Friday, Oct 07, 2022 at 00:30
John, you don't say how big the holes were that you plugged, or how they were acquired.
The best rule of thumb for tyre repairs is that if no plies have been fractured, and the hole has been made by a nail, a screw or a sharp piece of metal - then a plug should be a satisfactory repair.
The problems start when plies have been fractured by a large stake, which can then also lead to ply separation in the tyre carcass.
I rarely use plugs, but they're not banned by anyone, and they need to be used with a degree of care.
The biggest problem is that if a tyre receives some severe damage that potentially has fractured plies, it needs to be dismounted, and the interior of the tyre and the hole checked for carcass damage that could affect the tyre adversely down the track.
Even with nails and screws, I still dismount tyres (I have my own tyre changing machine), remove the offending item,
check the tyre thoroughly, and then patch it from the inside with a properly buffed and glued patch.
I've used Michelin tyres from the mid 1960's in W.A., and back in those days, the Michelins were tubed radials - as were all the truck tyres.
Bell Bros were the Michelin agents and had a huge tyre supply and repair depot in South Guildford - which depot would repair sidewall damage to both car and truck radials - using a vulcanising process - provided the plies were largely only separated, and not substantially fractured.
Bell Bros repaired tens of thousands of radial tyres in this manner, and I had many radials repairs done by Bell Bros after staking them in the sidewalls - sometimes with lengthy cuts.
As long as the break didn't reach the bead or the tread plies, Bell Bros were happy to repair the damaged tyres - and they guaranteed their repairs.
It's testament to Bells repair work that one could probably still find some old Michelins sporting their vulcanised tyre sidewall repairs.
However, with the advent of cheaper and cheaper tyres in recent years, tyre wall repairs have become uneconomic - and pressure from safety authorities and lawyers has made tyre people decline to repair substantially damaged tyres today.
Bell Bros repairs involved buffing back the damaged rubber around the hole and installing fresh liquid rubber, which was vulcanised in their tyre repair machines.
I still have a portable 240V tyre wall vulcaniser, but the work required to repair a seriously damaged tyre wall is so substantial, it's not really economic, unless the tyre is an expensive truck tyre, and it is nearly new.
Most large stakes from timber and sharp rocks usually damage a number of plies in the wall (or tread), thus making any major (vulcanised) repairs to wall or tread, a no-no.
Cheers, Ron.
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Follow Up By: John Baas - Friday, Oct 07, 2022 at 02:06
Friday, Oct 07, 2022 at 02:06
Hi Ron.
Many thanks for your extensive reply.
Yes, I was short on detail re the original damage... sorry all.
It was a 'micro' pinhole slow leakage, that I had expected one plug to suffice. Very surprised it took three. But it's still a pinhole and there's no way the plugs would blow-out, as they might from a 'slash'.
And thanks re the vulcanising. I have had, back in the day, a number of sidewalls repaired in that way. Sadly, as you note, no more.
I wasn't going to comment earlier on another issue my thread has occasioned comment, but I'll take this opportunity, for those who doubt the ability for a 200 series to maintain a straight line after catastrophic tyre failure (rocks thru the sidewall - instant deflation) to say that it has happened to me four times. And one of them at 100 kay ph (this time plugs did blow out of a NT slash repair - going up to
Katherine) on bitumen.
What happens is, one hears the 'explosive report', the tyre is immediately flat, one hits the brakes, and the car holds the line immaculately until stopped. I've been amazed each time but, that dear punters, is what happens.
Just as an aside to all, I've really enjoyed all the inputs this thread. Takes us all back to those days the
Forum was so alive.
Cheers.
John.
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