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spring rates for bec
gaz_gaz - 25/7/11 at 01:44 PM

hi guys,

just looking for recommended spring rates for my early MNR with outboard suspension and yam r1 engine

car weight was/is around 500kgs

any opinions

thanks

[Edited on 25/7/11 by gaz_gaz]


eddie99 - 25/7/11 at 01:58 PM

For a road car, Would be something like 175 all round or maybe 200 front 150 rear, in that sort of ball park.


gaz_gaz - 25/7/11 at 02:10 PM

I really only use the car for track days so what would you recommend for track only?

Thanks


mark chandler - 25/7/11 at 02:31 PM

I keep winding mine up for the track, car is wet 450kg with blade engine.

You need to work out the leverage when comparing:

The angle of my front shocks give a 1: 1.5 ratio (steep slope, shock points at lower ball joint
The position on my rear shocks give a 1:1:75 ratio (Just off vertical 1/3 in from the outside)

My front are at 275lb so if directly acting on the wheel ~183kg
My rear are at 300lb so if directly acting on the wheel ~171kg

Its still very comfy, grips well on slicks with plenty of control as it brakes away, rear first.

I started off with 200lb front 150lb rear from memory.

Regards Mark

[Edited on 25/7/11 by mark chandler]


phelpsa - 25/7/11 at 03:19 PM

Don't be fooled into going too stiff. A lot of people increase spring stiffness to compensate (not wishing to sound too much like Matt Procomp ) for what is actually a damping problem. I almost made the same mistake until I was advised to start playing with my damper settings and become more confident. Using the damper and adjustable front ARB I can now make the car feel almost perfect in the wet or dry and on smooth or bumpy surfaces.


mark chandler - 25/7/11 at 03:46 PM

Agree with that.

I have been working my way up so on the 4th combination now, the car is still very compliant and comfortable but I found the back breaking away to early which I put down to camber change when loaded heavily in the corners.

Initially the handling was beyond my skill, as I have increased confidence and ability I have found issues.

I also take a lot of care corner weighting (okay its only bathroom scales but I do balance them and make sure the surface is true) and setting camber and caster each time, not just throw springs at it and expect things to get better.


procomp - 25/7/11 at 05:37 PM

Hi

175Lb at the rear is relatively ball park dependent on whether it's one up or two up. At the front if it has the high angle of dangle damper position IE 45Deg and the lower damper mount is way in from the ball joint then you will be needing something like 275-300Lb But to be honest i would want a pic as there's no 2 the same as they keep chopping and changing.

Cheers Matt


gaz_gaz - 25/7/11 at 08:38 PM

thanks for the info guys. really appreciate it,

here is a picture Matt.


mark chandler - 27/7/11 at 10:07 PM

Looking at that I would guess 2" wheel movement = 1" shock movement so you are looking at 300lb to provide a wheel rate of 150lb

Regards Mark