Assioma power meter SPD pedal hack

I’ve been running an Assioma pedal based power meter on my road bike for a while. Although I am at best a moderate cyclist, it has been fun to collect stats on my output power so that I can tell after a ride how hard I was working, as opposed to how hard I felt I was working. I have the single sided version that is a pretty good value.

About three weeks ago I was having problems getting clipped on on my right shoe, and after doing a post ride inspection of the cleat, it was obvious that the flange on the toe side of the cleat had completely worn off.

Here is the left cleat as a comparison.

In retrospect, it made sense that the right cleat would wear faster since it was always the one that I unclipped while rolling to a stop.

At the same time, I was wishing for some SPD pedals since they would be more compatible with shoes that were walkable. However, I wasn’t about to drop $1.2K USD for a pair of the only SPD power meter pedals available.

Through the magic of Google, I found out that a very clever person had noticed that the Assioma pedals seemed to have the same axles as SPD pedals from Xpedo, and that it was possible to swap out pedal bodies between the Assoima, and the Xpedo M force 4.

Of course, since this was discovered, it became difficult to get the M force 4.

There are now several videos showing how to do the pedal swap, and that it was possible to do it with the Xpedo CXR pedal as well.

After getting a pair of the CXR pedals, I did the swap myself about a week ago. Here is the starting point.

You’ll need a 6 mm Allen, and a 9 mm socket. Also a 8 mm Allen to remove the Assioma pedal from the crank.

Here are the two left pedals disassembled. It’s important to keep track of which nut and end cap goes with which body as they are slightly different.

You’ll also see that the two axles are quite different. In particular, the spd pedals have an o ring seal on the inboard side, and the lengths are not the same as well. However, what is important is that the location and the inner diameters of the pedal bearing is the same.

Re assembly was a snap. One thing that was not mentioned in any of the videos is that after tightening the fixing nut, there was still a little side to side play in the pedal. However, this went away when I reinstalled the end cap. I’ll have to keep an eye on this, and also on the inboard side which is not sealed the way it was with the original axle/pedal combination. I don’t know if this is because I used the CXR pedal rather than the M Force 4.

One other point: depending on the shape of your shoe, you might have to grind away a little of the sole to clear the body of the powermeter, which is on the inboard side. In my case, the shoe did clear, but I wanted it not to touch even when twisting out of the cleat so I did a little work with the dremel.

This is what the finished product looks like.

So far, everything is working, and it is great to be back with double sided spd pedals that are easier to get in and out of since I do a fair amount of riding on city streets.

Word is that Assioma and other vendors are working on their own SPD power meter pedals, so it might be prudent to wait. In my case, this hack let me avoid buying another set of power meter pedals.

Update December 28, 2020. I’ve had absolutely no issues with the converted pedals, after having logged almost 3000 km on them. Also, as of this date, the SRM SPD pedals are still “coming soon” although it looks like “prototype units” are being sent out to reviewers.

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