Stan’s Arch MK4 Alloy Wheels Rival Pricier Carbon Options [Review]

The Stan's Arch MK4 alloy mountain bike wheels are a high quality set designed for riding downcountry to all-mountain.
Photo: Chris Kelly.

Stan’s Arch wheels have been around for a while, and the current MK4 version is officially the fourth generation. This trail-optimized wheelset is light enough for downcountry bikes, but strong enough for all-mountain rides. At least that’s what Stan says. I wanted to see for myself so I bolted a set of these wheels onto my Canyon Neuron trail bike to see how they would fare.


Stans Arch MK4 wheel specs

  • 28mm internal rim width
  • 6069 alloy rims
  • Hubs: 216 points of engagement / 1.66°
  • Available in 27.5″ and 29″ diameters; six bolt or Centerlock brake mounts; XD, Microspline, or HG driver body; 142mm, 148mm, or 157mm rear spacing
  • Weight: 830g front, 997g rear (with valves)
  • Price: $995 / pair
  • Buy from Worldwide Cyclery.

Rims

Starting at the outer edge, the Stan’s Arch MK4 wheels features an asymmetrical 6069 aluminum alloy rim with 32 spoke holes. The 28mm internal rim width is a couple millimeters narrower than the 30mm width a lot of trail wheels are using at the moment, though Stans says this is just the right width for 2.2-2.5″ tires.

What’s just right? That’s hard to say, and it depends on the tire since there isn’t a lot of consistency from brand to brand or even within a brand’s tire lineup. In general you want a nice round shape that’s neither bulb- or bell-shaped.

I found the Hutchinson Wyrm tire shown above measures 64mm (2.5in) wide on the 28mm Stan’s Arch MK4 rims. On a 32mm rim, this same tire measures 61mm (2.4in) wide. Officially the Wyrm is 29×2.40 so clearly the 28mm Stans Arch rim gives the tire some extra width. Whether that’s a good thing or a bad thing depends on both the tire and the rider I suppose. Subjectively I can say the narrower rim doesn’t make this particular tire too bulb-like, and it still corners about the same. I think a slightly narrower 2.3mm tire is probably ideal for the Arch wheels, which is just to the left side of the recommended 2.2-2.5″ range.

The Stan’s Arch MK4 wheelset comes with the rims pre-taped and ready to roll tubeless. It’s a premium tape, and after hundreds of miles of testing there’s no sign of the tape shifting or losing its grip. My wheelset came with a set of Stan’s brass valves which are pretty basic but get the job done.

The rim edges on the Arch MK4s measure about 1.7mm wide. Wider rim edges are said to reduce pinch flats, and while 1.7mm is on the narrow side for today’s MTB rims I haven’t experienced any flats in spite of numerous square edge rock hits.

The 18.9mm rim depth is pretty standard for a set of modern mountain bike wheels.

Spokes

Stan’s Arch MK4 wheels feature 32 Sapim D-Light 2.0/1.65/2.0 J-bend spokes laced three cross front and rear. A single spoke length between the wheels promises to makes replacements a little less frustrating.

The Stan’s asymmetrical rims with offset spoke pattern allows for a more balanced spoke tension between the drive- and non-drive side. Previous Stan’s rims saw 58% tension balance between sides, and the MK4 designs claim 92% balance. I took some rough spoke tension measurements following my testing and found the spokes still averaged about 87% tension balance which is pretty impressive.

It’s normal to see spoke tensions vary around the wheel, even when freshly built, and especially after hundreds of miles of rough riding. The real test is whether the wheels still run true, and in this case they most certainly do. There’s no visible or perceptible wobble up or down, or side to side.

Stans says the rider weight limit for the Arch MK4 wheels is 230lb. The wheelset comes with a five-year hub warranty, a three-year warranty on the rims, and a one-year crash replacement warranty.

Stan’s M-pulse hubs

It’s a shame that Stan’s M-pulse hubs don’t get more hype. I suspect it’s because they’re seen as sort of a house brand hub, though that’s not the case. M-pulse hubs are designed and manufactured by Project321 and the ratcheting pawls use strong, rare-earth magnets instead of springs to reduce friction and drag. While you may not feel the reduced drag on the bike, it’s readily apparent how smooth and fast the hubs spin in a work stand; it’s as if they’ll never stop. Premium Enduro bearings help ensure that smoothness lasts.

Not only that, the Stan’s Arch wheels use a preload adjustment system designed to reduce friction further. It’s easy to set the preload when you first install the wheels, and doesn’t require further adjustment when you swap tires.

The hubs deliver quick engagement too: 1.66° between clicks with 216 points of engagement. They’re buzzy on the trail, but certainly not the loudest out there. Here’s what they sound like if you’re curious.

Photo: Chris Kelly.

On the trail

A lot of us have it in our heads that carbon wheels are tops when it comes to performance, and that may be so. But I’ve come away impressed with this premium set of alloy wheels.

On the climbs the Stan’s Arch MK4 wheels are snappy and responsive. Some wheels can feel wallowy or worse, mushy, when you put the power down, but not the Arches. And they feel surprisingly lightweight too, despite the overall 1,800g+ heft. It’s easy to get the bike in the air without feeling weighed down by boat anchors.

Reviewer profile height: 190cm (6’3″) weight: 72.5kg (160lb) testing zone: Southeast, USA

Compared to Stans carbon rims, these alloy rims are just 26g heavier. Sure, that’s rotational weight but c’mon. We’re talking about a 0.9 ounce steak. One bite. The Arch wheels spin up quickly, likely thanks in part to the low friction hubs front and rear.

I really love descending on the Stan’s Arch MK4 wheels. There’s something about rolling on alloy rims that adds just a bit of confidence to ride harder, and to let a little more air out of the tires for added grip. There aren’t any dings in the rims as far as I can tell, though if there is one I can likely bend it mostly back into shape.

Looking at the rim edge width I worried these might be more prone to pinch flats than other wheels I’ve tested, but so far so good.

Stan’s is the “No Tubes” brand and so the Arch MK4s have to be on point when it comes to tubeless performance. My tires aired up immediately with just a floor pump, and have held consistent pressure from ride to ride with minimal top-offs necessary.

All told, they’ve performed flawlessly and clearly have a ton of life left to give, as they should.

Photo: Chris Kelly.

Pros and cons of the Stans Arch MK4 trail wheels

Pros

  • Excellent hubs with plenty of engagement and low friction
  • Impeccable tubeless performance
  • Serviceable design

Cons

  • 28mm internal width gives some trail tires wider than 2.3″ the wrong shape
  • Narrow rim edge may be more pinch flat prone than wider edges
  • Included brass valves are basic. We want the rad alloy ones!

Bottom line

Stan’s Arch MK4 wheels meld the durability and affordability of alloy rims with high-end hubs, a quality build, and premium design, all while keeping the price under a grand for the pair.