The Review | ENVE Mountain Carbon Stem

Carbon fibre stems are nothing new to the market and have been used for many years on road and XC bikes, but until now we have yet to see a carbon stem that is strong enough for AM / Enduro use. After years of R&D the carbon fibre wizards at ENVE have now re-written the rule book and produced the ENVE Mountain Stem, a hard hitting enduro stem that weighs an incredible 86g. However, this giant advance in strength/weight comes with an equally giant price tag.

When it comes to upgrading it’s easy to overlook the humble stem, however, its function in the cockpit is vital. Sitting in the middle of the chain between rider and bike, not only does the stem transfer all the riders weigh and inputs down to the wheels, but its stiffness and compliance play a large factor in steering feel. A good stem needs to be stiff, reliable and hold the handle bar in place securely, and if it’s light that’s a bonus.

With most premium short stems weighing around 140-150g we were blown away that ENVE have managed to trim down their Mountain Stem to just 86g (in the 40mm version tested). Producing a product that is 30% lighter than the established competition is never cheap, and the Mountain Stem is indeed frighteningly expensive at €280. However, considering that the stem is made entirely in house in Ogden, Utah and includes titanium M5 bolt hardware and cutting edge carbon manufacture to squeeze out every last gram, you can start to see why the price is sky high.

The stem uses the standard 31.8mm bar clamp and comes in lengths of 40, 55, 70 and 85mm. The +/- 6 degree rise and flip-flop graphics mean that the stem can be run upside down if needed to lower a high front end, and the 37 mm stack height is nice and compact.

Stems are generally stressed from all directions through bending, torsion and shear forces and often it’s hard to extract the maximum weight saving properties of carbon fibre, which is strongest in one direction. Previous carbon stems have used so much material that the weight saving is negligible. The ENVE Mountain Stem is manufactured from uni-directional carbon fibre and the bladders have been removed from the material to maximise the weight/strength ratio.

Initial setup was a little more involved than with a normal stem. We found that it is a very tight fit around the steerer, and care needs to be taken to ensure that the correct torque is used to avoid stressing the carbon threads. ENVE retain a cold-forged aluminium face plate to reduce the clamping torque required on the handlebar, but care is needed to ensure that the top and bottom gap on the faceplate is even. ENVE also recommend that a spacer is used both below and above the stem to ensure enough contact to avoid slippage. We used anti-slip paste on the steerer and encountered no issues with slippage while riding.

We tested the stem in combination with ENVEs new HDR bars (full review coming soon) in the 40mm length. Analysing the performance of a stem is always tricky, as unless they show a catastrophic failure most short stems do a great job. In fact, when it comes to steering accuracy and vibration damping, handlebar choice has a much larger impact on performance. When paired with the new ENVE RSR bars the cockpit felt exceptional. When compared back to back with an aluminium stem and bar, the carbon cockpit was in a different league – filtering out high frequency vibrations exceptionally well. Steering was beautifully precise and accurate without any hint of harshness. Swapping in the aluminium bar onto the carbon stem lost some of the superb feel, demonstrating that it is the carbon ENVE RSR bar that’s responsible for a lot of the benefits we observed.

Bottom line

Does manufacturing a stem out of carbon fibre have an observable effect on the ride quality of the bike, no, not really! However, the stem is gorgeous, beautifully made and exceptionally lightweight which will be enough to justify the high cost for many riders. However, we expect that most customers looking at the ENVE Mountain Stem will be looking to invest in ENVE bars too, and run with the ENVE RSR bars the cockpit becomes exceptionally good! Incredibly lightweight, accurate and precise with enough engineered compliance to filter out trail buzz. It’s expensive for sure, but for purists who desire the lightest and best – the cost will be unimportant.

For more information check out the ENVE website

Words and photos: Trev Worsey

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