Outer shell of a tyre on the motorway - question

[mikeymikec]

It has always puzzled me when I see a broken ring of the outer layer of a tyre (the bit with the textured gripping surface) on the side of a motorway. Presumably when this happens a truck/lorry doesn't imminently have an accident? How does it happen, does anything happen afterwards to the vehicle?

 

[etrigan420]

Most semi truck tires are re-treads, where they basically glue a "tread-ring" around a bald tire. What you're seeing is usually a thrown "tread-ring".

 

[Throckmorton]

I'm guessing most truckers don't use retreads on the front tires, even though that doesn't seem to be illegal

http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=393.75

 

[mikeymikec]

So would you keep your distance even more from a vehicle if you just saw this happen?

Presumably truck drivers are as legally obliged to carry a spare tyre as a normal car driver is? Why is this a truck thing, is it just the case that truck tyres being significantly larger are also significantly more expensive?

I'm surprised that re-treads aren't illegal.

 

[etrigan420]

So would you keep your distance even more from a vehicle if you just saw this happen?

Presumably truck drivers are as legally obliged to carry a spare tyre as a normal car driver is? Why is this a truck thing, is it just the case that truck tyres being significantly larger are also significantly more expensive?

I'm surprised that re-treads aren't illegal.

I'm not sure of what the exact laws are regarding them.

I've never personally heard of anyone being injured by one, but would imagine it's happened at some point in the past. If I just saw it happen I would increase my distance from the truck, just to be safe. The driver is probably going to pull over and/or exit the roadway post haste to check the status.

If I had to guess, I'd say the increased size and cost play into it, in addition to the beating that they take from the increased weight and mileage over passenger cars.

I *think* that you can actually buy retreaded passenger car tires too...someone correct me if I'm wrong there...

 

[Itchrelief]

I've heard that a good percentage of those are passenger car tires and not truck treads. I don't know if it's true or not, but the most recent one I passed on the highway was followed about a quarter of a mile later by an SUV stopped on the shoulder. Once the sidewalls disintegrate blown out tires remains seem to look fairly similar to what you would expect a thrown tread to look like.

 

[manimal]

I remember a story of a motorcyclist in LA being beheaded by one.

 

[thedarkwolf]

I'm not sure of what the exact laws are regarding them.

I've never personally heard of anyone being injured by one, but would imagine it's happened at some point in the past. If I just saw it happen I would increase my distance from the truck, just to be safe. The driver is probably going to pull over and/or exit the roadway post haste to check the status.

If I had to guess, I'd say the increased size and cost play into it, in addition to the beating that they take from the increased weight and mileage over passenger cars.

I *think* that you can actually buy retreaded passenger car tires too...someone correct me if I'm wrong there...

The first car I ever bought way back in 1993 came with retreads on it. They never gave me any problems.

My friend's wife ran over a truck retread last year and did a lot of damage to their van.

 

[mikeymikec]

Until manimal's comment I wasn't thinking of people being injured by them, but a truck going around with bald tyres after the retread has come off is a pretty scary idea IMO. Combine that with poor road conditions.

 

[Throckmorton]

Until manimal's comment I wasn't thinking of people being injured by them, but a truck going around with bald tyres after the retread has come off is a pretty scary idea IMO. Combine that with poor road conditions.

What happens is the tire disintegrates. You don't get left with a bald tire. It's not that bad in the rear because they have so many tires, but in the front it would be catastrophic probably.

They do carry spares.

 

[jaedaliu]

your windshield gets pelted with little bits of rubber, there's a smell, and lots of smoke, but the truck pulls over without too much problem. (this is according to my massive sample size of 1.)

 

[JulesMaximus]

I'm not sure of what the exact laws are regarding them.

I've never personally heard of anyone being injured by one, but would imagine it's happened at some point in the past. If I just saw it happen I would increase my distance from the truck, just to be safe. The driver is probably going to pull over and/or exit the roadway post haste to check the status.

If I had to guess, I'd say the increased size and cost play into it, in addition to the beating that they take from the increased weight and mileage over passenger cars.

I *think* that you can actually buy retreaded passenger car tires too...someone correct me if I'm wrong there...

If one hit a motorcyclist it sure as hell would injure him/her. I had one hit the right front fender of a company pickup truck years ago on the 710 freeway in Los Angeles and it broke the headlight out of its mount and left a nice dent in the hood.

But in this country we care more about corporate profits than we do safety.

 

[phucheneh]

The tire IS bald after the tread cap flies off. They shave them down to the soft rubber before gluing on the retread bit. And I don't think that's where they come apart, anyhow; it's more likely that the old rotting rubber underneath lets go of the steel belt.

Of course, trucks can also lose tires in the same way that passenger cars do- being run flat (or just very low on air) until the sidewall shreds.

I don't know if retreads are illegal on the front of trucks, but trucking companies generally have policies against it. Doesn't stop some idiot from putting them on the front of his car, though (yep, there are passenger retreads and they're abysmal).

 

[manimal]

http://mythbustersresults.com/episode80

 

[mmntech]

I hear highway crews going around picking up tire debris all day.They're not safe and they waste the highway crew's time. Why retreads are still legal baffles my mind.

 

[Demo24]

I hear highway crews going around picking up tire debris all day.They're not safe and they waste the highway crew's time. Why retreads are still legal baffles my mind.

Trucking industry has enough pull, that's why.

They can be quite dangerous for all involved, and you can often spot them as they start to go, which is when I quickly get away from said truck. I feel like it might be coming less common though, especially with the move towards 4 large tires in the back versus 8.

 

[SyndromeOCZ]

Oh yeah they can be deadly. If they hit your car they can do a good deal of damage even if everyone is ok.

I was next to one of these on the interstate one day.. Looked over and saw the tread coming off, about 10 inches was flapping around. I put my throttle down and got about 3 car lengths ahead of it and BOOM. Tire pieces went everywhere and the whole interstate was engulfed in dust. Very glad I saw it and moved.

 

[Zenmervolt]

especially with the move towards 4 large tires in the back versus 8.

Ah, the Michelin Super Singles. Fleets are moving to those because of weight savings and lower rolling resistance. The general consensus is that they're good for between 0.3 and 0.5 miles per gallon better fuel mileage. I know that doesn't seem like much, but when you realise that a semi gets between 6 and 8 miles per gallon you're looking at an improvement of roughly 4 to 8 percent. Adds up fast for fleets where hundreds of trucks are each covering 1/4 million miles a year.

ZV

 

[Demo24]

Ah, the Michelin Super Singles. Fleets are moving to those because of weight savings and lower rolling resistance. The general consensus is that they're good for between 0.3 and 0.5 miles per gallon better fuel mileage. I know that doesn't seem like much, but when you realise that a semi gets between 6 and 8 miles per gallon you're looking at an improvement of roughly 4 to 8 percent. Adds up fast for fleets where hundreds of trucks are each covering 1/4 million miles a year.

ZV

I was wondering what they were called, noticed them gaining adoption rather quickly this year. Always wonder what the drivers think about them, doesn't look like there would be significant traction loss since the contact patch looks to be about as big as 2 tires. Look a little funny though :awe:

 

[Meghan54]

Oh yeah they can be deadly. If they hit your car they can do a good deal of damage even if everyone is ok.

I was next to one of these on the interstate one day.. Looked over and saw the tread coming off, about 10 inches was flapping around. I put my throttle down and got about 3 car lengths ahead of it and BOOM. Tire pieces went everywhere and the whole interstate was engulfed in dust. Very glad I saw it and moved.

Similar thing happened to us a few years ago, except it was without notice. One of the rear trailer tires, left side, blew its tread off just as we were going to pass a rig. Had already pulled into the left lane and was just a couple of car lengths behind when the tire blew and disintegrated. The major pieces of the tread that separated luckily flew over our Blazer and hit those behind us.

And the driver didn't act like anything happened. Truckers call those cast off tread hunks gators, from what I remember. Some even think it's funny when it happens.


And, yes Throck, a bald tire is left when a recap has its tread come off. Of course, when the tire is driven on after the tread separates, the carcass does disintegrate and leave just the frayed sidewalls on the wheel, sans the center of the tire, but initially there is a "bald" tire. Seen it waaay too many times on trucks and have experienced it myself back in the '70's. Was a kid back then and too cheap for my own good. Thankfully, the tire that threw its tread was on the rear.

They came off the car soon thereafter.

 

[pcgeek11]

WTF is a Tyre?

 

[EagleKeeper]

WTF is a Tyre?

English donut

 

[IronWing]

I lost a tread on my Suburban. Quite an invigorating noise as the loose tread slaps against the wheel well. My first reaction was to duck. The tire held air even with about a foot of loose tread falpping. I pulled off the highway and changed it, no problems.

My understanding is that retreads are less likely to delaminate than original treads.