Getting a new bike is exciting, but heading straight for the trails without checking yoursuspension can ruin the ride. Properly tuned suspension helps isolate you from bumps andkeeps your wheels planted for better traction and control. In this guide I’ll walk you through how I set up both the fork and rear shock on a fresh bike, so you can hit the dirt with confidence.

Sag refers to how much your fork or shock compresses under your weight[1]. Too little sag andthe bike will feel harsh; too much and you’ll blow through the travel and lose efficiency.Manufacturers provide recommended sag ranges based on travel and bike category –cross-country bikes with 80–100 mm of travel typically run 15–25 % sag, trail bikes with 100–160 mm travel around 20–30 %, and freeride/downhill bikes 25–35 %[1]. Staying within theseranges helps the suspension follow the terrain and keeps the tyres gripping the ground[2].

1. Gather your gear

Put on everything you normally ride with – shoes, helmet, pack, even water bottles. Suspensionis tuned to rider weight, and leaving gear off will result in less sag than you have on the trail.You’ll also need a high-pressure shock pump and a measuring tape or the sag indicators printedon your fork and shock.

2. Prepare the fork

• Release lock-outs and open rebound: Turn off any lock-out levers and wind therebound adjuster to its fastest or most open setting. Cycle the fork up and down a fewtimes to reduce stiction and make sure it’s moving freely.
• Set baseline air pressure: Most modern forks have a pressure chart printed on the back of the leg. Use this as a starting point, pumping air in or out until you hit thesuggested pressure for your weight.
• Measure and adjust sag: Slide the fork’s O-ring down to the dust seal, then carefullyclimb on the bike without bouncing. Adopt a neutral attack position and gently wiggleor back-pedal to let the fork settle. Dismount without compressing it further. The O-ringshould indicate roughly 20–30 % sag for a trail bike[1]. Too much sag means you need toadd air; too little means you should let some out. Remember to cycle the fork a fewtimes after each adjustment to equalise the pressure.
• Dial in rebound: Starting from the slowest setting, compress the fork and feel how itreturns. Gradually open the rebound one click at a time until the fork extends quicklybut doesn’t kick back or top out[2]. A good test is to roll off a curb – the fork shouldcompress and return once without pogoing.

3. Set up the rear shock

The rear shock follows the same principles as the fork:

• Baseline pressure: Many brands offer pressure guides based on rider weight. Use yourshock pump to reach the suggested starting psi.
• Sag: With the O-ring against the seal, sit on the bike in a neutral position and gentlypedal to settle the suspension. You’re aiming for roughly a quarter to a third of theshock’s travel, matching the 20–30 % sag window for trail bikes[1]. Adjust pressure andcycle the shock after each change.
• Rebound: Close the rebound adjuster fully, then open it incrementally until the shockreturns smoothly without bucking you off the saddle. Manufacturers often listrecommended rebound settings as a starting point.

4. Final checks and maintenance tips

Once both ends feel balanced, check that front and rear sag are in a similar range and that thesuspension rebounds at comparable speeds. After each ride, wipe the fork and shock stanchionswith a soft cloth to remove dirt and prevent scratches; damaged stanchions can tear seals andshorten the life of your suspension[3]. REI also recommends performing regular maintenanceor having your suspension serviced annually or after about 100 hours of riding[3].

If you’ve just bought a new mountain bike or haven’t adjusted your suspension since unboxingit, this guide is for you. Even experienced riders can benefit from revisiting sag and reboundsettings when switching to a new frame or when their riding kit changes. Correctly setsuspension keeps your wheels planted and your body comfortable, which means moreconfidence and more fun on the trail.