Bilstein 8112 Baseline Settings (and some shock notes)

[chon]

I finally got my Bilstein 8112s installed and in my quest for some baseline settings I watched (and rewatched) many youtube videos.

At this point I am a shock tuning youtube expert!

So far my favorite video (that actually shared settings) was this one for baselines followed by this video for tuning.

Basics

Some basics (from a self proclaimed youtube expert!)

• Compression - when the shock compresses (gets shorter); also called "bump"
• Rebound - when the shock rebounds (gets longer); also called "droop" or "extension"
• Bottom Out- the shock at full compression; usually a violent transition from the shock controlling the shaft velocity to no longer being able to move
  • most shocks have bump stops to ease this transition; but still something you feel and it feels bad!
• Top Out - the shock at full rebound; transition from when the shock is controlling the shaft velocity extension to no longer being able to move
  • happens when you "jump"; negative G events when you leave the ground (or maybe just feel like you did)
  • not as violent as bottom out since the mass that is striking at a top out is the unsprung
• Mid-Stroke - the shock at rest; the shaft should be in about the middle to a little above that middle to be ready for the next bump (or droop) event
• HSC - controls high speed shaft movement in compression
  • the "ride quality" knob
  • anything that moves the shaft into the body relatively quickly
    • road bumps
    • sudden strikes
  • and things that would normally be considered LSC but that happen more quickly
    • the immediate response on a left/right direction change
    • the immediate response on a brake stab
• LSC - controls low speed shaft movement
  • the "handling knob"
  • anything that moves the shaft into the body relatively slowly
    • vehicle weight transition
    • weight transition when turning (roll)
    • weight transition when braking (yaw)
  • and things that would normally be considered HSC but that happen more slowly
    • road bumps hit while traveling so slowly that the shaft moves slow (like when crawling)
• JCO - controls the shaft movement at the extreme end of compression
  • the "bump stop squishiness adjuster"
  • important to note that the JCO adjuster doesn't change where this occurs in shaft position but rather how much it slows the shaft when the region is entered
  • tune to just barely feel the transition from HSC damping to JCO damping
  • the last "ride quality" before your on the bump stop
  • based on the videos it sounds like if you stiffen JCO too much it will limit travel in compression (in bump)
    • my gut is that this shouldn't happen because the know should only control the shaft velocity and have nothing to do with the distance it travels
    • would be interesting to do some experiments on an RTI ramp!
  • too soft JCO you risk blowing through and bottoming out
  • too firm JCO will feel like a softer bottom out
  • tune along with HSC so the transition from HSC to JCO is smooth
• Stacking- when the shock keeps getting shorter with each compression event and you end up bottomed out
  • the shock isn't able to rebound to mid-stroke position before the next compression event
  • happens when rebound is too stiff relative to compression and compression events are happening too fast relative to those settings
  • the shock sort of ratchets itself shorter and shorter until its on the bump stops and then its a really horrible ride from there!
  • fix: soften rebound, stiffen compression, or slow down (with 8112 we can't adjust the rebound)
  • spend money fix: reduce unsprung weight: get lighter wheels, tires, a-arms for faster recovery

Anyhoo.. So right away I'm thinking just like Bowman! I want the most LSC (the most bestest handling!) and the least HSC (the smoothest ride); but then he tells us how that didn't work out in his follow on video.

Baselines

I scoured it (with some help from gemini) and came up with the following baselines:

	Front*			Rear*
Test	LSC	HSC	JCO	LSC	HSC	JCO	Timestamp	Video Link	Comment
Street	11	4	3	11	4	3	07:06.000	Watch
Hill Climb	4	2	2	6	2	2	12:09.000	Watch
Frame Twister (Run 1)	4	2	2	6	2	2	16:32.000	Watch
Frame Twister (Run 2)	2	2	2	2	2	2	18:12.000	Watch
Fire Road	6	2	2	8	2	2	20:32.000	Watch	"low speed cranked up a fair amount"; explained at 24:38.000
Handling (Run 1)	6	2	2	8	2	2	24:38.000	Watch
Handling (Run 2)	8	2	2	10	2	2	26:48.000	Watch
Whoops	8	5	5	10	5	5	31:20.000	Watch	Answered in YouTube comment [highlighted]

*from full soft

NOTE! With the 8112 the adjustments are clicks from full soft. This is unusual for shock adjustments. Normally we fully tighten the shock to full stiff (where the adjuster bottoms out) and then count rotations or clicks from that. Bottoming out gives us a consistent point to adjust from; and most adjustable shocks get a little vague at full soft (and some the needle will come out completely!) The 8112 is the opposite. You can't get these things to full stiff HSC without a special wrench. And we are never sure that we really got it all the way in.. So we start from full soft. And full soft on the 8112 has a consistent stopper so we're good.

Tuning

Its important to note that these are just baselines. So many things will change how you want to set up your vehicle from the vehicle it self (unsprung weight (wheel/tire/suspension bits)), vehicle weight, and personal preference.

Vehicle itself:

• unsprung weight (wheel + tire + a-arms..)
• vehicle weight (and all of the stuff you are carrying this trip)

Personal Preference:

• How fast you go (avoiding stacking)
• How smooth you like the ride (lower HSC)
• How you like it to handle (LSC front/rear tuning)
  • more stable: stiffer LSC in front
  • more rotation: stiffer LSC in rear

So once you have a baseline reference this video for tuning for yourself.
I agree with this video that there's no one setting that will be right for you. And also that there's no set it and forget it setting for all situations.
But I disagree with the implication that this means we can't share baselines!
Sharing baselines is critical for choosing a starting point before tuning.

Tuning is a balancing act between handling (LSC) and comfort (HSC) while avoiding stacking and abrupt HSC to JCO events.
The video highlights a few important things:

• don't use extreme settings (don't go full stiff LSC and full soft HSC dreaming of 'best handling' with 'smoothest ride'); it doesn't work out the oil will use the other path ([4:58])
• adjust HSC and JCO together to make the transition from HSC to JCO smooth ([3:05])
• the unhappy speed range on washboards; where the shocks aren't comfortable - tune to drive through this zone ([5:20])
  • choose a speed that is transitional for you; that you'll drive through
  • use LSC to move the speed zone (soften to move down and stiffen to move up)

Final Notes

I'm not an expert! Please let me know what I have wrong, what I missed! Or if there is other reading I need to do or videos I should watch.
And share your baselines!

I just installed and so far have seen a massive improvement on road. Off road I've only done a couple trips and both were very low speed technical trips where, frankly, there was no real difference to the stock Bilsteins.

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