The rear shock linkage on the Helius FR has changed for 2008. Pre-08 there were 4 holes in the rear shock linkage for travel adjustment – the highest position was max travel, the lowest hole the lowest travel. Only a very small number of FR owners were using the adjustable travel and the frame is now optimized for full 167mm travel with either a coil or air shock.
The lower hole on the 2008 linkage is used for 57mm stroke shocks (generally coils at 200mm eye-to-eye.) whilst the upper mount is used for 50mm stroke shocks (generally air shocks at 200mm). Using a 57mm shock in the upper mount will give more than 167mm travel and result in the rear wheel colliding with the seat tube, using a 50mm stroke shock in the lower mount reduces the travel.
The adjustable front shock mount is NOT intended to be used to change geometry and you do so at your own risk.Â It is intended to allow the use of shocks of different eye-to-eye lengths.Â For example, the Rock Shox Pearl is available at 57mm stroke in a 222mm length.Â Of course you can’t run a shock with a much longer stroke (such as a Fox 222mm 75mm stroke) as you’ll increase the travel and your back wheel will hit the seat tube!