At first glimpse the best mountain bike stems may seem simple, but they can still have an impact on the performance of your bike. Elements like weight, stiffness, and length all play a part, and can influence the way your bike responds to steering inputs. We’ve tested a range of different stems to find out, not only which ones are the best on offer, but also which are best for a range of different applications and riding preferences.

Looking to refresh your whole cockpit set up, to improve comfort, performance and control? Then check out our guides to the best mountain bike handlebars and best MTB grips.

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1. Race Face Turbine R 35

Best overall stem and available in loads of lengths and colours

Weight: 124g (32mm) | Colours: Loads | Lengths: 32, 40, 50, 60, 70mm | Clamps: 35mm only | Stack height: 43mm | Rating: 10/10

Reasons to buy:

• Loads of colour and length options

Reasons to avoid:

• On the expensive side

With a rainbow palette of anodised colours, the Race Face Turbine R stem indulges your creative side. Whether you choose to go mild or wild, the sturdy forged and CNC’d body is stiff enough for the widest of bars and burliest of builds, and even comes in a stubby 32mm length if you’re looking for a truly direct steering response. The gapless clamp holds bars securely and spreads loads evenly, while the rounded-off edges of the steerer clamp keep the opposing bolts away from your knees.

What we really like about the Race Face Turbine R35 is that it’s pretty stiff for a lightweight machined stem. Even with a matching 800mm Next R bar fitted, the steering feels precise and immediate, with just the right amount of resilience.

Read our full test review of the Race face Turbine R 35 stem

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2. Spank Spoon 350 stem

Best for eye-catching colours

Weight: 140g | Colours: Nine options including black | Lengths: 35mm, 45mm | Clamps: 31.8mm, 35mm | Stack height: 35mm | Rating: 9/10

Reasons to buy:

• Super solid and resilient
• Flex-free
• Great value

Reasons to avoid:

• Not the most polished stem out there
• rough construction in places

Being forged, rather than machined, gives the Spank Spoon stem plenty of strength. This 350 model uses a 35mm clamp, but there’s also a 31.8mm clamp option called, you guessed it, the 318. Spank hasn’t gone for a zero-gap design on the bar clamp, which does mean there’s a gap at the top of the faceplate, and you need to be careful to tighten all four bolts evenly.

The stack height is low, and there’s no rise, so it’s a good stem if your frame has a tall head tube and you can’t get the bars low enough. While there are only a couple of lengths, they’re the most popular options, and Spank makes up for it with loads of colours to choose from! It’s not got the perfect finish of the Race Face Turbine, but it’s also cheaper.

Read our full test review of the Spank Spoon 350 stem

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3. E*Thirteen Base 35

Best knee-friendly stem design

Weight: 155g | Colours: Black | Lengths: 40, 50mm | Clamps: 35mm only | Stack height: 40mm | Rating: 10/10

Reasons to buy:

• Does everything you need for minimal cash
• Nice rounded design is knee-friendly

Reasons to avoid:

• Not as sexy as some designs

Top value for a stiff, good-looking stem, and available in stumpy 40mm and 50mm lengths, the E*thirteen Base really impressed us with its function and detailing. Opposing stem bolts with T25 heads are just one such feature, while the gapless faceplate is makes it easier to avoid over-tightening the clamp bolts.

The bar is held by a wide clamp and all the edges are softly rounded off, which reduces the chance of clanging your knee cap when out of the saddle. Suitable for 35mm bars, this is a great option if you’re looking for a snappier cockpit without breaking the bank.  An excellent stem at a great price.

Read our full test review of the E*thirteen Base stem

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4. Nukeproof Horizon

Best budget stem

Weight: 135g (35mm) | Colours: 7 options | Lengths: 35, 50mm | Clamps: 31.8, 35mm | Stack height: 35mm | Rating: 9/10

Reasons to buy:

• Boutique looks
• No-gap face plate
• Seven colour options
• Keen price

Reasons to avoid:

• Not the stiffest on test

Nukeproof’s Horizon range includes some well-designed products that undercut the competition. It’s no surprise the brand actually started out making components, before it became better known for bikes. One of the key advantages with the Horizon stem is the low stack height – useful for steerers cut too short, or head tubes that are too long.

With a 5º rise, you can even flip the stem upside down to really lower your cockpit. We like the smooth, rounded edges and neutral styling, making this a good upgrade option even if you don’t own a Nukeproof frame.

Read our full review of the Nukeproof Horizon stem

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5. DMR Defy 35

Best stem for a super-low stack height

Weight: 174g | Colours: Black, silver | Lengths: 35mm, 50mm | Clamps: 31.8mm, 35mm | Stack height: 28mm | Rating: 9/10

Reasons to buy:

• Super secure
• Raises your front end whilst having low stack height
• Good price

Reasons to avoid:

• Typically robust weight
• Square edge aesthetic may not suit some bikes

The Defy stem is designed to be a perfect match (aesthetically speaking) with DMR’s own Wingbar, but has a few features that make it a very attractive package for any cockpit combination. Twin face plate clamps use a Top-Close clamp design where you tighten both top bolts until they touch the stem body before tightening the lower bolts, ensuring simple, safe and effective bar installation.

The bar clamp tapers down the steerer clamp to create one of the lowest stack heights on the market. At just 28mm this makes the Defy perfect if you want to play a little more with stem/bar height (and thus you bike’s effective reach distance), or have cut your steerer too short (we’ve all been there). One of the best – and pretty unique – aspects of the Defy stem is that its stubby 35mm length also packs in a bit of rise (at least 5mm), which is really handy if you want to elevate your bar height without resorting to stem spacers or a new handlebar.

Read our full test review of the DMR Defy 35 stem

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6. Burgtec Enduro MK3

Available in ‘Goldilocks’ 42.5mm length

Weight: 155g | Colours: Nine | Lengths: 35, 42.5 and 50mm | Clamps: 31.8mm, 35mm | Stack height: N/A | Rating: 8/10

Reasons to buy:

• Unique length offering

Reasons to avoid:

• Split front clamps are fiddly to install

For this, the brand’s third version of its Enduro stem, Burgtec has switched to a cold-forged construction method. This has really upped the stiffness quotient of the stem compared to the previous Enduro MK2 stem. The bar clamping width has also been increased. So too has the steerer clamp depth, which has resulted in a greater stack height, so this may no longer be a viable option for riders with minimal fork steerers.

Perhaps the main USP of the Burgtec Enduro MK3 is that it is available in a 42.5mm length. It may sound daft and all rather Princess-and-the-pea, but a couple of mm here and there with stems can certainly be felt by experienced riders. So if you’ve tried 40mm and 45mm stems and not quite gelled with them, here’s the (42.5mm length) stem for you!

Read our full test review of the Burgtec Enduro MK3

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7. Renthal Apex 35

Best for weight saving

Weight: 116g (33mm) | Colours: Black & gold | Lengths: 33, 40, 50, 60mm | Clamps: 31.8mm, 35mm | Stack height: 40mm | Rating: 9/10

Reasons to buy:

• Lightest stem on test
• Wraparound bar clamps
• Distinctive looks

Reasons to avoid:

• Expensive. No colour options
• Care needed when fitting
• Six degree rise only

The Renthal Apex uses a twin face plate design, like many other stems. But the clamps here are 240° wrap-around affairs that help support the bar. You’ll need to careful when installing the bar though, as it’s easy to scratch the surface or end up with a cockeyed alignment. It’s also a really good idea to use a torque wrench to ensure the bolts are done up just-so.

It’s also noteworthy for offering a bit of rise (approximately 6°), which is a welcome and all-too-rare feature on sub-50mm long stems. Secondly, as with Renthal’s handlebars, there is a tiny but noticeable flex apparent when really loading up the front end. Which could be an advantage or a disadvantage depending on your position. If you’re currently feeling like your 35mm standard front end is overly harsh, Renthal’s Apex stem could be the answer to your prayers.

Read our full test review of the Renthal Apex

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How we tested the best mountain bike stems

With plenty of stems to evaluate, we spread them between a mix of test bikes and trusted testers to put the miles in and assess long-term durability. If we have an outlier in terms of stiffness, we then go on to test it back-to-back against a benchmark model on the same bike on the same track to put the performance into context. All bolts were greased as necessary, and tightened to the recommended torque settings using a torque wrench.

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What to look for with the best mountain bike stems

A mountain bike stem connects the handlebars to the fork steerer. They come in different lengths and different rises, allowing you to tune your cockpit position Modern stems are typically under 70mm in length, with 40mm and 50mm being the most popular measurements. Generally there are twin bolts to clamp around the steerer tube, and four bolts at the face plate to attach the handlebar.

First job is to work out what stems will actually fit on to your bike. You’ll need to know your fork’s steerer size and handlebar diameter.

Your fork steerer is almost certainly going to be the usual 1-1/8in diameter (the other option is 1.5in but it’s very rare these days). Use a tape measure or vernier calipers to measure the diameter of your headset top cap and you’ll instantly see if it’s not for a 1-1/8in fork steerer fork. You’ll also need to check the handlebar diameter. This will either be 31.8mm or 35mm on modern mountain bikes. Make sure you measure the area at the clamp, not the ends at the grips.

What’s best: 31.8mm or 35mm diameter?

Unfortunately there’s no simple answer here, as it depends on the bike, the rider and the terrain, as well as what you are trying to achieve. If you’re 95kg and riding a powerful e-bike on bike park trails and enduro tracks, the answer is probably going to be 35mm. But for most people, 31.8mm is going to be fine, and indeed preferable in terms of harshness. It’s rare we ride a 31.8mm bar/stem at 780mm wide and think it’s too flexy.

What length do I need? Is shorter better?

Again the answer is not a simple one, but if we were to look at the average stem length across the mountain bike market in 2023, the answer would probably be 40mm. Then, if you want a snappier steering or feel like you have too much weight over the front wheel, you could go shorter. Conversely, if you can’t get enough weight over the front, or feel like the bike is too cramped, and have tried playing with the bar height and bar roll, then a longer stem might be worth trying. In this case, we probably wouldn’t go longer than 50mm. For more ways to tune your weight balance and your bike’s handling, read this article.

What size bolts are used on stems?

4mm and 5mm Allen bolts are most common on mtb stems, with the heavier, larger-diameter bolts typically enabling higher torques and subsequent clamping forces. Some stems come with T25 Torx bolts, which are less prone to rounding off.

What is stack height?

This refers to the vertical real estate the stem demands on the steerer tube. In other words, it’s the height of the steerer clamp on the stem. This is important if your fork steerer is too short, and can also relate to the handlebar height achievable and overall stiffness of the stem.

What is meant by a zero-gap clamp?

More and more stems are now featuring a zero-gap bar clamp design, whereby one pair of clamp bolts fasten fully, and the remaining bolts tighten to lock the bar in place. The design prevents uneven tensioning and reduces the number of bolts you need to fix to a precise torque setting, making set-up easier.

What is stem rise, and is it important?

Rise is the difference in height between the clamps. Most stems are zero-rise, which means if you flip them over they don’t change the bar height. However, a six-degree rise stem allows you to effect a plus or minus six-degree change in bar height by simply turning the stem upside down. It’s not critical, as cockpit height can be adjusted by moving the stem on the steerer, or changing the handlebars.

What’s better? CNC machined or cold forged?

Stems are either 3D forged or CNC machined from an aluminium billet (basically a chunk of metal). Forging sees aluminium squeezed under immense pressures into (close to) the stem’s final shape. The technique compresses the material around high stress areas, and it’s argued produces a stiffer product with a better-aligned, denser grain structure. The initial forging cost is expensive and the finish is sometimes less angular, although you do see stems that are forged initially and then tidied up on a CNC machine.

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