pull your shock out and measure the free eye to eye length, there is usually only one matching stroke for a given i-i, expect the 7.785" i-i shocks, they come in both 2.25" and 2" stroke.
Re which shock, depends on what you do with the bike... a good all rounder for that might be a roco TSTR air, save some weight too.



I am looking at upgrading my rear shock on my 2008 Giant Reign X2 but I don't know what exactly I have as far as configuration. It is the factory default but I don't know the measurements.
Question 1 - The rear shock is a Marzocchi Rocco R and I'd like to replace it with a RockShox Vivid 5.1. The vivid comes in 267 x 89mm (10.5 x 3.5), 240 x 76mm (9.5 x 3.0"), 229 x 70mm (9.0 x 2.75"), 222 x 70mm (8.75 x 2.75"), 216 x 63.5mm (8.5 x 2.5"), 216 x 60mm (8.5 x 2.36"), 200 x 57mm (7.875 x 2.25"), 200 x 51mm (7.875 x 2.0"). Which one fits?
Question 2 - Has anyone used a Vivid 5.1 and would they recommend it or something else?
Thanks in advance.