Tire Siping: What It Is, Pros & Cons, and Is It Worth It?

Short answer: Tire siping cuts thin slits across a tire's tread to add more biting edges. It is mainly done to improve grip on snow and ice. Siping can be worth it on all-season and all-terrain tires that see winter driving. It is not right for every tire, and some tire makers exclude siped tires from warranty coverage, so check the tire's warranty first.

This guide covers what siping is, how a tire siping machine works, the pros and cons, and when it makes sense for drivers and for a tire shop. You can compare the machines we carry on our tire siping machines and tire grooving tools page.

What is tire siping?

A sipe is a thin slit cut into a tread block. Many tires already leave the factory with molded sipes, especially winter tires. Aftermarket siping adds more of these slits with a machine, usually cut across the tread at a set depth. Each new slit adds edges that can bite into snow and ice, and lets the tread blocks flex a little more as they meet the road.

How a tire siping machine works

A siping machine holds the tire and turns it slowly while a set of rotating blades crosses the tread, cutting the sipes to a fixed depth. Two machines on our site show how this works in practice:

• TSI STE-M Tire Siper: sipes both non-mounted and mounted tires on the same machine. Expandable rims cover non-mounted tires from 13" to 24.5". A tire can be mounted, siped and dismounted in about 3 to 4 minutes. Adapters are sold separately.
• TSI ST Tire Siper: sipes most tires from 12" to 24.5" with the available adapters, in as little as 4 minutes per tire. It comes with twelve cutting blades and four lead screws for siping depths of 5/32", 7/32", 9/32" and 11/32".

Both TSI machines can sipe new, recapped or used tires as long as the tire has at least 5/32" of tread left. Accessories include the 6005 Automated Cycle Feed, which moves the blade across the tire on the STE-M without hand cranking, and the WLA-STE-M Wheel Lift Attachment for lifting heavy tires onto the STE-M.

Pros of tire siping

• More biting edges on snow and ice. This is the main reason drivers ask for siping.
• Works on tires you already own. On our machines, new, recapped and used tires with at least 5/32" of tread can be siped.
• A quick shop service. On the TSI machines above, a tire takes a few minutes.

Cons and when not to sipe

• Warranty. Some tire makers exclude siped tires. For example, Yokohama's limited warranty lists tread siping among the treatments that are not accepted for warranty if the treatment causes a failure, and some brands state that any siping voids the warranty. Read the warranty for the specific tire before siping it.
• Not every tire is a good candidate. Shops that offer siping commonly advise against it for summer and high-performance tires, and for tires that are already heavily siped, such as dedicated winter tires.
• Low tread. Our siping machines need at least 5/32" of tread. A worn tire has little depth left to sipe and may be due for replacement anyway.
• Handling trade-offs. Because siping lets tread blocks flex more, it can affect wet and dry handling and braking on some tires.

Siping vs. regrooving

Siping and regrooving are often confused. Siping cuts thin slits into the existing tread. Regrooving cuts the tread pattern deeper into the undertread rubber, and it should only be done on tires designed for it, which are marked "Regroovable" on the sidewall. Federal motor carrier rules also limit where regrooved tires can run. For example, a bus may not run regrooved tires on its front wheels (49 CFR 393.75). Our SG Upright Groover is listed for re-grooving approved truck, bus and fleet tires, and the RHHG Rillfit Hand Held Groover shapes and cuts groovable tires.

Is tire siping worth it?

For drivers: siping is most useful on all-season or all-terrain tires that will see some snow, ice or slush. If you already run dedicated winter tires, or your tire's warranty excludes siping, it is usually not worth it.

For tire shops: siping can be an add-on service in regions with winter weather. When choosing a machine, check:

• Whether you need to sipe mounted tires, non-mounted tires or both. The STE-M does both.
• The tire sizes you see most, and which adapters you need, such as the 6138 19.5" adapter or the 6143 22.5" adapter.
• Whether an automated feed is worth it for your volume.

Frequently asked questions

What is tire siping?

Tire siping is the process of cutting thin slits across a tire's tread with a machine. The slits add biting edges that help grip on snow and ice.

Does siping void a tire warranty?

It depends on the tire maker. Some warranties exclude siped tires, or exclude failures caused by siping. Check the warranty for the specific tire before siping.

How much tread do you need to sipe a tire?

The TSI siping machines we sell need at least 5/32" of tread left on the tire.

Can used tires be siped?

Yes. On the TSI ST and STE-M, new, recapped and used tires can be siped as long as they have at least 5/32" of tread.

How long does siping take?

On the TSI STE-M, a tire can be mounted, siped and dismounted in about 3 to 4 minutes. The TSI ST takes as little as 4 minutes per tire.

Is siping the same as regrooving?

No. Siping adds thin slits to the existing tread. Regrooving cuts the tread deeper and is only for tires marked "Regroovable".

Ready to add siping to your shop? Browse tire siping machines, adapters and grooving tools, or contact us with your tire sizes and we will help you match a machine and adapters.