Im struggleing to understand the sprin rate calculator results, Mojo and Tf seem to give me different info and the fox one has extra info im not sure about, im 13.3stone rear wheel travel on my 2011 Heckler 6″ the shock is 8.5×2.5 216×63.
Do i need a 450?

yes you do – just

Leverage ratio and amount of sprung weight figures?

Alot depends on the valving inside the shock. I know TFs calculator is designed around the shock being valved correctly for the weight of the rider and frame design. If it is the shock that came with the frame originally I would go with TF. If its a secondhand frame I would talk to LOCO about having it revalved.

The sag % that you want can make quite a big difference to the spring weight needed.

Yeah WackoAK’s right. Spring weight is dependant on the sag you want to achieve so 2 different people of the same weight might plausibly opt for different springs. And remember spring weight and damping are seperate issues (unless I’m mistaken?). You need to start with getting the correct/desired sag through spring weight and then consider what damping characteristics you are looking for.

im not 100% about the sag, i usualy run 30% ish, but this will be the first coil i have had on a bike, the shock will be a new stock Fox van R, its probably only going to get a week of riding a year while im on holiday anyway, and carried incase the RI-P23 packs up. the choice i have is 400 and 450, once i get the thing and have a tinker i can figure out how i want it to run.

Who are you buying it from?
Give them a ring and ask their advice?

The frame will affect it with how progressive it is.
The shock will affect it as you can run more compression to compensate for a lower spring rate, epecialy with more ‘platform’ shocks.

Try this one..

http://www.igorion.com/_coilspring/

it’s usually spot on for me. if you find yourself in between spring rates buy both springs either side and see which you prefer. (or if youmhave the money, Ti springs come in 25lb increments)

Cheers GW that one made more sense.
The people im getting it from cant help, they just sell them, pretty sure somewhere near will be right enough, i’m a keen moto trial rider and ride one of the few single pivot bikes ever made the Scorpa SY, i just set rebound to just under springy and ride, i compete regulaly and do well. I got the Heckler as the rear end feels identical to the Scorpa, im hoping that once its somewhere near spring rate i can just adjust the rebound to suit, for the money the shock will cost (sub £100) i will take a chance if a can figure out roughly what spring is needed.

I’ve got a DHX 4.0 in that size sitting here which I am selling. Just serviced by TFT and I have 400 and 450 springs for it 8)

Looking for £125. I was going to buy a Van shock but was put off by the Pro-Pedal nonsense – with the DHX shock you can turn it “mostly” off – unless you get the Van tuned it will have a pre-set level of pro-pedal, I much prefered the DHX to the Van I had before because of this.

thepimpmessiah@gmail.com

I always thought that i you needed more than 2 turns of preload your spring wa sthe wrong one, that site suggests not