Deity Copperhead stem review – brass-necked steering control

This is a new version of Deity’s Copperhead stem with an oversized 35mm bar clamp, meaning if you want to run it you will need a corresponding 35mm diameter handlebar. It’s CNC machined from 6061 T6 aluminum, available in two lengths and eight slick anodized colors.

Design and specifications

Deity doesn’t want to pigeonhole the stem but it does claim the Copperhead is light enough for all-mountain/enduro but strong enough for gravity riding. I think most modern MTB stems pass muster for any discipline but it’s good to know this stem can handle harder riding. To back this up, Deity offers a Lifetime Crash Replacement Policy for the original owner. 

Fitting the stem is a lot easier than say a Renthal Apex 35 because you don’t have to slide on the clamps, but it’s not as quick as a Race Face Turbine. That’s because the Turbine uses an ‘Overbite’ design, meaning the top edge of the faceplate closes fully before you lock down the lower two bolts. You don’t have to use a torque wrench, you can just snug them up and then lock the other two bolts down, alternating between them to get even tension.

With the Copperhead, you have to tighten the four bolts in a criss-cross pattern to achieve even loading on the faceplate and that is a bit more of a hassle to setup. If you don’t follow this procedure, you can risk over-tightening, and uneven clamping of the faceplate. While none of these really takes that much time, you’re only fitting this once after all, I think that the gap between the body of the Copperhead and the faceplate doesn’t look sleek and also dirt can get in there – though this minor issue is true of many other stems out there too.

The Copperhead does have a slightly lower stack height than the Turbine, which is good if you’re trying to drop your front end or worse you’ve cut your steerer too short. All the edges have a nice radius, so this isn’t going to scuff the handlebar as you fit it. There’s no grease or Loctite on the threads of the M6 fasteners but you can easily add some. The black coating on the bolts has started to wear on the edges, which isn’t a deal breaker but I’d expect better on a stem costing this much.

Performance

What we’re looking at here is a 35mm x 35mm (bar clamp and overall length) stem, which means it is pretty bomber solid. I did some back-to-back runs with the Race Face Turbine using the same Race Face Atlas alloy handlebar and I couldn’t really feel any difference. The extension tube (that’s the section between the clamps) is an I-beam design on the Copperhead and this adds a ton of rigidity. The stem is also pretty broad at 55mm across the front and that stops the bar from flexing too heavily when you are pulling hard out of the saddle or pounding down a rocky descent. 

Verdict

Since we’ve gone to more sensible geometry on mountain bikes, stem length has become about handling rather than fit, and you now often see one stem length across a range of different-sized bikes. Most stems now only come in 35mm and 50mm, but that means the difference in feel is a lot closer, so you sweat the details. The Deity Copperhead is a similar weight and price to the award-winning Race Face Turbine, and even comes in a kaleidoscope of colors, but the fasteners and faceplate design are not quite as accomplished. 

Tech specs: Deity Copperhead stem

• Price: $104.99 / £94.99
• Weight: 135g
• Clamp size: 35mm
• Lengths: 35mm and 50mm
• Stack Height: 33.5mm
• Materials: Aluminum with steel hardware
• Colors: Black, Red, Purple, Green, Blue, Orange, Platinum and Bronze