How to Repair a Cut Tire Sidewall with Vulcanizing Compound

Can you repair a cut tire sidewall? In some cases, yes — especially on off-road, rock crawling, ATV, UTV, farm, equipment, and other non-road-use tires.

After slicing the sidewall on one of my 40-inch Maxxis Trepador sticky tires during a rock crawling trip, I wanted to see if the tire could be saved instead of throwing away an expensive tire that still had plenty of life left in it.

This was not a normal plug repair. A sidewall cut needs a much more involved repair process using proper tire prep, primer, vulcanizing compound, and, depending on the damage, an internal tire patch.

In this article, I’ll walk through the basic process we used to repair the cut sidewall, the tools and materials involved, and where to find the actual vulcanizing compound used in the video.

Quick Answer

A cut tire sidewall can sometimes be repaired on off-road, ATV, UTV, farm, equipment, and other non-road-use tires
This is not the same as plugging a tread puncture
A proper sidewall repair requires cleaning, grinding, rubber prep, primer, vulcanizing repair compound, and sometimes an internal patch
My tire held air, so this repair was mostly rebuilding the damaged rubber on the outside of the sidewall
It is possible to repair large holes but you will be grinding a large hole in the side of an expensive tire and putting a patch on the inside
If the cut goes through the casing or cords, an internal tire patch may also be required
This type of repair is intended for off-road and specialty tire use. Use proper judgment and follow local laws and tire industry safety standards before attempting any sidewall repair on a highway vehicle.

Important Sidewall Tire Repair Warning

Before getting into the process, this needs to be said clearly: sidewall repairs are not something to mess around with on normal road-going passenger tires.

This article and video are focused on off-road and specialty tires where people are often trying to save expensive tires used on trail rigs, rock crawlers, ATVs, UTVs, farm equipment, mud trucks, and similar non-road-use applications.

If this is a highway tire, daily-driver tire, tow rig tire, or anything carrying your family down the road at speed, use proper judgment and follow local laws and tire industry standards. A sidewall failure at speed can be extremely dangerous.

In my case, this was a 40-inch sticky compound rock crawling tire used on an off-road rig, not a normal highway tire.

The Tire Damage

The tire in this repair was a 40×13.5 Maxxis Trepador sticky compound tire on a 17″ steel weld-on beadlock wheel.

I had been running the tires at around 7 PSI, and between the weight of the rig, the low pressure, and the usual rocks, stumps, and trail abuse, I ended up slicing a gash into the sidewall. Trepadors are not known for the strongest sidewalls, especially at single digit pressures.

The damage was not the end of the world, but it was not something I wanted to keep wheeling on without repairing. These tires are expensive, so saving the tire was worth the effort.

Tools and Materials Used for the Tire Sidewall Repair

This is the important part. The biggest issue with this kind of repair is that most people know the repair is possible, but they do not know what product to use or where to get it.

Here are the main products and tools used in this repair:

Check out all my recommended shop tools and equipment here: Pathmaker Amazon Storefront

Some of the links above are Amazon affiliate links. If you buy through them, I may earn a small commission at no extra cost to you. It helps support the videos, trail repairs, and tech articles on this site.

Looking for the Vulcanizing Compound? This is the hard-to-find part of the repair.

Shop the Vulcanizing Compound

Step 1: Remove the Tire from the Rig

The first step was getting the tire off the rig. I removed the valve core, let the air out, and pulled the tire and wheel off.

Step 2: Break the Bead and Remove the Tire from the Wheel

If you have access to a tire machine, this part is obviously easier.

I did not have a tire machine, so I used the usual sketchy home-shop method: a Hi-Lift jack, pry bars, wedges, and too much effort.

Sticky tires are even more annoying because they do not just stick to rocks — they also stick to the wheels.
I used a Hi-Lift jack under the rock slider with a block of wood against the tire sidewall to push the bead down and break it loose from the wheel.

Once the bead was broken, tire spoons or a tire machine will get the tire completely off the wheel. After the rim was removed we could actually see the sidewall damage properly and start prepping it for a proper sidewall tire repair.

Step 3: Open Up the Sidewall Cut

This part feels wrong, but it is important.

To repair the sidewall properly, you need to open up the damaged area enough to find the end of the crack and expose fresh rubber. If you just smear repair compound over the outside of the cut, you are not really repairing the damage.

The damaged rubber needs to be ground, feathered, and cleaned so the repair compound can bond into the tire instead of just sitting on top.

Think of it like prepping a crack before welding. You do not just weld over the surface. You open it up, clean it, and give the repair material somewhere to go.

On this tire, the cut did not go all the way through the casing. That meant my repair was mostly rebuilding the damaged rubber on the outside of the tire. If your tire is cut all the way through, the repair becomes more involved and may require an internal patch.

Step 4: Grind and Feather the Damaged Rubber

The next step is grinding the damaged area and feathering the edges of the repair zone with the grinder cup in the tire repair tool kit.

The goal is to remove loose rubber, expose clean rubber, and create a smooth transition for the vulcanizing compound. You want the repair area rough enough for bonding, but you do not want to unnecessarily grind into the cords or casing.

If you see broken cords, separated belts, or the tire is cut right through, you need to be much more careful. That is where an internal patch becomes important because you are no longer just rebuilding surface rubber.
If you have broken cords or the hole goes all the way through you have to grind back far enough to find uncut cords. A small sidewall cut can quickly turn into a much larger repair once you start chasing damaged cords and grinding back to solid material. A one-inch slice can easily become a fist-sized repair area.

Step 5: Clean the Repair Area

Once the damaged area is ground and feathered, it needs to be cleaned properly.

This step matters. Dirt, rubber dust, grease, old tire slime, and general shop filth will all hurt the repair. Clean the repair area thoroughly before applying primer or repair compound.

In the video, we used rubber cleaner and worked the area until the fresh rubber was clean and ready for the next step. Use the scraper from the repair kit to remove any remaining contamination and expose fresh clean rubber before moving onto primer.

This is also the point where you should decide whether the tire needs an internal patch. If the cut goes through the casing, or if the cords are damaged badly enough, the outside repair alone may not be enough.

Step 6: Apply Tire Repair Primer

After cleaning, the next step is applying the SC-BL Cement Primer that comes in the vulcanizing compound kit I recommend.

The primer helps the repair material bond to the tire. Do not rush this step and do not contaminate the surface after it has been cleaned and prepped.

A small brush or disposable applicator works well for getting primer into the repair area.

Step 7: Mix the Vulcanizing Compound

The repair compound used in this video is a two-part vulcanizing compound. It has a black part VC4-A and a white part VC4-B that are mixed together in equal amounts.

Once mixed, the compound becomes the material used to rebuild the damaged sidewall rubber.

This is the product that makes this repair different from a basic plug, glue, or tire slime repair. The compound is designed to bond into the tire and cure into rubber.

You cannot wear gloves for this next step — you just have to trust the process.

Mix equal amounts of the two compounds together by hand and start kneading them thoroughly. It gets sticky, messy, and takes far longer than you expect.

After several minutes the compound begins activating, stops sticking to your hands as badly, and starts turning into a putty-like ball. Continue kneading until the consistency feels similar to Silly Putty.

Hard-to-Find Tire Repair Compound The vulcanizing compound is the key product in this repair. It is often sold through tire repair suppliers or dealers, which is why a lot of people have trouble finding it.

Get the Vulcanizing Compound Here

Step 8: Apply the Repair Compound

Once the compound is mixed, push it into the repair area and work it into the prepared rubber.

You want to force the compound into the cut, not just smear it over the top. If the tire is cut through, the compound may need to be pushed through from the outside and worked from both sides before the internal patch is installed.

In my case, the tire still held air, so the repair was focused on rebuilding the damaged sidewall rubber and sealing the cut area properly.

Work the compound into the prepared area, shape it as best you can, and rebuild the damaged sidewall. It will probably look ugly at first. That is normal. Keep working it around and as it cures it will smooth out.

Step 9: Let the Repair Cure

After the compound is applied, the repair needs time to cure.

Do not rush this part. Let the repair material set up properly before reinstalling the tire, airing it up, or putting it back into service.

The exact cure time can depend on the compound used, temperature, and repair size, so follow the instructions for the product you are using. You typically want at least 24hrs with the temperatures above 16*C or 60*F.

Step 10: Add an Internal Tire Patch if Needed

Not every sidewall repair will need the same patch process.

My tire did not need an internal patch because the cut did not go all the way through and the tire still held air. But if the tire is cut through the casing or the cords are damaged badly enough, an internal patch may be required.

Now that the outer compound is cured you can grind the inside of the compound smooth, use the rubber cleaner again and scraper to clean surface and apply the patch.

When using a reinforced tire patch, pay attention to orientation. Many sidewall patches have markings showing which direction should face the bead. That matters because the reinforcement in the patch needs to line up correctly.

Use the SC-BL Cement Primer on the cleaned rubber. Put the Tire Patch Cement on the inside of the tire and apply patch to the inside of the tire, lining up arrows toward belts. Roll out air bubbles and allow another 24hrs to cure.

This is the type of tire patch used for repairs like this.

Step 11: Reinstall the Tire

Once the repair is cured, reinstall the tire on the wheel.

In my case, because I had been having some inner bead issues with these tires compared to my old Iroks, I also added a couple wraps of Gorilla Tape around the inner bead area of the wheel before remounting the tire. This can really help your inner bead staying on at low pressures.

That was not part of the sidewall repair itself, but it helped tighten up the bead fit on this specific tire and wheel setup.
You can check out a video of that process here.

Once the tire was remounted, I reinstalled the beadlock ring, aired the tire up, and put it back on the rig.

Can You Repair a Sidewall Cut with a Tire Plug?

A tire plug can work well for some tread punctures or small holes, but a sidewall cut is a different problem. A tire plug is great for getting you off the trail after a tread puncture, but a sliced sidewall is a completely different type of repair.

For a sidewall cut, you need to think in terms of rebuilding the damaged rubber, bonding the repair properly, and adding reinforcement if the casing is compromised.

A plug kit is still worth carrying on the trail, but it is not the same as a proper vulcanizing repair.

This is the tire plug kit style I recommend carrying for normal trail punctures.

What Tires Can This Type of Repair Work On?

This kind of vulcanizing repair is most relevant for expensive specialty tires where replacing the tire may not be the first choice.

Examples include:

Off-road tires
Rock crawling tires
Sticky compound tires
Mud terrain tires
ATV tires
UTV tires
Farm tires
Agricultural tires
Equipment tires
Other non-road-use tires

Was the Tire Worth Repairing?

For me, yes.

A 40-inch sticky compound Maxxis Trepador is not a cheap tire, worth almost $1000. Throwing it away over a sidewall cut that had not gone all the way through the casing would have been painful and unnecessary.

With the right prep, the right compound, and help from someone who had done this before, it made sense to repair the tire and keep using it on the trail.

Final Thoughts

Repairing a cut tire sidewall is not the same as plugging a nail hole in the tread.

If the tire is used on-road at highway speeds, sidewall damage should be taken very seriously. But for off-road, ATV, UTV, farm, equipment, and other specialty tires, a proper vulcanizing repair can sometimes save an expensive tire that would otherwise be junk.

The biggest thing is using the right materials. Do not just smear glue into a cut and hope for the best. Proper prep, primer, vulcanizing compound, and the correct patch when needed are what make this type of repair possible.

If you want to see the full repair process, watch the video below.

Watch the Full Tire Sidewall Repair Video

This video walks through the full process including tire removal, breaking the bead, grinding the damaged rubber, cleaning, primer, mixing the compound, applying the repair material, curing, and reinstalling the tire.

Tools and Products Used in This Video

Check out all my recommended shop tools and equipment here: Pathmaker Amazon Storefront

Some of the links above are Amazon affiliate links. If you buy through them, I may earn a small commission at no extra cost to you.

How to Repair a Cut Tire Sidewall with Vulcanizing Compound