Review: Rotor INpower

When Rotor announced the development of their new INpower system of cycling power measurement earlier this year, I was definitely one of the first to pay attention. The new power meter is housed entirely within the bottom bracket spindle of any of their 30mm BB cranksets, including the battery, which is an easily-replaceable standard AA with a claimed 300+ hours of life. The options include all 30mm models which means their off-road cranksets too. The power is read from the left, non-drive-side, crank arm in this case, whereas most others are on the drive side. Swings and roundabouts right...?

I've been using their cranks for a few years now, and have also become a convert to their Q Ring ovalised chain rings. With the INpower, Rotor offer both the full crank arm set, and the option of just buying a replacement left crank arm. This meant that actually I'd only need to switch out the non-drive-side crank arm on my 3D+ crankset, and I'd be riding with one of the latest power meters on the market, and one that was actually designed to work with the Q Rings to refine the exact position of the oval for maximum pedaling efficiency.

When I put my latest bike together earlier this year, though still unaware of Rotor's big plan, I had included a 3D+ crankset with the MAS (Micro-Adjust Spider). I'd had the plan to add a power meter, but just wasn't sure which one to go for. I currently run a Power2max power meter on another 3D+ set, and though this works perfectly well, they're not that easy to get hold of, and grotesquely over-priced outside of Europe. The INpower was going to cost me just over half of what I was looking at previously. I was a dog with two tails!

So the immediate benefit of this new product was a saving of a good chunk of Euros. However, Rotor also claim that the specific design of the power meter to work with their Q Rings includes an analytical software to determine the optimal position of the ovalised ring to compensate for the dead spots in your pedal stroke.

ON THE ROAD

A direct comparison with my other power meters reveals very similar performance. That means 'good' as far as I'm concerned. It gives me power and cadence with reasonably consistent readings at a comparable time lag of somewhere around a couple of seconds from crank impulse to power displayed. I'm using the Garmin 810 that has been my trusted companion for the past year or so, and the ANT+ wireless communication works. I have to remember to do a power-meter search on the Garmin each time I switch bikes, but it's a necessary pairing of one-to-one as with all of these things.

Loading up the data - my favourite nerdy scientist bit - there are a couple of extra parameters measured that aren't on my previous meters. One is Pedal Smoothness, and the other is Torque Effectiveness. Both are only measured on the left crank arm, though there is a reading given for the right arm. I got some feedback from Rotor on this, after they saw the print-out below from my Garmin Connect, and apparently I may not have calibrated the unit correctly.

After calibrating it again in the way described to me, I came up with numbers that look quite different for the right crank arm so I would guess that I'm closer to the truth now.

One issue with calibration is that in the manual it describes the process in a slightly confusing way. The correct way to calibrate is in 2 steps. Set the calibration on your head unit with the pedal mounted, and the left crank arm in the 6.00 position, then turn the crank backwards 2 full cycles and with the arm in the same position again, press calibrate on the unit a second time. You should apparently not need to re-calibrate again after that.

I did initially have a small issue with this meter in that I found myself changing battery 3 times in the first couple of months, as I would get no reading despite repeated attempts to activate the pairing with my Garmin. It seemed I was not getting anywhere near the 300+ claimed hours of battery life out of it. In retrospect it may just have been a lag in repeated pairing of the Garmin with different power meters. As I said, I switch bikes using the same head unit (the Garmin Edge 810) with 2 different power meters, sometimes every other day, and it does sometimes take a couple of attempts before it recognizes the INpower. I've persevered with the same battery now for around 2 months, so I think I was probably a little hasty to assume a change of batteries was needed.

After consultation with Rotor, it appears there have been some software issues, especially paired with Garmin head units. They say this has been addressed with their latest firmware update.  It is remarkably easy to find AA batteries pretty much anywhere, and it really is very easy to replace the battery, even with mitts on, so it's possibly with the ease of this solution that I failed to persevere with the lag in pairing. If I ride the same bike on consecutive days the Garmin generally does not need to search for the unit again.

It is perhaps the most understated of all power meters on the market though, and whether you like that or not, it does mean that all of the delicate stuff is tucked neatly away and protected by some of the strongest bits of the bike. As long as the seal stays tight it can probably withstand some ugly environments and rough treatment - ideal for MTB or Cross?

I love it when things just work. When you turn them on and they do what they're supposed to do, and never stop doing that. But it doesn't encourage lengthy discussion really. And so the summary of this review is basically that the INpower system does everything it should without a fuss and at a fraction of the cost of some of the top-end, and rather more finicky power meters on the market.

I've yet to get to grips with the pedal-stroke diagnostics. Having downloaded the required analytical program, it seems that I need a "translator" program to run a Windows OS software on my Mac, and the one suggested doesn't seem to work. I'll get down to this when I have more time. It all seems to be working well for the moment, so I'm not at all sure that I need much tweaking. I will get there.

All-in-all I would give this product a "highly recommended".