PRO Vibe Carbon stem

PRO's new Vibe Carbon Stem is a very good option for stiffening up the front end of your bike. The slim design and low weight are very impressive, just watch out for the low torque setting on the top cap.

You wait ages for one carbon stem to arrive and then two come along at once. I'd only just fitted the Zipp SL Sprint stem when the Pro Vibe Carbon arrived for testing. Still, it's a great chance to ride them back to back and see how two very different designs work.

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Both are claimed to be very stiff but Pro and Zipp go about delivering this in very different ways. Where the Zipp has a very chunky design, the Pro Vibe is still quite slender. I really like the design of the Pro Vibe. It doesn't look out of place on a skinny-tubed bike and the slim form factor means that space on narrow bars isn't going to be an issue.

Getting my head down and opening up a sprint or two suggested that there are no stiffness issues here. The Pro Vibe is a solid platform that I couldn't twist, even on the steepest power climbs where I really start wrenching on the bar.

Pro has redesigned its 'puzzle' clamp for the new Vibe carbon stem. The two alloy pieces that make up the faceplate hook onto protrusions on the stem, and everything is brought together by two alloy bolts. It's a clean setup that looks great and is easy to install.

Talking of installation, this is where I found my one and only gripe with the Vibe Carbon stem. The top cap is also carbon and comes with a very strict 2Nm torque limit. If you exceed this, you're in danger of pushing the top cap bolt straight through the carbon.

This isn't really an issue, I'm just warning you. If you've got a difficult setup that requires you to put a bit more pressure on the top cap then you can simply use an alloy top cap to set the preload, nip up the steerer bolts and then pop the carbon top cap on in place of the alloy cap.

The stem's faceplate design allows you to use the stem in either the -8 degree or the +8 degree option. There are no other tilt options, but I find that -8 is a good choice for a stem that is going to be primarily used on race bikes. You're well served for lengths, though: the Vibe Carbon stem comes in 10mm increments from 80mm to 130mm. The 120mm that I have here tips our scales at 147g, an impressive weight given the stiffness. Zipp's SL Sprint in the 110mm was 173g.

> How to choose the best stem length for your bike

At £249.99 it's just a few quid less than the Zipp SL Sprint at £254. Both are premium options, but both work perfectly.

As with Zipp's SL Sprint, you're likely buying the Pro Vibe Carbon for the stiffness, and it really delivers. You also get a smaller form factor than the SL Sprint, and a lower weight too.

Verdict

Stiff and slim design is a real winner