28 Jul, 2016

Messy Business, Part Deux!

Following on from the previous issue, where The Gentleman Racer discussed what to do when your tyres decide to leave you in the lurch… in the middle of nowhere… this month we delve into what happens when all of the tips, tricks and solutions we’ve already given you don’t work.
So, a shard of glass from a broken bottle has slashed the sidewall of your tyre and left a hole way too big for even a wad of your biggest tyre plugs (see pic 1). There is no hope of repairing this, the only thing to do is to make a plan to get home. But wait, because this is where the tried and trusted tyre gater comes into play. (It’s a good idea to have one of these stashed with your spares).
A gater is generally a swath of rubber just big enough to cover an area roughly a third of a tyre’s interior surface width and about five centimetres in length. The idea behind a gater is to line the inside of a tyre, sitting between an inner tube and the tyre, preventing the inflated inner tube popping out from the sidewall slash.
Installing a gater is much the same as putting in a tube, as discussed in last month’s issue, only one places the gater between the tube and the slashed tyre (see pic 2). Again, check the interior of the tyre for thorns, as this might puncture the tube. Nine times out of 10 this fix will get you to the finish, where you can deal with the aftermath over a few cold ones!
Oftentimes I’m asked to remove tyre plugs from a tyre and patch the hole, as many folks trust a vulcanized patch more than a simple plug. This can be a simple long-term fix, but judgement needs to be exercised as to the viability of patching. Sometimes a hole is just too big, for instance where three large plugs have been jammed into the hole.
In this case, a patch on the inside won’t mend a tyre carcass that’s been severely compromised. Instead, the traditional method of sewing up a tyre can be used, but the chances of it then forming a perfect seal are very small. In this case, unfortunately, that expensive tyre is likely a throwaway.
Patching a tubeless tyre is exactly the same as patching an inner tube. Locate the hole, abrade the surface, apply solution and when almost dry but still tacky, apply the patch. The only bugbear with a tubeless tyre is that when sealant is used in a tyre it will prevent the solution from adhering to the tyre.
I take care to strip away the ‘skin’ of sealant and clean the area of the tyre being patched with a good cleaning solution (like isopropyl alcohol) before applying solution.
There are some times when I don’t recommend repairing tyres – the chief culprit is when the bead of the tyre is damaged. The bead has to work very hard in a mountain bike tyre, having to resist the forces of braking and cornering while still maintaining an airtight seal against the rim. Because of this, I hardly ever have a go at plugging or patching damage in these areas, but again, on-the-spot judgement will always hold sway.
So there you have it, the conclusion of tyre repairs under the Brutally Basic Tech section. Remember that we are dealing with products made from rubber, which hardly ever behaves the same way every time. Therefore, practice will help to make perfect, but the results may still vary. No two tyres are alike, and just because a fix worked perfectly last time, doesn’t mean the result will repeat itself.
The advice in these articles will give you a very good chance of getting back up and running in very little time – and rescue a potentially disastrous day out in the veld on your ‘bushbikes.’ Till next time, rubber side down!