FIX

Whether it happens out on the road or overnight while you’re sleeping (and you discover it when you open your garage to grab your bike to head out for a ride), a flat tire is a bummer.

Unless a leaky valve stem is the culprit, your tubeless tire almost certainly has a hole in it (and typically somewhere on the tread surface), so replacing the tire is really the only proper long-term fix.

But that can take days and will cost you $200$300, or more. So unless you have the time and patience for that, and your air loss is due to a simple and common middle-half-of-the-tread puncture such as that caused by a nail or screw (and not a sidewall or edge-of-tread wound), you’re left with the temporary quick-fix option — which is to plug the tire.

Your typical rope-plug installation. Looks messy, works pretty well. Right: Aerostich’s compact “tire repairification” kit, which includes plugs, patches, cement, tools and a handy air compressor for roadside re-inflation duty. $87 at aerostich.com

ROPE, SPEAR or MUSHROOM?

If you haven’t been down this road before, you may well ask yourself, “What sort of plug?” It’s a good question. If you’re simply looking to temporarily fix the tire without removing it from the wheel, you’re looking at two options: a “rope-type” (or “spear-type”) plug, or a “mushroom” plug.

Both involve inserting a rubber plug of a particular shape (thus the “rope” and “mushroom” descriptors) into the hole created by the nail or screw (or whatever) with a special tool. Keep in mind that a larger or non-linear/jagged hole often renders these two methods ineffective, as the plugs are designed for small, narrow-diameter holes, and not ones caused by tearing or slicing from, say, a piece of sharp steel, etc. In the latter case, a tire replacement is your only option.

Rope- and spear-type plugs are typically pretty similar, with rope plugs getting slathered with some sort of rubber cement goo before being pushed into the tire with the aforementioned special tool per kit instructions. Once they’re in place and the tool has been removed, the goo dries and bonds the plug to the rubber and belts below the tread surface.

There’s usually some extra plug material sticking out of the tire once the tool is pulled out; you can slice it off at tread level with a razor blade or knife, or leave it alone, as it will wear off pretty quickly once you get back on your bike.

The spear-type plug works basically the same way, but typically uses no bonding agent. Our experience says to go with the rope-type, which has shown to be more secure and tends to hold more air and for a longer period.

The mushroom-shaped plug goes into the tire in similar fashion, but has a bulbous head on it that ends up — once you’ve yanked on the excess plug material from the outside — sealing against the inside of the tire, with a little help from the pressure inside the tire. You’d think this type of plug would be ideal, but testing results we’ve seen show this type, like the spear-type, to be less effective than the tried-’n’-true rope-type plug.

BETTER, BUT TRICKIER

Don’t confuse mushroom-type plugs with an “internal patch” plug, which is actually the most effective and long-term fix for a small and linear hole because it’s done from the inside of the tire, which means pulling it off the rim, something you can’t do along the side of the road. This method involves a ropeor spear-type plug with a integral patch on the inside that bonds via pressure and adhesive to the inside of the carcass.

And that is the issue here; if you have the time to have the tire pulled off the rim, you’re better off replacing it, as about half of tire manufacturers, when asked, will tell you to never use a plug in a holed tire, with the other half saying it’s okay but only in very limited situations. You’d expect that given the product-liability situation in this country, and in many cases that is good advice. But if you need a quick fix for temporary use, plugs do work if installed correctly in an appropriate hole. Just follow the directions in the kit you’ve purchased for the job.

There are stories galore out there about folks who’ve ridden thousands of miles with a plugged tire. We don’t recommend that, as you’re taking a risk, but this author can report that, when he first purchased his 2013 Ducati Multistrada last summer, its nearly-new Pirelli Angel GT rear tire had a temporary plug in the center of the rear tire — and he rode it for a couple of weeks while waiting for a new set of Michelin Road 6s to arrive…with no issues.

Just be wary out there when you’re pluggin’ away, eh?

—Mitch Boehm