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Added a SRAM AXS power meter to my Force groupset

SRAM AXS Force Power Meter Spider

Should I buy a power meter? It’s one of those questions that has been discussed amongst friends, within clubs and across internet forums for decades. The experts will tell you that you’ll see bigger gains if you train by power. All the pros use power meters, at least in training if not also in races. You can more easily regulate your efforts with the use of power data, to ensure that you don’t blow up before the top of that long climb or before the final run in of your race. Of course all of this just explains the usefulness of power meters but doesn’t answer the question of ‘should I buy one?’ as that question surely boils down to individual choice.

For my SRAM AXS Force groupset there is a power meter spider available as an add-on and it’s something that I always had in mind when I bought the groupset in the first place. And I’m the type of person who likes to look through his data post ride. Also I have never had a power meter in the past either so it’s a new experience for me; maybe that’s part of the answer to my original question – maybe everyone should have one at least once? Anyway, I had in mind the idea of getting the spider version for my groupset and so when I saw that it was available from a the reduced price, I decided to take the plunge.

SRAM AXS Power Meter Fitted
SRAM AXS Power Meter Fitted

Fitting is very simple as long as you have the correct tools. It requires a torque wrench and you will need to make sure that you have the right Torx bits for the wrench. Also the wrench will need to be able to regulate the torque down to 4Nm, as that is what the spider bolts should be set to. My Topeak D-Torq DX wrench has an advertised range from 4 up to 80 Nm, fortunately it will start showing a reading on the display from 3 Nm upwards. This is useful as you can see it approach the necessary set value of 4 Nm as you apply force, it then audibly beeps when you reach your set value. The fitting of the power meter just needs you to remove the crankset (one bolt), remove the chainring(s) (4 bolts), and remove the spider (8 bolts). Then fit the new power meter spider (4 Nm, T20 bit), the chainring (12 Nm, T30 bit) and the crankset back onto the bike (54 Nm). I have a single chainring as I ride 1x however even if you ride 2x I understand that the chainrings come as a one piece fitting.

Topeak D-Torq Wrench DX
My Topeak D-Torq Wrench DX

Once fitted just remove the piece of tape from the battery compartment, sync up your cycle computer or phone appropriately and go ride. It’s self calibrating, so there’s no need to fiddle with any settings and although you can add it to your bike in the AXS phone app it is not a requirement. Firmware is updated via the app should you want/need to. And so now it’s just a case of going for some rides and seeing what power you can produce! Of course if you’re planning on using power for training, you’ll want to set some zones in your training software and on your cycle computer. And to set your zones you’ll want to doing an FTP test. I’m not going to go into the ins and outs of FTP tests and power training here; there are plenty of online resources for that if you want to swat up. Just that if you plan to do an FTP test outdoors on the road, you really want to choose a quiet time of a quiet day like an early Sunday morning and also find a piece of road that you can ride hard along and keep going for 30 minutes. So something with very few junctions to navigate ideally. You also want to avoid any downhills as keeping the power output high while travelling downhill is near to impossible.

If you’ve already been training by heartrate with an app or website then you may also need to make some allowance for the training effect data to change over from heartrate only to power & heartrate. It may be that your app suddenly thinks you’re now riding much stronger than you have been or the opposite. My FTP test resulted in a score of 214 Watts, which I think is pretty average for a recreational rider like myself and of my age and weight. In watts per kilo it comes out at around 3.3 W/Kg.

Example data from an intervals session
Example data from an intervals session

So far I’ve been perfectly happy with the power meter. It’s never missed a beat, hasn’t needed a new battery and hasn’t needed any re-sync with the Garmin computer or anything like that. It automatically turns itself on as I wheel my bike out of the garage and is very much a ‘fit and forget’ item from the bike side of things. It allows you to then focus on interpreting the data, setting up a dynamic training schedule in response to the data and just generally enjoying knowing how powerful you are! And hopefully track your progress upwards!

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