Rocky Mountain have a curious mix of ancient and relatively modern suspension designs in their range, and now they’ve added a whole new one.

The ETS-X (ETS - Energy Transfer System) has – according to their press release- "been designed to be the smoothest, most energy-efficient suspension XC bike in the world." That’s clear enough then, but some of the other details seem a little contradictory.

The ETS-X uses a single rear ‘fork’ to support the wheel, which is linked to the frame by two big CNC linkages. We haven’t got the technical Lego and pencils out yet, but first glance would presume that the action of the linkages would move the rear axle in a roughly vertical path. However Rocky Mountain’s press release contradicts itself on this one; "a unique double A-arm style linkage that creates a radically new projected pivot point located out in front of the bike" – Aah, so it’s a shallow curve!

But then;

"This results in a near perfect vertical rear-wheel travel….." – Hey, you just told us it was a curve?

"..and optimized chain growth." and "no matter what the terrain the rear wheel is being forced into constant contact with the ground" - Hang on, if the chain grows during the travel and pedalling forces it into the ground, then it can’t be that vertical. It must move away from the bottom bracket (thereby lengthening the chain) throughout its travel.

"The Linkage also allows movement of the top end of the shock changing travel from 3.5 inch 'Race' to 4 inch 'Epic' or even the dizzying 4.5 inch depths of 'All Mountain'"- Funny, we never knew an inch of travel made that much difference!

However, as with any new bike it’s the ride that counts, not the theory. Rocky Mountain make a habit of building good riding bikes using systems that other people abandoned years ago. For example the Pipeline uses a semi "Sweet Spot" URT, while the 3D-Link of current XC bikes is pretty much the old Giant (and others) knuckle rocker of the mid ‘90’s.

The rest of the bike build sounds good too, using a new oval version of Easton’s RAD tubeset, cunningly spliced at the headtube of a conventional triangular mainframe. The rear end gets full cartridge bearings throughout.

Two bikes are being launched with the new system – the X50 with Deore level componentry and Marzocchi MXR fork and the X70 with a Marathon fork and XT/ XTR kit. Both come with disc brakes and a Fox air shock with lockout lever.

We’ve no release dates for the new bikes yet but as soon as they’re here you can bet we’ll by trying to get on board. Hopefully we’ll sort out the marketing contradictions by doing what Rocky Mountains do best – Riding their arse off!