in, 27.5in and 29in versions, the Crest MK4 rim weighs 374g for the 27.5in version and 399g for the 29in version.

Arch MK4 rims are the ‘most versatile’ of all Stan’s rims and are ideal for a wide range of trail riding, the brand said. They have an internal width of 28mm for 2.2-2.5in tyres and an offset of 2.5mm. Available in 24in, 26in, 27.5in, and 29in, the 27.5in Arch MK4 rim weighs 451g, while the 29in version weighs 481g.

Flow MK4 rims have an internal width of 30mm for 2.3-2.6in tyres. Available in 26in, 27.5in, and 29in versions, the Flow MK4 rim weighs 487g in 27.5in and 521g in 29in.

MK4 complete wheelsets will be available in late 2021 and will feature a new M-Pulse hub design that will be shared with all Stan’s high-performance aluminium and carbon wheels.

Like the MK4s, Stan’s S2 rims have also increased in width, but they are manufactured with 6061 aluminium using a durable sleeved joint and stainless steel rim eyelets, and they rely on Stan’s conventional symmetrical Bead Socket Technology for easy inflation. S2 rims come in the same widths and are for the same recommended tyre sizes as the MK4 rims. The Crest S2’s 25mm internal width is ideal for gravel tyres from 40mm up to 2.3in mountain bike tyres. The internal width of the Arch S2 is 28mm, and it is optimized for 2.2 to 2.5in tyres. Flow S2 rims have an internal width of 30mm, ideal for 2.3 to 2.6in tyres.

Well suited for e-bikes, S2 wheels are built with Stan’s new E-sync hubs to handle additional weight and drivetrain stress. They have a 47% increase in max torque load capacity over Stan’s previous Neo hubs. The new E-sync hub has reinforced pawls that distribute stress away from bearings, chromoly axles, and enduro brand bearings, including a double row bearing in the freehub to maximize durability.

E-sync hubs provide fast 8.18º engagement, with all pawls engaging simultaneously. E-sync’s endcaps and freehubs are backward-compatible with Stan’s previous Neo hubs.

S2 rims are being spec’d on select complete bicycles, and S2 complete wheelsets will be available from independent bike shops and online stores in August. For more information, visit

In other news...

Troy Lee Designs launches new Flowline MIPS helmets

Troy Lee Designs has announced the launch of its new Flowline range of MIPS helmets, which includes …