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.
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.
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.
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.
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...
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
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road.cc 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"
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.
With a one-piece design there is little to fail.
Stiffness comes at a cost here as it's on the chunky side.
Very stiff so you need a bar with some flex to offset this.
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
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.
About the tester
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
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!