Low Speed Compression (LSC) vs High Speed Compression (HSC)
The "speed" in LSC and HSC refers to shaft speed inside the damper, not how fast you are riding. LSC controls slow shaft movement — braking dive, pedalling bob, rolling compressions through berms and G-outs. HSC controls fast shaft movement — square-edged rock hits, landing from drops, harsh impacts that catch the wheel.
They are independent circuits on mid- and high-end suspension (Fox Factory/Performance Elite, RockShox Ultimate). Most confusion comes from riders thinking "high speed" means descending fast — it does not. A slow descent over a sharp rock still triggers HSC. A fast pedal stroke on smooth ground still triggers LSC.
RockShox Fork Compression Settings — Pike, Lyrik & Zeb
RockShox Charger 3 damper compression clicks for Pike, Lyrik, and Zeb by riding style. Click counting direction is OPPOSITE to Fox — see warning below the table.
| Riding Style | Pike LSC | Pike HSC | Lyrik LSC | Lyrik HSC | Zeb LSC | Zeb HSC |
|---|
| XC | 3 clicks | 2 clicks | 4 clicks | 3 clicks | 5 clicks | 4 clicks |
| Trail | 5 clicks | 3 clicks | 6 clicks | 4 clicks | 7 clicks | 5 clicks |
| Enduro | 7 clicks | 4 clicks | 8 clicks | 5 clicks | 9 clicks | 6 clicks |
| Downhill | 9 clicks | 5 clicks | 10 clicks | 6 clicks | 11 clicks | 7 clicks |
⚠ RockShox counts compression clicks from fully CLOSED (firmest) for the Charger 3 damper — same direction as Fox. (Note: RockShox rebound uses the opposite convention from Fox. Compression is the same direction.) Always verify with your specific damper manual. Source: SRAM/RockShox Charger 3 setup guide.
RockShox Rear Shock Compression Settings
| Riding Style | Super Deluxe LSC | Super Deluxe HSC |
|---|
| Trail | 5 clicks | 3 clicks |
| Enduro | 7 clicks | 4 clicks |
Super Deluxe Ultimate has dedicated LSC and HSC adjusters. Deluxe Select has a single compression switch only.
When to Adjust Compression vs Rebound vs Air Pressure
Compression damping is the LAST thing to touch in suspension setup — not the first. The correct order is: 1) Air pressure (sag), 2) Rebound, 3) LSC, 4) HSC. If your fork dives under braking but sag is wrong, adding LSC will not fix the problem — it will mask it and create harshness elsewhere. Always start with our MTB sag calculator, then dial in rebound damping on a curb, then use this page for compression starting points. Tyre pressure also affects how the suspension feels — see our MTB tyre pressure calculator.
Climb Mode / Lockout vs Compression Damping
Most trail and enduro forks have a 3-position climb switch (Open / Medium / Firm on Fox; Open / Pedal / Lock on RockShox). This switch adds a large amount of LSC — typically equivalent to closing the LSC dial 6–10 clicks. It is a quick way to reduce pedalling bob on smooth climbs without re-tuning your normal setting. Use the climb switch for pedalling efficiency, use the LSC dial for ride quality. Never use the lockout position on technical climbs — the suspension cannot track the trail and you will lose traction. For descents, always return the switch to fully Open before adjusting the LSC dial.
Frequently asked questions
What is the difference between LSC and HSC?
LSC (Low Speed Compression) controls damping for slow suspension movements: braking, pedalling forces, and gradual compressions. HSC (High Speed Compression) controls fast impacts: square-edged rocks, drops, and high-speed hits. They affect different shaft speeds in the damper, not riding speed.
Do Fox and RockShox count compression clicks the same way?
Yes for compression — both Fox and the modern RockShox Charger 3 damper count compression clicks from fully CLOSED (firmest). However, RockShox counts REBOUND clicks from fully OPEN (fastest), while Fox counts rebound from fully closed (slowest). The confusion is real: compression is the same direction across brands, but rebound is opposite. Always check your specific damper manual.
Should I use the same compression settings front and rear?
No. The rear shock typically needs slightly more LSC than the fork because the leverage ratio amplifies low-speed inputs (pedalling, G-outs) through the linkage. HSC can be matched or slightly less than the fork. A good test: ride the same section twice and feel if front or rear bottoms out first — add HSC to whichever bottoms first.
My fork has a 3-position switch, not clicks — what should I use?
Budget forks (Fox Rhythm, RockShox Select) use a 3-position climb switch instead of click-adjustable LSC. Use Open position for descents, Medium/Pedal for rolling trails or rough climbs, Firm/Lock for smooth seated climbs only. Never use Lock on technical climbs — you lose traction. The 3-position switch is essentially a preset LSC at three fixed levels.
Should I start with more or less compression?
Start with the manufacturer's mid-range setting and adjust from there. Most Fox and RockShox forks leave the factory close to mid-range compression. Adding too much compression makes the ride harsh; too little causes excessive dive and poor small-bump sensitivity.
My fork dives a lot under braking — which adjuster?
Braking dive is a low-speed movement, so increase LSC (turn clockwise, add damping) by 2 clicks. If dive is still excessive after 4 clicks, also check that sag is set correctly, as too much sag increases braking dive.
My fork feels harsh over small roots and pebbles — fix?
Reduce LSC by 2 clicks (counterclockwise). Small-bump sensitivity is primarily controlled by LSC and negative spring volume. If reducing LSC makes the fork dive too much under braking, you may need a volume spacer removed or a different damper tune.
What is platform/pedalling mode?
Many trail and enduro forks and shocks offer a platform mode (ProPedal on RockShox, Trail mode on Fox) which adds LSC specifically to reduce bobbing while pedalling. This is separate from the main LSC adjuster. Use platform mode while climbing, open it for descents.
Does compression affect sag?
No — compression damping does not affect the static sag. Sag is determined by air spring pressure alone. You can change compression damping without affecting sag or rebound settings.
What is the correct setup order?
Always set up in this order: 1) Sag (air pressure first). 2) Rebound. 3) LSC. 4) HSC. Setting sag first ensures the spring rate is correct before tuning damping. Tuning compression before sag is set correctly wastes time as you will need to readjust.
My shock has only one compression adjuster — which is it?
Budget and mid-range shocks (RockShox Select, Fox Float Performance) typically have a single compression adjuster that blends LSC and HSC. Use the LSC value from this calculator as your starting point. Dedicated LSC and HSC adjusters appear on Shimano, Fox Factory, and RockShox Ultimate level components.