Dirt Bike Bearing Maintenance: Wheels, Steering Head, Swingarm And Linkage

Where The Bearings Are On A Dirt Bike

Everything on the chassis that turns or pivots rides on bearings. The steering stem turns on two bearings in the frame's head tube. Each wheel hub carries sealed ball bearings with spacers between them. The swingarm pivots on bearings at the frame, and the rear shock works through a linkage with three more pivots of its own. KTM's manuals call the swingarm the link fork, so when the KTM service schedule says "fork bearing" it means the swingarm pivot.

Press each step to light up one location. The hint under the figure gives KTM's check interval and torque for that bearing.

These bearings carry the whole bike and rider through every landing, and they sit in the dirtiest places on the machine. The linkage lives right behind the rear tire, in the roost. The steering head sits behind the number plate where mud packs in. None of them is visible without taking something apart, which is why they get ignored until the bike starts to feel wrong.

Why Pressure Washing Kills Bearings

A sealed bearing is two hardened steel rings, called races, with a row of steel balls rolling between them in grease. A rubber lip seal on each side keeps the grease in and the water out. That lip is designed to hold back splash and mud. It is not designed to hold back a jet of water at pressure washer force.

Both factories say so in writing. Honda's 2025 CRF250R owner's manual says not to use high-pressure washers, and if you do, to avoid spraying the steering head bearings, suspension pivot points, drive chain, brake master cylinders and several electrical parts. KTM's 2024 250 SX-F manual says high pressure forces water into bearings, tells you not to aim the jet at bearings, and gives a minimum distance of 60 cm (23.6 in) between the nozzle and the part.

Drag the nozzle slider, then press the steps. Inside KTM's 60 cm line the lip starts to lift and water gets past it.

Once water is inside, three things happen. The grease thins out and washes away. The bare races start to rust. Then the balls roll over rough, pitted steel. Bearing engineers at SKF describe a related failure called false brinelling, where vibration while the bearing is not turning wipes out the lubricant film and wears small dents into the race at the same spacing as the balls. A steering head is a likely candidate because it barely rotates when you ride in a straight line while the whole front end vibrates. That last point is our reading of the SKF description, not something SKF says about motorcycles.

Whatever made the dents, the result is the same. The balls drop into the low spots, and you feel each one as a click or a notch.

Symptoms Of Worn Dirt Bike Bearings

• Notchy steering. The bars want to sit in the center or catch at certain angles. KTM calls these detent positions.
• A clunk from the front end. Play in the steering head lets the stem shift in the head tube when you brake or rock the bike.
• Vague or wandering front end. Loose steering bearings let the front wheel move off line, and a notchy head makes small corrections feel sticky.
• A wheel that rocks on the axle. Grab the tire at the top and bottom and push and pull. Any knock is play in the wheel bearings.
• A gritty or rough wheel spin. Spin the wheel by hand with the brake pads not dragging. It should run smooth and quiet.
• A harsh rear end on a fresh shock. A dry, notchy linkage fights the shock. Our troubleshooting guide points at linkage bearings when a rebuilt shock still feels stiff.
• Uneven brake pad or chain wear. Honda ties wheel alignment to brake pad life, and play in the swingarm or wheel bearings lets the rear wheel sit crooked.

The wheel-rocking and spin tests are long-standing shop practice rather than steps printed in the owner's manuals. KTM's manual simply tells you to check each wheel bearing for damage and wear when the wheel is out.

How To Check Steering Head Bearings

This is KTM's procedure from the 2024 250 SX-F owner's manual, and it works on any bike.

1. Put the bike on a lift stand so the front wheel is off the ground.
2. Point the bars straight ahead. Grab the fork legs and push them back and forth in the direction of travel. KTM says play should not be detectable.
3. Turn the bars slowly from lock to lock. They must move easily over the whole range with no detent positions.

Try it on the figure below. Rock the forks, turn the bars, then use the sliders to see what the adjuster screw is actually doing.

The sliders show why a torque spec is only half the story. Bolt torque, clamp force and thread friction are tied together by T = K x F x d, where K is the torque coefficient and d is the bolt diameter. NASA's fastener design manual notes that the textbook K of 0.2 is only a rough figure, that about 0.15 is more typical for steel on steel, and that controlling preload by torque alone is only good to about 15 to 30 percent. Clean the threads, use exactly what the manual specifies, and recheck the play after you tighten everything.

KTM is blunt about play. Its manual says to correct it immediately, because riding with play damages the bearings and the bearing seats in the frame over time. Honda puts the steering head bearings on the pre-ride inspection list in the 2025 CRF250R manual.

Adjusting Steering Head Play On A KTM

Source: KTM 250 SX-F 2024 owner's manual, PDF p. 70. The bottom triple clamp screws are M8 at 12 Nm (8.9 lbf ft), torque table PDF p. 160. If the bars are still notchy after you set the play, adjustment will not fix it. The races are damaged and the bearings need replacing.

How To Check Wheel, Swingarm And Linkage Bearings

Wheel bearings

With the bike on a stand, rock each wheel by the tire at the top and bottom, then spin it and feel for roughness. When the wheel is out, KTM's procedure is to check each wheel bearing for damage and wear and replace a bad one, clean and grease the shaft seal rings and the contact faces of the spacers with long-life grease, and lightly grease the wheel spindle before reinstalling. After the front wheel goes in, KTM has you pump the front brake and compress the fork a few times so the fork legs line up before tightening the axle clamps. KTM also notes that a chain adjusted too tight wears the rear wheel bearings faster, so check your chain slack while you are back there.

Swingarm and shock linkage

KTM's schedule lists a check of the swingarm bearing and the shock absorber heim joint for play, plus the shock linkage. A common shop check is to unload the shock, lift the rear wheel and feel for side play at the swingarm, then move the swingarm through its travel and feel for notches or binding. While it is apart, look over the frame and swingarm for cracks. KTM does not allow repairs to either part.

If the linkage pivots are dry, rusty or notchy, they need to come apart, get cleaned and regreased, and any pitted needle bearings, sleeves or seals replaced. That job is easy to put off and it is the one that makes a suspension setup feel wrong no matter how you set the clickers. See how dirt bike suspension works for what the linkage does.

Chassis Bearing Torque Specs (KTM 250 SX-F)

Source: KTM 250 SX-F 2024 owner's manual, torque table PDF p. 160. The KTM 250/300 SX and XC two-stroke and 450 SX-F manuals list the same pivot and linkage values. Honda's CRF250R and CRF450R owner's manuals do not print chassis bearing torques and send you to the Honda service manual for these jobs. Use the numbers for your exact model and year, and keep them in one place with our torque specs page.

These are safety fasteners. A loose axle, pivot or steering clamp can drop you on the track. Use a calibrated torque wrench, never guess.

How Often To Grease And Check Dirt Bike Bearings

Sources: KTM 250 SX-F 2024 owner's manual service schedule, PDF p. 41 to 42; Honda CRF250R 2025 owner's manual maintenance schedule, PDF p. 44 and pre-ride inspection, PDF p. 45. The KTM 450 SX-F and 250/300 SX and XC manuals follow the same pattern.

The trail schedules split differently by brand. KTM's 2026 300 XC-W enduro manual keeps the same bearing checks as the race bikes, with steering play and wheel bearing play every 15 hours and steering head grease every 45 hours, and its PDS rear end has no linkage row (PDF p. 54 to 55). Honda's CRF250F trail bike inspects the steering head bearings after the first 100 miles, then at 1,200 miles (12 months) and 2,400 miles (24 months), and checks wheels and tires every 600 miles, with no linkage grease interval (CRF250F 2025 OM, PDF p. 53). Follow the schedule printed for your own bike. Race schedules assume racing, and mud, water crossings and frequent washing shorten every bearing interval.

The two factories do not agree, and it is worth saying plainly. On their motocross race bikes, Honda greases the linkage every 7.5 hours of racing. KTM's owner's manual table only calls for a linkage check every 15 hours and has no separate linkage greasing line. Honda inspects the steering head bearings every 22.5 hours, while KTM greases them every 45. If you ride in mud, water crossings or wash the bike often, use the shorter number. KTM's own manual says heavy rain, mud and sand can justify shorter intervals than its table. You can see each brand's full schedule on our KTM 250 SX-F and Honda CRF250R pages.

How To Wash A Dirt Bike Without Killing The Bearings

1. Plug the exhaust outlet so water cannot get in.
2. Knock the loose mud off with a soft stream of water first. KTM's washing procedure starts with a soft jet.
3. Use warm water, motorcycle cleaner and a brush or sponge on the heavy dirt. Never put cleaner on a dry bike.
4. If you use a pressure washer, keep it at least 60 cm (23.6 in) from bearings, seals and electrics, per KTM, and keep it off the steering head, wheel hubs, swingarm pivot and linkage, per Honda.
5. Let the bike dry, then lubricate the moving parts and pivot points once it has cooled, as KTM recommends after washing.
6. Pump the brakes a few times at low speed before you ride to dry the pads and rotors.

When To Hand It To A Shop

Checking play and greasing seals is home-garage work. Replacing bearings is a step up. Wheel bearings and steering head races are pressed into place, and steering races are seated in the frame. Driving them out crooked or hammering on the wrong surface damages the new bearing or the bore. If you do not have the right drivers and pullers, a shop will press them for a modest bill. Have a shop look at any crack in the frame or swingarm, since KTM does not permit repairs to either.

Track Bearing Service By Hours

On a Honda CRF250R race bike, a 7.5 hour linkage interval comes around in a few weekends. MotoMind tracks engine hours, entered by hand or added by its GPS ride tracker, and shows tasks like steering head bearing, linkage grease, swingarm bearing and wash and inspect as upcoming, due or overdue in the app. You can log the parts and cost of each job and export the service history as a PDF. Hour-based tasks show their status in the app; date-based tasks such as a 24 month steering head grease can also send a reminder.

FAQ

How do I know if my dirt bike steering head bearings are bad?

Put the bike on a stand, point the bars straight and rock the fork legs back and forth. Any play you can feel is a problem. Then turn the bars lock to lock. If they catch, click into the center or feel notchy, the races are pitted and the bearings need replacing.

How often should I grease steering head bearings on a dirt bike?

Follow the schedule for your own bike. KTM’s 2024 250 SX-F motocross manual and its 2026 300 XC-W enduro manual both say to check play every 15 hours and lubricate the steering head every 45 hours or 24 months. Honda’s 2025 CRF250R race manual inspects them every 9 races, about 22.5 hours, and its CRF250F trail bike at 1,200 and 2,400 miles. Mud and frequent washing justify the shorter end.

Does pressure washing ruin dirt bike bearings?

It can. Honda’s owner’s manual says not to use high-pressure washers and to keep the spray off steering head bearings and suspension pivots. KTM says high pressure forces water into bearings and to keep the nozzle at least 60 cm (23.6 in) away.

How often should I grease the linkage on a dirt bike?

Honda lubricates the swingarm and shock linkage every 3 races, about 7.5 hours, on its CRF250R and CRF450R motocross race bikes. KTM’s SX-F owner’s manual checks the linkage every 15 hours and the swingarm bearing every 45 hours. Honda’s CRF250F trail schedule has no linkage grease interval. KTM says heavy rain, mud and sand can call for shorter intervals than its table.

How do you check dirt bike wheel bearings?

With the wheel off the ground, grab the tire at the top and bottom and rock it, then spin it and feel for roughness. With the wheel out, turn each bearing with a finger. KTM checks wheel bearing play every 15 hours on both its race and enduro bikes and greases the seals and spacers at every wheel install.

Can you just tighten notchy steering head bearings?

No. Tightening removes play, but notches come from pitted races. If the bars still click into a notch after the play is set to spec, replace the bearings and races.

What torque is a KTM rear axle nut?

KTM lists 80 Nm (59 lbf ft) for the M22x1.5 rear wheel spindle nut and 35 Nm (25.8 lbf ft) for the M20x1.5 front spindle screw on the 2024 250 SX-F. Check your own model’s manual.