XC Hard tail suspension advice

I’m doing some XC this year, including the European Cross Duathlon Champs in Portugal - which will mainly be on light trail, cobbles, plus some stairs!

I’m reasonably technically-minded, but a lot of the jargon around suspension set-up does my head in.

Is there a simple guide to hard-tail fork suspension setup that clearly explains the various terms (sag, linear, ramp up, stroke, etc.)?

I have a Trek Procaliber 9.6 with a Rockshox SID-SL fork, so lots of stuff to play with (pressure, rebound, tokens, etc.) - just no idea what any of it really means.

Thanks in advance :slight_smile:

Cheat code - see if you can borrow or rent a shockwiz (or buy one). Makes it a lot easier to get your fork (or shock) dialed in. Basically - you hook it up, calibrate it, pressurize the fork, and go ride. Then it makes recommendations on adjustments. Repeat until it tells you you’re good…

Here’s my take on a couple for you:

Sag - this is the amount the fork or shock compresses when you’re sitting on the bike at rest. Let’s say you have a 100mm fork, and you want 20% sag, you want it to compress 20mm from full extension when you’re just sitting on it at rest.

Linear refers to how resistance in a shock or fork builds. If it’s linear pressure increases at the same rate as the fork compresses. Let’s say you add volume tokens - that decreases the volume inside the fork and makes it more progressive, i.e. pressure and resistance builds faster and faster as the fork compresses to keep you from bottoming out as you get towards the end of your travel.

If you really want to confuse yourself - start trying to wrap your head around high/low speed compression and rebound damping and what adjustments you need to be making (Seriously, check out the Shockwiz!)


There’s also a bracketing method, which doesn’t really require any understanding of all that crap, it’s all about how you feel. Basically:

  1. Find a lap course.
  2. Lower your fork pressure to the extreme (like… 20ish psi below the factory recommended sweet spot).
  3. Do the lap.
  4. Pump it up to 20psi above the sweet spot.
  5. Repeat the lap.
  6. Go back to the sweet spot.
  7. Repeat the lap again.
  8. Now compare the feelings at a sweet spot with how you felt at higher/lower pressures. Adjust in the direction you liked it more. Or don’t. Rinse and repeat.
  9. All the same for a rebound.

Disclaimer: I never tried it myself because I never cared enough (I usually just follow the weight-based recommendations for pressure/rebound and go ride my damn bike). But the theory of it makes a lot of sense to me.

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Thanks - I’ve found some places that rent out a Shockwiz. Might just do that. Does it still require a decent understanding of all the jargon or does it just say ‘twiddle this, turn that, don’t do the other’?

You select the mode, calibrate it, and then it tells you what adjustments to make. i.e. - it’ll tell you to add a volume token, it’ll tell you to add or subtract air pressure, and it’ll advise you what to do with Compression and rebound. You basically follow recommendations in sequence, it’ll even tell you the type of terrain to go ride.

You’re best off starting with the Fork’s factory recommendations, and after that, it pretty much walks you through it.

Get the Rockshox app. It will give you really good baseline settings. Then play with things until you are happy.


Also check out the guides on the Rockshox Sid SL product service page. RS has the ”Suspension setup and tuning guide” that walks you thru the setup options of the fork.


Is that separate from the Shockwiz app?

Pressure - most modern bike suspension uses an air spring (vs coil or rubber block).

Sag - how much suspension travel is used up at rest (with rider on bike). Usually 20-30%. More pressure - less sag.

Tokens - also called volume spacers. Take up room in the air chamber. More tokens - more progressive. Less tokens - more linear (plush on small bumps, usually).

Rebound - the speed at which the fork returns to rest after being compressed. Too fast and the front wheel can leave the ground. Too slow and the fork won’t return to rest between bumps.

Compression - how fast the fork compresses on impact. Similar to rebound, too much and the fork feels stiff and bouncy. Too little and the smallest bump uses all the travel.

Generally you’d set sag/pressure based on manufacturer chart for your weight. Go ride a hot lap. Then adjust token if needed (if you’re average weight, you might not need to). Then use rebound and compression to fine tune. Sometimes you do a few rounds of tweaks.

On many forks, the compression knob is also the lockout. It’s usually the only one you’d adjust while riding.

Adding/removing tokens should be done off the trail, as you have to pull part of the fork apart. Not hard, just should keep it clean.

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Yes, totally separate. Shockwiz is not just an app, it’s also a piece of hardware that measures pressure changes real time. The Rockshox app probably just links to the setup guides or similar.

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Also, FWIW, I’ve found the initial setup guides provided by the bike manufacturer to be fairly close (at least from Trek). I haven’t cross-checked their advice against the suspension manufacturer’s guides.

Shockwiz is a little Bluetooth “dongle” that you attach to the shock’s air valve (short hose then zip tie the “CPU” to the fork crown). You input some fork details then do some static setup (let air out of fork, lift up, push down, so the device knows how much air volume there is). Then pick ride style (race, enduro, etc) and go do a hot lap. The app gets fed air movement info from the on-bike device and makes recommendations. IIRC, it starts with tokens, moves to sag/pressure, then rebound and compression. You’ll probably get really close after one set of adjustments (2 hot laps), and then one or two more to get really close. It doesn’t give you raw data (shock curves, etc) - just “do X, then do Y” instructions. Which is probably as much as most of us need - only the nerdiest non-pros are going to be able to use anything more detailed.

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I bought a Shockwiz several years ago. Really does help set things up faster. Not needed, but eases the process. Really great if you are new to understanding what everything does.