The 8-bolt MTB spider for SRAM cranksets is a newer standard from SRAM that is quickly becoming popular. Many manufacturers put SRAM cranks on their mountain bikes and a spider-based power meter is a great way to add power. The SRAM Quarq XX1, SRM SRAM PM9 8-Bolt and Sigeyi AXO SRAM 8-Bolt power meters are feature packed and great options to for your 8-bolt crankset.
Installation is simple and these power meters are accurate, reliable and measure power from both legs. There are also many chainring options for both these power meters, including both round and oval. In addition, they can be used on standard, boost chainlines and super boost bikes.
SRAM Quarq XX1 vs. SRM SRAM PM9 vs Sigeyi AXO SRAM 8-Bolt Comparison Table
|SRAM Quarq XX1||SRM SRAM 8-bolt PM9||Sigeyi AXO SRAM 8-Bolt MTB|
|Power Measurement||Both legs||Both legs||Both legs|
|Chainline Spacing||Standard, Boost, Super Boost||Standard, Boost, Super Boost||Standard, Boost, Super Boost|
|Communication Protocol||ANT+, BLE||ANT+, BLE||ANT+, BLE|
|Claimed Accuracy||+/- 1.5%||+/- 1.0%||+/- 1.0%|
|Active Temperature Compensation||Yes||Yes||No|
|Weight||114 grams||114 grams||84 grams|
|Battery Type||CR2032 Replaceable||Rechargeable||Rechargeable|
|Battery Life||200 hours||100 hours||300 hours|
|Smallest Round Ring||30T||30T||30T|
|Smallest Oval Ring||32T||32T||32T|
|Warranty||2 years||2 years||2 years|
While these three power meters are largely similar, the main key difference is price. While the SRM PM9 8-bolt offers a better claimed accuracy and a rechargeable battery, it comes at almost double the cost of the Quarq SRAM XX1. The Sigeyi is the lightest and most affordable, but does not have Active Temperature Compensation. If you’re an SRM fan, you’ll likely love the features of this unit. The Sigeyi is a great option for those looking for an affordable power meter. The Quarq is a well rounded power meter that has great features while maintaining a reasonable price.