Patched tires and towing

[daugen]

less load on the front tires, more on the rear while towing, but the front tires for sure are wiggling back and forth while the rears just keep on rolling straight.
So from a squirm standpoint, I can see why the fronts would be challenging. I'm very sure it was a plain old plug, though they sure took their time with it.
I guess the real question is how many of you have towed heavy loads with patched tires and have you ever had a problem?
I'm hearing no problems...

 

[Diamondpilot]

Move it off your steer wheel to the rear ...

Check your advise. Its actually more dangerous to have a blow out on a non steer wheel tan a steer wheel.

Chris

 

[zzvyb6]

If you have a matching spare tire and the opposite side front tire is still relatively new, rotate the spare into the plugged position. Then run this combo until you decide to replace both fronts. You could even swap the wheels if one is an alloy wheel and the spare is on a plain steel wheel. Since the nail caused only a slow leak, the carcass is probably in good shape. If the nail was in the tread area I'd be OK with it. If it was in the sidewall or near the edge of the tread, I'd replace them in pairs. You want to have the same wear state on an axle. Sidewall takes the most stress in a rolling load condition. Pressure is the tire's best friend, so keep an eye on it, especially under heavy loads..

 

[vsteel]

Check your advise. Its actually more dangerous to have a blow out on a non steer wheel tan a steer wheel.

Chris

I keep hearing that and I have been googling but I have not found a solid answer. To me it seems better to blow out a rear, you still have the most control, your drag is behind your center of gravity, more braking because you have both fronts (not that you want to slam on the brakes) and you just keep the front on the road and the rear will take care of itself. Seems like it would be like losing the rear on the ice, just keep the fonts pointed straight and you will be OK, loose the front and you are just screwed.

I would really love to hear a solid scientific answer or is this for the general public who can't drive where it is better to lose the front because they can't handle a car? People who know how to drive (30% of the population?) would be better off with a rear blowout but this is a one size fits all answer?

 

[zzvyb6]

ALWAYS better to loose a front than a rear:

Loosing a rear means the rear axle cornering stiffness is down by a factor of 2 vs. the front. This means the vehicle will be unstable oversteering regardless of the actions of the driver. Loosing a front means you now have 1/2 the front axle cornering stiffness and the vehicle will be understeering and still be stable regardless of what the driver does. Understeering = stable, oversteering = unstable. When you turn a vehicle at a decent speed, the rear axle actually steps out the opposite direction until the rear wheels generate a balancing sideslip angle to counteract the yaw moment induced by the front axle. With reduced rear lateral stiffness, the rear will NEVER be able to counter the yaw moment and you will spin out. Braking acts the same way on the vehicle. With a rear flat, the soft tire will not balance the yaw moment induced by the good rear tire and the vehicle will tend to spin. With the front in good shape, the front counter steering is most likely to over correct the tendency to turn and the vehicle will spin because it is in an oversteering trim.

The unsteered rear wheels of a vehicle act like the tail on an airplane. Same principle. You need it to dig/stick in order to avoid a 'tailspin'.

All of this is accentuated by a driver attempting to maintain control. Best solution is to do NOTHING, let the vehicle slowly decel, do as little as possible, steering only to stay in the roadway, and NO quick, large, jerky or sudden steer or brake applies. Of you have separate trailer electric brake controls, apply them smoothly to stop quickly. The trailer brake force with a long hitch length will help stabilize your vehicle combination.

There are other readings of your trailering that can help you. A blowout is one special condition. But more often, a tire goes soft slowly. You should evaluate the truck and trailer handling periodicly on long trips by putting small pulse inputs into the steering wheel (I said SMALL, not more than a couple of degrees) and evaluate the truck and trailer reactions. If one starts to get a little oscillatory, stop and check yout loads position (maybe it shifted) and kick a tire. Better yet, measure the pressures. Use a good gauge. Some gauges will let more air out of a tire than should be allowed because they are awkward to use, have leaky parts, and you can't read the numbers. Pencil gauges are the worst for acuracy, legibility and clumsy to use.

 

[Diamondpilot]

I keep hearing that and I have been googling but I have not found a solid answer. To me it seems better to blow out a rear, you still have the most control, your drag is behind your center of gravity, more braking because you have both fronts (not that you want to slam on the brakes) and you just keep the front on the road and the rear will take care of itself. Seems like it would be like losing the rear on the ice, just keep the fonts pointed straight and you will be OK, loose the front and you are just screwed. I would really love to hear a solid scientific answer or is this for the general public who can't drive where it is better to lose the front because they can't handle a car? People who know how to drive (30% of the population?) would be better off with a rear blowout but this is a one size fits all answer?

Think of the police maneuver called PIT. It's so easy to make a car spin out with the slightest upset of the rear end.

Personal experience with blow outs tells me I would much rather lose a steer tire vs a drive.

Chris

 

[daugen]

I have been watching my tpms readings each day and the tire is fine. It's when I hook up the trailer that I was worried about. Max pressure on tires is 45 pounds, I keep them inflated to 42 while the door sticker says 39. The hitch weight is about half of the truck's capacity so I'm not overloading the rear wheels.
The nail was in the exact center of the tire, in a groove, almost flush with the tire, which I found interesting because it means the nail was driven in further by simply driving on it. I'm assuming that happened as the tire went flatter losing air.
They spent about half an hour on the tire so while I did not ask, I am confident they used the proper patch. Brand new Chrysler Ram dealership.

This question originally was raised by my concern that the plug material was softer/different than than the tread material, would wear at a different rate or more
at issue would overheat due to less engineering in that simple tube of rubber vs all the plies in the tire. In other words, a weak spot that due to different materials might overheat and fail prematurely. That was my original concern. Clearly this has not happened to any of you, though normal driving was not my concern, it was
towing at just below the truck rating.
Good info here, thank you.

 

[zzvyb6]

The real problem you face is whether water intrusion into the tread belt area will corrode steel wires in there. Salt on roads in winter is the main problem. When that happens, you face a tread separation and catastrophic failure from a blowout.

Tires (OEMs, sometimes not replacements) are way over spec'd in terms of fatigue, airloss (permiation), tread life and durability. The pressures on the door placard are a compromise between ride, handling durability, noise, traction, fuel economy and tread life. It would probably take over 100 psi to burst one and the chances are that the wheel inself would fail first (bead area). But it helps all concerned when you can sleep better because you have eliminated that one element of a potential safety issue. Just pick up and carry a naked tire sometime and evaluate how much stress and strain that thing takes in supporting a few thousands pounds of load. They are a bargain in that respect. I worked in this arena at an automotive manufacturer for 40 years and have seen it all. Forseeable misuse is the main guideline for all tires put on a new vehicle, even taking into account the intermix of the cheapest, smaller sized, recapped and blemished baloney skins from overseas.

 

[TMGT]

I think your over analyzing it, if in doubt call the dealer and ask what method they used to repair your tire. I worked as an auto tech for a long time, family has a large independent shop and I worked in the building that had all the good tire equipment so I had the privilege to see most of the tire problems.
My preferred repair was the plug/patch that, it was installed from the inside like a normal patch but had a plug built onto it that filled the void left by whatever caused the leak. Never had a comeback or problem and I would change out worn tires that I had previously repair when they were almost new.

I personally towed a triple axle 3car trailer daily for a few years that I had repaired tires on using this method.

As for what's the better axle to lose a tire on? If your towing I would rather have it on the steer axle, there's a reason duallies have the extra wheels on the back, besides added vertical load capacity.