Magene P505 Power Meters

Magene makes a spider-based power meter for road and gravel bikes, called the P505. The P505 power meter bolts directly onto your existing crankset, which allows you to keep your current cranks and bottom bracket. They also offer the power meter as a complete crankset with crank arms. Magene P505 power meters measure power from both legs, are accurate to up to +/- 1.0%, feature left/right balance, Bluetooth SMART and auto-zero, among other features.

Additional Magene Power Meter Info:

P505 vs. PES vs. QED Power Meter Cranksets

Magene currently offers three versions of its power meter. The P505 is offered as a power meter spider only and mounts to your existing crankset. It is available in options that are compatible with SRAM 3-bolt, SRAM 8-bolt and ROTOR Road direct mount interfaces.

The PES P505 comes as a complete crankset with power meter, crank arms and axle. It uses a 24 mm spindle which is perfect for those using a Shimano crankset and are looking to upgrade to a power meter, without wanting to swap bottom brackets.

Magene also offers the QED power meter crankset that features improved accuracy, lighter crank arms and a SRAM DUB spindle when compared to the PES P505 power meter crankset.

Installation

With the Magene P505 spider, you simply mount it on your existing crankset and install your chainrings on the spider.

The Magene PES is a crankset that uses a 24 mm spindle. If you are currently using a Shimano crankset, you will remove your Shimano crankset, install the Magene PES crankset and install the chainring on the power meter spider. If you are not using a crankset that is compatible with a 24mm bottom bracket, you will also need to swap bottom brackets.

The Magene QED installs the same way as the PES, however uses a lager 29 mm spindle and therefore requires a DUB bottom bracket.

Weight

The P505 spider weighs 110 grams. The PES crankset weighs 650 grams and the QED cranksets weighs 618 grams.

Power Measurement

These power meters measure power at the spider. Therefore, they are able to measure power from both legs. They also have some additional features such as left/right balance and pedal smoothness.

Additional Features

Magene power meters feature automatic calibration, backpedal calibration, and manual calibration. Each power meter is also rated IPX7 for durability against the elements.

Batteries

The P505, PES and QED power meters are rechargeable and have a 200 hour battery life.

Communication Protocol

Magene power meters support both the ANT+ and Bluetooth wireless protocols. Therefore, they are compatible with any head unit, as well as phones, tablets and indoor training apps.

Accuracy

The P505 has a +/- 1.0% power accuracy, the PES has +/- 1.5% and the QED +/- 1.0%. These are all very accurate by industry standards.

Cadence Detection

These power meters use an accelerometer to measure cadence. This just means that the electronics inside the power meter are able to determine your rotational rate. This is how most modern crankset power meters measure cadence.