How To Set Dirt Bike Suspension: Sag, Clickers And Setup By Rider Weight

Start With A Bike That Is Ready To Set Up

Setup only works on suspension that is in good shape. Check that the fork seals are dry, the linkage and swingarm bearings move freely, and the fork and shock are within their service intervals. Owner's manuals put suspension service on an hour schedule for a reason: the 2026 KTM 450 SX-F manual calls for fork service and shock service every 45 operating hours. If your bike is overdue, service it first and set it up afterwards.

Also check the basics that change ride height and feel: tire pressures, chain slack and fuel level. Factory Connection recommends measuring with the fuel tank at least three-quarters full so the bike's weight matches how you ride it.

Race Sag Versus Static Sag

Race sag, also called rider sag or riding sag, is how far the rear suspension compresses from fully extended with you sitting on the bike in full riding gear. It sets the bike's ride height and geometry, so it changes how the bike turns and how stable it feels.

Static sag, also called free sag, is how far the rear compresses under the weight of the bike alone. Factory Connection describes rider sag as the measurement that should always be set, and free sag as the check that confirms the correct spring rate is installed. Static sag is not something you set directly. It tells you whether the spring is right for you.

How To Measure Race Sag, Step By Step

You need a helper, a tape measure or sag scale, and a fixed reference point on the rear fender directly above the rear axle. KTM's owner's manual describes the same three-measurement method below.

1. Measure fully extended. Put the bike on a stand so the rear wheel hangs free. Measure from the center of the rear axle straight up to your reference mark. This is dimension A in KTM's manual (L1 in Race Tech's method).
2. Get on in full gear. Take the bike off the stand. With a helper holding the bike upright, sit in your normal riding position with your feet on the footpegs and bounce a few times so the suspension settles.
3. Measure loaded. Have the helper measure from the axle to the same mark again. KTM calls this dimension C.
4. Calculate. Race sag is the fully extended measurement minus the loaded measurement (A minus C).
5. Remove stiction. Race Tech's method takes the loaded measurement twice, once after pushing the rear down and letting it rise and once after lifting it and letting it settle, and averages them: Sag = L1 minus ((L2 + L3) / 2). If the two readings differ by more than 4 or 5 mm, Race Tech says the linkage needs attention.
6. Measure the same way every time. Factory Connection warns that measuring from a point outside the swingarm arc can throw the reading off by as much as 15 mm. Use the same marks and the same stand every time.

How To Measure Static Sag

1. Measure fully extended with the rear wheel off the ground, exactly as above.
2. Put the bike on the ground with no rider. Hold it upright and let it settle.
3. Measure from the axle to the same mark. Static sag is the extended measurement minus this one.

Sag Targets From Owner's Manuals

Your owner's manual gives the target for your bike. These examples show the range manufacturers use:

Honda's CRF450R handbook explains the trade-off well: less race sag (90 mm) helps the bike turn on tight tracks at a small cost in straight-line stability, while more race sag (110 mm) adds stability on faster tracks but turns slightly worse.

Adjusting Race Sag With Preload

Race sag is adjusted with the shock spring preload collar. More preload raises the rear and reduces sag; less preload lowers the rear and increases sag. Loosen the lock ring, turn the adjusting ring, retighten, and measure again. Keep going until race sag matches your manual. Clean the threads first, and follow your manual's instructions, because some bikes require the shock to be removed to change preload or springs.

Spring Rate By Rider Weight

Once race sag is set, measure static sag. This is where you find out if the spring suits you. Honda's 2004 CRF450R handbook gives a static sag window of 10 to 25 mm once race sag is set, and says that if the bike sags more than 25 mm under its own weight, the spring is too stiff for your weight. The opposite case is a spring that is too soft: Honda notes it needs so much preload to reach race sag that the rear tops out when the rider gets off, which shows up as very little static sag.

Manufacturers set their bikes up for an average rider. KTM's manuals state that its off-road bikes are delivered for a standard rider weight of 75 to 85 kg (165 to 187 lb) in full protective clothing. They add that small weight differences can be corrected with shock preload, but large differences need different springs. Honda's 2004 CRF450R handbook says its fork springs were about right for riders weighing 150 to 160 lb without gear.

Spring rates are model specific, and Factory Connection notes that the right spring depends on weight, height, ability and intended use, not weight alone. They also stress that springs are chosen to carry the rider's load, not to make the suspension feel stiffer or softer. That job belongs to the clickers.

Setting An Air Fork For Your Weight

Many current motocross bikes use air forks, where pressure replaces the spring. The 2026 KTM 450 SX-F uses a WP XACT air fork and lists pressures by rider weight:

These pressures change between model years, so use the manual for your exact bike. The 2024 KTM 450 SX-F manual has no rider weight table: it lists one standard pressure, 10.4 bar (151 psi) for the SX-F EU and BR and 10.7 bar (155 psi) for the SX-F US, changed in 0.2 bar (3 psi) steps within the same 7 to 12 bar range.

KTM's manual says to raise the pressure if the fork bottoms out frequently and never to set it outside the allowed range. Check it under the same conditions each time, at the earliest 5 minutes after switching the engine off, with the bike on a stand so the front wheel is unloaded (KTM 2024 owner's manuals).

Clicker Basics

Clickers adjust damping, which controls how fast the suspension moves. They do not hold the bike up. That is the spring's job.

• Compression damping slows the suspension as it compresses. More compression holds the bike up in big hits and under braking but can feel harsh on small bumps.
• Rebound damping slows the suspension as it extends. Too little and the bike kicks and feels nervous. Too much and the suspension packs down through a series of bumps.
• High-speed and low-speed compression. KTM's manual notes that these refer to how fast the shock compresses, not how fast the bike is moving. High-speed compression shows up on sharp hits and jump landings; low-speed compression shows up in slower movements such as weight transfer.
• Direction. KTM's manual states that turning an adjuster clockwise increases damping and counterclockwise reduces it. Settings are counted out from fully closed.

Start from the manual's standard settings. As an example, the 2026 KTM 450 SX-F (standard models, SX-F EU and BR) lists a standard shock low-speed compression of 15 clicks out, high-speed compression of 1.5 turns out, shock rebound of 15 clicks out, and fork compression of 12 clicks out, with Comfort and Sport alternatives either side. Make one change at a time, two clicks at a time, on a section of track you know, and note the result.

Troubleshooting Table

Use this table after sag and spring rate are confirmed. If a fix needs huge clicker changes, go back and check springs and sag.

Race vs trail. Follow the suspension schedule printed for your bike and the way you ride it. KTM lists fork and shock service at 45 hours on both its 250 SX motocross bike and its 300 XC-W enduro bike (KTM 2026 250/300 SX OM, PDF p. 40; KTM 2026 XC-W OM, PDF p. 55). Honda's CRF250R race bike changes fork oil about every 22.5 hours, while the CRF450X trail schedule only inspects the suspension every 1,200 miles or 12 months (Honda CRF250R 2025 OM, PDF p. 44; CRF450X 2025 OM, PDF p. 47). Pro suspension tech Bones Bacon says no interval is set in stone, and that sand is harder on suspension than hard-pack. His method is to log hours, notice when you keep adding stiffer and slower clicks to get the same feel, and ask the tech how worn the parts were, then build your own timeline. He also says the oil is usually the last thing to wear out, so a fork oil change alone is not a full service.

Keep A Setup Log

Write down race sag, static sag, spring rates, air pressure and every clicker position, with the date, track and conditions. Suspension changes slowly as oil ages, so a log also tells you when the bike has drifted from where it was good. In MotoMind you can keep these notes with the bike, track the suspension service intervals by engine hours, and give the sag check task a date interval if you want a push reminder to re-measure.

Skip the arithmetic with the free dirt bike sag calculator, which compares your numbers with KTM, Husqvarna, GASGAS and Honda manual targets. For controls, tire pressure and gearing, and setup advice by rider level, see the dirt bike setup guide.

Model-specific setup notes: YZ250F setup guide, YZ125 setup guide, CRF250R setup guide, and the general 4-stroke and 2-stroke setup guides.