Verve Cycling Infocrank Classic

The Verve InfoCrank is a reliable crank-based power meter that supplies data for both your legs independently. It's not the cheapest option out there, but once set up there's virtually nothing to think about.

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Setup

InfoCrank is available as a 2D forged chainset (chainrings included) with a 30mm axle, compact (50/34-tooth) and mid-compact (52/36-tooth) options, and a choice of bottom brackets to suit different bikes (£1,149), but we have the InfoCrank Classic with a 24mm axle, 130mm BCD (bolt circle diameter) 53/39-tooth chainrings and no bottom bracket.

Setting it up was straightforward enough. I just took off my existing chainset and bolted the InfoCrank in place without any drama. It's a simple Allen key job. Obviously, this means you have to ditch your shiny Dura-Ace cranks for something that arguably looks more workmanlike and less glitzy. Then it was just a question of fitting cadence magnets to my frame.

There are a couple of ways to attach the magnets, one of which is just to remove some backing tape and stick them to the bottom bracket shell, although I fastened them in place using the bottom bracket chain guide bolt. It doesn't look the neatest design ever, but it works fine. Since I started using the InfoCrank, Verve has released a firmware update that means you no longer have to use the magnets. That's cool with me because it was a bit of a faff.

You can check compatibility with your frame here.

You need to put two SR44 (hearing aid) batteries into the little pocket on each of the cranks. That's a fiddly job with a 2mm hex key (leaning your bike on its side will save you scrabbling about under the fridge to find them). These batteries aren't as readily available as the CR2032s that most other brands use, so buy a batch and stash them in a drawer. According to Verve, you can expect about 500 hours of use before you need to change them. I'm still on my first set.

Once the InfoCrank was in place, I gave it a spin and paired it up with a Garmin Edge 510 bike computer. It linked up first time and the connection has never dropped once during testing. I've tried linking it to other head units too and it has been just as easy. Head units have to communicate using the ANT+ protocol; InfoCrank isn't Bluetooth compatible.

An ANT+ USB stick is included in the pack so you can transmit the data to your computer and ride on Zwift, for example. 

I guess the whole setup process took about 30mins, including reading the instructions, deciding on the best way to do things, and adjusting it properly, although I didn't need to replace the bottom bracket. I've heard of other people saying the setup can be a bit of a faff but it was easy on my bike and would probably take 10mins a second time, or if swapping the InfoCrank from one bike to another.

In use

Once set up, InfoCrank couldn't be easier to use. You spin the cranks to wake them up – LEDs flash to show they're working – and that's it. There's never a need to calibrate, so there's no protocol to get wrong, and Verve says there's no drift with temperature.

Verve also says that you can switch InfoCrank between bikes or, if you're loaded, have a set on more than one bike, and there will be no difference between the watts measured. In other words, readings will be directly comparable.

'The strain gauges are bonded into symmetrical pockets in the inner and outer faces of the crank,' says Verve. 'Variations between left and right cranks in a pair, or from pair to pair, are vanishingly small, amounting in no case to greater than a 1 watt difference as manufactured – eliminated in any case by factory calibration.'

Those strain gauges measure only the tangential load, the force that generates power as you rotate the cranks. As well as total power and cadence, the unit transmits left/right leg power, torque effectiveness (how much of the power delivered to the pedal is pushing it forward) and pedal smoothness (how smoothly the power is delivered throughout the pedal stroke).

Whenever we review power meters we point out that it's not possible for us to measure their accuracy, as such. What we can do is compare the data we get from different power meters used at the same time. In this instance, I've been using the InfoCrank alongside a PowerTap G3 hub and the results have been very similar.

I've tried everything I can think of: short blasts, long rides, hill intervals, turbo sessions, plus gravel and stone surfaces as well as normal roads, and the InfoCrank has generally given slightly higher readings than the Powertap, but not by far, and they react equally well to changes in pedalling intensity – there's no lag.

Here's a chart showing InfoCrank (green) and PowerTap (pink) data on a 30min section of a recent ride I did, for example (it's time along the X axis and power – 0-600 watts – on the Y axis, obviously). I warmed up and then did a climb starting at around 14mins, finishing it at about 19:20, then I carried on riding over a rolling route, sticking in a few harder efforts to try to confuse the power meters.

As you can see, the green InfoCrank line is generally a little higher than the pink PowerTap line, although there's not a great deal in it. Does it matter if a given amount of power is labelled 200 watts or 203 watts, for example? Probably not. Chances are that you're going to use a single power meter rather than switching (like me) from one system to another, so it's unlikely to be an issue. Say you're going to do a ride at 80% of your functional threshold power (FTP) as measured by the power meter you're using. The important thing is that you ride at 80% of your FTP figure; the number assigned to that 80% makes no real difference.

What's more important is how closely the lines on the chart track one another, and in this case they follow each other very closely. The lines are often furthest from one another at the top of a spike (that's not unusual or surprising), the InfoCrank giving a higher peak than the PowerTap. Is the InfoCrank over reporting, the PowerTap under reporting, or a bit of both? I don't know – as I said, I can only compare the figures – but there's not a great deal in it. That big spike at about 23mins, for example: the InfoCrank gives it as 669.7 watts and the PowerTap gives it as 660.3 watts – that's a difference of about 1.4%.

Towards the end of the climb from 14mins to 19:20mins, the PowerTap gave slightly higher readings than the InfoCrank. That was unusual. It was nearly always the other way around throughout several months of testing. Even there, we're talking about a difference of a handful of watts and that's within the levels of accuracy claimed for each system.

Verve says lab tests have shown that each of its InfoCrank chainsets is accurate to within +/-0.5%, while PowerTap claims +/-1.5% for its G3 hub. Say I was putting out 400 watts for a short period of time. According to the manufacturers' claims, the InfoCrank could report that as high as 402 watts while the PowerTap could report it as low as 394 watts – a difference of as much as 8 watts. The difference in readings between the two systems during that climb were usually much smaller than that, with only small spikes where they diverged more. Over the whole climb, the average power recorded was virtually identical.

> Read our guide on how to choose a power meter

I could go on comparing data for hours and hours but I'll spare you that. Suffice to say that there's nothing in the data I've seen over several months that makes me question whether either system performs to its claimed level of accuracy.

Overall, the InfoCrank is a very good system. It's easy enough to install (especially now you don't need magnets), and once set up, that's it. You don't need to do anything else until the batteries run out, and that's likely to be many months down the line. It's unobtrusive, reliable, and super-easy to use.

Verdict

Dual-legged power meter that provides reliable data without any fuss