The 3-bolt MTB spider for SRAM cranksets is one of our best-selling power meters. Many manufacturers spec SRAM cranks on their mountain bikes…and a spider-based power meter is a great way to add power. Installation is simple and these power meters are accurate, reliable and measure power from both legs. You can also run pretty much your chainring of choice, including both round and oval. They are also compatible with standard, boost and super boost frames.
power2max and SRM both make this type of power meter. The power2max SRAM MTB Power Meter comes in two versions: the NGeco and the upgraded NG. The SRM SRAM MTB Power Meter also comes in two versions: the PM7 and the upgraded PM9. The table below compares these power meters across several key attributes.
power2max vs. SRM Comparison Table
|power2max SRAM NGeco||power2max SRAM NG||SRM SRAM MTB PM7||SRM SRAM MTB PM9|
|Power Measurement||Both legs||Both legs||Both legs||Both legs|
|Chainline Spacing||Standard, Boost, Super Boost||Standard, Boost, Super Boost||Standard, Boost, Super Boost||Standard, Boost, Super Boost|
|Communication Protocol||ANT+, BLE||ANT+, BLE||ANT+||ANT+, BLE|
|Claimed Accuracy||+/- 2%||+/- 1%||+/- 2%||+/- 1%|
|Active Temperature Compensation||Yes**||Yes**||No||Yes|
|Weight||125 grams||120 grams||114 grams||114 grams|
|Battery Life||300-400 hours||150 hours||100 hours||100 hours|
|Smallest Round Ring||30T||30T||30T||30T|
|Smallest Oval Ring||32T||32T||32T||32T|
|Warranty||2 years||5 years||2 years||2 years|
Most Popular = power2max NGeco
We’ve highlighted in red what we view to be the key differences. As you can see, the power2max SRAM MTB NGeco is a solid option and it’s by far the most popular. It’s the most affordable by about $400 and short of power balance, has pretty much all the features you could want. We run NGecos on many of our bikes here and they are very nice units.
Upgraded Units – p2m NG and SRM PM9
If you are looking for an upgraded unit (better accuracy and power balance), both the power2max NG and the SRM PM9 deliver the goods. However, it’s important to note that there’s a $300-350 price difference between the two, with the p2m NG being much more affordable. So unless you really want to have an SRM on your bike (and there’s nothing wrong with that!), you might want to consider the NG.
That leaves the SRM PM7. It’s a bit of an outlier here. It doesn’t really have any standout features, but it’s as expensive as the upgraded p2m NG. So unless you must have an SRM and the PM9 is out of your budget, we think you are better off with one of the other power meters on this table. That’s not to say the PM7 isn’t a solid unit because it absolutely is…it’s just pricey for the features it delivers.
* The power2max NGeco measures power from both legs right out of the box. It also has the ability to measure power balance, however you must upgrade the power meter to access this information. You can upgrade your NGeco using the power2max app once you receive the power meter. The cost to upgrade is 50 euros.
* The power2max doesn’t have Active Temperature Compensation the same way the SRM does, however it does have Auto Zero. This feature zeros (calibrates) your power meter every time you coast for at least three seconds during a ride. So this effectively acts as a temperature compensation feature and keeps the power meter accurate at all times.