The Best Power Meters for Triathlon

Triathlon makes one demand of a power meter that road cycling does not: the number has to mean the same thing in the aero position on race day as it did in the saddle on the trainer in February, on a different bike, months apart. The cleanest way to satisfy that is to own one instrument and move it, which is exactly what a pedal meter lets you do. Unbolt it from the trainer bike, bolt it to the tri bike, tell the head unit the crank length, go.

Dual-sided matters more here than almost anywhere else. Dropping into aero shifts your hip angle and your pelvis, and riders who are balanced upright are often not balanced on the extensions. A single-sided meter doubles one leg and cannot see that; the Assioma Duo measures both. It claims ±1%, weighs 151.5 g per pedal, and is IP67 rated. Our Assioma Duo review covers it in full, and Assioma Duo vs Uno is the one-side-or-two decision in detail.

Everything the Assioma Duo does well, the Pro RS-2 does with a better battery and a lower stack. Favero quotes up to 160 hours and a 15-minute fast charge, which is the single specification on this page that is genuinely a long-course feature: a full-distance bike leg plus the taper week plus a travel day without thinking about it, and a usable top-up in the time it takes to rack a bike. The pedal is 124.8 g with a 10.5 mm stack, a 54 mm-class Q-factor addition, and it measures 0 to 3,000 W across 10 to 250 rpm.

The honest caveats are the ones Favero itself publishes. Over Bluetooth the RS-2 sends power, cadence and balance; the fuller metric set wants ANT+ or Favero's app. The battery is sealed and the charger is proprietary. And the fitting rules are strict — no extenders, no crank shorteners, and the spindle has to protrude at least 1 mm past the crank thread, which rules out cranks thicker than 15 mm there. Independent reviewers have reported it tracking within a few watts of trainers and crank meters; our Assioma Pro RS review collects those findings with their sources.

For a triathlete, ecosystem is not a trivial consideration. If your run, swim and bike data already flow into a Garmin watch and your race-day head unit is an Edge, a Rally pedal removes a category of race-morning risk — nothing new to pair, nothing to translate between apps, data fields you have already laid out. Add up to 90 rechargeable hours and SPD-SL cleats and it is a very easy product to live with.

Installation is where to be careful. Garmin's manual is specific: right pedal first, a thin layer of grease on the spindle, tighten to 25 ft-lb (34 Nm) with a torque wrench or as tight as possible with a pedal wrench, then rotate the crank and check chain clearance. If the chain rubs you may add one washer per pedal, and Garmin explicitly warns against more than one. Our Rally RS210 review covers the whole range, and Assioma vs Garmin Rally is the head-to-head.

There is a legitimate triathlon argument against pedal meters: a tri bike's pedals get mounted with shoes already clipped in, thrown about in transition, and occasionally dropped. A spider meter puts the electronics in the middle of the bike instead, and leaves the pedal choice completely open — which matters if you have settled on Speedplay, or on a pedal chosen for stack height rather than for having a strain gauge in it.

SRAM claims ±1.5% here rather than ±1%, and reports total power with an estimated balance rather than a true per-leg measurement. In exchange you get MagicZero, which recalibrates on its own, OmniCal, which lets you change chainrings without recalibrating, and a CR2032 good for around 200 hours. The limit is fitment: this is a SRAM AXS part and it stays on the bike it fits. Our Quarq power meter review covers the range.

If the budget is the binding constraint, the Uno is the honest answer rather than a compromise. It is the same pedal platform, the same ±1% claim on the leg it measures, the same rechargeable battery and the same portability, for considerably less. For pacing a bike leg and for training to an FTP figure, a consistent doubled-left number does the job.

The caveat is specific to this page. The strongest reason a triathlete wants dual-sided is to see whether the aero position changes how the legs share the load — and that is exactly the measurement the Uno cannot make. If you later decide you want it, Favero sells the right-hand sensor pedal and the Uno becomes a Duo, which is the cleanest upgrade path in the category. The best budget power meters puts it against the cheaper alternatives.