Why does "Rear spins / loses traction on climbs" happen?

The most common causes are: Rear tire pressure, Finding traction on steep, slippery climbs, Low-speed compression. Check them in this order; it is often the setup, sometimes the technique.

All symptoms

Rear spins / loses traction on climbs

When your bike shows "Rear spins / loses traction on climbs", these are the most likely causes - ranked by relevance: Rear tire pressure, Finding traction on steep, slippery climbs, Low-speed compression. LAISA separates setup causes (adjusters, components) from riding technique.

Short answer for this problem

Recommended starting point: Check first: Tire: Rear tire pressure
Most important change: Smallest documented change: 0.05 bar
Why: Too much rear pressure shrinks the contact patch - lower it (easy with a mousse) for more grip.
How to test it: Read the current value off the bike and compare it with the recommended one. Write it down before you change anything.
Source: LAISA diagnosis catalogue, drafted automatically and editorially released Methodology →
Last reviewed: No review date documented

Pick your bike to apply the fixes directly →

The order comes from the stored strength of the symptom-cause link in the catalogue - per symptom, not across symptoms. These are not probabilities and not measurements.

Suspension

Shock: Low-speed compressionCheck next

Why this could fit: The rear low-speed compression is too firm - the wheel can't follow the ground; open it a little.

How to check it: Read the current value off the bike and compare it with the recommended one. Write it down before you change anything.

Smallest change: 1 click - clicks out from fully closed

Shock: SagRarer

Why this could fit: Too little sag lifts the rear out of its working range - check your sag.

How to check it: Read the current value off the bike and compare it with the recommended one. Write it down before you change anything.

Smallest change: 1 mm - loaded, rider in gear

Tires

Tire: Rear tire pressureCheck first

Why this could fit: Too much rear pressure shrinks the contact patch - lower it (easy with a mousse) for more grip.

How to check it: Read the current value off the bike and compare it with the recommended one. Write it down before you change anything.

Smallest change: 0.05 bar

Technique

Finding traction on steep, slippery climbsCheck first

Why this could fit: Snatchy throttle and too much weight forward break traction - sit down, smooth and early on the gas.

How to check it: Ride the drill deliberately for a few laps on the same section and watch whether the behaviour changes.

How to set your sag →

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Related symptoms

Arm pump after a few laps Engine stalls in tight technical sections Fork harsh on small roots and braking bumps Front deflects off roots and rocks

A starting point to verify on the bike - not a safety guarantee. Change one thing at a time and check on track.