Clutch Control

The clutch is precision traction. It meters torque in smaller steps than your throttle hand can, keeps the bike moving below walking pace, and lets you recover when the trail gets too steep, tight or broken for clean momentum.

Hard enduro spends much of its time at walking pace or slower, on roots, rock steps, steep loose climbs and off-camber switchbacks where the rear tyre is always close to spinning. A spinning tyre digs, loses drive and throws you off line. The clutch is what stops that happening. With the throttle held steady, a small movement of the lever changes drive to the tyre smoothly, so it grips instead of spinning.

That is why top riders talk about the clutch as much as the throttle. Sherco rider Cooper Abbott told Enduro21 that on big, steep climbs he keeps the front end down "because you're able to modulate, you're making small changes with the clutch". Dirt Bike Magazine's balance feature holds a bike's pressure against two logs using "the clutch, rear brake and a steady throttle". Neither of those is possible with the throttle alone. On a steep pitch at Sea to Sky, Graham Jarvis talks through the order: he builds the revs up first, then slips the clutch in to pull himself forward.

The clutch also buys you recovery. When you stall on a hill, drop into a hole or hit a root at the wrong angle, a rider with a good clutch hand can stop, hold the bike and go again. A rider without one lets it roll back or pins it and hopes.

Pull the lever and the clutch plates separate; the engine spins but nothing reaches the rear wheel. Let it out fully and the plates lock together; all the engine's drive goes to the tyre. The friction zone is the band in between, where the plates slip against each other and pass on only part of the drive.

Three things follow from that:

• Small lever movements make big differences. The useful part of the friction zone is a short stretch of the lever's travel. That is why you control it with fingertips, not a fist.
• Slip makes heat. Every moment the plates slip, energy turns into heat in the plates and the oil. KTM's owner's manual for its 250 and 300 two-strokes says it plainly: "Avoid frequent and longer slipping of the clutch. This causes the gear oil, engine and cooling system to heat up." Short, deliberate slips are fine. Riding the whole trail half-engaged is not.
• The bite point moves. It changes from bike to bike and shifts as the clutch wears or its adjustment changes. Find it by feel at the start of every ride instead of trusting a remembered lever position.

Some clutches are easier to control than others. Abbott switched to a diaphragm-spring clutch because it gave "a good modulation and a smooth release point", where many clutches feel "more on-off". You don't need special parts to learn clutch control, but it helps to know that clutches do differ and that some fade sooner on long climbs.

A lever you can't reach with relaxed fingers makes clutch control harder than it needs to be. Check these before your first session:

• Reach. Stand on the pegs in your normal riding position. With your index and middle fingers resting on the lever, you should be able to pull it without stretching or letting go of the grip with your other fingers. On hydraulic clutches, such as the one on KTM's 2024 250 and 300 EXC, reach is set with an adjusting screw at the lever. KTM's manual says to set it "to your hand size", turn the screw by hand only and never adjust it while riding.
• Angle. Rotate the lever on the bar so your wrist is straight when you stand. A lever set flat for sitting forces your wrist to bend when you stand, which tires the forearm and dulls feel. The arm pump guide covers lever setup alongside the other habits that spare your forearms.
• Free play (cable clutches). A cable clutch needs a little slack so the plates are fully engaged when the lever is out. Dirt Rider says a clutch adjusted too tight "will not only wear out your clutch plates quicker and make your clutch fade sooner", and that you should check free play with the engine cool, not hot.
• Fluid (hydraulic clutches). KTM notes that the fluid level in the handlebar reservoir "rises with increasing wear of the clutch facing discs". If the bite point wanders or the lever feels soft, check the reservoir and bleed or service the system as your manual describes.

If you run an automatic or assisted clutch, the skills below still apply for when you pull the lever. For how sprocket choice affects clutch heat, see the gearing guide.

Clutch control works best from a relaxed body. Stand with your knees and hips bent, your weight through the balls of your feet on the pegs, and your elbows soft. If you grip the bars hard, your fingers lose the feel of the bite point.

One finger or two? Both work, and top riders use both. Dirt Rider tells beginners to use the middle and index fingers because it will "allow your other two fingers to hang onto the handlebar". Johnny Aubert, testing KTM's clutchless gearbox prototype at Erzberg, told Enduro21 he has always ridden "with one finger on the lever". Start with two if the pull is heavy or your hands are small. Move to one once the bike's lever and your hand allow it. Never use all four: you lose your grip on the bar the moment you pull the lever.

Keep your right foot over the rear brake pedal. The rear brake is the other half of clutch control. It holds the bike still, stops it rolling back and brings the front wheel down if you give it too much. You will use the two together in almost every drill below. The body positioning lesson covers the standing stance in more detail.

Work through these in order on flat, open ground with good grip. Stay at each step until it feels boring, then move on. Keep the throttle steady throughout: the point is to teach your left hand, not your right.

Use a flat, grippy area with a gentle slope nearby. Take a two-minute break every ten minutes so the clutch and your hand can cool.