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Post by silverdragon on Jun 27, 2015 6:51:06 GMT
And I know this is a tyre myth, but is it enough to be a "headline" standalone myth?...
Have you ever been there?...
Scenario, car in a tight corner, at "reasonable" speed, on motorway/interstate at say around 60mph, and the tyre "blows" (sudden decompression)
The back-end starts to want to overtake the front.
This has happened to me... -sort of-... we were doing 40~50 ish on a link-road between two motorways when the rear right tyre on a right handed corner blew. (Exact speed unknown, I was kinda busy?..)
(I slow down for that high-level corner, its not nice, partly blind, and whilst over the other motorway I take a good look to plan my merge.)
If it had been the tyre on the "Outside" of the corner, as in the left tyre on the right hand corner, would the result have changed significantly?.. the load is over the outside tyre?... I suspect from all I know, yes it would, as I have seen a 70mph(plus) incident where that happened and it just span off into the scenery.
With our lower speed, I managed to get to the hard shoulder, get parked sort of safe, get out, and swap the tyre real quick, and as that is an "observed" part of the motorway, as it it has more camera's than the BBC outside broadcast unit, I got that swapped before the Po-lice came to investigate.
"You should stay in the car and await help"
"I fixed it before you got here, how long extra before a tow truck would get here?.."
And yes, I had deployed a safety triangle warning sign 100yds back, unique one of my own design, with a flashing amber (BRIGHT) LED attachment in the top corner to make it High-Vis.
I would safely say we were on our way again quicker than we needed to be, because apart from having a time waster chat with the dibble, I wasnt hanging about.
My passenger only knew something was wrong when I stopped....
No use worrying him when I had it under control (sort of) he thought it was wind pushing the car about.
However, at a High[er] speed?...
I dont know the loading specifics for that vehicle, its a car-derived-van "Verso" mini-MPV 5 seater high roof with plenty of luggage space type, Front wheel drive.
I suspect at speed and under load, a rear axle driven car where the outside tyre looses traction/blows/de-laminates/whatever would have reacted many times worse than my slower <=50~ish mph incident.
Can you recover that?...
I suspect highly trained [Stig?} driver with plenty of space maybe could do that.
Then repeat the whole experiment with a FRONT tyre blow-out....
Half steering, does it matter?.. (yes) will inside or outside tyre change the result (Oh yeah) will speed multiply the result (Weeks wages say you bet'cha...)
How to test...
...Sort of not that hard.
Skid-Pan training, there are cars out there with hydraulic extra "castor" wheels that can be used to jack the tyre off the ground to simulate loss of traction.... you dont need to blow the tyre out, so can re-use the same wheel again and again.
You can raise one single tyre if you so wish to simulate blown tyre.
The actual rig fits to the outside of the car, but if the MB's cant borrow one, can they rig up just the one side to test on right and left handed corners.
I would also say test the results against one single blown out tyre experiment to show the results of a lifted wheel are the same as a blown wheel.... you know how "some" people may pick that up?...
I suggest that type of rig and a cone laid roadway course on a large space, see if you can stay inside the cones.
Or a cone'd lane on a "oval" trackway to give some space outside the lane to stop in in emergency...
Preferably away from a hard wall outside, so NOT a speed-way or the "Brick_Yard" type track.
Use an "average" reasonable driver without speed or skid-pan training as a base line for the average motorist.
Test low speed, then high speed, rear wheel drive, see what difference that makes, then test "inside" and "outside" tyres in respect to the direction of the corner to see what difference that makes.
Then repeat with a FRONT wheel drive car.
Maybe the position in the corner matters, hard braking into and high acceleration out of the corner may vary results?...
Repeat the whole experiment with "trained" driver.
Maybe even train up either Adam or Jamie to skid-pan level and compare results?...
My suspicions....
Front wheel drive with "Inside" tyre blown, not all that noticeable at low speed until maybe you start to straighten up.
High speed under acceleration (exiting the corner maybe) with "Outside" tyre, pick a soft spot in the scenery.
Front wheel blow-out whilst cornering, outside tyre under braking, "what corner"....straight line pick-a-soft-spot.
Trained versus untrained, I suspect more recoverable scenarios, but certain situations, such as front-wheel outside on braking, there is NO recovery that can be useful, pick-a-soft-spot.
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Post by silverdragon on Jun 27, 2015 8:09:45 GMT
Secondary test, "spilled load"
Everything from sheet-rock to Oil, even "Hit a brick", if that is introduced to the corner, what loss of control would occur.
The oil is easy, same as simulated black ice, semi-lift all four tyres on that Skid-pan car to introduce low or no traction, where are you going?...
Of course, if you can stop in the distance you can see, you shouldnt be driving that fast, but, what if its the vehicle in front of you "dripping" oil?....
(Yeah, I know, you shouldnt be that close should you?..)
The "Hit a brick" could be simulated by a small ramp to throw the tyre up, using the ramp so it doesnt destroy the tyre.
Anyone else got anything they could introduce to upset the control of a car?...
How about a "sudden sheep".
Or anything that could suddenly jump out on front of you....
Idea, a "Skit" on that, could be a cart with a mail box on it deployed from a hidden position in front of the vehicle, they were not expecting THAT were they?...
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Post by c64 on Jun 27, 2015 21:47:31 GMT
Secondary test, "spilled load" Everything from sheet-rock to Oil, even "Hit a brick", if that is introduced to the corner, what loss of control would occur. The oil is easy, same as simulated black ice, semi-lift all four tyres on that Skid-pan car to introduce low or no traction, where are you going?... Of course, if you can stop in the distance you can see, you shouldnt be driving that fast, but, what if its the vehicle in front of you "dripping" oil?.... (Yeah, I know, you shouldnt be that close should you?..) The "Hit a brick" could be simulated by a small ramp to throw the tyre up, using the ramp so it doesnt destroy the tyre. Anyone else got anything they could introduce to upset the control of a car?... How about a "sudden sheep". Or anything that could suddenly jump out on front of you.... Idea, a "Skit" on that, could be a cart with a mail box on it deployed from a hidden position in front of the vehicle, they were not expecting THAT were they?... There are too many factors to have a clear answer. It mostly depends on the car and the situation. The longer the wheelbase, the lower the forces while steering, especially on the rear axle. Usually, a blown rear tire is worse than a front tire since the rear is what keeps your car stable. When the rear starts to slide sideways, you are likely to spin out of control. With a blown front tire, you have a very good chance to keep the vehicle in the intended path by just turning the steering wheel harder. Modern ESP can compensate a blown tire quite well. If you are not close to the limit of the "intact" car, you will have no problem to keep your vehicle under control. And during normal driving, If you are half way to the limit of your car or more, you do something seriously wrong. I had a blown tire at ~100mph once, no problem, just really scary and the rim was destroyed which made it more expensive. I've never left my lane but there are no tight turns on the Autobahn. During a turn, I would have needed more room until getting used to the new behaviour of the car. The main important rule is don't brake hard. First keep your car stable, then gently probe how hard you can brake, brake as little as you can afford to stop the car safely within a reasonable time. |
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Post by the light works on Jun 28, 2015 15:03:05 GMT
how did I miss this thread?
I have seen both ends of the spectrum. I blew a front tire on a work truck on a twisty road at close to max speed, but it was only a blowout, not a catastrophic blowout. I was able to drop throttle and coast it down to an easily controllable speed while I looked for a pullout. on the other end, we had a crash where a SUV pulling a travel trailer threw a rear wheel on an outside corner. there was no recovery, because it is hard for countersteer to be effective when your front wheels are parallel to the ground instead of perpendicular.
as for test rigs - I don't know if they still use them, but some driving schools used to have blowout trainer cars. it was simply a car with central inflation and BIG dump ports on all four wheels. the student drives along the track, and the instructor hits the dump port, letting all the air out of the tire.
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Post by c64 on Jun 28, 2015 16:31:28 GMT
how did I miss this thread? I have seen both ends of the spectrum. I blew a front tire on a work truck on a twisty road at close to max speed, but it was only a blowout, not a catastrophic blowout. I was able to drop throttle and coast it down to an easily controllable speed while I looked for a pullout. on the other end, we had a crash where a SUV pulling a travel trailer threw a rear wheel on an outside corner. there was no recovery, because it is hard for countersteer to be effective when your front wheels are parallel to the ground instead of perpendicular. as for test rigs - I don't know if they still use them, but some driving schools used to have blowout trainer cars. it was simply a car with central inflation and BIG dump ports on all four wheels. the student drives along the track, and the instructor hits the dump port, letting all the air out of the tire. The training I had was much more simple. There was a plate on the track which could me moved sideways hydraulically. When your front or rear wheel is on top (programmable), the plate slides to the side. Then you need to recover. The effect is close to a tire blowing out of a sudden. True, it's somewhat easier because you have all tires to recover but the training is useful. |
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Post by the light works on Jun 28, 2015 21:57:51 GMT
how did I miss this thread? I have seen both ends of the spectrum. I blew a front tire on a work truck on a twisty road at close to max speed, but it was only a blowout, not a catastrophic blowout. I was able to drop throttle and coast it down to an easily controllable speed while I looked for a pullout. on the other end, we had a crash where a SUV pulling a travel trailer threw a rear wheel on an outside corner. there was no recovery, because it is hard for countersteer to be effective when your front wheels are parallel to the ground instead of perpendicular. as for test rigs - I don't know if they still use them, but some driving schools used to have blowout trainer cars. it was simply a car with central inflation and BIG dump ports on all four wheels. the student drives along the track, and the instructor hits the dump port, letting all the air out of the tire. The training I had was much more simple. There was a plate on the track which could me moved sideways hydraulically. When your front or rear wheel is on top (programmable), the plate slides to the side. Then you need to recover. The effect is close to a tire blowing out of a sudden. True, it's somewhat easier because you have all tires to recover but the training is useful. the blowout training I had was simpler than that - they showed movies of someone else driving the training car and sad "do it like that" |
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Post by silverdragon on Jun 29, 2015 6:35:01 GMT
Skid pan training, "old school".
We drove to a large "parade ground" type squared off bit of tarmac.
the local Fire engines turned up and hosed the area down with suds... yep, soap suds. Drains were blocked to prevent drain-away. the course is around the cones that marked the drains.
We are told "Drive round that"
In a small van, to get used to it.
Those that get the idea are sent out again...
In a double decker bus.
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Post by silverdragon on Jun 29, 2015 6:47:22 GMT
Rear wheel blow-out "worse" than front wheel blow-out. "At speed"
Either way, I think you are picking a soft spot, and for anyone who thinks driving with only three wheels is easy, try a Reliant Robin...
You may remember Jeremy Clarkson had problems with one of them.
And they are designed to run on three wheels.
Seriously, I know some of you have anecdotal evidence of vehicles with deflations issues, but the "Fair weather pilot's" amongst us IRL, and there I point at Adam and Jamie, who's "Top up or Top Down" test where they had to take instruction in heavy rain driving was probably a good idea, but left us UK viewer wondering if they ever have rain over there, leaves us with the question "Average Joe", who has never left tarmac, can he manage in a sudden unexpected blow out.
Is a rear wheel blow-out in a FRONT wheel drive as bad as it gets?
I say no.
From experience.
Maybe in a rear wheel drive under acceleration....
But FRONT wheel blow out whilst cornering "Hard", on the outside tyre, thats not nice.
Think unexpected curve and perhaps your going a little faster than you should on an approach to a curve...
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Post by the light works on Jun 29, 2015 14:12:25 GMT
Rear wheel blow-out "worse" than front wheel blow-out. "At speed" Either way, I think you are picking a soft spot, and for anyone who thinks driving with only three wheels is easy, try a Reliant Robin... You may remember Jeremy Clarkson had problems with one of them. And they are designed to run on three wheels. Seriously, I know some of you have anecdotal evidence of vehicles with deflations issues, but the "Fair weather pilot's" amongst us IRL, and there I point at Adam and Jamie, who's "Top up or Top Down" test where they had to take instruction in heavy rain driving was probably a good idea, but left us UK viewer wondering if they ever have rain over there, leaves us with the question "Average Joe", who has never left tarmac, can he manage in a sudden unexpected blow out. Is a rear wheel blow-out in a FRONT wheel drive as bad as it gets? I say no. From experience. Maybe in a rear wheel drive under acceleration.... But FRONT wheel blow out whilst cornering "Hard", on the outside tyre, thats not nice. Think unexpected curve and perhaps your going a little faster than you should on an approach to a curve... you're being awfully liberal with your use of "designed" I've driven with a flat rear tire, I've driven with a low rear tire (shouldn't have taken the kid's word for it that it wasn't low) I've driven as I said with a blowout on the front. rear blowout in a front drive is most definitely not as bad as it gets. it can range from "oh, that was the noise I heard" to "drive the front end where you want to go and don't let your a** end pass you." in general, if a car loses a drive wheel on the outside of a corner, it will take a lot of room to recover. that is the tire doing most of the controlling and losing it sets up a guaranteed skid. - and as I said, losing the outside rear wheel with a trailer will tend to take the rest of the wheels off the ground immediately. but average car, modern average driver - probably not going to have the ability to recover. |
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Post by c64 on Jun 29, 2015 15:48:24 GMT
You may remember Jeremy Clarkson had problems with one of them. And they are designed to run on three wheels. Not at all. They are made mostly from overproduction of car parts and designed to be cheap to obtain, cheap to own (tax) and - most important - no need to have a "real" driver's license. In Germany, the Messerschmitt Kabinenroller (along with other other tin cans) was created for the same reasons. Until the 60s, you didn't had to own a driver's license for motorcycles with a reasonable engine size. And since a motorcycle could have a sidecar, the definition was "Motorcycle = less than 4 wheels". And even with a bigger engine, a motorcycle license is a lot cheaper than a car's license and more like a formality. It was similar in the UK, but they installed the single wheel on the wrong end of the vehicle. The Brits did it like the Italians. They also have lots of 3-wheeled vehicles. But they have a different reason. Rome wasn't built with motorized vehicles in mind so most streets are way too narrow. In most parts of Rome you are not allowed to drive a car except on the few main roads. But you were allowed to ride a bicycle or motorcycle. And they had the same definition as Germany - so they made 3-wheeled delivery trucks and on a truck it makes more sense to put two wheels under the cargo area instead of just one. but left us UK viewer wondering if they ever have rain over there, Looking at UK made cars, especially the Brittish Elend Leyland ones, and seeing how quickly you can close the roof of convertibles, seeing open cars without any roof option and looking at how watertight the cars are and how the windscreen wiper mechanics is designed, we also wonder if there is any rain in England! Is a rear wheel blow-out in a FRONT wheel drive as bad as it gets? I say no. From experience. Maybe in a rear wheel drive under acceleration.... But FRONT wheel blow out whilst cornering "Hard", on the outside tyre, thats not nice. Think unexpected curve and perhaps your going a little faster than you should on an approach to a curve... The rear wheels are highly critical to keep your vehicle stable. If you loose grip on the rear axle, the car can spin around and then you loose all control for sure. That's why cars used to brake 20% at best on the rear axle until ABS or other means of situation dependant regulation came up. A blown front wheel can be compensated by turning the steering wheel further. The car might not exactly go where you want it to go but this is far better than sliding sideways into a very wrong direction. |
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Post by the light works on Jun 30, 2015 4:13:16 GMT
a rear blowout on a front drive car is often quite uneventful because they have 75% of the weight at the front. if they are driving sedately, they may not notice until they actually look at the tire. I drove mine HARD with a very low back tire, and while I was suspicious that there was a problem I took my passenger's word for it the tire wasn't low until I actually saw it for myself.
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Post by silverdragon on Jun 30, 2015 6:48:32 GMT
Which strangely is the best advice on how to drive a mini.
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Post by silverdragon on Jun 30, 2015 6:56:06 GMT
The reason the brake balance is at the front is the same reason the brakes on a Motorcycle work, under braking, all of your weight is transferred forward, over the front wheel.
You use the front brake to slow down, the back brake to slow down the transmission, and slightly to keep the back wheel under control only.
Unless its one of them Yank things that have more weight than a small micro-car... thinking HardlyDriveable or even the Honda Goldwing Aspencade 1500cc and above.
Any bike that has a reverse gear....
Blow a tyre on a cycle, (at speed), rear is a pain, you have to slow down gently.
Front is tank-slapper, and pick a soft spot time.
Its not because the rear is a stability problem, its because loss of steering is worse than you expect, especially on a tight corner.
Front-Wheel drive, all the back wheels do is stop the back end rubbing on the tarmac.
Again, a Mini quote.
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Post by the light works on Jun 30, 2015 14:04:54 GMT
Which strangely is the best advice on how to drive a mini. it is the best advice on how to drive any front drive car in iffy traction. |
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Post by silverdragon on Jul 1, 2015 5:34:29 GMT
Which strangely is the best advice on how to drive a mini. it is the best advice on how to drive any front drive car in iffy traction. Erm... let me fix that a while... "it is the best advice on how to drive any front drive car".... .....do you need anything else?... |
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