Tyre worn flat in the centre

The tread is worn into a flat band in the middle, while the edges still have deep tread. Seen from behind, the round profile looks square. This is normal on bikes that ride mostly upright on straight roads, especially rear tyres carrying heavy loads. Over-inflation and hard acceleration make it worse. A squared tyre feels slow to lean, then drops suddenly into turns.

Is it safe to ride?

Yes, while the centre tread is above the wear limit. Once the centre reaches the wear indicators, replace the tyre: grip in rain is poor.

Quick checks first

• Measure the tread depth in the centre and at the edges.
• Check cold pressure with a good gauge.
• Note how the bike is used: long straight roads, heavy loads, passengers.
• Does the bike feel reluctant to lean, or fall into corners?

Diagnose it step by step

1. Is the centre tread at or below the wear indicators or the wear limit? (K-Light 125 manual: 1 mm; local law may set more.)

• Yes: replace the tyre now (Replace a tyre).
• No: go to step 2.

2Is the cold pressure above your bike's value?

• Yes: set it correctly (Check tyre pressure). Too much air makes the tyre ride on its centre and wear it faster.
• No: go to step 3.

3Is the pressure too low for the load (passenger, cargo)?

• Yes: under-inflation with heavy loads also wears and heats the tyre. Use the loaded value from your manual, if given.
• No: go to step 4.

4Is the wear even from side to side across the flat band?

• Yes: this is normal wear for your type of riding. Plan a replacement, and check pressure weekly.
• No, more on one side: check wheel alignment and chain adjuster marks (Inspect tyres for wear and damage, Bike pulls to one side).

5Does the bike feel unstable or weave at speed?

• Yes: a squared tyre can contribute. Also check Bike weaves at high speed.
• No: ride on and monitor.

Causes, most likely first

Reference values (K-Light 125)