Words Dean Mellor
A tubeless tyre retains air pressure thanks to the seal between the bead of the tyre and the rim of the wheel. If this seal is broken the tyre will need to be reseated on to the rim.
Down at your local tyre shop or service station, seating the tyre’s bead onto a rim is a straightforward process; once the tyre is in place just pump in high-pressure air through the valve stem and voila! The tyre will pop into place with a bang. But when you’re out in the scrub and you’re relying on your portable 12V air compressor to pump up a deflated tyre, it likely won’t be able to provide enough air fast enough to easily reseat the bead. Fortunately, there are a couple of tricks that will make the job not only possible, but also quite easy.
If you’re out four-wheel driving and a tyre has come off the rim there’s a good chance it’s going to be dirty. Whether dusty, sandy or full of mud, the first thing you’ll need to do is clean up the inside of the rim and the tyre bead where the two surfaces will meet to create a seal. If you don’t, chances are the seal won’t be good and air will leak out from between the tyre and the rim.
When you have new tyres fitted to your vehicle, or you have a tyre repaired at the local servo, the tyre fitter will liberally coat the tyre bead with a lubricant such as Rim Ease. This helps the tyre bead to slide up the inner surface of the wheel rim as air pressure builds inside the tyre
Of course, when you’re out in the bush you might not have such a lubricant on hand, but if you can find a substitute it will make reseating the bead much easier. If you’re out camping, chances are you’ll have some dishwashing liquid or other soap, which can be mixed with water and applied around the tyre bead and the inside of the wheel. Alternatively, you could apply some grease to this area or spray it with a water dispersant lubricant such as WD-40, or a silicone spray.
Despite most 12V air compressors not being able to supply a huge volume of air in a hurry, which is precisely what you want when trying to reseat a bead, there’s always a chance that manipulating the tyre by standing on it and moving around while inflating will create enough of a seal between the bead and the rim for inflation to begin, at which point reseating of the bead will eventually take place as pressure builds.
Sometimes you’ll have to exceed the recommended tyre inflation pressure before the bead reseats against the rim, in which case you’ll just need to let some air out after it has sealed completely.
Make sure you never get your hands too close to the tyre bead and the rim of the wheel while inflating, because you never know when it’s going to reseat… and when it does you don’t want to get your fingers caught in there.
Still no seal?
If you’re still struggling to attain a seal between the tyre and rim and the wheel, wrap a ratchet strap around the tyre and ratchet in until the tyre flexes enough to create a seal. Start inflating the tyre and, if you see pressure building up you’ll know there’s now a seal, in which case you can loosen and remove the ratchet strap. Again, don’t get your hands anywhere near the bead and the rim while inflating.
Check for leaks around the bead of the tyre and at the valve by pouring over soapy water and looking for air bubbles. If it’s all good, put the wheel back on the rig and you’ll be on your way.