When your lawn mower isn’t cutting evenly it can really show—in streaks, ridges, or patches of grass left too long or cut too short. A big reason can be that the mower deck isn’t level. In this post I walk you through why deck leveling matters, how to do it step by step, and a few extra pro tips to get the best cut.

Why Deck Leveling Matters

Your mower deck is the platform under which the blade (or blades) spin. If the deck is tilted or out of alignment:

One side of the cut might be lower than the other → the lawn looks uneven.

If the front of the deck is too high relative to the rear, you may not cut effectively or you might mulch poorly.

If the deck is too low in the front you risk “scalping” the lawn (cutting into the soil) when riding over uneven ground.

A properly levelled deck ensures that all blade tips are at the same relative height and the deck has the right “pitch” front to back.

In short: accurate deck leveling = cleaner cut + less turf stress + better results.

Pre-Adjustment Checklist

Before you touch link rods, nuts or bolts, make sure you have the foundation right:

Park the mower on a flat, level surface. A concrete pad or flat driveway is ideal.

Engage the parking brake, shut off the engine, remove key/power and disconnect spark plug or battery (safety first).

Check tyre/tire pressures: Uneven tyre pressure means the machine tilts, which makes deck leveling useless until you fix that. For many riding mowers the rear tyres may be at about 10 psi and the front tyres around 14 psi (but always check your machine’s manual).

Set the deck to its mid-cut height (this makes the leveling process work at a realistic height).

Ensure the blades are in good condition (not bent, balanced) and the deck is clear of debris. A warped or damaged deck/spindle will compromise anything you do.

Step-by-Step: Leveling the Deck

Here is a general procedure (for a riding mower or large walk-behind with multiple blades). Always consult your specific model’s manual for exact specs.

 1. Level the deck Side-to-Side

With the blades disengaged, rotate one blade so the tip is facing directly left → right (i.e., the blade points across the deck).

Measure the height of the blade tip above the ground on the left side and then on the right side.

The difference between left & right should be very small — typically no more than about 1/8″ (≈ 3 mm).

If there is a difference, adjust the lift link or side-adjuster rod on the lower-side until the heights match. Each turn of the adjusting nut will raise/lower one side.

2. Set the front-to-back pitch

Now rotate a blade so its tip faces front → rear of the deck.

Measure blade tip height at the front and at the rear of the deck.

Most manufacturers recommend the front blade tip be slightly lower than the rear — common range around 1/8″ to 1/4″ (≈3-6 mm) lower at the front. This helps draw grass up into the blade and improves cut while aiding discharge.

To adjust: loosen the jam-nut on the front link/adjuster, then turn the adjuster nut until the desired difference is achieved. Retighten jam-nut.

3. Re-check everything

Once you’ve done side-to-side and front-to-back, go back and re-measure both axes (because one adjustment can slightly affect the other).

Make a test mow: set the deck to your usual cutting height and mow a short strip. Inspect for ridges, uneven length, or visible tilt.

If there’s still an issue, check for a bent blade, worn spindle or warped deck shell — those can undermine even perfect link adjustments.