Power Meters
The Best Power Meters for SRAM Bikes
Rival, Force and Red AXS give you three in-family ways to measure power and two published tolerances that are very different from each other. Here is what fits a SRAM bike, ranked on the specifications the makers actually publish.
The short answer
Quick picks
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  SRAM Red / Force AXS Power Meter Spider The in-family pick for a SRAM AXS bike: true total power at ±1.5%, automatic zeroing and chainring changes without recalibration. | Best for a SRAM AXS bike overall | 8.68.6 out of 10 | $436.93 · View on Amazon #ad We may earn a commission · Price as of October 21, 2026 |
| 2 |  Favero Assioma Duo The answer when the SRAM compatibility question is the thing you want to avoid entirely — and the most accurate claim here. | Best if you want real per-leg data and portability | 9.09.0 out of 10 | $539.93 · View on Amazon #ad We may earn a commission · Price as of October 21, 2026 |
| 3 |  SRAM Rival AXS Power Meter Crankset Good value and well protected, as long as your bike is SRAM DUB 12-speed and you accept a ±3% total figure. | Cheapest complete-crankset route on SRAM DUB | 7.87.8 out of 10 | $385.00 · View on Amazon #ad We may earn a commission · Price as of October 21, 2026 |
| 4 |  4iiii Precision 3+ The third-party crank-arm route: a tighter accuracy claim than SRAM's single-sided meters, if your exact crank is supported. | Cheapest credible power that keeps your crankset | 8.48.4 out of 10 | $437.49 · View on Amazon #ad We may earn a commission · Price as of October 21, 2026 |
| 5 |  SRAM Rival Power Meter Spindle The budget in-family option: left arm plus power spindle on a DUB crankset, with an accuracy figure SRAM does not publish accessibly. | Cheapest in-family upgrade if you keep your crank | 7.57.5 out of 10 | $195.00 · View on Amazon #ad We may earn a commission · Price as of October 21, 2026 |
There are two ways to shop for a power meter on a SRAM bike, and most people only consider one of them. The first is to stay in the family: SRAM sells the measurement as a spider, as a spindle, and as a complete crankset, all built around the DUB interface. The second is to buy a meter that has no relationship with your drivetrain whatsoever — which is what a pedal meter is, and what a bonded crank arm half is.
The reason this matters is that the published tolerances are not close to each other. Inside SRAM's own range the gap between the spider and the Rival crankset is ±1.5% against ±3% total, and a pedal meter claims ±1%. That spread is wider than the difference between any two trainers in our smart trainer rankings, and it is the first thing to settle.
What SRAM actually publishes
The Red / Force AXS spider measures total power — both legs through one sensor — and SRAM publishes ±1.5%. It reports an estimated balance rather than a measured one, which is an honest distinction worth knowing if left/right data is why you are buying.
The Rival AXS crankset measures in the spindle, on one leg, and doubles it. SRAM states ±1.5% for the measurement and ±3% for the total figure. Both numbers are correct; the one that describes your power file is ±3%.
The Rival power meter spindleis the same single-sided architecture as a separate part, and we could not verify a published accuracy figure for it in an accessible spec sheet. Rather than infer one, we record it as unpublished and treat the Rival platform's single-sided behavior as the guide.
Two features on the spider are specific enough to be worth naming. MagicZero recalibrates the meter automatically, which quietly removes the habit most riders forget. OmniCal means a chainring change does not require recalibration — useful because a spider measures through the chainring interface, so it is the one format where swapping rings would otherwise matter.
| Power meter | Type | Fitment | Sided | Claimed accuracy | Battery |
|---|---|---|---|---|---|
| SRAM Red / Force AXS spider | Spider | SRAM AXS cranks | Total power, estimated balance | ±1.5% | CR2032, around 200 h |
| Favero Assioma Duo | Pedal | Any pedal thread | Dual-sided, measured | ±1% | Rechargeable, magnetic |
| SRAM Rival AXS crankset | Crankset, spindle-based | SRAM DUB 12-speed | Single (left), doubled | ±3% total (±1.5% measured) | Coin cell |
| 4iiii Precision 3+ | Bonded crank arm | Must match your crankset and length | Single (left), doubled | ±1% of measured torque | CR2032, up to 800 h |
| SRAM Rival power spindle | Left arm with power spindle | SRAM DUB cranksets | Single (left), doubled | Not published accessibly | Coin cell |
Rival, Force or Red: does the groupset tier change the answer?
Less than you would think. The spider is a Red and Force part, so on a Rival AXS bike it is not a straight bolt-on — that is the real reason the Rival crankset and spindle exist. Going the other way, a Red or Force bike can take any of these, including the pedals, so the tier question collapses into a budget question.
What the tier does change is whether replacing the crankset makes sense. Buying the Rival power meter crankset for a bike that already has a perfectly good Rival crankset means paying for chainrings and arms you already own in order to acquire one sensor. On that bike, the spindle or a bonded 4iiii arm is usually the better-value route to the same number.
1x, DUB and chainring changes
DUB is the fitment rule that matters. The Rival crankset is DUB 12-speed and nothing else; the spindle fits DUB cranksets; the spider must match your AXS crank. The two drivetrain-agnostic options skip all of this.
If you run 1x and change rings,the spider is the format designed for it, thanks to OmniCal. Pedal meters, bonded arms and spindle meters are unaffected by a chainring change in the first place, so this is a point in the spider's favor rather than a strike against the others.
If your gravel bike is also your trainer bike, read best power meters for gravel bikes alongside this page — the cleat argument there changes the shortlist, and three of these five picks appear on it. If your other bike is Shimano, our best power meters for Shimano bikes page is the same exercise from the other side.
Then make the number trustworthy
Whichever you buy, the install torque and the zero-offset habit do more for your data quality than the last half-percent of tolerance. How to install a power meter covers the fitting, including why spider and complete-crankset installs are a reasonable thing to hand to a shop, and how to calibrate a power meter is the two-minute routine that keeps it honest. If you are also riding indoors, expect your trainer and your meter to disagree by a few percent — how accurate are power meters explains why that is normal.
Not sure the drivetrain should decide it?
See the full power meter rankingsThe full reviews
Every pick, in detail
#1 · Best for a SRAM AXS bike overall
SRAM Red / Force AXS Power Meter Spider
8.68.6 out of 10#ad We may earn a commission · Price as of October 21, 2026
The in-family pick for a SRAM AXS bike: true total power at ±1.5%, automatic zeroing and chainring changes without recalibration.
- Type
- Spider-based, total power
- Claimed accuracy
- ±1.5%
- Battery
- CR2032, around 200 hours
- Calibration
- MagicZero automatic recalibration
- Chainrings
- OmniCal — swap rings without recalibrating
- Connectivity
- ANT+, Bluetooth
What we'd praise
- Measures total power at the spider rather than doubling one leg, which is the tightest published tolerance of the three SRAM options here
- MagicZero recalibrates on its own, so a cold start in a garage is not a calibration task
- OmniCal lets you change chainrings without recalibrating the meter
- Around 200 hours on a CR2032, so nothing to charge
- Your pedal and cleat choice stays entirely yours
What we'd flag
- Reports an estimated balance rather than a true per-leg measurement
- Fits SRAM AXS cranks only, and the spider has to match your crank
- Stays on the bike it fits, so it does not move to a second bike or a trainer bike
- A spider swap is a more involved install than a pedal
If your bike is SRAM AXS and you want the measurement inside the drivetrain rather than out on a pedal, this is the one to buy. It measures total power at the spider — both legs passing through one sensor — and SRAM publishes ±1.5%, which is tighter than either of the single-sided SRAM options below. Two features that read like marketing are genuinely useful: MagicZero recalibrates automatically, which removes the one maintenance habit riders forget, and OmniCal lets you fit a different chainring without recalibrating.
The trade-offs are fitment and portability. The spider has to match your AXS crank, and once installed it stays on that bike. If your road bike and your trainer bike are two different frames, a pedal meter is the better architecture. Our Quarq power meter reviewcovers SRAM's spider platform in more detail.
#2 · Best if you want real per-leg data and portability
Favero Assioma Duo
9.09.0 out of 10#ad We may earn a commission · Price as of October 21, 2026
The answer when the SRAM compatibility question is the thing you want to avoid entirely — and the most accurate claim here.
- Type
- Dual-sided power meter pedals
- Claimed accuracy
- ±1%
- Cleat system
- Look Keo compatible
- Power
- Rechargeable, magnetic charging
- Connectivity
- Bluetooth and ANT+
- Install time
- Minutes, with a pedal wrench
What we'd praise
- Does not care that your bike is SRAM — a pedal thread is a pedal thread, AXS or not
- Dual-sided ±1% with a real measured left/right balance rather than an estimate
- Moves to a second bike, including a dedicated trainer bike, in minutes
- Tighter published tolerance than any SRAM option on this page
What we'd flag
- Look Keo cleats, so SPD-SL riders need new shoes or new pedals
- Rechargeable, not coin cell
- The electronics sit out on the pedal where a crash or a rock strike finds them
This page exists because SRAM owners assume they need a SRAM power meter. They do not. Two of the five picks here have no relationship with your drivetrain at all, and the Assioma Duo is the better of them: dual-sided ±1%, a measured balance rather than an estimated one, and a five-minute fit with a pedal wrench.
For a rider with more than one bike — a road bike and a winter trainer bike, say — the portability argument usually wins outright, because a crank, spindle or spider meter cannot follow you. Power meter pedals vs cranks is the format argument on its own, and our Assioma Duo review covers the product.
#3 · Cheapest complete-crankset route on SRAM DUB
SRAM Rival AXS Power Meter Crankset
7.87.8 out of 10#ad We may earn a commission · Price as of October 21, 2026
Good value and well protected, as long as your bike is SRAM DUB 12-speed and you accept a ±3% total figure.
- Type
- Spindle-based, left leg doubled
- Claimed accuracy
- ±3% total (±1.5% measurement, doubled)
- Battery
- Coin cell
- Fitment
- SRAM DUB, 12-speed
- Sold as
- Complete crankset
- Connectivity
- ANT+, Bluetooth
What we'd praise
- Comes as a complete crankset, so there is no crank-arm part number to match
- Electronics live in the bottom bracket area rather than out on a pedal
- Coin cell, so nothing to charge
- The cheapest way to put power on a Rival AXS bike without touching your pedals
What we'd flag
- SRAM states ±3% for the total figure, because the ±1.5% measurement is doubled from one leg — the widest tolerance on this page
- SRAM DUB 12-speed only
- No true left/right balance
- Replacing a working crankset to add a sensor is a lot of parts for one number
SRAM's AXS groupsets are everywhere, and the Rival power meter crankset is the cheap way to add power to one. The measurement is in the spindle and it arrives as a complete crankset, so there is no arm-matching exercise and nothing bonded to the outside of an arm. For a rider who does not want to change pedals, the position of the electronics is a real advantage.
Be clear about the accuracy claim, because it is the single most misquoted number in this category: SRAM specifies ±1.5% for the measurement it takes and ±3% for the total, because the total is one leg doubled. That is the honest figure to plan around. Single vs dual-sided power meters explains what doubling does and does not cost you.
#4 · Cheapest credible power that keeps your crankset
4iiii Precision 3+
8.48.4 out of 10#ad We may earn a commission · Price as of October 21, 2026
The third-party crank-arm route: a tighter accuracy claim than SRAM's single-sided meters, if your exact crank is supported.
- Type
- Non-drive-side crank arm
- Claimed accuracy
- ±1%
- Battery
- CR2032, up to 800 hours claimed
- Weight added
- 9 g
- Power range
- 0 - 4,000 W
- Connectivity
- ANT+ and Bluetooth Smart
What we'd praise
- ±1% claimed for the torque it measures, which is tighter than SRAM's single-sided figure
- Up to 800 claimed hours on a CR2032
- Adds 9 g and sits inside the crank arm
- 4iiii supports SRAM arms as well as Shimano, so your groupset is not a dead end
What we'd flag
- Must be the correct arm for your exact crankset and crank length
- Single-sided and doubled, with no balance data
- Bonded to that crankset, so it does not follow you to another bike
- Not every SRAM crank is on the supported list — check before ordering
4iiii bonds a strain gauge to the inside of a non-drive-side arm, adds 9 g, measures 0 to 4,000 W and claims up to 800 hours on a coin cell — and it supports SRAM cranksets as well as Shimano ones, which makes it a genuine alternative to SRAM's own parts rather than a Shimano-only option.
The compatibility exercise is the entire job: you order the arm that matches your crankset model and your crank length. Get that right and installation is around ten minutes with a hex key and a torque wrench. Note the claim carefully — ±1% applies to the torque it measures on the left leg, not to your total, which is that figure doubled. Our 4iiii Precision review goes through what that means in practice.
#5 · Cheapest in-family upgrade if you keep your crank
SRAM Rival Power Meter Spindle
7.57.5 out of 10#ad We may earn a commission · Price as of October 21, 2026
The budget in-family option: left arm plus power spindle on a DUB crankset, with an accuracy figure SRAM does not publish accessibly.
- Type
- Left crank arm with power meter spindle
- Interface
- DUB spindle
- Crank length
- 165 mm as listed
- Measurement
- Single-sided, doubled
- Fit
- SRAM DUB cranksets
- Published tolerance
- Not verifiable in an accessible spec sheet
What we'd praise
- The lowest-cost route to power on a SRAM DUB bike of anything on this page
- Keeps your existing drive-side crank and chainrings
- Coin-cell powered like the rest of SRAM's crank-based range
- Pedals, cleats and shoes are untouched
What we'd flag
- SRAM does not publish an accuracy figure for this part in a spec sheet we can verify, so treat it as the Rival platform's single-sided tolerance
- Single-sided and doubled, with no balance data
- Crank length is fixed by the part you order — 165 mm on the current listing
- DUB cranksets only
This is the smallest, cheapest SRAM part that turns a DUB crankset into a power meter: a left crank arm with the measurement in the spindle, swapped in where your existing non-drive arm was. If the goal is power on a SRAM bike for the least money, nothing else here comes close.
Two honest caveats. First, we could not find a published accuracy figure for this specific part in an accessible Shimano-style spec sheet, so rather than invent one we record it as unverified and point you at the Rival platform's single-sided behavior: ±1.5% on the leg it reads, doubled. Second, crank length is whatever the listing says — 165 mm at the time of writing — and crank length is a fit decision, not a shopping convenience. Best crank power meters puts it against the alternatives.
Good questions
Frequently asked questions
What is the best power meter for a SRAM bike?
For a Red or Force AXS bike, the SRAM Red / Force AXS power meter spider: it measures total power at a published plus/minus 1.5%, recalibrates itself with MagicZero and allows chainring changes without recalibration. If you want the tightest accuracy claim and the ability to move the meter between bikes, the Favero Assioma Duo claims plus/minus 1% dual-sided and fits any pedal thread regardless of drivetrain.
Do I need a SRAM power meter if I have a SRAM groupset?
No. A pedal-based meter such as the Favero Assioma Duo has no relationship with your drivetrain at all, and a bonded crank-arm meter such as the 4iiii Precision 3+ only needs to match your crank arm, not your groupset tier. SRAM's own meters are the right answer when you want the measurement inside the drivetrain and are happy for it to stay on that bike.
How accurate is the SRAM Rival AXS power meter?
SRAM specifies plus/minus 1.5% for the measurement it takes and plus/minus 3% for the total power figure, because the total is the left leg doubled rather than both legs measured. The plus/minus 3% number is the one that describes the power file you actually ride to, and it is the widest published tolerance among the options on this page.
Will a SRAM power meter spider fit a Rival AXS crank?
The AXS power meter spider is a Red and Force part, so it is not a straight bolt-on for a Rival crank. That is precisely why SRAM sells the Rival power meter crankset and the Rival power meter spindle: they are the Rival-tier routes to the same data, at a wider published tolerance.
What does OmniCal do?
OmniCal lets you change chainrings on a SRAM spider-based power meter without recalibrating it. It matters because a spider measures power through the chainring interface, so on that format a ring change would otherwise affect the calibration. Pedal, bonded crank-arm and spindle meters are unaffected by chainring changes to begin with.
Is the SRAM Rival power meter spindle accurate?
SRAM does not publish an accuracy figure for that specific part in a spec sheet we were able to verify, so we record it as unpublished rather than infer a number. Architecturally it is the same single-sided, doubled measurement as the Rival AXS crankset, so the crankset's published figures are the closest honest guide: plus/minus 1.5% measured, plus/minus 3% total.
Can I move a SRAM power meter to another bike?
Only to another bike that takes the same part. A spider has to match an AXS crank, and a spindle or crankset has to match a DUB bottom bracket, so in practice these meters stay where they are fitted. If you have a road bike and a separate trainer bike, a pedal meter is the format that transfers in minutes with a pedal wrench.
How we sourced this
- SRAM — road power meters range and specifications (manufacturer)
- SRAM / Quarq — AXS power meter spider specifications, MagicZero and OmniCal (manufacturer)
- SRAM Rival AXS power meter: hands-on and first rides (DC Rainmaker)
- 4iiii — PRECISION 3+ powermeter specifications (manufacturer)
- 4iiii — complete guide to the PRECISION 3+ powermeter (manufacturer)
- Favero — Assioma DUO specifications (manufacturer)
- Favero — Assioma road range: DUO, UNO and DUO-Shi (manufacturer)
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