Garmin Rally RK200 Review: Watts, Balance and the Metrics Nobody Uses

The Garmin Rally RK200 is a pair of Look Keo-compatible pedals with a power meter in each one. Garmin claims ±1% accuracy, both pedals sense independently so left/right balance is measured rather than inferred, they run on replaceable cells for roughly 120 hours, and they transmit over both ANT+ and Bluetooth. They also produce a long list of extra metrics under the heading Advanced Cycling Dynamics.

The specifications are not really in question — this is a mature product from a company that has been building pedal power meters since the original Vector. What is worth a review is the part buyers actually get wrong: deciding which of the numbers it produces should change anything about how you train.

Dual-sensing is the feature you are actually paying for

Strip away everything else and the reason to buy a 200-series Rally over a 100-series or a single-sided crank meter is that both pedals measure. A single-sided meter reads your left leg and doubles it. That is fine for training — imbalance is usually small and stable, so the number moves with your fitness rather than with your asymmetry — but it is an assumption, and there are three cases where the assumption matters.

Injury and rehabilitation. If you are coming back from a knee or hip problem on one side, balance data is the entire point, because it tells you when you have stopped guarding the leg. Bike fit work. A persistent asymmetry can be a saddle height or cleat position issue rather than a strength issue, and you cannot chase it without measuring it. Comparing to other devices. A dual-sided number lines up with a trainer or a spider meter far better than a doubled single-leg estimate does.

If none of those three describe you, be honest about it — the single-sided options in our budget power meters roundup will serve you just as well for less. Our single vs dual-sided guide is the longer version of this argument.

Cycling Dynamics: two useful metrics and a lot of scenery

Garmin bundles a set of pedaling metrics with the dual-sensing pedals, and this is where new owners lose weeks. Here is our honest audit.

Left/right balance — useful. The core reason for dual sensing. Watch it over blocks rather than within a ride, because it moves with fatigue and intensity.

Seated versus standing time — useful. Genuinely actionable for pacing long climbs and for understanding why a hard indoor session felt different from an outdoor one. Also the metric most riders are surprised by.

Power phase and peak power phase — interesting. Where in the stroke your force is applied. Fascinating, and almost impossible to act on without a coach and a fit studio, because deliberately changing your pedal stroke usually makes you slower before it makes you faster, if it ever does.

Platform center offset — interesting, occasionally useful. Where on the pedal your foot presses. A consistently large offset can point at a cleat position worth adjusting, which is a real fix. It is a bike-fit diagnostic, not a training metric.

None of this is a criticism of the product. It is a warning against buying a power meter for the dashboard and then never using the one number that actually drives training, which is your wattage over time. Everything else is optional.

Batteries, and why replaceable cells matter more than they should

Garmin uses replaceable cells rather than a rechargeable pack, quoting around 120 hours. That is genuinely the right call for a power meter, and the reason is behavioral rather than technical: a rechargeable power meter is a thing you can forget to charge, and a flat power meter on the morning of a race is worse than a slightly heavier one.

The practical advice is to change both sides at once, keep spares in your toolbox, and be careful with the battery door seal — it is the part that determines whether water stays out. Cross-thread it or over-tighten it and you have created a problem the electronics never had.

The pedal-strike question

This is the one genuine structural risk of the pedal category and it deserves stating plainly. Your power meter is the part of the bike closest to the ground, on the outside, at the widest point. A crank meter is protected by the crank; a pedal meter is not protected by anything. A hard strike on a curb or a rock can end an expensive pedal in a way it would never end a crank arm.

For road riding on tarmac this is a low-probability event and not a reason to avoid pedals. If your riding includes gravel, technical corners or racing in a bunch where contact happens, weigh it seriously — a crank power meter is the risk-free alternative, at the cost of never moving between bikes.

Living with them indoors

Worth knowing if this is an indoor-first purchase: on a smart traineryour pedals and your trainer will both report power, and they will not agree exactly. That is normal. They measure at different points in the drivetrain — pedals at the source, trainer after the chain — so drivetrain losses alone account for a few percent, before either device's tolerance is considered.

The fix is not to chase the difference but to pick one source and stay with it. Most riders set the power meter as the power source and the trainer as the controllable device, which gives consistent numbers indoors and out. Our accuracy guide explains why repeatability beats absolute agreement, and how to calibrate a power meter covers the zero-offset routine that keeps the pedals honest.

Who should buy it

Buy the RK200 if you already ride Keo cleats and want the most convenient dual-sided power meter available; if you own several bikes and want the meter to follow you; if you have a genuine reason to care about left/right balance. It is a mature, accurate, well-supported product and the installation is trivial.

Skip it if your shoes are SPD-SL — buy the RS200 and keep your cleats. Skip it if you own one bike and do not need balance data, because a crank meter delivers the same training-relevant number for considerably less. And skip the 200 for the 100 if the balance figure is the only thing pushing you up a tier — same accuracy claim, one sensing pedal, less money. The whole field is ranked in best power meter pedals.