Spring rates & adjustable suspension/OEM

[Rosssub]

Anyone know the difference in Front/Rear OEM spring rates between BE and BH and BH GTB? only spec I\'ve found was in wiki that said the B4 rear OEM was 4.84kg/mm. I\'ve read a few posts about people fitting BE rear coilovers in a BH and getting a saggy rear end so figure the BH rear would be 1.5-2kg/mm more.

My non damper adjustable Cusco fronts are knocking and I\'m on the hunt for a second hand full set or just replacement fronts. I\'ve been quoted $250 per shock by Shockshop Christchurch for recon which they will need to go to Auckland for. Looking at second hand sets which I can\'t see part numbers on to get the exact spring rates for, I\'ve taken some averages through set I\'m looking at for comparison (also to match my cusco rears if I only buy fronts). All for BE and BH. (N/mm to kg/mm conversion is 1KG = 9.81N)

Tein: BE/BH 6kg/mm Front & 6kg/mm Rear

Eifle: BE/BH 6.75kg/mm Front & 6.75kg/mm Rear

BC Gold: BE/BH 8kg/mm Front & 8kg/mm Rear

Cusco: BE 8kg/mm Front & 6kg/mm Rear

BH 8kg/mm Front & 7kg/mm Rear

Tanabe: BE 8kg/mm Front & 6kg/mm Rear

BH 8kg/mm Front & 8kg/mm Rear

OEM: BE 2.55kg/mm Front & 4.84kg/mm Rear

I assume the factory loaded spring rates are so different because of the difference in spring size front to rear, yet most after market coilovers are about the same F & R.

[Rosssub]

This is in Lbs, multiply the Lbs rate by 0.0179 to convert to Kg.

Found as an attachment here:

http://www.subaruoutback.org/forums/81-wheels-tires-brakes-suspension/27136-spring-rates-specs-eas-legacies-imps.html

Also found this chart in Lbs. But covers Heaps of aftermarket Subaru gear:

http://www.northursalia.com/techdocs/spring/spring.html

[Rosssub]

So that makes OEM spring rate for

BE: 2.36kg/mm Front & 2.36kg/mm Rear

BH: 2.36kg/mm Front & 3.4kg/mm Rear

But still don\'t know the BH5 gtb rates?

[Guest]

Aftermaket springs arent normally progressive like factory or replacement springs.

[sobanoodle]

Would this be any helpful?

Main specs are for the STI parts, but at the bottom you can see some specs for GT-B(MT)

[Rosssub]

The second chart shows which rate values are loaded or progressive.

Does the GTB use the same BH5 springs on Bilsltein struts, or does the GTB sit lower needing a higher spring rate?

[Rosssub]

 sobanoodle said:

Would this be any helpful?

Main specs are for the STI parts, but at the bottom you can see some specs for GT-B(MT)

Close, that\'s the \'progressive spring rate\'. I\'m after the \'loaded spring weight\'.

[Rosssub]

 evowrx said:

Aftermaket springs arent normally progressive like factory or replacement springs.

Ahh, so the GTB has \'Progressive\' springs, softer at the top end of suspension travel and stiffer at the bottom.

But BH & BE have \'Linear\' springs that have the same increasing \'bounce\' rate from top of travel to bottom?

BE 2.36kg/mm front & 2.36kg/mm rear

BH 2.36kg/mm front & 3.4 kg/mm rear

BH GTB 0.912kg-2.183kg/mm front & 1.28kg-3.9kg/mm rear