The Best Power Meters for Mountain Bikes

Almost every power meter argument on a road bike is a compatibility argument, and on a mountain bike it is worse: suspension linkages, boost spacing, wide-range 12-speed drivetrains and proprietary cranksets between them rule out most crank-based options before you start. A pedal sidesteps the whole conversation, which is why the MX-2 is the pick here.

What makes it a mountain bike product rather than a road product with a different cleat is the geometry. An 11.2 mm stack and a 54 mm Q-factor are unusually low and narrow for an off-road pedal, so you are not being asked to raise your saddle or widen your stance to get the number. The body is hardened aluminum, and the measurement claim is the same ±1% IAV figure Favero publishes across the Assioma line.

The honest caveat is exposure. A pedal on a mountain bike meets rocks, and Favero's quoted runtime of at least 60 hours is the shortest in the family because two sensors draw from two batteries. If you ride rocky trails hard and often, read the crank-based options before you commit.

For training purposes the MX-1 does the same job as the MX-2. You get the same pedal body, the same cleat, the same stack height and the same measurement principle on the leg it reads. What you give up is the second leg, which means no balance figure and no pedaling dynamics.

That trade is easier to accept on a mountain bike than on a road bike, because off-road power is spiky and position-dependent anyway. You are using it to pace a climb, structure intervals and compare efforts, and single-sided data does all three. Our single vs dual-sided explainer goes through what the doubled number actually hides.

The upgrade path is the real argument. Buy the MX-1 now, add the sensing right pedal when you want balance data, and you end up at an MX-2 without having bought a second power meter.

The one real objection to pedal power meters off-road is that pedals get hit. A bonded crank-arm meter answers that objection completely: the strain gauge sits on the inboard face of the non-drive crank, protected by the crank itself, adding 9 g and about 5.5 mm of thickness.

The cost is compatibility. 4iiii bonds its sensor to a specific crank arm, so you are buying a crank, not a sensor, and mountain bike cranksets are the hardest category to match. Check your exact model and length against 4iiii's list before you order, and check clearance: short chainstays, suspension pivots and frame bags all live close to where this sits.

If it fits, it is the lowest-maintenance power meter on this page. A coin cell rated to 800 hours means a battery change roughly once a season, and there is nothing to charge. Our 4iiii Precision review covers the measurement side in detail.

A very large share of current mountain bikes run SRAM DUB cranks, and for those bikes this is the tidiest answer: a complete crankset with the measurement built into the spindle, nothing bonded, nothing exposed and nothing to charge.

Read the accuracy figure carefully, though, because SRAM publishes it honestly and most retailers do not. The measurement tolerance is ±1.5%, but the meter reads one leg and doubles it, so SRAM states ±3% total. That is three times the Favero claim, and on a page where the other picks claim ±1% it is the reason this sits fourth rather than first.

It is still the right pick for a rider who wants power on one bike, already runs DUB, and is not planning to move the meter anywhere. Our best power meters for SRAM bikes page goes through the rest of the SRAM range.

The P505 is here as the price floor for a crankset-based meter that publishes a tolerance at all. ±1.5% is wider than Favero's claim, but it is published, which is more than several cheaper cranksets manage.

It also reports balance and pedaling smoothness, which neither single-sided pick here can, because a complete crankset carries gauges on both arms. For a rider rehabilitating an injury or chasing a known asymmetry, that is worth more than a tenth of a percent of accuracy.

The warning is fitment. This is primarily a road crankset, so chainring interface, crank length and bottom bracket standard all have to be checked against your mountain bike before you order. If any of those does not line up, go back to the pedals — that is the whole reason pedals win off-road.