i want to replace the coil on my vanR shock for a titanium one.
The steel spring currently fitted is a 450lb x 2.37"

I know that the 450lbs is calculated to the rider weight etc but what does the 2.37" mean"

would it matter if i fitted a 450lbs x 2.5" for instance?

thanks

shock stroke length

The 2.37 refers to the stroke of the spring i.e 2.37" this would usually be fitted to a 2.25" stroke shock to allow a a few turn of preload to be put on the spring without it bottoming out/becoming coil bound.
You can fit longer springs like a the 2.5" stroke one (if they'll fit) you mentioned but you better to get the correct length as they weigh less.

thanks LoCo & scienceooficer,

it is fitted to a 2.25" shock so i think i'll lookout for a 2.37"