All below is only my opinion.
Tire plugs existed long before internal combo patch/plugs (like Tech Uniseal) ever did.
Obviously the new patch/plug combo is more likely to NEVER leak than just a plug, a plug is more convenient than driving to a tire shop and waiting half a day; it is not the $25 and yes many shops like Discount Tire repair tires for FREE. Some shops exclude about half the treed on top as NOT repairable like 1.5" away from the edge... Seems excessive!
DOT from what I can find does NOT prohibit tire plugging. They really do not get into how repairs are carried out and defer to industry. Some tire manufacturers have gone so far as to say 0 repairs are acceptable of any kind.
Let's look at it as a tire shop:
- Tire shops have an interest in selling tires vs working 20 to 30 minutes for $25 (or FREE)
- Tire shops have a TON of liability ... If you or I ran a shop, we would use an industry approved methods only, too.
Are tire plugs dangerous:
- People are dangerous driving all sorts of vehicles that should not be on the road.
- Tires that are dry-rotted, well beyond their DOT age (i.e. plenty of 10+ year old tires on the road), with slipped belts, out of round, with sidewall bubbles, checkered, chunks missing from the sidewall from curbing the vehicle, ran very low, worn down below the wear bars or into the belts... are all examples of:
- Some tires simply MUST be replaced regardless of if they hold air, and the biggest problem with DIY tire repairs is that some people just keep plugging holes anywhere in any tire and keep driving on the same roads we do with total disregard for safety.
- Should never repair a hole bigger tan 1/4" or 3/16" depending on which literature you read.
Why shops remove the tire:
- #1 reason is to look inside and see if someone ran it flat or very low causing it to internally turn to chunky bits while looking good on the outside!
- Yes, once a tire is removed, only a fool would use a plug vs a proper plug/patch
Are plugs unsafe?
- Well they can never fix an unserviceable tire. Never do a sidewall or crown repair.
- Plugs can NEVER safely repair an area that a proper internal plug/patch could not! (doesn't stop some people)
- Where can a patch/plug or plug repair in reality? A: They are the size of a nickel or quarter with a plug centered. They have to be able to sit flat, so no crown repair, but probably about 1/2" to 1" from the side-wall is probably the real minimum to make the patch internally sit flat. Depends on the tire! A plug should certainly NEVER be used to get closer to the sidewall than an internal plug/patch.
- Rumor: Plugs cause structural weakness or rust to get inside the belts.
- A: An internal Patch/Plug is unlikely to seal the channel/hole doing any better keeping moisture out though it might be better at keeping air in!
- A: An internal repair with some thin rubber the size of a nickel or quarter cemented in (after buffing away rubber) is not likely to make the tire stronger than just a plug.
- A tire plug is softer and VASTLY safer than a screw or nail being left in a tire!
- A failed tire plug will most likely slowly leak air, which if someone drives on an underinflated tire is very dangerous!
- Partially mitigated by TPMS
- Some tire plugs like Safety Seal are made in the USA, and I cannot find anywhere they say it is a temporary repair. Others like Slime make it abundantly clear it is a temporary repair.
In short, do what you want. I personally am going to plug (and then monitor) safe tires especially for a few days after plugging. Anyone's life is worth more than a tire, so if you do decide to plug like I do, exercise good judgement.
P.S. Project Farm on Youtube did some testing and put as many as 100 plugs in a tire and it held fine to a LOT Of abuse. Yes, the tire would obviously be compromised, but it gives me hope how durable a good plug job can be.
