Flat tires suck. Even worse than getting a flat on your car or truck is being unable to change your tire. And there isn’t much worse than thinking you’re prepared–with a good lug nut wrench, portable jack, and properly inflated spare tire–and finding your old lug nuts are stuck on and won’t budge.

Here are several of your options:

• Call professional roadside assistance
• Use a penetrating oil to break rust free
• Buy a longer wrench or extend your wrench to free “over-torqued” lug nuts

What causes a lug nut to get stuck?

Rust and overtightening. In rare cases, lug nuts left in place for years will rust to the threads of the studs that hold your tire and rim in place. It’s more common to find your lug nuts were overtightened by a mechanic. But the result is the same: you have a flat tire and find you can’t change it by hand.

Rust happens. A lug nut left in place for years will rust, and it may be difficult to spin it off its threads. Enough force should “break” it free of this rust and leave it spinning easier. A purpose-designed penetrating oil may dissolve the rust in your way. Even tapping the head of the bolts with a hammer may vibrate the rust free and allow you to spin your lug nuts.

Most mechanics use air-powered and electrical “impact wrenches” to speed up jobs. But if they aren’t careful, these advanced tools allow them to tighten lug nuts much more than you can release by hand. It’s smart to make certain all your lug nuts are loose enough that you can free them up with whatever wrench you carry in your vehicle. If you tighten them as much as possible with this wrench, you should be safe to remove them with the same wrench.

How do you loosen a lug nut that won’t budge?

If possible, get roadside assistance from a professional with the right tools. There are several ways you can safely apply more pressure to the lug nut: find a longer wrench, extend your wrench with a length of pipe, or even put some weight on the wrench handle. A penetrating oil can also free up any rust that has formed on your lug nuts.

A flat tire is a bummer. But injuring yourself while trying to free up a lug nut is a quick way to turn a bad day into a worse day. If you are trying to change a tire and find your lug nuts won’t budge, your best option is to call for roadside assistance. A professional with an electric impact wrench or a long wrench called a “breaker bar” can free up even the tightest lug nuts–safely.

If you notice that your lug nuts won’t budge while inspecting your car, you have a few options. If you suspect they are rusted in place, you can buy some penetrating oil and try spraying them. Let it soak through the rust between the lug nuts and threads for a few hours before spraying them again. Eventually, it may dissolve enough rust that the lug nut will spin freely.

You can also try a longer, sturdier tool than the lug wrench that came with your car. One option is a “four-way” purpose-built lug wrench. Another is the proper size socket and a breaker bar. Either of these may offer enough leverage to loosen stuck lug nuts.

Breaking a stuck lug nut free in an emergency

In an emergency situation, such as a flat tire while off-roading, you can increase your leverage to loosen a lug nut that won’t budge. One trick for stuck lug nuts is to fit a length of pipe over the handle of your breaker bar or wrench to make it even longer. You can also set the handle of your wrench horizontal with the ground and press it down with your foot. If this doesn’t work, you can stand on the handle. Be very careful to hang on to something (such as a roof rack) in case the lug nut does break free.

I’ve talked to folks who dropped a rock onto their wrench handle to break stuck lug nuts free. Personally, I would rather have one or even two people carefully step on the wrench handle, as a rock could ricochet and hurt you.

See some tricks for stuck lug nuts yourself in the video below:

Can I use WD40 to loosen a lug nut?

WD-40 is a multi-use oil and not the best penetrating oil to dissolve rust and loosen stuck lug nuts. But if it’s the only tool you have, it can’t hurt to try. A better tool would be a specifically designed penetrating oil.

To be blunt, WD-40 is like an adjustable wrench or a pair of vice grips. It is a genius multi-purpose tool, but it is never as effective as single-purpose tools. It can be used as a moisture displacer, lubricant, rust preventative, and penetrating oil. But WD-40 will never do as good a job dissolving rust between a lug nut and threads as a real penetrating oil.

Purpose-built alternatives include: Blaster PB Spray, Liquid Wrench penetrating oil, Sea Foam penetrating oil, and WD-40 “specialist” rust release penetrant spray.

Next, read about the major upgrades to your tire-changing tools you should make to be prepared, or find out what to do if your rim is rusted in place instead of your lug nuts.

You can see more tips on safely jacking up your car and changing its tire in the video below: