Steer tire blow out - Few lessons learned

[slmink]

Originally Posted by journey15

Michelin has a very good video on what to do in case of a blowout... I would highly advise each and every motorhome owner to watch this video. While we did not have the Safety Plus on our 40 foot coach when we had our blowout, this video no doubt saved us. We had watched it based on someone's very good advice. We had a right front blowout and was just merging onto a 4 lane highway when it happened.
Husband was driving and I started screaming, "Don't mash the brakes" just as his foot hit the accelerator. It was this instinct that saved us of that I have no doubt.
https://www.michelinrvtires.com/tire...dle-a-blowout/

Thanks so much for this link. New to RV'ing and have taken about 6 trips. This is such valuable information.

[Cloud Dancer]

Originally Posted by cadillac_al

I'm not understanding why it is better to accelerate than to apply the brakes. When do you slow down and stop?

*
I can see that it's confusing. I'll try to give a better answer:
*
In event of a front tire blowout on a large motorhome: You do NOT need to step on the gas OR accelerate,...it makes things worst (the reason is scientific). Slowing down is very important, and the sooner the better. But, applying the brakes has to be done in a very precise manner, and technique. So, don't mess it up. The very MOST important thing is to NOT lose control (which means stay in your lane). The only primary system you have that's specifically designed for staying in your lane or for changing direction is the STEERING SYSTEM (with power steering). Therefore, the MOST important first things that the driver has to do is maintain uninterrupted alertness AND STEER/STEER/STEER, stay in your lane!!!! Also, make sure the cruise control is OFF. BE aware, If you do not do this within the first 3(seconds) of the blowout, you might be facing a "recovery from a loss of control situation".
This should not scare you at all. IT's intuitive and you have been learning it since you started driving. And, you have some important things on your side. First of all, a front tire blowout does NOT create a lateral sideforce. It can't. The energy released by the "explosive" loss of air pressure is NOT organized. It goes in many random directions. It is NOT a vector. What actually happens is simple. You will feel, at the steering wheel, that something is trying to steer to the side of the blowout (some people call this a "pulling force"...). It's actually caused by the fact that the flat tire has a greature resistive force than the inflated tire. This, in turn, causes a steering action through the spindle and steering linkage. But, the driver and the power steering can easily steer the motorhome with only ONE good steer tire (on pavement). You see this on videos over and over). I'm pretty sure I could do it with one hand.
Send me a private message if you have a specific question about my reply.

[Lakeman1]

Originally Posted by journey15

Michelin has a very good video on what to do in case of a blowout... I would highly advise each and every motorhome owner to watch this video. While we did not have the Safety Plus on our 40 foot coach when we had our blowout, this video no doubt saved us. We had watched it based on someone's very good advice. We had a right front blowout and was just merging onto a 4 lane highway when it happened.
Husband was driving and I started screaming, "Don't mash the brakes" just as his foot hit the accelerator. It was this instinct that saved us of that I have no doubt.
https://www.michelinrvtires.com/tire...dle-a-blowout/

Thank you for the link.

[Cat320]

I have looked at that video a number of times on various forums. It makes no more sense now than when I first saw it. I had a right front blowout a few years ago, with the cruise control on, well within the tire's weight limit, it was properly inflated and had not aged out. We had just crossed a small bridge, and the emergency services driver thought we had run over something that caused the catastrophic failure. When the tire failed the steering wheel started vibrating rapidly back and forth with a slight pull to the right. I immediately tapped off the cruise control and, as we slowed, gradually moved to the shoulder. The biggest problem we had was that the shoulder was very narrow, with a 45 degree angle drop off. My Velvac mirrors have three lenses, the bottom is oriented on each respective tire, so I could see exactly how far I needed to get off the hard stand before I started down the embankment. Even getting as far as I could into the grass left us dangerously close the highway. Every 18 wheeler that went by, shook the entire coach. The emergency services driver managed to get the remnants of the old tire off, and the new tire on, without removing the rim.As I look back on this experience, the last thing I wanted (or needed) was more speed, or thrust, it would have caused more damage and exacerbated the problem. At no time was I in danger of loosing control of the coach or was the vibration or pull to the right severe. Attempting to accelerate or increase thrust never entered my mind. As a long time both fixed and rotary wing aviator, with a few harrowing experiences, my only thought was..."slow down and get off the road...as I inched my way off the interstate. And that's what I did.

The Michelin video sounds good and looks good, however, all the scenarios are scripted with safety the primary consideration. It's like a lot of "school solutions," every aspect of the demonstration is planned. However,based on my experience, regardless of the physics, when doing it for real, I doubt it's merit, it just doesn't make sense.

[Cloud Dancer]

Cat320,...I'm with you. There are several points in the video that "do not make sense". I will keep on saying it because it has to do with safety (the safety of the driver and the passengers AND the safety of others who are in the vicinity of the blowout event). But, let's face it. The subject of the videos is technical and in order to understand it we need to know something about science. HOWEVER, some of the key points also have to do with common sense. For example, in order for a steer tire on a large motorhome to produce it's maximum designed TRACTION it must be inflated to within a certain range of air pressure. Also, it must be on a typical high-traction surface, and loaded within a certain range of weight. Also, in order to perform its STEERING job, it has to be rolling and has to be commanded to turn such that it will be at an angle (reference the bearing line of the vehicle). This implies that in order for the driver to cause a change of direction, the driver must turn the steering wheel. Let's stop right there. Can we agree that all this is so "common sensible" that it is not taught in driver's ed. It is assumed that students already know it.
There's more. But, it has to be taken in "steps".

[beach house]

Originally Posted by Cat320

I have looked at that video a number of times on various forums. It makes no more sense now than when I first saw it. I had a right front blowout a few years ago, with the cruise control on, well within the tire's weight limit, it was properly inflated and had not aged out. We had just crossed a small bridge, and the emergency services driver thought we had run over something that caused the catastrophic failure. When the tire failed the steering wheel started vibrating rapidly back and forth with a slight pull to the right. I immediately tapped off the cruise control and, as we slowed, gradually moved to the shoulder. The biggest problem we had was that the shoulder was very narrow, with a 45 degree angle drop off. My Velvac mirrors have three lenses, the bottom is oriented on each respective tire, so I could see exactly how far I needed to get off the hard stand before I started down the embankment. Even getting as far as I could into the grass left us dangerously close the highway. Every 18 wheeler that went by, shook the entire coach. The emergency services driver managed to get the remnants of the old tire off, and the new tire on, without removing the rim.As I look back on this experience, the last thing I wanted (or needed) was more speed, or thrust, it would have caused more damage and exacerbated the problem. At no time was I in danger of loosing control of the coach or was the vibration or pull to the right severe. Attempting to accelerate or increase thrust never entered my mind. As a long time both fixed and rotary wing aviator, with a few harrowing experiences, my only thought was..."slow down and get off the road...as I inched my way off the interstate. And that's what I did.

The Michelin video sounds good and looks good, however, all the scenarios are scripted with safety the primary consideration. It's like a lot of "school solutions," every aspect of the demonstration is planned. However,based on my experience, regardless of the physics, when doing it for real, I doubt it's merit, it just doesn't make sense.

You may not realize it, but your experience actually proves that the Michelin video is correct. Many unfortunately misunderstand the instructions, as mentioned by others, the instruction to hit the accelerator is only for a split second to help you gain control, as control is gained in a quick moment, the gradual deceleration begins. The reason why you had only a small pull on the wheel is because in that split second that the tire blew, it created instant resistance, slowing the coach down, and instantly the cruise control responded to the drop in speed by giving the coach throttle, which helped you keep the coach under control, having the coach under control, you instinctively disengaged the cruise control and proceeded to slow down gradually and very cautiously. Had you not have had the cruise control on, it is highly likely you would have had a very different experience. It all boils down to simple physics (dynamic forces).

For the same reason when cruise control is used in slippery weather (on RWD vehicles), it has the danger of spinning you out in an instant, because as the vehicle starts to slide, it loses speed causing the cruise control to give more acceleration, thus spinning the vehicle out. In the tire blowout situation that same acceleration force is what actually provides the momentary needed force to keep the coach in control.

I hope I have explained it clearly enough, as I often have trouble verbalizing what is in my head, which usually results in poor but well intended explanations.

[hedhunter9]

Having had a Right Front tire Blow out as we crossed from Florida into Ga. on a bridge with out cruise control on, I can say, I did NOT do the step on the gas even momentarily. We were doing about 55-60MPH when it blew.
When the tire blew on our 24,000lb Class A Outlaw, the MH immediately dropped down some and wanted to go right slightly. I just let off the gas and steered slightly left. Just enough to keep it straight.

Got it slowed down to a crawl, but there was No where to pull over on the bridge, so I slowly moved on down the road several Hundred more feet.

No sudden braking, No jerking the wheel. Just smooth controlled Movements.

Bob

[Cloud Dancer]

2nd part to my #75
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Keep in mind that the example vehicle, and enviroment, are the same. So, the only way for the large motorhome to change direction by itself is by somehow using its steering system. And, the only way the driver can make it change direction is by turning the steering wheel. How, and why, does the total steering system work? When all is normal, all we need to know is that it works. So, when a front tire has a blowout, let's look at what happens that makes it dangerous. The first danger is if the driver is overly startled by the noise, the vibration, the dust, PLUS whatever it is that's trying to turn the steering wheel. THIS startled driver likely will experience a "brain freeze" for 3 seconds or more. That's all it takes to lose control of a motorhome that's cruising at 98 feet per second (67 mph). Why? Because one steer tire has normal rolling resistance, while the blowout tire rapidly INCREASES its rolling resistance. Be aware that the rolling resistance is a resistive force made possible by the forward motion/energy of the mass of the motorhome (which is a much greater vector). And, if the driver is not managing the steering wheel there is no power steering action to resist the steering spindles from being rotated by this powerful force. Be aware that only the turning of the steering wheel shaft will "wake up" the POWER STEERING. NOW, at what point of the scenario do the videos want the driver to floorboard the throttle. IMO no driver is going to get on the throttle if the MH is pointing towards the ditch. And, if it's pointing straight down its lane this means to me that the driver is in control. AND, if you increase the forward propulsion, it's going to try to break the traction of the only steer tire that's working. If you're using this steer tire to stay in your lane, DO NOT mess with its marginalize traction. It makes no sense. Another notable thing is, the power of resistive force is proportional to the velocity of vehicle. Therefore, you should want to slow down right away,...NOT speed up. * (not looking for a debate, nor argument. Got a question? Send me a private message)
It easy to demonstrate how a flat, or semi-flat, front steer tire causes a steering input from the bottom, whenever the steering wheel is NOT properly attended. It's also easy to demonstrate that the blowout itself does NOT create a sideforce. Also, it's easy to demonstrate that steering and changing direction does NOT require a side force. Normal Steering is done by introducing a resistance to the forward motion of the vehicle together with a new path of least resistance.

[MSHappyCampers]

Thanks for sharing your experience and for the good advice!

[LETMGROW]

Originally Posted by HK2NY

Wow. Sounds like a scary experience. Thank God you are OK.

Has anyone considered or does anyone have MultiSeal Tire Sealant?

https://www.lichtsinn.com/rv-parts/multi-seal-view

I just got my first flat tire on my 2015 Winnebago View, but like another poster, it was an inside rear tire and I didn't even notice. But it was shredded when I finally looked under there. That got me thinking about a front tire blow out and this MultiSeal stuff. The videos are impressive and show punctures sealed instantly without loss of tire pressure. According to their information "long term field evaluations show that MultiSeal prevents up to 95% of tire failures from punctures and underinflation."

Any thoughts on that?

I don't think I'd want to be driving on a tire which had a puncture and instantly repaired it self. It would take a lot of time and effort to convince me this would be a permanent repair. Once a tire has been punctured it has been compromised. Time to get it off and replaced.

[ftodaro]

With all this talk about tires blowing out, this is a good time to point out that a major cause of blowouts is under inflation. I have owned my rig for 5 years and I occasionally tow an 24' enclosed trailer about 7,000 lbs. Finally this year i rolled it across the Cat scales and found that by the charts my rears were 15psi underinflated when i tow. So if this thread has you thinking you really hope you do not have a blow out, and have not yet weighted your coach, then you should put that on your list.

[Cat320]

Originally Posted by beach house

...You may not realize it, but your experience actually proves that the Michelin video is correct. Many unfortunately misunderstand the instructions, as mentioned by others, the instruction to hit the accelerator is only for a split second to help you gain control, as control is gained in a quick moment, the gradual deceleration begins. The reason why you had only a small pull on the wheel is because in that split second that the tire blew, it created instant resistance, slowing the coach down, and instantly the cruise control responded to the drop in speed by giving the coach throttle, which helped you keep the coach under control, having the coach under control, you instinctively disengaged the cruise control and proceeded to slow down gradually and very cautiously. Had you not have had the cruise control on, it is highly likely you would have had a very different experience. It all boils down to simple physics (dynamic forces)...

I appreciate your comments, but don't agree with your analysis. My cruise control was tapped off a fraction of a second after the blow out, almost as fast as the cruise realized the tire blew out....nearly instantly. I fail to see how more speed/thrust would help a situation where slowing down and getting rid of that speed is the key to getting safely off the road. More speed will certainly not help you gain control, one of your tires is gone....you need to slow down.

[fullmoonguru]

I can't believe people are still arguing about this. The next time you're on the highway floor the gas peddle. You will notice that the vehicle does not immediately accelerate with the front end lifting up, front wheel contact patches getting smaller, etc. We're not driving light weight, high powered sports cars here.

Especially with the added rolling resistence of a flat tire, all that's going to happen is that you will maintain current speed and give yourself a chance to look around and start a safe exit from the road.

[BillJinOR]

Better yet have two firm hands on the wheel thumbs not wrapped. Personally after having blowouts in my tractors without losing control , I imagine more likely is someone with a coffee, soda ,snack or fiddling with the gps or radio. Surprise! Of course someone is going to say “the wheel was turned and ripped from my hands “ ( maybe more accurately one hand or just fingers )
It’s easy to forget driving is 100% attention, when these things are so easy to drive. I’ve seen many Motorhomes pass me with the driver one handing it.