Do you buy the same length as your shock for e.g, a coil shock that is 200mm eye to eye takes a 200mm length coil?

No. you buy to match the stroke of the shock and the required spring weight (lbs/in). Free length rarely comes into play

Ok, so 500lbs and 2.25 is all i need to know?

Yup, unless your shock is an odd size (or an RS Vivid) that should be it

More or less – different brands have different naming conventions.

But if you have a fox shock with a Fox spring, then yeah, match the stroke (2.25) to the spring you have, and get the weight (the 500) you need.

Free length might be an issue at the extremes – some heavier springs can be too long to fit the shock body (this is the free length measurement) – worth checking for a heavy spring on a smallish shock.

So for instance this
http://www.chainreactioncycles.com/Mobile/MobileModels.aspx?ModelID=15335

Isnt 200mm in length just for a 200mm shock?

tbh that’s a pretty strange way to list them. As shocks have a good amount of adjustment on the spring collar you might be able to use them on a longer/shorter shock too. Free length is better as it tells you how much room you need between the spring collars in order to mount the spring. e.g. http://www.tftunedshox.com/Catalogue/Manitou/Manitou/Manitou-Rear-Shock-Springs who just list the stroke and spring weight

astura – Member

Isnt 200mm in length just for a 200mm shock?

Not really sure what you mean there? There’s nothing on that link to tell you how long the coil is (and tbh it’s not that important).

It’s an odd way to list it, because the shock length is important as well as the stroke- for instance they list both 2 inch and 2.25 springs for 200mm shocks. Correct, but it doesn’t tell you which to use (200mm shocks commonly come in 50mm and 57mm, ideally you’d choose the 2 inch spring for a 50mm and the 2.25 for a 57. Though, might get away with mixing it up.)

By and large shocks have well established length/stroke ratios- in theory you could make a 9 inch shock with 1 inch stroke but in practice, a 9 inch shock will normally be 2.75, and so on. otherwise compatability would be a nightmare.

So, in turn if you buy a 2.75 spring, you don’t really need to know the length, because it’ll have been designed with a 9 inch shock in mind.

Thanks for the comments. So it doesn’t really matter what coil I get aslong as it has the right lbs and stroke.

Northwind, did you manage to find a coil with this weight and stroke, if not il grab one from crc as I want to ideally get my bike sorted for Saturday so I can go riding.

Got your email but just digesting dinner 😉

Apologies 🙂