Ride height & spring rates
Discussion
Hi
Quick question. I am thinking of increasing my spring rates but I'm conscious that increasing the rate has an impact on ride height due to static load.
If I understand my physics right, if I increased from 300 to 400 lbs/in, then if I kept the spring length the same, it would only deflect to 0.75 (300/400) of the original which means if I had a 9" spring originally, then I would need a 0.75 x 9" = 6.75" spring to account for the increase rate.
Is this right?
I need to consider my spring seats, which are adjustable, to make sure they can crank down another nearly 2" though.
Also, I take it that buying the same length and then crushing the spring 2" using the adjustable spring seat isn't a good idea because the spring will fully compact under driving conditions as its already been squashed 2" before a load is applied.
See the image to see what I'm trying to say if its not clear.
Quick question. I am thinking of increasing my spring rates but I'm conscious that increasing the rate has an impact on ride height due to static load.
If I understand my physics right, if I increased from 300 to 400 lbs/in, then if I kept the spring length the same, it would only deflect to 0.75 (300/400) of the original which means if I had a 9" spring originally, then I would need a 0.75 x 9" = 6.75" spring to account for the increase rate.
Is this right?
I need to consider my spring seats, which are adjustable, to make sure they can crank down another nearly 2" though.
Also, I take it that buying the same length and then crushing the spring 2" using the adjustable spring seat isn't a good idea because the spring will fully compact under driving conditions as its already been squashed 2" before a load is applied.
See the image to see what I'm trying to say if its not clear.
Hi
Thanks. Yes I see that I got the maths right but the application wrong. If for example I had 250kg in the corner, then that is 550 lbs and so I can work out deflection in a 300 and a 400 lbs spring and that's the difference.
As has been said, its not exact due to the various angles in the suspension set up so its only applicable in a linear vertical situation.
I have AVO adjustable dampers (apparently bump and rebound in the one adjuster). I can probably get advice from the manufacturer on the limits of spring rates to give me an idea on this.
It was the suspension wiki that I was looking at that made me think to increase spring stiffness based on comments and settings in there.
I suppose that's why I'm asking here as it'd be good to hear what happened to others when they changed their setup and what else to watch for. I hope I don't have to do a full geometry set up as if all returns to the same ride height wouldn't that mean camber, toe in/out, etc are unchanged?
If I do this, I'm changing both front and rear to probably 400 / 375 F/R.
Thanks. Yes I see that I got the maths right but the application wrong. If for example I had 250kg in the corner, then that is 550 lbs and so I can work out deflection in a 300 and a 400 lbs spring and that's the difference.
As has been said, its not exact due to the various angles in the suspension set up so its only applicable in a linear vertical situation.
I have AVO adjustable dampers (apparently bump and rebound in the one adjuster). I can probably get advice from the manufacturer on the limits of spring rates to give me an idea on this.
It was the suspension wiki that I was looking at that made me think to increase spring stiffness based on comments and settings in there.
I suppose that's why I'm asking here as it'd be good to hear what happened to others when they changed their setup and what else to watch for. I hope I don't have to do a full geometry set up as if all returns to the same ride height wouldn't that mean camber, toe in/out, etc are unchanged?
If I do this, I'm changing both front and rear to probably 400 / 375 F/R.
Hi Big G!
yes thanks for letting us experience your car. I am definitely convinced now to change my set up to something like yours. Makes it easier for me to specify as I can just pretty much go like for like. I phone AVO and they said my shocks could handle up to about 450 - 500 lbs/in spring rate before the damping starts to be affected so that's good news.
yes thanks for letting us experience your car. I am definitely convinced now to change my set up to something like yours. Makes it easier for me to specify as I can just pretty much go like for like. I phone AVO and they said my shocks could handle up to about 450 - 500 lbs/in spring rate before the damping starts to be affected so that's good news.
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