No expert here but tend to go around the middle for the rebound (hare tortoise) but I usually go a little slower on the back as too fast and rhe back comes up too quickly and I feel like Im being thrown over the front. For sag, wear your heavier items and any backpack and then adjust to around 30% based on weight including kit.

Watch a youtube video on suspension setup if you haven't already.

Then if you're keen, buy or borrow a Shockwiz. They can help a fair bit.

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Start at the 4 minute mark with Jordi from Fox Suspension • I did this before a trip to Bike Park Wales and it made a world of difference 

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“Quick, trail side, reset of your suspension, if you don’t know where you are and you don’t know what you’re doing” 

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https://m.youtube.com/watch?v=GPQnjSe6rdw

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Jordi has a nice way of explaining things, but as he is a Fox mechanic, it may confuse you 

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You mention trailhead app, which is Rock Shox, in which case you may find the video below more relevant

https://m.youtube.com/watch?v=42qZnhQXN7k

Pogo feeling could largely be down to rebound being set too fast, so the rebound should be turned towards the tortoise.

What tyre pressure are you running? Harder tyres can also help with the pogo feeling as they don't soften as much when hitting things.

Chat GPT or such like

Transformed my suspension. Mine had been the opposite that it packed down in bumps, now it just floats over the top

I just gave details of the bike and the exact fork, my weight (much more than you think when including all riding gear) 

Also put that I wanted it setup for Llandegla black and jump lines and it even described what those trails are like and what type of setup they need.

It gave me settings and changes I could make to change the feel.

After trying the settings the front end felt loads better but a little vague. I put that in as a statement and it recommended a slight tweak that solved it.

Edit: you can also add tyre type to get even more detailed setup

I think this old video is still by far the best idiots guide I've seen

See also 02:40 to 03:40 in the follow up video

Edit:

Links don't seem to be working so google 

10 Minute Suspension Setup | Get Your MTB Dialled FAST!

and 

Advanced MTB Suspension Setup - How To Find The Perfect Balance

Both videos by Seb Stott / BikeRadar.

I found the trailhead app to be completely ass. And it doesn't account for tokens, riding style, terrain, geometry etc.

Personally I've been using chatgpt and it gets it almost bang on. 

I tell it what bike I have and what frame size, tell it to look up the specs for geometry and suspension fitted, tell it my weight fully kitted up, tell it what type of riding I'm doing (bike park, trail center, off piste) and give it some example locations, that I like quite a supportive and playful suspension tune but don't want it so firm that I get rattled on chattery roots but not so soft it dives into corners or what % sag i generally tend to like which for me is about 27%, tell it how many tokens I've got fitted, what travel the suspension is and tell it whether I've got high speed or low speed compression or just standard compression adjustment, and what psi I'm running my tyres (or I ask it what psi I should be running my tyres based on all the above with wheel size and tyre brand/model) and ask it to tell me what it should be.

Been doing this for a year now and it's usually always within -5psi of what feels amazing and maybe 2-4 clicks of rebound and a click of LSC, and for tyres usually 2/3 psi of being perfect. It's always wildly different to what trailhead recommends 

Happy to give this a try as well, but...how do you word the query? With ai, that is the key bit to get right, wording the query properly to get the information.

My suspension seems to be working well just now but always happy to see what can be suggested...

Having ordered up my first suspension seatpost the other day from Trek (had to for £9 plus p&p), I've since discovered that it might have a hex key thread that I should tweak to get ~25% sag when sat on it on the bike, similar to front suspension fork setup.

how old is the suspension, is it due a service?

if you can justify it, TFTuned always improved my suspension, they just know how to get the most out of it, and they tune it to the bike/frame kinematics, and your rider weight.

Thanks for the replies, much to see and read about it. Yes, its all pretty new, RockShox Lyrik Select + RC2 150mm, RockShox Super Deluxe Select + RT, which are, I’ve been told, pretty good, so they shouldnt be making me jump up off the trail!

Cane Creek have a web app you can use. I haven't personally used it, but I did use their old Dialed app a lot to good effect. I don't believe the app is Cane Creek specific.

https://www.canecreek.com/pages/shocktuner?srsltid=AfmBOooX13dezaGXEBIek8QaeN8wXi834mnb8mtH0qTrubHcrEHdPECE

Find a bit of trail you can easily repeat and is fairly typical for the type of riding you do. Follow the instructions and do some laps. Simple

Yeah - I struggle with this in terms of understanding what eg High & Low speed compression do / are meant to be in different riding scenarios.

Generally, I'd like my suspension to be both plush, but firm & supportive. I want to use most of the travel, but not dive through it too quickly.

I understand what is meant by, and how to set sag, and adjust the air pressure. And I understand about the rebound.

But I'd like a general steer on what I should be doing in eg the following scenarios:

1. Steeper, natural, slow speed stuff, with some rocks & roots which I'd not be hitting hard or fast. (Stainburn off-piste)

2. Fast rocky/chunky armoured trails. Big hits, although not really much air or big landings. The kind of trail where you end up feeling beaten up at the bottom. (Stainburn red trail)

3. Fast, flowy but mostly smooth and jumpy-ish stuff eg Poppity Ping at BPW.

4. Fast flow/tech, eg Surfing Bird, Rim Dinger, Hot Stepper, Route Manouvres at BPW

5. General trail/mountain riding, big days in the Lakes or Peak?

Any good starting points, and good explanations about what (and why) HSC and LSC are doing/need to be set in those scenarios?

wording the query properly to get the information.

I just start with

”Ive got xxx bike with xxx fork with 1 token. I weigh xxx with all gear. I want my fork setup to ride Llandegla black/jump lines. (Or just describe what you like riding) Give me start settings for my fork.”

I then ask it to give me the information in a table with suggested settings to change

Hardtailonly - ChatGPT 

Great question. Once sag and rebound are dialled, compression (LSC/HSC) is what really lets you tune the bike for different trail styles. Think of them as controlling how easily the suspension moves under different speeds of impact.

First: What LSC and HSC Actually Control

Low-Speed Compression (LSC)

“Low-speed” refers to shaft speed in the shock/fork, not how fast you’re riding.

LSC mostly affects:

• Pedalling bob
• Pumping through rollers
• Brake dive
• Body weight shifts (berms, G-outs)

More LSC (firmer)

• Bike rides higher in travel
• Better pumping & support
• Less brake dive
• Can feel harsh on chatter if overdone

Less LSC (softer)

• More grip
• Easier small bump absorption
• More dive / wallow

High-Speed Compression (HSC)

HSC deals with fast, sharp impacts:

• Rocks
• Roots
• Square edges
• Harsh landings

More HSC (firmer)

• More bottom-out resistance
• Better for big hits
• Can feel harsh / deflective

Less HSC (softer)

• Softer over rocks
• Better tracking on rough ground
• Easier to blow through travel

How This Applies To Your Scenarios

I’ll assume a typical modern trail/enduro fork/shock setup.

1. Steep, Natural, Slow Tech (Stainburn Off-Piste)

Roots, rocks, low speed, grip is everything.

Goal: maximum traction and ground tracking.

Recommended direction:

• LSC: fairly open
• HSC: fairly open
• Rebound: slightly slower than average

Why:

• You want the wheels moving easily over roots.
• Too much compression = deflection and loss of grip.
• Slightly slower rebound helps maintain traction on steep rough ground.

Typical feel you’re aiming for:

• Bike feels planted and calm
• Not pinging off rocks
• Front tyre stays stuck to the trail

2. Fast Chunky Armoured Trails (Stainburn Red)

Classic “arm pump and getting beaten up” terrain.

Goal: absorb repeated big hits without harshness.

Recommended direction:

• LSC: moderate
• HSC: slightly open
• Rebound: not too slow

Why:

• Big square edges need low HSC so suspension can move quickly.
• Too much HSC = harshness and fatigue.
• Some LSC helps keep the bike from wallowing or diving under braking.

Common mistake here:

People run too much HSC, making the bike feel brutal.

If it feels harsh → open HSC first.

3. Fast, Smooth, Jumpy Flow (Poppity Ping)

Lots of pumping, compressions, and jumps.

Goal: support and pop.

Recommended direction:

• LSC: higher
• HSC: moderate
• Rebound: slightly faster

Why:

More LSC:

• Gives support in berms
• Helps pump rollers
• Makes the bike feel lively

Moderate HSC:

• Prevents harshness on landings

Slightly faster rebound:

• Helps the bike pop off lips

Typical feel:

• Bike feels playful and energetic, not dead.

4. Fast Flow + Tech (Surfing Bird / Rim Dinger / Hot Stepper)

Mixed terrain: berms, rocks, speed.

Goal: balance support and compliance.

Recommended direction:

• LSC: medium
• HSC: medium-open
• Rebound: middle

Why:

You need:

• Support for berms and pumping
• Compliance for rocks

So this is basically your neutral setup.

5. Big Natural Days (Lakes / Peak District)

Long descents, rough terrain, fatigue matters.

Goal: comfort + traction over long periods.

Recommended direction:

• LSC: slightly open
• HSC: open
• Rebound: slightly slower

Why:

You want:

• Less fatigue
• Maximum traction
• Suspension working freely

Too much compression here = beaten up after 5 minutes.

A Simple Mental Shortcut

Many experienced riders think of it like this:

There was more but got to the limit of what I could copy from ChatGPT 

id recommend you put all your info into ChatGPT then it will come up with recommendations for settings for each scenario too

+1 on check if they need a service. I had a pal once have a nasty crash on Stanage Edge and I discovered his forks were basically dry after 2+ years of use without any checking - so no damping at all.

I’ve found the manuals that come with the bike/shocks [edit. Or downloaded from the support website] fairly clear at explaining what the different knobs change and how to set up, test, and adjust. Then it’s a matter of setting time aside to do it.

I suppose for hardcore folks you also get used to what adjustments might be needed for particular trails. 

Some of the linked videos look worth watching for improving my tuning efforts.

As with any experimentation try and keep to changing one variable at a time. Pick a place to test with repeated runs. Maybe set the fork and shock pressure to the suggested default (I’ve found RockShox OK with these) and sort out the tyre pressures. Then tweak the fork and shock pressures to your desired sag. Then twiddle with the rebound. Then the LSC & HSC.  Others might suggest a different order. 

What is generally a good sag starting point for forks (150mm Lyrik if it matters)? I'm sure I've read that it should be around 20%, but Claude is adamant it should be closer to 30%. 

I've just asked Chat GPT, it's just told me that I'm running "A beast of a set up" so immediately i want to believe it!! 

Generally, I'd like my suspension to be both plush, but firm & supportive. I want to use most of the travel, but not dive through it too quickly.

I took all the tokens/volume spacers out of my suspension. I'm not fussed about it being mega plush in the carpark. I found due to the ramp up caused by tokens, to have enough support, I'm only using 50% of the travel. Removing the tokens reduces your fine motion at the top, but returns a much more linear progression.

I bought my bike 2nd hand in November 2022.  The shop set it up for me.  About 18 months ago I sent the fork off to Jtech.  I haven't touched the fork or shock air valves ever,  even though I carry a shock pump every ride. 

It rides fine. (wait for the post from hospital after tomorrow's ride).

I've also tried Chat GPT for the first time, and plesently impressed with the answers given.

It kept on making suggestions and I kept on giving it more info to any questions.

I was somewhere near with the fork but a fair bit out on the shock.

Although I've altered the bike to the recommended settings, I've yet to try it out 🤔

I'm really impressed with how Chat GPT works, fingers crossed it's made the suspension better 🙏

Similarly impressed with Gemini and what it gave me. Seemed to keep referring back to the bike, shock, fork and what I was looking for. I need to check.my settings as I think they won't be too far off (or I hope they won't be).

Thanks for the pointers in phrasing my initial question.