Hi guys!
I've readed tons of threads about it and especially BC Coilovers and I have several questions about springs and how to comfort daily driving on my SC400:
I've installed BC Racing coils BR-RS Series with 14k/180mm front and 10k/200mm rear (according to the BC Racing site it's factory rates for springs for ours SC300/400) and even on the softest settings it's not comfort for me - feel every joint and pebble on the roads. Have 235/40 R18 8J Toyo Proxes Sport, maybe the tire is too stiff for the streets?
After Zeal coilovers BC are certainly softer, but I would like even softer coz my daily driving style is not so aggressive anymore)

Can I replace my 14kg-180F and 10kg-200R springs with 10k/200mm front and 8k/200mm rear?
After setting it up, will it all work correctly? I mean сan the springs be the same length on front and rear without negative outcome?

Have a set of Bilstein with stock springs and I was already thinking of changing BC and switching to Bilst.
But! I love how responsive my SC on the road with BC and I want to make them softer by springs replacing if it's possible.
Thx in advance!

 

I'm currently running 10k front/ 7k rear on my KWV3's with swift springs and they are much more livable. You should contact BC and have them give you the measurements for the springs to use. Also 4k drop in the front might require a revalving to match the springs.

 

Thank you for information!
I received an answer from BC support guys and here it is:
”hi,
you can use a shorter or longer spring as long as there is enough room on the shaft to mount them.
Change of weight up or down 4kg wont need revalving and will perform well”

 

Awesome, then I'd suggest going on the swift site and finding the spring, at your desired spring rate, that has the right amount of usable stroke in the metric coilover springs section. Most coils use 60mm ID but I don't know if thats actually the case for BC. you can find that out as well. Your stroke is basically the distance your shock can travel so you need to make sure the spring you get has a stroke thats longer than the shock stroke otherwise you run the issue of coil binding. You'll also need to put the correct amount of preload on the spring. The way you determine that is by loading the suspension when your new shocks and springs are on and making sure that your shock is about 45-50% compressed. if you don't put enough preload you'll be riding close to the bumpstops, if you put too much preload, you'll be lifting wheels on hard turns. There are videos out there that do a much better job explaining it too.