New Wider, Asymmetric Rims and All-New Hubs
Almost 20 years after Stan Koziatek created his first tubeless-ready rims, Stan’s NoTubes is proud to introduce the new Crest, Arch, and Flow MK4 and S2 series aluminum rims and wheelsets. Full information is available here
. MK4 Rims and Wheelsets
Building upon their experience making asymmetric carbon rims that incorporate their patented Bead Socket Technology (BST), Stan’s developed the MK4s, their first asymmetric aluminum rims. The BST-Asymmetric design allows for an improved bracing angle and nearly equal spoke tension balance, while also maintaining the easy inflation and reliable airtight seal that have made Stan’s the leader in tubeless rim design. 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 dedication to tubeless performance led to a total rethink of asymmetric rim design and resulted in wheels that are stronger overall than previous versions. 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 balanced pressure along the drive and non-drive-side tire beads and consistent impact resistance on both sides of each rim.
Crest, Arch, and Flow MK4 rims are made of 6069 aluminum with a welded seam, have a reinforced spoke bed and walls, and feature a matte-blasted finish. MSRP in the U.S. is $129.00. MK4 rims include a three-year warranty with crash replacement support and are available now.
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 optimized for 40mm gravel tires up to 2.3” mountain tires. Offered in 20”, 24”, 26”, 27.5”, and 29” versions, the Crest MK4 rim weighs 374g for the 27.5” version and 399g for the 29” version.
Arch MK4 rims are the most versatile of all Stan’s rims and are ideal for a wide range of trail riding. They have an internal width of 28mm for 2.2-2.5” tires and an offset of 2.5mm. Available in 24”, 26”, 27.5”, and 29”, the 27.5” Arch MK4 rim weighs 451g, while the 29” version weighs 481g.
The legendary Flow rim has earned Downhill World Cup and Enduro World Series wins and is a favorite among gravity and trail riders everywhere. With emphasis on strength and durability, Flow MK4 rims have an internal width of 30mm for 2.3-2.6” tires. Available in 26”, 27.5”, and 29” versions, the Flow MK4 rim weighs 487g in 27.5” and 521g in 29”.
MK4 complete wheelsets will be available in late 2021 and will feature an entirely new M-Pulse hub design that will be shared with all Stan’s high-performance aluminum and carbon wheels. S2 Rims and Wheelsets
Like the MK4s, Stan’s S2 rims have also increased in width, but they are manufactured with 6061 aluminum using a durable sleeved joint and stainless steel rim eyelets, and they rely on Stan’s proven conventional symmetrical Bead Socket Technology for easy inflation. S2 rims come in the same widths and are for the same recommended tire sizes as the MK4 rims.
The Crest S2’s 25mm internal width is ideal for gravel tires from 40mm up to 2.3” mountain bike tires. The internal width of the Arch S2 is 28mm, and it is optimized for 2.2 to 2.5” tires. Flow S2 rims have an internal width of 30mm, ideal for 2.3 to 2.6” tires.
Well suited for eBikes, S2 wheels are built with Stan’s all 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 to ensure reliable engagement under high loads. 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. They will have an MSRP in the U.S. of $595.00 and include a three-year warranty on E-sync hubs, and a two-year warranty on S2 rims.
More information is available here
I will admit that the NEO hubs do need improvement; broken axles and blown up freehub bodies are not uncommon. However, when evenly and properly tensioned, I haven't had a single issue with rims cracking! I have noticed deformation around the drill for the nipple, but not a single crack. I do not use nipple washers either.
For what it's worth, I am very pleased with all of my Stan's wheelsets and rims, and when you do need warranty support, I have found that they are very easy to deal with.
On nipple washers, Stan's MK3 rims have fairly narrow drilling, 7.5mm holes, and the profiling of the spoke bed around the spoke holes means not all washers will fit or be compatible/work optimally. I have a couple I keep in stock that work okay/improve the situation somewhat, but neither will do the job that the DT PHR washers do inside DT rims; none will spread the load as well. I still build with them (washers), but I know folks who don't with the MK3s and also get on alright - the key is careful tensioning. Stan's MK3 spoke beds are not overly thick and it pays to keep an eye on them.
These new rims are interesting. Looks like a shot peened finish, and profile features that are entirely different that the MK3s. I would almost bet they are coming out of a different factory than the MK3s. Chatting with another rim geek here as well as I write this, who has pointed out they look a lot like WTB Asyms, in the smaller details. Pure speculation on my part, but I would wager they are made being produced somewhere different than the MK3's, so perhaps the conversation on cracking older rims is a moot point.
Just aiming for max is a fools method of building. IMHO you need to bring tension up in stages, stress relieve and watch how the rim is responding. Often the rim will tell you when to stop, before you hit max.
I had a stan’s flow mk3 wheelset and the bearings blew up every 2-3 months until they eventually sent me a replacement wheel with a hope pro 4. Great customer service from them, just terrible hubs
By comparison, you can get Newman 30mm wide 510g 32h rims for $90ish USD.
A DT Swiss EX511 is $140ish, but includes nipples. 570g.
As mentioned elsewhere, Ibis was selling their S35 for $100 and it was decently light.
Spank rims of similar weight and width are $90-$99.
Easton/RF Arc rims seems to be the bottom of what's decent and they can be found around $80.
Does anyone have any feedback on MK4 durability ? They seem way cheaper to build but is that at expense of quality ?