Colin Wood
Colin Wood Associate Editor
11/30/20 3:25 p.m.

https://www.youtube.com/embed/8X2GMD1TPzg

In an effort to reduce overhead—as well as reuse tires instead of throwing them in the dump—some heavy truck tires are specifically designed to be retreated for future use. Here's how the magic happens. 

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1988RedT2
1988RedT2 MegaDork
11/30/20 4:29 p.m.

Mostly I wonder why it isn't a crime to allow trucks to run tires to the point where they randomly explode and throw rubber shrapnel all over our interstate highway system.  The next time you drive a stretch of interstate, take note of just how much truck tire debris is laying in the shoulder.  The current policy of running a tire until it explodes and then replacing it really ought to be re-examined.

Dusterbd13-michael (Forum Supporter)
Dusterbd13-michael (Forum Supporter) MegaDork
11/30/20 4:39 p.m.

If you notice, most of them still have good tread. I was always told that they blow primarily because of heat and load, not due to being worn out

Error404
Error404 Reader
11/30/20 4:40 p.m.
1988RedT2 said:

Mostly I wonder why it isn't a crime to allow trucks to run tires to the point where they randomly explode and throw rubber shrapnel all over our interstate highway system.  The next time you drive a stretch of interstate, take note of just how much truck tire debris is laying in the shoulder.  The current policy of running a tire until it explodes and then replacing it really ought to be re-examined.

But who is going to spend the money to have it changed? That is, potentially, a lot of dough to shell out in opposition to the trucking companies. Would probably get politicized as an added roadblock to anything happening. To be clear, I'm in favor of preventative tire replacement, particularly after seeing what those things can do to someone in the crummy position of "near" them when they blow. (Mythbusters)

californiamilleghia
californiamilleghia SuperDork
11/30/20 6:21 p.m.

if you drive much in Europe you will not see all this rubber  on the road , 

can you imagine going down the autobahn at 120mph and big chunks of truck tires are in your lane !

Do they retread tires in Europe ?     

David S. Wallens
David S. Wallens Editorial Director
11/30/20 7:02 p.m.

A year ago I hit one of those highway gators. I was between semis and didn't have an out. The world is poorer one AMG air dam. :(

M2Pilot
M2Pilot Dork
11/30/20 7:03 p.m.

A local tire company has had the NC contract for re-treading truck & school bus tires for around 30 years.  There's been some controversy over the past few years, not sure they still have the contract.

The owner of said company seems to have a lot more $ than I have.

David S. Wallens
David S. Wallens Editorial Director
11/30/20 7:07 p.m.

Also, we had a Bandag in Athens. TIL that it's part of a network now owned by Bridgestone. 

No Time
No Time SuperDork
11/30/20 7:39 p.m.

In reply to 1988RedT2 :

Typical failure causes are heat from running low pressure, overloading (possibly due to its partner being soft of failing), physical damage to the carcass, or puncture leading to the first two. 

Running them to the point of failure due to wear isn't likely and can definitely lead to headaches if subjected to a DOT inspection. Once you include that it is significantly cheaper (and a lot less aggravating) to have them changed out at a shop than having to pay to have it done on the side of the road, its doubtful they are purposely run until failure. 

03Panther
03Panther Dork
11/30/20 11:43 p.m.
1988RedT2 said:

Mostly I wonder why it isn't a crime to allow trucks to run tires to the point where they randomly explode and throw rubber shrapnel all over our interstate highway system.  The next time you drive a stretch of interstate, take note of just how much truck tire debris is laying in the shoulder.  The current policy of running a tire until it explodes and then replacing it really ought to be re-examined.

Actually it IS a crime! Many other factors cause “gators” in the road. Being run to failure, intentionally, is almost never one of them. As was pointed out, it’s way less expensive not to. The wildcat truckers of the 70’s are no more. Except for log trucks. Don’t think many of them know how to spell safety smiley

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
12/1/20 12:46 a.m.

Tires basically generate heat by flexing, which means that most heat-related failures started as either underinflation (could be gradual or sudden loss of pressure) or overloading. Pretty much any case of a tire separating into more than one part is heat related. Since pretty much all heavy trucking uses tandem axles, overloading of one tire is something that can occur BECAUSE of underinflation in another. I.e. one tire loses pressure and stops carrying its share (and gets hot and eventually flies apart) and the adjacent tires go from loaded appropriately to overloaded. This can cause cascading tire failures, and it may not be immediate. So the ruined tire gets replaced, but the adjacent ones probably don't and they may fail at some future date for seemingly mysterious reasons. Some tires and their symptoms of failure are separated from the driver by 65 feet and 10s of thousands of lbs of damping weight, so the solution here is basically TPMS. It's been required by law on all passenger cars for 12 years now. The lobbyist-per-driver ratio of the general public is very poor compared to the trucking industry, but there are also a lot more regular drivers ignoring their mandated yellow warning light than there are 'underinflated semi tires with no warning system' on the roads at any given time, so basically everyone sucks. 

I thought the retreading process video was pretty interesting. The 'find holes with sparks!' thing was cool and I had no idea it existed, but it makes sense and as a mechanic i do the same thing with plug wires somewhat regularly so it feels relatable. I also didn't know that the 'cushion' belt layer existed. One thing i thought was sort of ironic was that the tire casing was 'trued up' by shaving/grinding before applying the new tread belt, but nothing is done about the horrible (if i can see it on video) runout of the new tread layer after it's applied. I mean, I get that it doesn't matter much in this application, but it's ironic and makes me think getting the consistent geometry on the shaved tire carcass might be more important for the assembly of the new layers than it is reflecting any concern for how lumpy the finished tire is going to roll. I'm still highly curious about 'fixing' tire runout with tread shaving. I hear there is a truck shop near me that can do it. I am really curious to talk to them about whether they can/would do it on 'consumer' vehicle tire/wheel assemblies as there are a ton of tires that I would gladly make the tread depth uneven on by grinding it down to 'lowest common denominator' tread depth if it made the tire 'drive better' until the lowest spot goes bald. cheeky

jharry3
jharry3 GRM+ Memberand HalfDork
12/1/20 7:49 a.m.

My grandpa had a tire business  he started in the '30's.   He had recapping for most of that time.  When Bandag came out with that system he didn't want to make the investment so our recaps were no longer economical to manufacture.   Plus our machines were not suitable for radial truck tires with steel belts.

Basically a bias ply truck tire was "buffed" on an large lathe running a multi-blade cutter head.  Once all the original tread was gone we sprayed on a mixture of rubber and rubber solvent and hand laid on a wide strip of raw rubber.  Then we applied a wide roller, like a rolling pin, and ran the tire on the lathe while pressing down the new tread.

The tire was then placed in a huge cooking machine that had tread dies inside.   The inside of the tire was pressed into the mold via an expanding mechanism operated by a screw jack.    The tread molds themselves were mounted in a clamshell arrangement which clamped around the tire. Clamping force came from a giant screw jack like  arrangement which was tightened  until all the surfaces of the clam shell were touching and the interior expanding mechanism was fully pressing the tire into the mold.  This baked for about 3 hours and allowed to cool.    I learned to do this when I was about 12 year old.  Too small to lift up the truck tires but could do all the other operations.    Better tires could be recapped this way several times.  Some were of such poor quality we declined attempting to recap them.    Lots of money in recapping for a small businessman back then.  More profit per unit than new truck tires.     Tire marketing is a very cut throat business - volume discounts from manufactures are crazy -  my family basically got out of the tire business when Walmart and Sam's were selling the same tires for less than we were paying "wholesale".  Volume discounts are that steep.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
12/1/20 9:41 a.m.
1988RedT2 said:

Mostly I wonder why it isn't a crime to allow trucks to run tires to the point where they randomly explode and throw rubber shrapnel all over our interstate highway system.  The next time you drive a stretch of interstate, take note of just how much truck tire debris is laying in the shoulder.  The current policy of running a tire until it explodes and then replacing it really ought to be re-examined.

Tire blowouts are due to carcass failures, not being worn out.

 

That said, for the number of trucks on the road, the number of failed tires is remarkably low.

chandler
chandler UltimaDork
12/1/20 10:01 a.m.
David S. Wallens said:

Also, we had a Bandag in Athens. TIL that it's part of a network now owned by Bridgestone. 

The company I work for was owned by Bandag when Bridgestone purchased them. We never fit in and we're sold off after ten years in 2017. As such I have been around and retreaded a LOT of tires, the company that owns us now also has recap facilities using an amalgam of Bandag and Oliver equipment. 
 

Most of the tires you see along the road are due to puncture, Very rarely are they recaps and you can usually see the difference because if a recap peels it will usually be "square" on the edges and there will be no belt package attached. Lots of misconceptions about retreading; if you want to see some really impressive info on it look to airplanes.

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
12/1/20 10:16 a.m.

Tires generally don't 'come apart' until they've been run long enough with no/under-inflation to build up a ton of heat and start losing adhesion between layers. Tires are basically a bunch of layers bonded together under heat. With enough heat they start to come back apart. 

 

Anyone here ever burned their hand on a flat tire? I have, minorly anyway. Not as bad as when i was a kid and had the bright idea that you could tell what was the intake and what was the exhaust on a lawnmower by seeing how hot the two boxes were. I had a 50/50 chance, and i lost. cheeky

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
12/1/20 10:23 a.m.

In reply to Vigo (Forum Supporter) :

I saw a smoking tire blow out.

 

Worst was the two tire fires I witnessed.  One was on a car hauler, when I came back the other way three hours later, they had a wrecker crane  removing the six now-destroyed cars it was carrying.  Totally involved, cars were just bare metal and ashes.

The other was a horse trailer, with two or three agitated horses in it, and they were limping it to the exit. sad

WonkoTheSane (FS)
WonkoTheSane (FS) GRM+ Memberand SuperDork
12/1/20 12:29 p.m.
jharry3 said:

Tire marketing is a very cut throat business - volume discounts from manufactures are crazy -  my family basically got out of the tire business when Walmart and Sam's were selling the same tires for less than we were paying "wholesale".  Volume discounts are that steep.

I've had this discussion with the local tire store in regards to intarwebs pricing. We always come to an amicable agreement on price, I've told them that I'm going to be giving money to someone and I'd rather they make enough to stay open rather than give it to some big corporation, but I can imagine it was a lot more lucrative for the tire stores before the internet existed.  Because of this I've seen what their price is and you're right, it's no where near what Discount Tire or whatever are selling for.

WonkoTheSane (FS)
WonkoTheSane (FS) GRM+ Memberand SuperDork
12/1/20 12:30 p.m.

Great video, thanks for posting it Colin!

matthewmcl (Forum Supporter)
matthewmcl (Forum Supporter) HalfDork
12/1/20 12:37 p.m.

I looked up info on the new super singles, about a year ago. I was curious to know what the truckers thought of them.  They seem to run more stable pressures (less heat from sidewall flex).  I was surprised to learn how long over the road tires last.  The drill seemed to be rotate every 50,000 miles and they would last 300,000 to 350,000 miles.

How long do the skinnier designs last?

chandler
chandler UltimaDork
12/1/20 1:22 p.m.
matthewmcl (Forum Supporter) said:

I looked up info on the new super singles, about a year ago. I was curious to know what the truckers thought of them.  They seem to run more stable pressures (less heat from sidewall flex).  I was surprised to learn how long over the road tires last.  The drill seemed to be rotate every 50,000 miles and they would last 300,000 to 350,000 miles.

How long do the skinnier designs last?

Steers are 100k+ if you rotate at half life and buy good ones, drives are 3-500k with the same advice. Trailers are til you get to many holes or have a bad alignment

Subscriber-unavailabile
Subscriber-unavailabile HalfDork
12/1/20 4:48 p.m.

My company uses re-treads on our trailers, only time we have issues is summer time. Most failures are not blowouts, tires start to come apart where they're joined together. Sucks being stuck on side of hwy for 2 hours just so company can save few bucks

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