Zipp SL-70 Aero handlebar

The Zipp SL-70 Aero handlebar is an expensive way to save some watts, but it certainly delivers on the stiffness and comfort front. Also, for an internally routed bar, fitting cables is a relative cinch.

Using a Computational Fluid Dynamics (CFD) program for the design, Zipp makes some decent aerodynamic claims for the SL-70 Aero's wing-like shape.

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According to Zipp, a round-tube section handlebar creates a drag of about 0.74 newtons, which it found requires about 7.5 watts of effort at 30mph (48.3kph) to overcome. The SL-70 Aero creates just 0.11 newtons of drag, a saving of 6.4 watts – not massive by any stretch of the imagination, but if you're the type of rider who wants to get as much out of every gain going, not to be sniffed at.

Without a wind tunnel those claims are hard for us to verify, and in the real world there didn't feel to be a huge advantage when out for a hard ride.

What I can give my findings on, though, are stiffness and comfort; always a tricky balance to get right, but something Zipp has achieved.

Yanking on the hoods when riding hard out of the saddle there is absolutely no flex whatsoever, nor is there when you are braking hard transferring your weight through the handlebar.

It's the same when you're down in the drops. This is a proper racer's bar.

With a reach of 70mm and a drop of 128mm, it isn't as shallow as some more endurance style bars but nor is it so deep that only the most flexible can make full use of the drops.

The wing shaped top of the bar is actually quite comfortable to use, even with the majority of it being untaped. Zipp seems to have got the carbon layup right in a way that the SL-70 Aero is stiff but without being harsh, even on rough roads.

Like many aero bars, the Zipp doesn't have much room either side of the stem for fitting a computer mount or lights.

Some handlebars with internal cable routing can be an absolute nightmare to set up but the SL-70 Aero was a relative breeze thanks to what Zipp calls Rapid Routing. The holes are positioned exactly where they need to be to be compatible with all groupsets, and while the Zipp website only mentions mechanical brake/gear systems, a bit of a scoot round on the internet shows no issues with hydraulic hose use.

I was using the bar on a rim brake-equipped bike fitted with Shimano Ultegra 6800. All the cables passed through and exited without getting caught inside the bar. It's obviously more of a faff than externally routing them, especially if you have to remove all of the cables from an internally routed frame too, but it went a lot quicker and easier than expected.

Weight-wise, the Zipp is in the right ballpark at 236g for this 42cm size. The Ritchey WCS Carbon Streem bar is 248g, although it is a bit cheaper at £270 compared to the Zipp's £296.

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Pro's Vibe Aero Carbon is slightly heavier at 261g and costs £299.99. It is aimed more directly at running Di2 internally, so routing a mechanical setup through the Vibe was nowhere near as easy as it was with the Zipp.

Overall, I really like the feel of the Zipp out on the road and got on well with the shape. And while the cost is high at nearly £300, it isn't massively overpriced against the opposition.

Verdict

Expensive, but easy to set up and delivers a great ride and performance