Let's be honest here: a lot of us, including myself, have an unreasonable craving for carbon. This is especially true when it comes to carbon rims, but, when you do the 'cost vs. weight vs. performance' math, it's aluminum rims that make the most sense for almost everyone, isn't it? Of course, which is why I've been putting Stans' $100 USD Arch MK3 rims through the wringer for the last handful of months.
At a reasonable 453-grams for the 29'' model, the new Arch MK3 is kind of an all-around rim, even if Stans says that it has been designed ''with input from our Enduro World Series teams.'' Prefer smaller wheels? Stans also offers the Arch MK3 in both 27.5'' and, gasp, even 26'' sizes.
Arch MK3 Details
• Intended use: trail / all-mountain
• Material: 6069 aluminum
• Sizes: 26'' / 27.5'' / 29'' (tested)
• Internal width: 26mm
• External width: 29.3mm
• Rim height: 16mm
• 28 or 32 hole (tested)
• Weight: 453-grams (29'')
• MSRP: $100 USD
The 6069 aluminum Arch MK3 rim is all-new for 2017, with a wider, 26mm internal width that's intended to mate best with 2.25" to 2.5" rubber, which is what most trail and all-mountain types are using these days. The rim's width isn't as massive as a bunch of other options out there, especially some much pricier carbon rims, but Stans is calling this 'wide but not crazy wide' design their WideRight theory. In a nutshell, they're saying that too wide of a rim combined with a tire not designed for it (and the very large majority of them aren't) will force the tire into a less-than-ideal shape. If you've ever put a high-volume tire on a skinny rim and found that the casing folds over too easily, or ran a tire with a more square cross-section on a very wide rim and found your bike's handling to be weird, then you know there's some truth to matching a rim and tire properly.
So while the 26mm wide (internal) Arch MK3 is best suited to tires between 2.25" to 2.5" wide, the 29mm wide Flow MK3
is made for tires up to 2.8'' in width because the wider profile offers more support to high-volume tires. The Flow, which is sometimes even used on downhill bikes, is also heavier than its skinnier brother, at 527-grams in a 29'' size compared to the Arch's 453-gram weight in the same diameter. The new Arch MK3 is also wider than the older EX version yet manages to weigh the same.
A UST (Universal Standard For Tubeless) rim design is considered mandatory by some to achieve a true tubeless setup, but Stans has long used their own BST (Bead Socket Technology) rim design to allow most non-tubeless tires to be setup up quickly sans tube.
BST consists of a large bead shelf to encourage a snug fit for easy sealing and a low sidewall with a profile designed to interact better with the round beads of non-UST tires. You don't always need a specific rim or tire combo to run a tubeless setup, but the idea behind BST is to make it easy to run normal tires, which are usually lighter than a UST option, and have the whole thing go together without needing an air compressor, drywall patching kit, and a counseling session afterward.
The Arch MK3 aluminum rim has seen a boatload of original equipment spec, including on Rocky Mountain's Element 990 RSL BC Edition cross-country bike that I've been abusing for the past handful of months. The 32-hole rims are laced to a DT Swiss 350 rear hub and a house-branded 15mm front hub with WTB spokes from the factory, and I've removed and re-installed the stock Maxxis DHR II front tire and Minion SS rear tire as well.
The Arch MK3 rims have also seen a set of burly Continental Der Baron 2.4 Projekt mudders
installed, two Vittoria Gato wet condition cross-country tires
, and now a set of Vee Rubber's sporty Trail Takers (review coming soon). So that's five different types of tires on the Arch MK 3 rims, but not a single episode of swearing and yelling during the installs. I have a Bontrager TLR Flash Charger floor pump in my workshop that makes things easy, but I also used it as a regular pump rather than an air tank just to see if I could get a few tires to seat up smoothly without relying on a massive rush of air. Still no swearing or yelling.
The different tires the Arch rims have seen required vastly different pressures, with the big German rubber seeing numbers as low as just 16 PSI and the much slimmer Trail Takers being pumped up as firm as 26 PSI, depending on the terrain and the day's conditions. But one thing that has been consistent is the burping - there hasn't been any. All of the tires fit snug but not so tight that I needed a set of steel levers to do the job, and none of them belched any air despite plenty of crooked landings and mistimed moves. That's story of my life, to be honest, but I had no trouble with any of the tires on the Arch MK3 rims.
Now, I know that the 100mm-travel Element (with a 120mm fork) isn't exactly a heavy-hitting all-mountain bike but, to be fair, my little black BC Edition test rig has probably seen more miles and rowdier terrain than a lot of bikes with 60mm more suspension. Does having less travel put more focus on the reliability of the bike's wheels? I think so, and the result is... not much, and I mean that it a very positive way. Aside from one quick session on the truing stand to fix a minor wobble, likely caused by that time I 50/50'd a large rock hard enough that I thought I was going to die, the rims have been essentially invisible while doing their job. There aren't even any flat spots, which I did kinda expect given their wide, low shape.
That the Arch MK3s are trustworthy in these days when the large majority of rims and wheelsets are quite reliable isn't enough to make them standout, although it's obviously a good thing. No, what makes the Arch rims worthwhile, at least in my mind, is how they feel. A lot of the carbon rims on the market, while being lighter, tend to pass chatter up through the bike and into the rider; this is something I've felt firsthand with tall, wide carbon rims. The aluminum, 16mm tall Arch MK3 rims have a softer, more forgiving feel to them, but without the vague sensation that a lighter weight, skinnier set of rims can be guilty of having. If you've ever run a set of deep carbon rims on a short-travel bike, or even on a hardtail, you might know that stiff, unforgiving ride that I'm talking about.