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RALLY EXPLAINER - Choosing a Tripmeter

Posted by Matthew Glade on

What is a Tripmeter?

The ability to measure traveled distance accurately, and correlate it with distances in a roadbook, is at the heart of Rally Navigation. A tripmeter at its most basic is simply an adjustable, highly accurate odometer. More advanced features can include measuring speed, providing compass headings for HP/OP sections, providing a clock, stage timer, hour meter for maintenance scheduling, and displaying waypoint information.

How do they work?

There are two main types of tripmeters:

  1. Wheel Sensor Driven

Wheel sensor tripmeters rely on a micro switch sensor usually placed near a front wheel hub that is triggered by a magnet usually located on a brake rotor. As the magnet passes over the sensor with each revolution of the wheel, a pulse is registered by the tripmeter. This pulse is multiplied by the conversion factor programmed into the tripmeter, and a distance is displayed to the racer. Wheel sensor tripmeters require very little electricity to operate, and can operate for periods without external power. Wheel sensor tripmeters are usually less expensive.

  1. GPS Driven

GPS driven tripmeters rely on a GPS antenna to provide course data to the tripmeter. In additional to displaying speed and odometer, GPS driven tripmeters can provide additional functionality like compass (CAP) headings. GPS driven tripmeters do not require the install and routing of a wheel sensor, but will not function without external power. NOTE: Some events such as Dakar or Rebelle restrict the use of GPS devices.

An in-depth discussion of the effective accuracy difference between GPS and Wheel Sensor is here, but for nearly all Rally purposes, we can consider the accuracy between the two to be equal. Nearly all of the (very rare) Tripmeter failures we see are related to cable damage. Both GPS and Wheel Sensor units can be equally reliable with careful install and cable protection.

ICO or RNS?

Since its release in 2017, the ICO MAX series has become the world standard. It’s rare to see a Dakar bike without at least one ICO MAX-2 (Wheel Sensor). The MAX series has a composite case and 25x65mm “Seven Segment” LCD screen (Similar to a digital clock) with bright orange backlight. The MAX-G has an external cabled GPS Antenna. The ICOs are designed and built in the USA.

The ICO MAX-2 (Wheel Sensor) is $325USD

The ICO MAX-G (GPS) is $425USD

The RNS GFX series was released in 2020 and is the next generation of Rally Tripmeters. The GFX series has an anodized billet aluminum case, and 35x60mm Transflective HD Graphics 172ppi LCD screen (Similar resolution to a tablet or laptop screen) with a bright blue backlight. This screen allows for the display of multiple data at once, and full text menus.  The Pro model has an internal GPS for durability and simplicity. It also has the capability to connect to an external GPS device that is loaded with Rally Stage data to display waypoint arrows when the device arrives within the radius of a WPMs. The RNS GFX Series is designed and manufactured in Germany.

The RNS GFX Standard (Wheel Sensor) is $440USD

The RNS GFX Pro (Internal GPS and Wheel Sensor) is $580USD 



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