Smart trainer compatibility for 12 and 13-speed drivetrains

Still choosing a trainer? Our smart trainer buying guide covers direct drive against wheel-on, the specs that matter and brand-listed prices. On a wheel-on trainer, see which trainer tire to use.

A direct-drive trainer is a rear hub without a wheel. The cassette goes on the trainer's freehub body. If the freehub does not match your cassette, nothing else matters. Most trainers ship with a Shimano HG-style body, and most 12 and 13-speed trouble starts there.

The details, with sources

• Shimano 12-speed road: Wahoo, Garmin and Elite list it on the standard HG body most trainers ship with, with a 12-speed cassette. Shimano's own pages disagree on whether the 11-speed road freehub takes it (see below).
• SRAM AXS road and XPLR (12 and 13-speed): needs an XDR freehub body on the trainer. Wahoo, Tacx, Elite and Zwift all list one. Some cheaper SRAM PG cassettes fit a standard body instead.
• Campagnolo 13-speed (Ekar and other N3W systems): the hard one. Wahoo says it is not compatible with KICKR, CORE or MOVE. Elite's Campagnolo body excludes Ekar. Garmin has a Tacx N3W body.
• Shimano Micro Spline 12-speed (MTB and some GRX): Wahoo says no body is available. Wahoo lists workarounds.

Why the freehub is the whole question

Wahoo's own summary is the clearest. The cassette on the trainer must match your drivetrain in cog count, smallest and largest cog, and sometimes brand. It also has to fit the freehub body. Using a cassette that does not match your drivetrain "can result in damage to the cassette or other parts of your drivetrain." (Wahoo)

Wahoo also warns about the largest cog. If the biggest cog on the trainer is larger than the one on your bike, "you can damage your drivetrain." (Wahoo) Match the cassette, or at least stay within what your derailleur can take.

SRAM XDR (12 and 13-speed AXS and XPLR)

SRAM says most AXS and eTap AXS cassettes need an XDR driver body. It tells you to check with your trainer maker for an XDR body. (SRAM) The 13-speed RED XPLR XG-1391 cassette (10-46t) is listed as "Compatible with XDR driver body." (SRAM) If you are still choosing a frame for 13-speed XPLR, our UDH and Full Mount gravel frames guide covers what the frame needs.

Elite puts it as a simple rule: if the smallest cog on your SRAM cassette has 10 teeth, you need an XDR body "regardless of the number of speeds." (Elite compatibility PDF)

SRAM's trainer setup page also covers chain length. If you put a different-size cassette on the trainer than on your wheel, you may need to change chain length and chain gap. AXS rear derailleurs are marked MAX 33T, MAX 36T or XPLR (MAX 44T), and no marking means 33T max. (SRAM)

What each trainer brand says

• Wahoo (KICKR v4 and newer, KICKR CORE, KICKR MOVE): Wahoo sells an XDR freehub body separately for SRAM XG and XS cassettes with 11 to 13 cogs, covering AXS and AXS XPLR among others. Wahoo lists SRAM Road AXS and XPLR with XG cassettes as compatible at 12 and 13 speeds with the Wahoo XDR freehub. (Wahoo)
• Wahoo's lower-cost option for 12-speed AXS road bikes with a 44t cassette capacity: a SRAM PG-1231 fits the stock Wahoo body. It starts at 11t, not 10t. (Wahoo) Wahoo lists no stock-body alternative for 13-speed.
• Tacx (Garmin): Garmin says FLUX trainers with the Shimano/SRAM body take any 8 to 12-speed Shimano or SRAM cassette that fits that body. Garmin lists a separate Tacx SRAM XD-R body for Type 1 and Type 2 FLUX trainers. (Garmin FLUX setup) We could not find a Garmin page that states which cog counts the Tacx XD-R body supports. Retailer listings say 11 and 12-speed. We have not repeated that as fact.
• Elite: Elite's XD/XDR freehub fits Drivo, Drivo II, Justo, Justo 2, Avanti, Rivo, Direto, Direto X, Direto XR, Direto XR-T, Suito, Suito-T, Kura, Turno, Zumo, Volano and Turbo Roteo. The product page says "compatible with 12-speed cassette" and not with SX or NX Eagle. (Elite) Elite's 2025 compatibility PDF lists the same body (1014279) for "SRAM XD/XDR 12/13 speed." (Elite PDF) The two Elite documents do not use the same wording about 13-speed. Check with Elite if you run 13.
• Zwift Hub: Zwift says the Hub comes with a Hyperglide freehub body, and you need to change it "if you're using a bike with an SRAM XD or XDR cassette." (Zwift support)

Shimano 12-speed

Road (Hyperglide+): Shimano's own pages disagree on whether these cassettes fit an 11-speed road freehub (see Sources and notes). Our advice, not Shimano's: if your trainer has an 11-speed road HG body, confirm with the trainer maker or your shop before you order. Wahoo lists Shimano HG 12-speed as compatible on the stock body with a 12-speed cassette. (Wahoo) Garmin and Elite also list 12-speed Shimano on their standard bodies. (Garmin, Elite PDF)

Micro Spline (MTB, and GRX 12-speed): Wahoo says Shimano Micro Spline 12-speed is not compatible with KICKR, CORE or MOVE because it "requires an unavailable freehub body." Wahoo lists workarounds that use the stock body (Wahoo):

• A SRAM PG-1210 or PG-1230 11-50t cassette, if your derailleur can take a 50t cog.
• For GRX 12-speed that cannot take 50t: a Shimano 105 12-speed 11-34 (CS-R7101-12) or 11-36 (CS-HG710-12).
• Wahoo notes that Micro Spline and SRAM PG cog spacing differs by 0.1 mm and "shifting/experience may vary."

These are Wahoo's workarounds, not Shimano's. We did not find a Shimano statement approving them.

Which cassette each GRX 12-speed rear derailleur takes, from Shimano's own spec tables, is in our GRX 12-speed compatibility guide.

Campagnolo 13-speed (N3W)

Campagnolo's Ekar 13-speed cassette sits on a freehub body Campagnolo calls N3W. Campagnolo says N3W is 4.4 mm shorter than the classic Campagnolo body. (Campagnolo)

• Wahoo: not compatible. Wahoo lists "13 speed Ekar or Super Record Wireless drivetrains (requires unavailable N3W freehub body)" as incompatible with KICKR, CORE and MOVE. (Wahoo) Wahoo's Campagnolo body covers most 10 to 12-speed cassettes. At 12-speed, the smallest cog must have at least 11 teeth, and 10t Super Record Wireless cassettes do not fit.
• Elite: Elite's Campagnolo body is for 9 to 12-speed cassettes and is "not compatible with 12-speed wireless cassettes and 13-speed Ekar cassettes." (Elite) We found no Elite N3W body.
• Tacx (Garmin): Garmin has a support article titled "Using the Tacx N3W Campagnolo 13 Speed Cassette Body." (Garmin) The page did not render for us, so we cannot quote which Tacx models Garmin lists. Retailers list NEO 2T, NEO 3M, FLUX 2 and FLUX S. Confirm on Garmin's page before buying.
• Zwift Cog: Zwift's product page says the Cog is "compatible with almost any 8-13-speed bike." It also says it does not fit Campagnolo freehub bodies. (Zwift) Wahoo says the Zwift Cog is not compatible with 13-speed Campagnolo Ekar or Super Record Wireless. (Wahoo) Zwift's own FAQ also says the Cog does not work with the Campagnolo N3W 13-speed chain. That FAQ page did not render for us, so we have not quoted it. Treat the Cog as not compatible with Campagnolo 13 unless Zwift tells you otherwise.

If you ride Campagnolo 13, check the trainer before you buy it. It is the combination with the fewest options.

Zwift Cog and virtual shifting

The Zwift Cog is a single sprocket that goes on a Shimano Hyperglide freehub body. Zwift says it is "not compatible with Shimano Micro Spline, SRAM XD/XDR, and Campagnolo freehub bodies." (Zwift) If you already swapped your trainer to an XDR body for SRAM, the Cog needs the HG body back.

Wahoo adds that bikes with SRAM Flattop chains (Red, Force, Rival, Apex AXS, Eagle Transmission) "may experience slightly accelerated wear" on the Cog compared with their outdoor wheel. (Wahoo) Wahoo also says Zwift virtual shifting only works on KICKR v6, CORE v1/2 and MOVE, though the Cog fits every KICKR version.

Before you order a freehub body

1. Read the cassette. Brand, speed count and tooth range are usually stamped on the largest cog. (Elite PDF)
2. Check the smallest cog. On SRAM, 10t means XDR. (Elite PDF)
3. Identify your trainer model and version. Wahoo's table covers KICKR v4 (2018) and newer. Garmin separates FLUX Type 1 and Type 2. Elite lists models by name.
4. Match the largest cog on the trainer to your bike, or stay within your derailleur's max.
5. Check your axle standard. SRAM and Garmin both point to axle adapters as a separate step. (SRAM)

Not sure which speed your groupset is? Our road and gravel groupsets 2026 ladder lists every current tier.

Disclosure: Pedal Brief may earn a commission if you buy through links on this page, at no extra cost to you. This version has no affiliate links. We did not test these setups. Everything below comes from the trainer, drivetrain or cassette maker, linked where it appears. Full disclosures.