Protaper MTB stem review – burly no-nonsense stem

Protaper aren’t messing around, their simply named MTB stem offers straightforward stout steering performance but it has a problem

Protaper MTB stem pictured review
(Image: © Graham Cottingham)

BikePerfect Verdict

The Protaper MTB Stem's strength and stiffness make it a solid performer for gravity riding – assuming you can get it tight enough to stay pointing in the direction out want to go.

Pros

  • +

    Direct steering

  • +

    Hardwearing finish

  • +

    Plenty of sizes

Cons

  • -

    Heavy

  • -

    Can slip around the steerer

  • -

    Not everyone will like the blocky appearance

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Protaper is a brand that has been producing MTB cockpit components for years, although many will be more familiar with them in their original guise of Answer. Protaper continues to specialize in handlebars and stems, and are now developing cockpits under the Hayes Bicycle umbrella. They currently have two stems in their line up and the simply named MTB Stem I have on test is their stubby gravity number. I have been putting the Protaper MTB Stem to the test to see how it stacks against the best mountain bike stems.

Protaper MTB stem pictured from behind

The stem has a classic stout and angular design (Image credit: Graham Cottingham)

Design and specifications

Protaper’s MTB stem has a very classic simple aesthetic, although they say many hours of 3D modeling and Finite Element Analysis (FEA), as well as plenty of real-world testing have gone into the design. The stem itself is 3D forged and machined from 6061 Alloy and the stem is tightened down with Torx A2 stainless bolts.

The MTB Stem covers the majority of sizes enduro and downhillers are interested in. You can get both 31.8mm and 35mm clamp diameters and a range of lengths from 30mm to 50mm. It also comes in either black with a white and yellow logo or black and grey Stealth. Protaper also sells their Carbon Team Issue handlebars with matching color schemes if you want to get fancy. 

Fitting is as you would expect, there is no fiddly two-part face plate to contend with here. Simply slide the stem on, fit the bar, and nip all the T25 bolts in an alternating pattern to ensure an even tension and equal gap between the stem and face plate. The stack height is 37mm so make sure you have enough steerer for fitting. It's also worth noting that it has a split steerer clamp so unless you are running a steerer tube spacer on top you only have 12mm to play with.     

Protaper MTB stem pictured from behind

The steerer has a 37mm stack height (Image credit: Graham Cottingham)

Performance

Steering performance feels stiff and precise even in the 50mm length – thanks to the stem's stout body. Up front, the 50mm faceplate securely holds your bars which helps boost accuracy when you’re properly wrenching on them. I found that the stem wasn’t able to clamp as securely to the steerer though. I didn’t experience any comedic yet terrifying turning the handlebars and nothing happening moments but I did notice that I would need to straighten the bars after every crash or big knock. This may be due to the smooth finish on the inside of the stem struggling to grip the steerer as I don't have the same issue with my SQlab 30X bar which has a gritty textured clamping area. Carbon paste can add some extra grip although it's not ideal.

It is a bit on the burly side, which is a polite way of me saying it’s heavier than many comparable stems. My 50mm test stem weighs 206g, although it's likely most riders looking to run this stem will probably opt for stubbier and therefore lighter lengths. Protaper quotes 175g which is presumably the weight of the shortest version which is a bit more reasonable, in comparison to the Renthal Apex 35 stem which is around 60g lighter. If light and longer is your aim, then Protaper’s Atac (50mm to 100mm) stem is probably a better option. 

The finish of Protaper MTB stem is great, all the edges are very precise and the paint has held up to plenty of rough and tumble too.

Protaper MTB stem pictured from above

I found the Protaper MTB Stem didn't grip the steerer as securely as other stems, being knocked squint more often (Image credit: Graham Cottingham)

Verdict

Protaper’s MTB stem is a simple no-nonsense stem design that combines stout construction for precise handling and plenty of durability although I would recommend a little carbon paste during fitment to keep everything inline. If you’re looking for a fit-and-forget enduro and downhill stem, then the Protaper MTB stem is a good option. 

Tech specs: Protaper MTB Stem

  • Price: $104.99 / £84.95 
  • Weight: 206g (50mm x 31.8mm)
  • Lengths: 35, 40, 45, and 50mm (35mm) 30, 35, 40, 45, and 50mm (31.8mm)
  • Materials: 6061 Alloy
Graham Cottingham
Senior reviews writer, Bike Perfect

Graham is all about riding bikes off-road. With almost 20 years of riding experience, he has dabbled in downhill, enduro, and gravel racing. Not afraid of a challenge, Graham has embraced bikepacking over the last few years and likes nothing more than strapping some bags to his bike and covering big miles to explore Scotland's wildernesses. When he isn’t shredding the gnar in the Tweed Valley, sleeping in bushes, or tinkering with bikes, he is writing tech reviews for Bike Perfect.

Rides: Cotic SolarisMax, Stooge MK4, 24 Bicycles Le Toy 3, Surly Steamroller

Height: 177cm

Weight: 71kg