Ohlins 12kg - Helper Spring and lowering cup questions
 

This winter I was going to move the 10kg springs on my Ohlins to the rear and purchase 12kg springs up front. The springs I was going to purchase were the 65mm x 8" Swifts (Z65-203-120). Then I read this and this, both posts suggests using helper springs when going with 12kg up fronts on the Ohlins. So my questions are what rate main spring and what rate helper spring do I need?

While on the subject of Ohlins, I do not intend to slam my car, if I went with the Ohlin recommended drop is there any benefit purchasing rear lowering cups for my car?

Thanks!

with 12k/10k, you can lower approximately 1 - 1.25" with the Ohlins supplied cups (using ~9mm rear preload).

You need a front helper that will eat up about 0.9" of gap. Use any spring longer than 1", with as light of a rate as possible, and make or buy some adapters to use 65mm compound springs.

You'll need to dial in a certain amount of preload depending on spring rate and length/collapsed length. If you're not good at this...you can always contact SBG for a ready-made setup with pre-determined preload amount.

Or you can run the 12K front spring with 0.9" of free slop and no helper spring.

Or just run 0mm of preload and YOLO. You should be fine with your proposed 1" drop.

I use the 0 preload and YOLO method up front. I haven't banged the fender on a bump or at a track yet. And my shit low.

BUT...the proper way is helper springs.

The un-cultured backwoods way is leaving a gap.

The reckless way is the way I'm doing it (I'll regret doing it this way at some point, I'm sure).

You can drop an inch off the stock spring length even at stock spring rates to save weight, and if your helper/perch combo is another inch thick fully compressed, you can drop another inch off your main spring. That will save more weight.

Do you think its OK to use Swift springs for only the front? I was thinking of doing a similar for my setup but I wasn't sure if it was going to be weird to not match the same type of spring for all four corners.

Yep...u good.

For reference, my fronts are 12KG Teins and my rears are 10KG Ohlins/Eibach.

Forgot to thank-you for this!

Update
 

My CR is parked for the winter and my Ohlins are off my Ap2, so it's time to set them up correctly!

I wanted to lower the car more but there's been a local crackdown on modified cars so I don't think I will go lower than Ohlins recommeded drop of 25mm.

Can someone tell me if I have this correct?

Based on the info that I have read, if I stick with the stock 10k/8k setup & go with a 25mm drop, for the rear, based on the SBG chart I should go with approx 15mm preload and the SBG lowerings forks won't be necessary.

If I go with a 12k/10k setup (no helper spring up front, using the B serious yolo method :LOL:), the rear I should add approx 9mm of preload (per post above, although the SBG chart suggests a different number for this spring) and once again the SBG lowering forks won't be necessary.

Now, if I wanted to go lower than 25mm, it would probably be advisable to buy the lowering forks.

Also, if I go with less than 25mm drop, I should just absolutely increase the preload!

^yeah, pretty much.

You don't seem to have issues getting them on/off.

So just set it up with the preload you want.

Then see if your wanted ride height is achievable.

If it isn't then buy forks.

What does SBG suggest for preload with 10K rears?

The SBG chart

https://cimg9.ibsrv.net/gimg/www.s2k...d1edf6d125.png

^that says 9mm with 10K rears also...

But says your max ride drop is 0.84" with that amount of preload and Ohlins original forks.

I might be wrong when I said you can drop the car up to 1.25" with that preload and Ohlins forks.