While there wasn't a blowout, I recently had to slow down and get in behind a semi to take my upcoming exit, and almost as soon as I got behind him, he either kicked one up from the road or lost one of his retreads and it came flying out from under the back of that trailer spinning like a helicopter blade, about a foot off the ground, heading right at me.
Luckily I wasn't real close to him and I was slowing down, because that thing landed on the freeway right before my front tire went over it.
I still see it; clear as the screen you're reading this on.

I can't believe that it landed right as I went right over the center of it.
Other than testing my pucker-reflex, no harm done.

 

Yup that is real. Tooling a little west of Atlanta one time in the right lane of I-20 west going about 70mph, a 18 wheeler cut in front of us(me and another rider). And as he did the right rear tire retread rolled off the rim. I was instantly freaked out thinking we’re screwed. Before I got to scared the rubber kept rolling left out of harms way…for us anyway. Lucky lucky lucky. That looks to be one big hunk of rubber.😱

 

Aside from the massive blowouts mentioned by the OP and others here, (I too have witnessed those!) I could go on and on about the other items that fall apart on trucks and trailers, every day. Trucks have more failures of components than cars, many times over.

I spent my late teens and first of my 20s working for a large truck dealership, and my *** was in the seat of a service truck doing road calls, and emergency calls around the clock. Broken brake drums being #1, blown hoses for coolant, fuel, and oil, wheel bearings failures, mudflaps and the brackets that hold them, drivelines, etc.

I have dodged half of a cast brake drum twice now. That chunk weighs 40 pounds and will **** you up for good.

I had a street bike even back then in my teens, and have always avoided riding next to or right behind a truck because of what I have seen.

I make a concerted effort whenever I can not to ride directly near them. I know it is not always possible to avoid it, and I am not going to panic over it. I just get away from them and find a safer spot when reasonable.

 

The tires only big rigs that are required by law to be new are the steering axle tires, the front tires. All other tires are retreads. When they come apart those chunks are moving at very high speed and can be deadly.
I never station myself next to a semi unless I’m passing, and I do that as quickly as I can.

 

Absolutely stay the F away from them,I had a blown recap nearly take me out a few years back passing a truck and I know better,I'm a truck driver.
I've had one explode while parked getting fuel and lost quite a few on the road,you never know when one will fail.

 

Correct,I had one blow on a drop/lift axle a few years back and it jammed in the fender and locked the wheel which turned hard right and nearly took me off the road at 60 mph and 105,000 lbs.

 

Yep. Generally, the tires that blow out because of low air pressure causing them to get hot and boom. I if I’m on the interstate whether on the bike or 4 wheeler, I try to get around the truck as fast as possible.

 

Exploding tire gator took off the top half of the old style windshield on the shovel, I saw it in enough time I was ducking hard so it bounced off my shoulder. Old lady been with me she'd have got it square in the face.

 

Loaded livestock trailers can be dangerous for other reasons too

 

Yep. I never linger anywhere near the big rigs .. unless I have no other choice due to traffic conditions. I pay special attention to thumping sounds as I pass. 98% of those big rig tire failures are retreads.

.. and .. you should keep an eye out for anything in tow .. Camper, flat bed or covered trailers.

Last year on the ride from Durham to Durango, It was my turn to lead. We were on a 4 lane highway. As I approached a big fifth wheel camper one of the tires blew. It was loud, the rig swerved for a few seconds sending large "pellets" of tire all over the road and me. I realized immediately what it was. Waited about 2 seconds to see if the rubber alligator would be presented .. it wasnt .. I twisted the throttle to get out of there. I dont linger near anything in tow.