This month’s column may be a bit controversial and against the advice of some of the tyre experts, as it includes some tricks that should really only be used in the case of a dire emergency.
Fact is, countless times we’ve been stuck on the roadside with a torn sidewall, or marooned in a dune with a tyre off its rim. What do you do in these situations, and how can you get home safely?
Let me first be clear that once a tyre has a torn sidewall, it is ruined and must be replaced. However, the problem arises – as it has with me on several occasions – where one has already used up the spare and the only tyre available had a cut in the sidewall large enough to force two fingers through it.
Staying on the roadside is out of the question, and calling for help deep in the Karoo is not only likely to cost as much as two new sets of tyres, but could take several days. In this case, ‘boer-maak-’n-plan’ mode sets in, and the puncture repair plugs come out. Be sure, at this stage, to have a full puncture repair kit including the awls, glue and plenty of plugs. And, of course, a compressor.
If the hole is small enough, a normal tyre plug can be used, and (in a couple of cases where I lacked the tools to perform a decent repair) I’ve used up to four doubled-up plugs, making eight cords, to block a sidewall hole. Note that anything larger than 1cm is all but impossible to plug.
The problem with plugging a sidewall is that a sidewall flexes, and as it gets warmer, the plugs slowly wiggle their way out. You have to drive at around 60km/h to prevent heat build-up − in addition to which, the slower speed is a safety precaution. I have found through experience with multi-plug sidewall emergency-fixes that normal road pressure should be used to reduce sidewall flex.
Any extra glue you can use to secure the plugs in place will also come in handy: this includes rubber cement or contact adhesive. I’ve even used melted glue sticks, which proved effective in sealing the leaks around the bunch of plugs in the sidewall.
I repeat, this sort of fix is very definitely a last resort. However, on one occasion, I managed to travel 350km at 60km/h with four plugs in the sidewall covered in big lumps of glue before I reached a tyre shop and was able to replace the tyre.
A much better option than a big lump of plugs, which have a high chance of failing, is to use patches. These were very common in older puncture-repair kits used for tubes, but can still be sourced in a world that’s moved to tubeless tyres. You could also augment your repair kit with thin wire and/or tough nylon thread, which can be used to ‘stitch’ a severely slashed sidewall.
Whatever the extent of the repair, you’ll first need to remove the wheel from the vehicle and get the tyre off the bead of the rim so that the puncture is accessible. This is easier said, than done. One method is to put the tyre under the vehicle to secure it, and use your car jack (or high-lift jack) to compress the sidewall, which will pop it off the bead. You’ll have to use large tyre levers to remove the damaged tyre completely off the rim to give you access to the inside wall.
Scrub the affected area with soapy water, and then use an abrasive tool in the puncture repair kit, or sandpaper, to roughen up the area before applying your rubber cement. Once the rubber cement is sticky, apply the largest patch that you have to block the hole from the inside. You could also source the so-called ‘mushroom plugs’ used by repair shops, and include these in your puncture kit, as they are more effective for larger cuts and holes.
This method should be far safer and more reliable than simply gluing a bunch of plugs in, but it takes significantly more effort. After you’ve levered the tyre back onto the rim, re-seat the bead with the steps mentioned below.
Re-beading a tyre
When driving off-road at extremely low pressures, such as when tackling sand dunes, the likelihood is very high of your tyre de-beading – unseating from the rim and losing its pressure. Thankfully, re-seating a tyre is easy enough, using the right techniques. This is the process:
1. The vehicle must be jacked up and the bead inspected. If the bead is dirty, or gummed with mud or sand, then wipe it clean it with a sponge and water. If there are stones or sand or water inside the tyre, do your best to remove most of it before you attempt to get to a safe area where the tyre can be blasted clean properly. Having detritus roaming around inside the tyre will cause an imbalance and may well damage your tyre long-term.
2. With the wheel off the ground and the bead clean, use a compressor to inflate the tyre while you and a buddy grasp the outer perimeter of the tyre and attempt to pull the de-beaded side of the tyre towards the rim. If both sides are de-beaded and air is still escaping, a ratchet strap wrapped around the circumference of the tyre and tightened to bulge the sidewalls will help the bead seal against the rim.
3. While inflating the tyre, wait for the loud pop as the tyre re-seats against the rim. If both sides were de-beaded, then wait for two loud pops, and remember that it may take up to four bars of pressure to re-seat the bead. Soapy water along the edge of the rim will make re-seating much easier.
A controversial and potentially dangerous method for reseating a bead is the ‘deodorant explosion’ method that you’ve probably seen on YouTube. This method re-seats the tyre by inserting a flammable gas from a can of deodorant (or the butane from a lighter) into the tyre cavity when it’s off the bead, and lighting it. Use a long-nozzle camping lighter to get the flame into the right place. As the liquid/gas ignites, it rapidly expands, reseating the bead. Because the bead is seated and the explosion is starved of oxygen, the tyre shouldn’t explode. This method does work, but takes some skill and speed to ensure that your hands are out of harm’s way. Don’t overdo the gas insertion.
The bottom line? When overlanding, and especially when you do not have a second spare, be prepared with a full puncture kit. In addition to plugs and awls, be sure to include mushroom plugs, rubber patches and wire/twine. Other vital hardware in your repair kit should include a high-lift jack (or standard hydraulic/scissor jack at a pinch), tyre levers, and an air compressor that can reliably deliver a high air volume. Practice a plug repair at home, so that you know what the drill is when you are out in the boondocks and conditions are far from ideal.
Disclaimer: This information is offered in good faith, and is intended as a guideline only. SA4x4 accepts no liability. use common sense, and engage your brain before engaging the gear lever.
By Andrew Middleton