Motorcycle tire tread depth: how to measure and when to replace

To check motorcycle tire tread depth, look for the tread wear indicators molded into the grooves, or measure the groove depth with a tread depth gauge in more than one place across the tire. Federal rules require motorcycle tires to have wear indicators that show when the tread has worn to 0.8 mm (one thirty-second of an inch), which is the point of "worn out," not a comfortable point to ride on. Replace tires before that, especially if you ride in the rain.

This guide shows how to measure, how to read wear patterns, and when to stop and replace the tire.

What is the minimum tread depth for a motorcycle tire?

The federal tire standard (FMVSS 119) says motorcycle tires must carry at least three treadwear indicators that let you see by eye when the tire has worn down to 0.8 mm, or one thirty-second of an inch. That is a manufacturing requirement for the tire, and it marks when the tire is considered worn out.

Some key points:

• The 0.8 mm figure is shallower than the 1.6 mm (two thirty-second) figure often quoted for car tires. Do not apply car-tire advice to motorcycle tires.
• State laws and inspection rules differ. Some states have a specific tread requirement, some set rules for tires in general, and some have no periodic inspection at all. Check your state motor vehicle agency. Our guide to whether your motorcycle needs a state inspection covers the basics.
• The legal or indicator minimum is not a safety target. Tires lose wet grip and handling feel before they reach it, and the tire's profile and condition matter as much as groove depth.

If you are weighing when to change a tire (and whether to replace both tires at once), the question is not "is it legal" but "does it still perform the way I need."

Why tread depth matters on a motorcycle

Tread channels water out from under the contact patch. As grooves wear shallow, the tire has less capacity to move water and can lose grip in wet conditions. A motorcycle's contact patch is small, so a small loss of grip matters more than it does on a car.

Tread depth is only part of the picture. The Motorcycle Safety Foundation's T-CLOCS checklist asks riders to check tires for "tread depth, wear, weathering, evenly seated, bulges, embedded objects," and to check air pressure when the tires are cold. Use all of those checks, not just depth.

Tools you need

• Tread depth gauge (a small, inexpensive tool, in millimeters or thirty-seconds of an inch). Use one with a narrow base that fits motorcycle grooves.
• A flashlight
• A tire pressure gauge, because pressure affects wear and your readings
• A paddock stand or center stand if you want to spin the wheel
• Rags, to clean dirt out of grooves
• Your owner's manual, for tire size and pressure

You do not need a torque wrench to inspect tires.

If a tire is due, our walkthrough on how to change a motorcycle tire covers the job, and our FAQ on whether you can mix motorcycle tire brands helps when you replace only one.

How to measure motorcycle tire tread depth

1. Check tires cold and clean

Measure when the tires are cold and the grooves are clear. Dirt and stones can hide the true depth.

2. Find the wear indicators

Look at the shoulder of the tire for small arrows, triangles or letters such as "TWI". They point to wear indicator bars molded across the base of the main grooves. When the tread surface is level with the bar, the tire has reached its wear limit. Check the indicators in several places around the tire.

3. Measure with a gauge

Press the gauge's pin into a main groove at the center of the tread, until the base sits flat on the tread blocks. Read the depth. Move the gauge around the circumference and take readings at several points. Do the same on both shoulders. Write the numbers down so you can see the trend.

4. Compare center and shoulders

On the rear, the center usually wears first for riders who spend a lot of time upright. The shoulders wear when you corner often. Read each zone on its own. A tire can look fine at the shoulders and be worn out in the center.

5. Check for uneven or unusual wear

Walk around the tire and feel it with your hand (engine off, bike stable). Look for:

• A flat strip down the center, called squaring off
• Cupping, scalloping or uneven patches
• Wear on only one side
• Cracks in the sidewall or in the grooves
• Bulges, cuts or embedded nails or stones

6. Check pressure, age and damage too

Check pressure with a gauge, using the number in your manual. See our guide to motorcycle tire pressure. Read the date code on the sidewall. Our tire date code guide explains how. A tire with deep tread can still be too old.

7. Decide

Replace the tire if it is at the wear indicators, damaged, badly cracked or flat in the center. Replace earlier if the bike no longer feels stable or grips as it used to. If you are not sure, a tire shop can look at it in minutes.

How to read tread depth numbers

Tire makers set a new-tire depth that varies by model and size. Because there is no single universal number, use the table below as a way to think about it rather than a set of pass/fail marks.

What you see	What it likely means	What to do
Tread clearly deep, even wear, no cracks	Healthy tire	Keep checking monthly
Tread getting shallow, especially in the center	Getting close to replacement	Plan to replace soon and avoid wet riding
Wear indicator bars level with tread	At the manufacturer's wear limit	Replace now
Flat or squared-off center	Profile changed, handling may suffer	Replace even if grooves remain
Cracks, cuts, bulges, cords showing	Structural damage	Stop riding and replace
Deep tread but old date code	Rubber has aged	Have a shop inspect it

Front and rear tire wear

	Front	Rear
Typical wear	Slower, often wears on the edges of the tread	Faster, often wears down the center
Common cause of fast wear	Heavy braking, low pressure	Hard acceleration, long highway miles, heavy load
Notes	Front tires often cup if suspension or pressure is off	Replace sooner than the front on most bikes

Do not assume the rear and front wear out at the same time. Check both. If you replace one, ask the tire shop whether to match brands or models, and check your manual for approved sizes.

Factors that change wear

• Riding style: Hard acceleration, hard braking and aggressive cornering wear faster.
• Tire pressure: Too low or too high pressure changes the contact patch and wear pattern.
• Load: Passengers and luggage add stress.
• Road surface and temperature: Rough or hot roads wear tires faster.
• Tire compound: Sport tires are often softer and may wear faster than touring tires.
• Suspension and alignment: Worn suspension or a bent wheel causes uneven wear.

Our guide on how long motorcycle tires last covers life expectancy, and the tire selection guide helps you pick what to buy.

What does it cost to replace tires?

Costs depend on tire size, brand and type, plus shop mounting and balancing fees. Varies by bike, region and shop. See our tire replacement cost guide for typical ranges.

When to see a mechanic

Stop riding and see a tire shop or mechanic if:

• Tread has reached the wear indicators
• You see cords, bulges, cuts or deep cracks
• The tire is losing air, or you see a nail or screw in it
• Wear is uneven on one side or in patches
• The bike wobbles, pulls to one side or feels unstable
• Your tires are old even if the tread looks good
• You are not sure what you are looking at

Do not try to repair or "boot" a bad tire for the road. Mounting, balancing and torquing wheel hardware are jobs for someone with the right equipment. Our tire shop services page lists specialists, and you can compare shops in your own city through the motorcycle repair directory.

Quick checklist

• Check tread depth at the center and both shoulders with a gauge.
• Find the wear indicators and replace before they show.
• Look for cracks, cuts, bulges and flat spots.
• Check pressure cold and read the date code.
• When in doubt, replace the tire.