SRM PM9 8-Bolt Spider

The SRM PM9 8-Bolt Spider is a power meter spider built around the universal 8-bolt interface, giving riders a way to add SRM's power measurement to a crankset they already own rather than buying a full crank replacement. It bolts directly onto 8-bolt crank arms from SRAM, Cane Creek, and Moots, and pairs with 110/110mm 4-bolt chainrings from groupsets including Shimano Dura-Ace, Ultegra, 105, and GRX, as well as SRAM Rival, Force, and RED eTap AXS. Chainrings are sold separately, so this spider is the power meter itself, not a complete crankset.

Inside, it runs SRM's PM9 platform, the company's current generation of power meter electronics. SRM claims accuracy within ±1%, and the PM9 architecture adds magnetless cadence sensing along with cycling dynamics data — combined pedal smoothness and left/right power balance — for riders who want more than a single wattage number. Connectivity covers both ANT+ and Bluetooth, so the spider pairs with head units, smart trainers, and training apps without a bridge or dongle. A rechargeable battery is rated for 100 hours of runtime between charges.

At 112 grams, the spider adds minimal weight to whatever crankset it's mounted on, and SRM backs it with a 2-year warranty. It ships in White, Red, or Yellow to match a range of build colors. At $1,299.00, the PM9 8-Bolt Spider is positioned as an upgrade path for riders already running compatible SRAM, Cane Creek, or Moots crank arms who want SRM's power data without switching crankset brands.