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ITM X-One Carbon Stem with GWS Grip Wedge System



A very good stem for the sprinters because of its phenomenal stiffness, but its weight will upset the weight weenies

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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It may be a bit of a 'chunky monkey' at 219g, but the X-One Carbon Stem with GWS, from Italian brand ITM, is one of the stiffest stems on the market. It's a rather stunning looking piece of design for your pride and joy too. Just don't expect to attach your computer to it.

It's all a bit old school having to feed your handlebar through a hole in the stem, just like the days when we were all riding quill stems (you young 'uns will have to ask your parents). You had to learn the knack of twisting and turning to feed your brand new bar through without leaving a scratch on it, just like playing one of those games where you feed the loop over the wire without the buzzer going off.

> Order this from your nearest dealer – find yours here

The X-One is a little different because it has a teardrop opening to accept the shape of the X-One Carbon bar (review to follow) to create a semi-integrated system. Once the 31.8mm diameter bar centre is in place, it's held there by the Grip Wedge System, a snappy title but it does the job it needs to.

It does have a little niggle, though: the position of the bolt which, when tightening, makes the system expand by pulling the three pieces together. If you are using the X-One bar with its wide, flat tops, you struggle to get an Allen key in there without catching the back of the bar; a torque wrench with adaptor is even trickier.

ITM stem fitted.jpg

For the initial setup I didn't use any carbon gripper paste between wedge and bar, to see whether anything moved under heavy braking or hitting a pothole; it did, but after a couple more tweaks of the bolt, things have stayed secure.

The theory behind the one-piece construction is to create stiffness by omitting the faceplate and securing bolts. It also provides minimal aerodynamic gains, and looks mighty fine.

Stiffness is where the X-One excels. Its wide, squarish profile uses a lot of material, hence the weight, but get out of the saddle and wring the bike's neck and you won't feel the tiniest bit of movement through the stem body whatsoever.

ITM X One Carbon Stem With GWS Grip Wedge System - underside.jpg

At the steerer end, the X-One is quite deep. I had to remove my only remaining 5mm spacer, so if you've already slammed your stem you might need to check the fit.

The X-One is actually designed for a 1 1/4in diameter steerer, but you also get a shim to bring it down to 1 1/8in. It does take away that one-piece design mantra for the majority of road bikes, but you don't notice any issues.

All this is finished off with ITM's specific teardrop shaped top cap.

> Find more reviews of stems here

If you like to mount your GPS/computer on your stem you'll find that because of its shape and width, the X-One doesn't really lend itself well to the likes of Garmin's rounded mounts, and if you're using the X-One bar there'll be nowhere to mount it there either.

Another negative for me is the 'Ride Your Best' tattooed down the centre of the stem. I'm not one for motivational quotes at the best of times, let alone when I'm out on my bike having a bad day and having to constantly read that...

ITM X One RYB.jpg

One thing to bring a smile back to your face, though, is the price – well, it'll make you chuckle either way, I suppose. To my mind, £129.99 is quite competitive against the top performing alloy stems, and quite a bit cheaper than other full carbon stems on the market.

Overall I really rate the X-One stem. I can overlook its slightly porky weight for the stiffness you get for really speedy riding. It's got a few niggles, yeah, and I'd like to see a little bit more care taken with the internal finish – it's a little rough around the inside of the steerer hole (would it really take much to rub a bit of sandpaper around when it comes out of the mould?) – but on the whole it's performance that matters, and I love it.


A very good stem for the sprinters because of its phenomenal stiffness, but its weight will upset the weight weenies test report

Make and model: ITM X-One Carbon Stem with GWS Grip Wedge System

Size tested: 31.8mm, 100mm

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

The X-One stem is part of a semi-integrated system for high performance riding. A one-piece design brings a stiffness level not often seen from stems.

Tell us some more about the technical aspects of the product?

One piece monocoque design.

GWS - Grip Wedge System for securing bars.

Angle - 10 degrees

Steerer - 1 1/4" & 1 1/8"

Rate the product for quality of construction:

A few rough edges on the inside of the steerer hole from where it's been removed from the mould. External finish is excellent though.

Rate the product for performance:
Rate the product for durability:

With a one-piece design there is little to fail.

Rate the product for weight (if applicable)

Stiffness comes at a cost here as it's on the chunky side.

Rate the product for comfort (if applicable)

Very stiff so you need a bar with some flex to offset this.

Rate the product for value:

About the same as many high end alloy stems but a lot cheaper than some of the other carbon offerings.

Tell us how the product performed overall when used for its designed purpose

Absolutely brilliant in terms of stiffness.

Tell us what you particularly liked about the product

The looks.

Tell us what you particularly disliked about the product

Being told to 'Ride Your Best' every time you get on your bike.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your score

If you're a powerful rider looking for a super-stiff stem then the ITM X-One can't be overlooked. The finish is good and the one-piece design gives your bike a clean look. The price is easily justifiable against top end alloy offerings. The only annoying thing is the position of the bolt on the Grip Wedge System and the weight, which knocks off a point.

Overall rating: 8/10

About the tester

Age: 37  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: Mason Definition

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed

As part of the tech team here at F-At Digital, senior product reviewer Stu spends the majority of his time writing in-depth reviews for, and ebiketips using the knowledge gained from testing over 1,500 pieces of kit (plus 100's of bikes) since starting out as a freelancer back in 2009. After first throwing his leg over a race bike back in 2000, Stu's ridden more than 170,000 miles on road, time-trial, track, and gravel bikes, and while he's put his racing days behind him, he still likes to smash the pedals rather than take things easy. With a background in design and engineering, he has an obsession with how things are developed and manufactured, has a borderline fetish for handbuilt metal frames and finds a rim braked road bike very aesthetically pleasing!

Add new comment


travsullivan76 | 7 years ago

Has anyone found a good option for an out-front mount?

eosp replied to travsullivan76 | 5 years ago
travsullivan76 wrote:

Has anyone found a good option for an out-front mount?


Hi travsullivan76, what did you do about this? I used the included out-front mount from the EDGE 1030. It's a bit sideways, I find it annoying sometimes. 

ridebeast | 7 years ago
1 like

Hi. The claimed weight of the stem in your writ is not correct @219gr. The X-One bar weighs 219gr (42cm). A X-One 100mm stem is roughly 125grm.

ChrisB200SX replied to ridebeast | 5 years ago
ridebeast wrote:

Hi. The claimed weight of the stem in your writ is not correct @219gr. The X-One bar weighs 219gr (42cm). A X-One 100mm stem is roughly 125grm.

This seems to be true.

Also, presumably it's impossible to fit certain aero bars through that hole?

Gasman Jim | 8 years ago

This design will make removing the bars when packing the bike into a flight case impossible, you'd have to remove the stem from the steerer instead. No thanks.

bendertherobot replied to Gasman Jim | 8 years ago
Gasman Jim wrote:

This design will make removing the bars when packing the bike into a flight case impossible, you'd have to remove the stem from the steerer instead. No thanks.

Is there any real practical difference between those two methods?

bendertherobot | 8 years ago

If you're feeling bad about your ride take "ride your best" to be your best bike. Where this will sit. So it's all good.

It's good to see ITM back and prospering.

Yorky-M | 8 years ago

Love the stem, agree with the 'Ride Your Best'

Its what my mum said to me 30 years ago when seen me get dropped at 2km the week provious....ah bless.

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