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Multi-way Adjustment dampers

Suspension Tuning & Optimization

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Discussion and questions related to the course Suspension Tuning & Optimization

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If you have dampers with independent high and low speed compression and rebound adjustment, how would you prioritise the adjustments? I have been told that low speed has a bigger impact on feel but even then, would you adjust both low speed compression and rebound at the same time?

The golden rule is only make one adjustment at a time, and this is where having a dyno report for your shocks is super useful as you will be able to tell how much difference each click will make at any speed.

Low speed has a bigger impact for 2 reasons: first is your dampers spend the most time here, ie even in a "high speed" bump (wherever you decide that speed is for your discipline) the shock has to accelerate through this part once it begins moving, and then back through it as it comes to a stop.

Second is every damper is different so it depends on the specific architecture but usually there is enough overlap that a change to the "low speed" clickers will affect the high speed too. Conversely that can mean if your low speed bleed is too open/soft then the high speed circuits are never opened and you will feel no change from adjusting those ones. Again, having dyno data here is GOLD

Having suspension data from your data logger would be the best place to gauge whether to change compression or rebound first, but otherwise I would suggest changing compression first as the rebound is somewhat dependent on the compression damping because it controls how quickly the shock extends from a certain point in the stroke, but the compression damping can alter how compressed the spring was before it changed direction.

Either way it would be best to try a few clicks of one, do a few laps then turn those back and try the other one and compare. That's usually what you will need to do anyway, and its only having some data on hand that can point you in a direction that will make bracketing the adjusters quicker.

As Jono said, it's really going to come down to testing.

For the most part, high speed will affect the wheel's control more, such as over ripple strips, and low speed the chassis/body - especially response to load transfer in braking/cornering/acc'n transitions.

Dampers are not position sensitive, they are velocity sensitive. Softening rebound is very effective at adding traction to the inside wheels when turning, or especially over crests on the track.

Hi,

firstly, the videos on this subject were unbelievably good - excellent delivery of course material!!

I have three-way suspension also and wondered following the answers above…

Would you say to set low speed compression and rebound to their softest settings, then increase over about 5 or so steps (as per video), from softest to hardest, the high speed compression? Find the ‘sweet spot’ for the high speed compression and leave it there, then adjust the rebound in the same way, then adjust the low speed compression last?

Thanks for your help :-)

As a driver, I like the feel of the car with stiffer damping settingss but the car is almost always ultimately faster with softer settings. The stiffer settings make the car feel more responsive and confidence inspriring to the driver. Once they have the confidence to turn into say the high speed turn without lifting, then when you soften the shocks they find it has more grip. However often they will not develop that confidence early enough if you start out soft.

So my recommendation, is start a toward the stiff end, and soften looking for grip. My starting point for most weekends is a couple of clicks sitffer then what I ended up with at the last time I ran that track. Build the confidence!

Thanks for the response, David, much appreciated :-). Makes complete sense, that’s pretty much how I used to do it in my previous car which had 1-way adjustable suspension. My new car has 3-way adjustable like the OP, Mechmike, though, which I’ve not had before. I need to get to my ‘first’ set of adjustments that feels confidence inspiring and provides good grip so I can make tweaks from there. i guess the question is, what is a good order to make the adjustments in for 3-way adjustable? Is it as per this:

set low speed compression and rebound to their softest settings, then increase over about 5 or so steps (as per video), from softest to hardest, the high speed compression? Find the ‘sweet spot’ for the high speed compression and leave it there, then adjust the rebound in the same way, then adjust the low speed compression last?

Well, give the steps in the video a try in the order they recommend.

From my experience, I suggest adjusting compression and rebound equally, unless you have a reason to make them different (for example, there is a hill brow, where reducing rebound will improve traction). You will only adjust high-speed either to suit a specific track, or to deal with high-speed events (like kerbs). My tuning is based on using Ohlins TT-44, and Penske 8760 three-way adjustable shocks on downforce producing sports racers and formula cars.

Keep good notes of the exact settings used for each session while you are learning. And in your debrief from each session write down your impressions, any weaknesses you noted, etc.

Good Luck!

Hi David,

Yeah the video only talks about the steps for one-way adjustable suspension unfortunately.

I’ll have a play on my next track day (next month) and keep notes. Hopefully one of the HPA team will see this question and give a pointer before I go.

My car is a saloon car (BMW M4) without aero so looking at mechanical grip.

Cheers for responding again :-)

Rob

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