I’ve not had a great deal of success with patches, as they either tend to bulge through the tear or refuse to stick to the inside of the tyre.
The not sticking is normally a problem with not getting the inside of the tyre completely clean and free of contaminants, but moulding marks and ridges can make it trickier sometimes too. Make sure you clean out any old sealant and cleaner residue and then let it properly dry out.
The bulging can be an issue on thinner carcass tyres, what I’ve done in the past is a multi-patch approach. Use a smaller patch over the hole, thena bigger one over the top of that, often does the trick, you can also try a ‘flexible sandwich’ approach if you can find a decent non-stretch material to do smallpatch-sandwich-bigpatch, but it doesn’t always work.
sew with dental floss or stout fishing line and refill with sealant and it could well be absolutely fine.
The worst one I’ve repaired is a gash about 50mm long in the sidewall of a Spesh Control casing. Stiched up with floss, liberally super-glued, and then patched on the inside, still holds air well over a year later.
