I have carbon 650B AM/Enduro rim options available from three different manufacturers (Atomik Carbon, Derby, and Nox Composites), and customers often aren’t sure which is the best fit for them.  In this post, we’re going to take a look at each offering and see how they differ from one another, compare the strengths of each, and help you get an idea of which is best for you.  And if you’re still not sure, I’m happy to help guide you to the right set of rims – or even the right mix of two different brands.

AT A GLANCE

RIM STARTING PRICE* WEIGHT INTERNAL WIDTH SIDEWALL TYPE SIDEWALL THICKNESS
Atomik Carbon 27.5 Mod-hook $1209 400g 24mm Modified Hook 3.8mm/4.5mm
Derby 650B $1230 440-485g 34mm Hookless 3.45mm
Nox Composites AM275 $1261 420g 28mm Hookless 3.55mm

*NOTE: Starting price is built with DT Swiss 350 hubs, DT Swiss Revolution spokes, and brass nipples, and does not include shipping or sales tax if applicable.  Other component choices will change the price.  Prices are current as of Sept. 30, 2014 and are subject to change.

ATOMIK CARBON

The Atomik rims are the lightest, least expensive, and have the thickest sidewall of the three options, but also the least wide.  Modern trends are wider is better (Pontiac was onto something with those ads back in the 90’s!), but super wide rims really pair best with really wide tires.  And remember, everyone used to ride and race on 19mm wide rims, so an inner width of “only” 24mm isn’t really narrow.  If you prefer not-so-wide tires, or if your frame clearances are tight, the Atomik’s are a good choice.  The low weight also makes them a good tough & light XC option for heavier riders.  They’re also a great choice if you bottom out your rims often – those burly sidewalls will take some punishment.  The 4.5mm thickness includes the hook, the 3.8mm is below the hook, so even the thinnest part of their sidewall is still thicker than the others.  The Atomik’s use a ‘Modified Hook’ design, the hook is minimal and is there to add to the strength, it creates a much wider and flatter “top” of the sidewall to better absorb hits.  The Atomik rims are the only ones with directionally drilled spoke holes for better spoke/nipple alignment, and the rim decals are available in 11 different colors!

The Atomik decals are available in lots of colors to coordinate with your bike.
The Atomik decals are available in lots of colors to coordinate with your bike.
The sidewalls on the Atomik are thicker than all the others and the hook creates a big flat top surface to better handle rim impacts.[/caption] Atomik's and Profile Elite hubs.  (29er version of the same rim pictured) Atomik's and Profile Elite hubs. (29er version of the same rim pictured)[/caption]

DERBY

Derby is all about width – 34mm inner width is flat out huge.  If you really want to go wide-wide-wide, without venturing into the ‘plus” sizes, Derby is where it’s at.  They also offer three different layup options: Light/XC (440g), Heavy Duty (460g), and Downhill (485g).  The extra carbon is added inside the rim cavity, so all three options have identical exterior dimensions, inner width between the hookless beads, and the same sidewall thickness.  Speaking of sidewalls, the Derby’s are a bit thinner than the rest.  That huge width means tires will take on a new shape and size.  As the sidewalls are pushed further out they are less protected and more susceptible to cuts, so I recommend using a tire with sidewall protection.  Moving the sidewalls further out also stands the edge knobs up.  This puts more rubber in contact with the trail, but also reduces the space between the knobs on the shoulder of the tire.  Your favorite tire may feel a bit different when mounted on such a wide rim.

Derby rim decal is small and minimal.
Derby rim decal is small and minimal.
Narrower tape that stays inside the rim channel works best on the Derby's.
Narrower tape that stays inside the rim channel works best on the Derby's.
The super wide and deep Derby rims make for a beefy looking pair of wheels.
The super wide and deep Derby rims make for a beefy looking pair of wheels.

NOX COMPOSITES

The Nox AM275 strikes a nice middle ground in both width and weight.  Wider than the Atomik’s, but not as light.  Not as wide as the Derby’s, but lighter and with slightly thicker sidewalls.  The Nox rims also use an asymmetric spoke bed, which helps to balance the spoke tension between each side of the wheel.  In other words, it raises the tension on the lower tension side of the wheel, which increases the load capacity of the wheel.

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Industry Nine Torch Classic hubs & Nox AM275s.
Nox AM275
Nox AM275
That's an Arch EX cross section sitting on a Nox AM275 rim.  The Arch EX used to be considered a fairly wide rim - it fits completely inside the AM275 That's an Arch EX cross section sitting on a Nox AM275 rim. The Arch EX used to be considered a fairly wide rim – it fits completely inside the AM275[/caption]

Now that you know the strengths of each rim, hopefully you have an idea of which is the best fit for you.  Another nice thing – they all three have a UD carbon finish, so if you remove the decals you can mix and the rims will still match.  If you like using a big tire on the front for a little cushion and traction with a smaller, lighter, faster rolling rear tire, use a Derby up front paired with a lighter Atomik or Nox on the rear wheel.  That’s the whole beauty of custom wheels – they’re built just the way you want them!