Giant Power Pro Ultegra R8000 Power Meter

Giant's Power Pro system adds dual-sided power sensing to Shimano's Ultegra crankset. I've found the power numbers to be repeatable and believable, and Ultegra cranks are hard to fault in operation. As a system, it's a good value option for dual-sided power.

What you're getting here is a Shimano Ultegra R8000 chainset in your choice of configuration – 165mm, 170mm, 172.5mm or 175mm cranks in either 50/34 or 52/36 – with Giant's own power-sensing technology fixed to both sides.

In that sense it's a very similar offering to the Stages LR power meter, which retails for about £85 less in the Ultegra spec (Mat tested an earlier Dura-Ace version back in 2015), and 4iiii's Precision Pro Ultegra power meter which is about £100 less.

> Buy now: Giant Power Pro Ultegra R8000 Power Meter from eBay for £590.00

The main difference is that the Giant system uses a rechargeable battery, whereas both the competitor systems use a simple 2032 coin cell on either side. The battery life is about the same at a claimed 100 hours per charge, but the internal battery means there are no battery covers or seals to worry about: the whole thing is sealed and rated at IPX7 for waterproofing. That's chuck-it-in-the-lake waterproof, so rain and road muck should have little effect.

The charging lead attaches magnetically to both sides for charging; it's a bit of a faff and of course you'll need the proprietary lead, so if it dies on a training camp or something, you can't just chuck another button cell in. But overall, it's a better solution than using replaceable batteries.

Many top-end Giant bikes already come with the Power Pro, and as a retrofit option it's as simple as taking off your current cranks and swapping them out. If you're replacing Shimano cranks all you'll need is a 5mm hex key and the little star washer tool. If it's another crank system then you might also need a new bottom bracket, depending on the spec of the axle.

We've reviewed the Ultegra R8000 groupset and there's not a lot to be said about it that hasn't already been said. If you're spending your own money on lightweight components for a road bike, it's hard to beat in terms of bangs per buck. The hollowtech construction of the crankset keeps things light and stiff, and shifting performance is among the best there is. So there aren't really any worries on that side of things.

To zero the cranks, Giant says you should use the Giant RideLink app on your smartphone. (There's a video here, showing you how to pair your Power Pro with the RideLink app.) You can also initiate over-the-air firmware updates from the app.

The app can record rides and show you graphical representations of your pedal stroke. That might be useful to you if, for example, you're riding indoors and working on making your pedalling smoother. But in the vast majority of cases you'll already be set up for recording your rides and you'll want the Power Pro to be easy to incorporate into your existing setup. Which I found it to be: I had no issues with linking to various GPS computers from the GPS computer drawer, and also no problems hooking up to my PC for indoor training. All good.

The cranks are dual Bluetooth/ANT+ compatible so they should work with pretty much any GPS head unit or indoor training system you could care to mention.

On to power, then. The numbers from the Power Pro appear to be repeatable, and accurate. Which is nice. Here's a section of an outdoor ride by way of an example comparing the cranks (blue) to Garmin's Rally RK200 pedals (purple):

As you can see, there's barely anything in it between the two. The average is within 1W, and at all times the two power meters track each other very closely. At some points the Garmin pedals read higher, at other points it's the cranks, but there's very little in it.

I'm very happy with both of these power traces. They're effectively measuring power at the same point, as there are minimal losses in the pedal bearings transferring power to the crank, so you'd expect them to read the same, and they do.

> The 10 best cycling power meters: which one is right for you?

Giant's claimed accuracy is +/- 2%, which is nominally less accurate than its direct competitors, but there were no issues with the power readings I got from the cranks. Left/right balance on both pedals and cranks was 51/49 left to right, which is what I'd expect. Like I said earlier, the RideLink app can be useful to look at your power balance and the power signature of your pedal stroke if you're having specific issues or want to address any weaknesses in your pedalling. But it's unlikely you'll switch to it as your primary means of gathering data.

Funnily enough the discrepancy in cadence between the two power meters was larger than the power gap was, which is odd seeing as it's such an easy thing to measure. The Power Pro uses an accelerometer for cadence sensing, so everything's handled internally. The difference is still only small here, and both of the units give solid readings with no drop-outs.

> 12 reasons why you should buy, and use, a power meter

Overall, the Power Pro cranks are a really good option if you want to measure your power directly. Eight hundred quid isn't small change, but they're a comparable price to other similar power meters and the weather-sealed, internal battery design is better. Giant's app gives you a bit more in terms of options for studying your pedal stroke, too. Shimano's Ultegra cranks are hard to beat, and overall this is a very well-considered package for adding power sensing to your bike.

Verdict

An excellent option if you want dual-sided power on your bike