It's all about the tourists, but not the foreign ones.

[Jeeper]

I had an instance of tread/carcase separation recently on my car. An odd wear pattern developed - a wave pattern around the whole circumference of the tread. Alternating high wear and low wear in waves about 150mm apart. That tyre got markedly noisier too. Easy to hear on the rear of a light commercial wagon with no sound insulation in the rear - but you'd never hear it on a bike.
It was pointed out to me by the WOF guy while it was on the hoist. It was actually legal within the regs - but got replaced next day...

Edit - it was still in balance. Most of my running is open road so I always get the rears balanced...

That often happens if shocks are worn out. That kind of rhythmic or harmonic wear could be shock oscilating and rebounding.

[Grumph]

That often happens if shocks are worn out. That kind of rhythmic or harmonic wear could be shock oscilating and rebounding.

Light commercial wagon - rear springing is stiff, as are the shocks.

I take kick's point about it being a common wear pattern - but the high points were actually spongy to the touch, pretty sure there was separation happening.
The noise was bad enough that I'd already checked the wheel bearings...

[Jeeper]

Soft and spongy spots, definitely agree seems likely delamination / separation starting. Mind you, I have had delamination on brand new tyre only after 500 kms. BF Goodrich, manufacturer, just replaced it as a defective item. No cost to me. Brand new defective products can happen, I just have a habit of checking things every couple of weeks.

[Kickaha]

The noise was bad enough that I'd already checked the wheel bearings...

It's the first thing we check when someone complains of noise, I would see it on vehicles every month

Considering the amount of tyres out there separations are pretty rare, from manufacturing faults even more so, there's several things that can cause them, the most common just being old age

[Swoop]

I've got 2 2000 Exploders,

The Simpsons made a decent parody of the ford exploder issue in one of their programmes.
The theme song is subtle, with the "unexplained fires are a matter for the courts" comment poking fun at the issue.

[actungbaby]

My tyres would have been manufactured around 2002 meaning they would have been made with a longer lasting compound technology wise than what was used in the 80s. I never saw any side wall cracking in them which no doubt would be an indication they had aged.

M honda interga 4 door had old tires well they on it when i brought it. funny that. shit one blew. i thought somone shooting at me . you chould see the steel belts. i took to tire place and told me it had died big time.
I was only driving around the block . that was a cruise mobile great car.
If been 100kph on the road. was the right rear though. but still.saw no visabe signs. correct air pressure . thinking about might been some side wall cracking. plenty of tread etc.
Id thought tire blow outs from the tube tire days only i was wrong.
My old man drove taxis in the 60,s vaxuall vb . swore that Michlean tires where great.
He get them retreaded , and still a great tire . shows construction is king. said he chould 4 wheel drift they thing.