3T's Arx II Pro stem is – you'll not be surprised to know – an evolution of its Arx Pro stem. It's nicely made, stiff, and available in a good range of sizes. The odd choice of steerer clamp bolt is the only real issue.
The Arx II Pro uses a standard alloy shaft and a similar faceplate to the previous design, with the cutout 3T logo, but the shape has been refined a bit and the look is a little more sculpted.
Torx T25 bolts take the place of 4mm Allen bolts in the faceplate, and at the steerer you get a single bolt instead of two. It's an M7 thread with a Torx T30 head: precisely no one will be carrying one out on your ride, so make sure it's done up before you go. In a pinch you can do it up with a 4mm Allen key but it's an odd choice of bolt and it means you'll need to take a specific tool if you travel with your bike, which is a bit of a pain.
We had a 130mm, +/- 6 degree stem. The Arx II Pro is available in 10mm increments from 70mm to 130mm, and there's a +/- 17 degree rise version too. You can run it either way, just flip the faceplate so the logo isn't upside down.
Once fitted the stem did all the things stems do, like holding the bar and turning the steerer, without any kind of fuss or complaint. It's nice and stiff and there's no discernible twisting when you haul on the bar: an alloy tube is hard to beat for resisting torsional flex, after all. All the bolts are good quality and a few wet outings haven't resulted in any rust spots.
At 159g for the 130mm (claimed 135g for 110mm, which seems about right) it's not the lightest out there, but given that you can pick this stem up for about £30 online and you're only adding about 40g over even the very lightest stems that cost many times as much, it seems like a sensible place to spend your money. Even at full retail it would be a decent buy.
Good quality stem available in a decent range of sizes and angles
road.cc test report
Make and model: 3T Arx II Pro Stem
Size tested: +/-6°, 130mm
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?
3T says: "Arx II is an evolution of the well-liked Arx alloy stem, which has found a place on every sort of bicycle since its launch in 2007. It's a subtle refresh of this classic design. The faceplate is drawn in tighter at top and bottom, for a more ovalized frontal appearance, while retaining the cutout 3T logo. The sides of the extension are slightly flattened for a more sculpted look by comparison with the tubular section of the first-generation Arx. A single M7 bolt clamps the stem to the fork steerer, in place of the twin M5 bolts used previously. Bolts are now the more-secure Torx-type fitment in place of the Allen bolts used previously."
Tell us some more about the technical aspects of the product?
Weight: 135g (110mm)
Length: 70, 80, 90, 100, 110, 120, 130mm
Material: AL 2010
Angle: +/-6°, +/-17°
Bolts: Torx T25
Finish: Shot Peened/Black Anodized
Very nicely made and finished.
Discharges its duties well. Big bolt is a faff.
Not much to go wrong here.
You can go lighter but it's not heavy.
Tell us how the product performed overall when used for its designed purpose
Tell us what you particularly liked about the product
Nice and stiff, well made.
Tell us what you particularly disliked about the product
Faffy big Torx bolt to tighten onto the steerer.
Did you enjoy using the product? Yes. Except that bolt.
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your score
A good quality, reasonably light stem for not too much cash. The odd choice of stem bolt marks it down a point.
About the tester
Age: 42 Height: 189cm Weight: 92kg
I usually ride: whatever I'm testing... My best bike is: Kinesis Tripster ATR, Kinesis Aithein
I've been riding for: Over 20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: road racing, commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.