I've used the TFT and mojo spring calculators and one is under 450 the other over. Should I get a 450 or 500?
I'd trust the TF tuned one personally as it takes the leverage ratio of your suspension design (or nearly).
Depends if your shock has been tuned for your weight / bike aswell. I got a new spring & sag was fine but it was compressing too much on landings / berms. Sent it off to LOCO who put extra compression damping on and it was loads better.
the shock has been pushed for the bike and my weight, i've been riding it with a 550 but think I'll change, just not sure which to get (450 or 500)
The TF one was spot on for me.
How much sag is your current 550 giving you with no pre-load on it? If you're getting sag of 25% - 30% of travel then you don't need a new spring.
If you're only getting 20%, then get a 500, less than 20% get a 450
