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JetBlack WhisperDrive Smart vs Tacx Flux S Smart

Quick answer

Both the JetBlack WhisperDrive Smart and the Tacx Flux S Smart are direct-drive trainers that accept the common road and MTB axles. The JetBlack WhisperDrive Smart (2500 W, ±5%, $1099) offers Shimano/SRAM HG (HyperGlide), Campagnolo and SRAM XD Driver Body; the Tacx Flux S Smart (1500 W, ±3%, $749) offers Shimano/SRAM HG (HyperGlide), SRAM XD Driver Body, SRAM XDR Driver Body and Campagnolo. Use the checker below to see which fits your exact bike.

Specs side by side

JetBlack WhisperDrive SmartTacx Flux S Smart
Drive typeDirect driveDirect drive
Factory model code—T2900S
Axle standards130 mm quick-release, 135 mm quick-release, 12 × 142 mm thru-axle and 12 × 148 mm Boost thru-axle130 mm quick-release, 135 mm quick-release, 12 × 142 mm thru-axle and 12 × 148 mm Boost thru-axle
Thru-axle adapterIncludedSold separately
Freehub (in box)Shimano/SRAM HG (HyperGlide)Shimano/SRAM HG (HyperGlide)
Freehub optionsShimano/SRAM HG (HyperGlide), Campagnolo and SRAM XD Driver BodyShimano/SRAM HG (HyperGlide), SRAM XD Driver Body, SRAM XDR Driver Body and Campagnolo
CassetteSold separatelySold separately
Max cassette speed12-speed12-speed
Virtual shiftingNoNo
ProtocolsANT+PLUS, ANT+FEC, BLUETOOTHANT+PLUS, ANT+FEC, BLUETOOTH
Power accuracy±5%±3%
Max power2500 W1500 W
Max gradient16%10%
Flywheel6.5 kg6.7 kg
MSRP$1099$749
StatusDiscontinuedCurrent

Which fits your bike — JetBlack WhisperDrive Smart or Tacx Flux S Smart?

29Drops straight in3Fits with parts1Not supported

Frequently asked questions

Both accept the same common road and MTB axles, so the deciding factor is the freehub for your cassette: the JetBlack WhisperDrive Smart offers Shimano/SRAM HG (HyperGlide), Campagnolo and SRAM XD Driver Body, while the Tacx Flux S Smart offers Shimano/SRAM HG (HyperGlide), SRAM XD Driver Body, SRAM XDR Driver Body and Campagnolo. Run your drivetrain through the checker to see which is a clean drop-in.