Big rigs and buses with flat tires?

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I was walking to the office and I heard a rumbling noise up the street and burning rubber. It was a MCI D4500 commuter bus like the ones used in NY/NJ and it had a flat. The tires were all-steel Goodyear transit-spec ones. From what I've read and seen about these MCIs, the rear axle is a steerable tag axle and can be "unloaded". The flat happened on the tag axle. In case a drive axle or a tag/tandem axle tire on a big rig or bus fails, can the driver proceed to safety, or it depends on loading and other factors? Is that also why retreads aren't allowed on the steer axle of a passenger bus as a margin of safety?
 
I know in the case of the tanker trucks my company runs, the drivers are required to pull off and have the tire changed. Most of our newer stuff uses super single tires instead of tandems. 10 wheeler as opposed to 18. You're done when they let loose.
 
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You dont want to drive on a flat. If it comes apart it will come up through the floor of the bus,truck or trailer. It can also tear the brake hoses off which makes the brakes come on and your stuck. Not going to move with the spring brakes on!
 
We are supposed to stop and get the flat tire changed. I haven't had too many flats/blowouts over the years, but I have always tried to get to an exit ramp to minimize the chances of getting hit by speeding vehicles passing by. If an exit is too far away, then I have to stop on the shoulder (put the reflective triangles out) and pray that nobody hits the truck or the person(s) changing the tire. It's a bad situation, doesn't matter what you drive. In over 3 million miles, I've had several blowouts. That includes a couple of nearly new (less than 50k miles) tires. I'm very handy with a tire gauge, but if you run over a nail or something else that punctures a tire, it's going to overheat and possibly let go.
 
Since all passenger vehicles are required to have tire pressure monitoring systems, on a big rig that would really be much more useful, since there are 18 tires to have a problem versus 4. Besides safety, it would save a lot of big tires. Plus advance warning to get off to a truck stop to repair/replace it, instead of being stuck on the side of the road with a destroyed tire.
 
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Common on many trucks today. I have this on my motorhome & my toad. https://tsttruck.com/product/tst-507sce-kit/
Originally Posted By: Traction
Since all passenger vehicles are required to have tire pressure monitoring systems, on a big rig that would really be much more useful, since there are 18 tires to have a problem versus 4. Besides safety, it would save a lot of big tires. Plus advance warning to get off to a truck stop to repair/replace it, instead of being stuck on the side of the road with a destroyed tire.
 
I drove tri-axle coal truck for 13 years and it happens. You don't even worry about the tag axle ( AKA lift axle) where you usually run junk tires anyway. The drive tires, if you have a flat outside you usually won't go loaded before you blow out the inside. You can usually limp in loaded with a inside flat. Empty it won't hurt a thing. They weigh 13 ton empty and single dual supports that. Re-caps are made for straight running. Turning tears them off. I know a company that ran super single re- treads on the front. Seemed dangerous but only one ever blew out. Took the entire fender with it. Surprisingly when a front tire blows on Tri-axles it doesn't do much, only sets down slowly. It's a keep your cool moment.
 
Originally Posted By: JTK
I know in the case of the tanker trucks my company runs, the drivers are required to pull off and have the tire changed. Most of our newer stuff uses super single tires instead of tandems. 10 wheeler as opposed to 18. You're done when they let loose.
I always wondered about that, I ride through the ports and I see trucks with Michelin XOnes or Bridgestone Greatecs(usually part of fleets, I haven't seen the small owner-operators with these). Is the rationale behind them fuel savings via less weight and better traction with a wider tire?
 
Originally Posted By: Panzerman
I drove tri-axle coal truck for 13 years and it happens. You don't even worry about the tag axle ( AKA lift axle) where you usually run junk tires anyway. The drive tires, if you have a flat outside you usually won't go loaded before you blow out the inside. You can usually limp in loaded with a inside flat. Empty it won't hurt a thing. They weigh 13 ton empty and single dual supports that.
When I saw the bus pull over to drop off passengers, I've heard the ABS actuate as the system controller thought it was an event that triggered it. It was 1.5 miles from the operator's San Francisco day yard, so I assumed the driver was either able to make it there or made it to the next stop and ping dispatch to send a mechanic out there. I'm not sure if they keep spare tires behind the front bumper - most tour/commute coaches have a provision for one.
 
Originally Posted By: nthach
Originally Posted By: JTK
I know in the case of the tanker trucks my company runs, the drivers are required to pull off and have the tire changed. Most of our newer stuff uses super single tires instead of tandems. 10 wheeler as opposed to 18. You're done when they let loose.
I always wondered about that, I ride through the ports and I see trucks with Michelin XOnes or Bridgestone Greatecs(usually part of fleets, I haven't seen the small owner-operators with these). Is the rationale behind them fuel savings via less weight and better traction with a wider tire?
I converted to Michelin XOne tires sometime in 2006 and ran them for about ten years. I weighed my truck before and after, and found that I shaved off 450 lbs. This was switching from 8 drive tires on aluminum wheels to 4 wide base tires on aluminum. It may not seem like a big deal to drop 450 lbs off a heavy truck, but it really does help out if you are often loaded to the legal limit. The wide base ("super singles") tires offer less rolling resistance and therefore better fuel economy.
 
Originally Posted By: dustyroads
... The wide base ("super singles") tires offer less rolling resistance and therefore better fuel economy.
How do they compare with conventional duals in cornering capabilities and stability? I think about that when large trucks running way over the speed limit pass me in the curves of the last 20 miles of I-40 in western North Carolina.
 
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There are a number of oilfield service companies around here. When I think about it ... they have run the “body load” 10 wheelers for decades with the jumbo tires only on the front. They don’t carry cargo ... just always full weight with pumps, engines, tanks, and thick wall pipe.
 
Originally Posted By: CR94
How do they compare with conventional duals in cornering capabilities and stability? I think about that when large trucks running way over the speed limit pass me in the curves of the last 20 miles of I-40 in western North Carolina.
First I think you are right to be concerned about fully loaded trucks driving down that stretch of highway. I get concerned about my ability to control MY car on that highway. But a super single has about the same amount of rubber on the road as a pair of duals, but 2 less sidewalls - and you can adjust the sidewall stiffness so the change is largely imperceptible.
 
Originally Posted By: CR94
Originally Posted By: dustyroads
... The wide base ("super singles") tires offer less rolling resistance and therefore better fuel economy.
How do they compare with conventional duals in cornering capabilities and stability? I think about that when large trucks running way over the speed limit pass me in the curves of the last 20 miles of I-40 in western North Carolina.
The wide base tires are fantastic in regards to handling and stability. They improve the ride, too. I guess having fewer sidewalls is what helps soften the ride. Another thing that I loved (I am running traditional duals on my newest truck) about the singles, was the ease of "chaining up". I not only put chains on (when required) in the mountains out west, but also when trying to get to my house in the winter. The big singles make it easy and quick. Driving through the gorge there in western N.C. requires patience. The speed limit is fine even with a heavy load and high center of gravity, but there's always a backup caused by someone who is inexperienced or just nervous. Many of the trucks are empty or lightly loaded and they pull out and pass the slower traffic. They're not supposed to, but they do. A truck will comfortably glide through that gorge when heavy, so for someone pulling an empty trailer it's probably very frustrating. I always find myself stuck in a convoy going 35-40 mph through there, but I just relax and enjoy the ride as best as I can.
 
Originally Posted By: Traction
Since all passenger vehicles are required to have tire pressure monitoring systems, on a big rig that would really be much more useful, since there are 18 tires to have a problem versus 4. Besides safety, it would save a lot of big tires. Plus advance warning to get off to a truck stop to repair/replace it, instead of being stuck on the side of the road with a destroyed tire.
While TPMS isn't required on heavy trucks, there are aftermarket products in use. Automatic inflation systems are also available. I pull a trailer with the auto inflation system and there's a light that is supposed to come on if there's a problem.
 
And when used on tandem axle trucks there should be enough there to get things shut down ... good point on TPM ... seems that is needed to reduce roll over potential and the gators that have ripped my air deflection plastic into shredded scrap
 
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