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TECH NEWS

InfoCrank power meters available in UK + video

Crank-based system offers separate left/right leg readings with pedal stroke analysis soon

Verve Cycling’s InfoCrank power meters are now available to buy and hire in the UK, and we met Verve’s president Bryan Taylor last week to find out all the details on the system.

InfoCrank is a crank-based system, as the name suggests, that incorporates two strain gauges on each side, so it is able to offer separate measurements for your left and right legs. For more info on the background to the product go to our story from last year

“This is the first commercially developed power meter – that is, a measuring device that is actually measuring the torque going through the crank multiplied by the cadence equalling watts,” said Bryan Taylor. “All of the power devices up until this one was released were measuring torque somewhere and then in some way trying to calculate the tangental force and then work out the watts, sometimes quite successfully.

“If you work out something in a convoluted way like that you can’t put an equals sign at the end, you have to put an approximate sign. With this product we can now honestly say that this equals that.”

The Verve Cycling engineers believe that there are fundamental problems with pedal-based power meters – or ‘power devices’, as they prefer to call them.

“The pedal joint is almost the weakest point on the bike, the bearings inside the pedal are particularly weak, and the problem when you get to the pedal is that there are forces going everywhere,” said Bryan Taylor. “It’s difficult to determine which force is which.

“With InfoCrank we are measuring only the tangental force. All the force is going down the edges of the cranks. We’ve carved them out as much as we can we and put the strain gauges where it is all happening.”

Each crank records 256 times per second and the average torque for the pedal stroke is sent every time the crank passes the system’s magnet. The data can be picked up on an ANT+ device from InfoCrank – it’s actually made for them by o-synce – or a third party like Garmin, for example.

Verve Cycling claim that InfoCrank is accurate to ±0.2 N m (newton metre) for measurements below 20 N m, and to 1% of actual readings for measurements above 20 N m. It has a power range of up to 3,000 watts, so it’ll cover everyone.

Although you can’t currently get pedal stroke analysis with InfoCrank, that information is on the way.

“We have software inside which we have not released yet where we are also able to take up using certain methodologies that enable us to show the entire pedal stroke,” said Bryan Taylor. “The software enables us to totally reconstruct the pedal stroke. It already in every set of InfoCranks and we’ll probably be releasing that to coaches soon.”

The head unit will store the torque information and you’ll upload it to a computer for analysis later on.

InfoCranks work on widely available SR44 batteries, two on each side. If you ride three hours a day, four days a week, they’ll need replacing once a year, according to Verve Cycling.

You can buy the chainset, including the chainrings and bottom bracket, for £1,365, or without the chainrings for £1,260. You can choose a chainset with 110 BCD (bolt circle diameter) and 52/36-tooth or 50/34-tooth chainrings, or 130BCD with 53/39-tooth chainrings.

Of course, the power meter world is getting ever more competitive with some systems less than half the price. If you’re interested in InfoCrank but you’re not sure you want to commit, you can hire one for three months at a cost of £85, plus a £150 deposit. 

Swapping InfoCranks between bikes isn’t as easy as with some other power systems. If you’re likely to be doing this often it’s probably best to have a relevant bottom bracket permanently on each bike and then just swap the chainset, which is a single-bolt Allen key job.

InfoCrank give a weight of 649g complete with the power module. The system is waterproof (to IPX7 standard) and it adjusts automatically for temperature so there’s never a need to recalibrate.

For more info go to http://infocrank.uk/

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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13 comments

Avatar
Eebijeebi | 8 years ago
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Toy or not, I have Infocrank with the Praxis rings and so far it does what it says on the tin.

Avatar
Eebijeebi | 8 years ago
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Toy or not, I have Infocrank with the Praxis rings and so far it does what it says on the tin.

Avatar
bdsl | 8 years ago
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"If you work out something in a convoluted way like that you can’t put an equals sign at the end, you have to put an approximate sign. With this product we can now honestly say that this equals that."

This doesn't make sense to me. All measurements are approximate. Some are more accurate or more precise than others.

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crikey | 8 years ago
0 likes

That's 30 years of racing, which is properly playing at it...

I'm not denigrating the use of things like this, but it serves us all well to occasionally remind ourselves that we are extremely privileged adults who have the opportunity to spend our leisure time in such a way. We can buy the same stuff that the professionals use, but it's important to remember that we are doing it for fun, not for a job, hence my definition of it as play...

Avatar
fukawitribe replied to crikey | 8 years ago
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crikey wrote:

That's 30 years of racing, which is properly playing at it...

I didn't think you meant you were 30  1

crikey wrote:

I'm not denigrating the use of things like this,

OK, but maybe best not to use generally pejorative terms like 'toy' then ?

crikey wrote:

but it serves us all well to occasionally remind ourselves that we are extremely privileged adults who have the opportunity to spend our leisure time in such a way.

Indeed - well put.

crikey wrote:

We can buy the same stuff that the professionals use, but it's important to remember that we are doing it for fun, not for a job, hence my definition of it as play...

By that definition, well then of course... but then I never said it was essential, quite the opposite. Here we agree I believe.

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crikey | 8 years ago
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No, I disagree. Even a bicycle is a toy unless you are earning a living from it or intending to.
Power measurement can be very useful for training, but it's still playing.
Nothing wrong with grown ups having toys, nothing wrong with people taking their 'play' seriously, but I think it is important to recognise that it is, really, just playing.

Edit: ...I've been playing at it for 30 years and I know my toys are better than yours...  3

Avatar
fukawitribe replied to crikey | 8 years ago
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crikey wrote:

No, I disagree. Even a bicycle is a toy unless you are earning a living from it or intending to.
Power measurement can be very useful for training, but it's still playing.
Nothing wrong with grown ups having toys, nothing wrong with people taking their 'play' seriously, but I think it is important to recognise that it is, really, just playing.

OK i'm not going to get into an argument about what you think 'play' means - and the use of 'toy' (e.g. "an object for a child to play with") as you did, typically used to denigrate something. That said, even discounting more casual users, i'm sure there are plenty of non-professional sports men and women who might find it somewhat offensive.

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fukawitribe replied to crikey | 8 years ago
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crikey wrote:

Edit: ...I've been playing at it for 30 years and I know my toys are better than yours...  3

Aaaah, young'uns - always so confident in their beliefs  3

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BikeJon replied to crikey | 8 years ago
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crikey wrote:

No, I disagree. Even a bicycle is a toy unless you are earning a living from it or intending to.
Power measurement can be very useful for training, but it's still playing.
Nothing wrong with grown ups having toys, nothing wrong with people taking their 'play' seriously, but I think it is important to recognise that it is, really, just playing.

Edit: ...I've been playing at it for 30 years and I know my toys are better than yours...  3

I use my bike to commute (virtually exclusively these days). I don't regard a form of transport as a 'toy'. Bike are highly functional, so this is just a silly thing to say. I think your argument about various gadgets being classed as 'toys' may hold more truth.

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crikey | 8 years ago
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Quote:

This is no pro-wannabe toy

Unless you are a pro, or are going to be one, that's exactly what it is. Nothing wrong with measuring power, nothing wrong with this tool to do so, but if you aren't being paid to ride it's a toy.

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fukawitribe replied to crikey | 8 years ago
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crikey wrote:

Nothing wrong with measuring power ... but if you aren't being paid to ride it's a toy.

No, it's a tool. It's hardly necessary for a lot of non-professionals but I think it's widely accepted that power measurement can be very useful for training purposes at many levels.

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slam that stem | 8 years ago
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I like the tech and anslysis driven approach. This is no pro-wannabe toy.

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pablo | 8 years ago
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Just picked up a quarq elsa r for £750 after some cash back. Ok you have to add rings (which I already have) but this looks expensive. The only advantage I can see is balance but the elsa does estimate balance. I'm normally +-2% which matches what I've seen on a computrainer. Weight was 560g + 150g for fsa rings.

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