CHUMBA Tech Article - Leverage Rates

There have been many exciting developments with CHUMBA over the last few months. But, before I get into that, I would first like to thank all of our loyal supporters and riders, and let everyone know that CHUMBA is truly on its way to becoming one of the world’s most prestigious bicycle brands. CHUMBA is focused on quickly developing and tuning our suspension technology, along with offering aesthetic and performance options unmatched by any other high-end company. Here are a few of the things we’ve been doing:

1. Identifying Suspension Curves and Accompanying Shock Settings to Maximize Performance

To make things easy – just remember that a decreasing leverage ratio means compression resistance is increasing; and increasing leverage ratio means compression resistance is decreasing. Just remember the analogy of a lever – imagine that you are trying to compress the shock with a lever. The longer the lever is the easier it will be to compress the shock; so the more you increase your leverage ratio, the easier it becomes to compress a shock. As your leverage ratio decreases, it will become harder to compress the shock.

As you can see in the chart above published by Trek’s R&D team, the leverage ratios at a given area in shock travel vary tremendously for some manufacturers. As you can see on the DW-Link Mojo – the dramatically varying and increasing leverage ratio towards the end of stroke means less bottom out resistance from the linkage. Additionally, the Santa Cruz Blur probably has one of the largest varying suspension rates, going from as high as 2.7 all the way down to 1.65. Further, on the DW Link and VPP, the leverage rates increase and decrease all throughout the curve – making for varying feels throughout the travel.

As you can see with the VF2 – the leverage ratio is predictably constant – making the travel feel extremely consistent and predictable when compared with the competition. You can see the variance of the compression resistance is minimal, being slightly regressive with a small amount of bottom out progressiveness at the end. Yamaha MX and CHUMBA test rider Dustin Nelson put it well when he says “linear rates give you the most amount of controlled feel over travel” – as you don’t need to compensate suspension feel with a varying leverage rate to try and make up for pedaling input from
the suspension.