Pedal PMs and mud

power-meter

#1

I have a gravel-trail-road bike and a triathlon bike. I want power on both without buying two power meters. Naturally I am gravitating to pedal based power meters but I would like to know if anyone has experience on the trails with the mud and dirt?


#2

Most, if not all pedal based power meters will use a road style cleat, so if you were hoping to use SPD cleats and MTB/CX-style shoes on those muddy days, you’d be out of luck. I don’t have any experience using a pedal based PM in those conditions, but what I’d worry most about is the seal for the battery and any associated electronics. I’m not sure what pedals you’re looking at, but I’d look to make sure they’re waterproof to some extent.


#3

Yeah. I am comfortable enough with road pedals in a muddy trail environment. I don’t really CX race. So performance from that perspective I’m ok with. I just wonder if PowerTap/Vectors/Assioma can handle the rigors of the trail.


#4

I’ve toyed with the idea of taking a road shoe and pedal setup for PM and bodging it into a “off-road” shoe with some lugs at the toe, mid and heal.

That, or take a MTB shoe and modding it to clear space for and drill holes for mounting a 3-bolt cleat. Probably not worth the effort, but an interesting possibility.


#5

I’ve gone the other way and ride spds everywhere including the road bike.


#6

No chance at a pedal based PM with SPD’s though.


#7

I know, but i can swap the crank arm between my road and gravel bike.

To be honest, as long as I don’t mind the look I could stick a 105 crank arm on an XT crank for my mtb


#8

That assumes the same crank length, which may or may not be common. A lot of mid sized road bikes use a 172.5mm crank while a similarly sized MTB is often 175mm (or sometimes 170mm).

MTB cranks don’t generally offer a 172.5mm length, and that means one of the most common road crank lengths isn’t appropriate for many MTB uses.


#9

I would not use a road shoe/cleat combination in a gravel setting. There is too great a chance that you may be off the bike and on foot several times or maybe even an extended portion of time due to conditions of the terrain or do to mechanical issues. You would be in a world of foot pain if you were in road shoes in such a situation. Unfortunately there doesn’t seem to be many options for transferring power meters between bikes meant for certain types of terrain. Pedals would be the worst.


#10

Yeah and that also assumes compatible spindles… Funny enough this is why I am posting haha. So I had a 4iiii left -side PM (Dec 2016) and it worked great. So when I bought a CX/Gravel bike I also purchased 105 crankset because FSA isn’t compatible. The obviously 2 months later my PM goes belly up. I’m “working” with 4iiii right now to try and get things right (my problem is the dreaded unstable power problem that seems to be the most common 4iiii issue). But if things aren’t made whole again you can be assured I will not be buying or endorsing 4iiii.

Anyways… long story short… I want a PM but I also want to limit the compatibility issues. But it needs to be robust. Can’t afford to drop 600+ (CAD) every 2 years on a new PM. :rofl::rofl::rofl:


#11

The hacking road cleats into MTB shoe sounds very interesting for this kind of problem. But if that ever happened and I was really really really stuck I would just remove the cleats off my shoes.

I definitely see your point but for my purpose this wouldn’t be an issue.


#12

This is true, and also manufacturer. But it’s far easier to get the right length crank across bikes by a bit of judicious eBay work than to buy multiple PMs, in my experience,


#13

Would like to know this as well. Some cx on easy trails with my gravel bike with big 650b tires. Can my Assioma’s handle the dirt…


#14

Roadie, so less experience with the dirt. I suspect your answer is that mag-coupled rechargeable batteries, like the Assiomas, are easier to seal than a replaceable battery. You might want to wash the pedals after gunking them up to avoid charging contact corrosion.

The following n=1 anecdotes might be helpful

Bought a pair of Assiomas in April 2018. In late April 2018, crashed on a turn that didn’t look that sharp until I was in it (doing 25mph). My arm, leg, butt and the drive side pedal took the brunt of the crash. The pedal body was ground flush against the retaining bolt head. Pedals continued to work fine until, eventually, the remaining fragment of tab holding the metal tab in failed. Replaced the pedal body at that point.

Before replacing the pedal body, they got hit with heavy splash from a 15 ft long puddle almost to the bottom bracket on a paved bike path–coming and going. No ill effects–in fact, they were probably cleaner after. :slight_smile: