2 new tires. Put on front or rear?

[lubricatosaurus]

Originally Posted By: Quattro Pete
.Some car manufacturers specifically advise against tire rotations.

I've seen that too. I guess the philosophy is, if you're getting uneven treadwear, then get a proper alignment! To me its a matter of whether or not your front tires (steering) wear a lot on the outside due to turning hard a lot; then you probably should rotate.

 

[chrisri]

Originally Posted By: Astro14
Your opinion is wrong. It seems instinctively true but is specious. We are not talking about hot laps on a track in exotic performance cars, on which you base your arguments. We are talking about safety in the real world in which the threat is loss of stability.

Testing has shown that even professional drivers, on a track, who know the loss of traction is coming, will lose control of a car that hydroplanes at the rear. They are able to maintain control of a car that hydroplanes at the front.

A regular driver on the street will not do better.

So, put the good tires at the rear.

We cover this every two months at BITOG. Bottom line: what you think you know about traction, stability and tires is not true. Put new tires on the rear.


I am a professional driver. I never experience rear end aquaplane, either in FWD car or a RWD van or track. Even on motorways' with Autobahn speeds. In practice it simply doesn't happen in Europe. Maybe because we do not drive cars with chassis and RWD cars with rigid axles on leaf springs with 'all season ' tyres? Maybe we just drive slow? Who knows?

 

[lubricatosaurus]

Originally Posted By: Astro14
.We are talking about safety in the real world in which the threat is loss of stability..So, put the good tires at the rear.


Would you fly an F-14 with the vertical tail fins on the front? So you're right, deeper tread tires on rear for yaw stability in the rain.

 

[Astro14]

Snobbery doesn't support your argument. We aren't driving antiques over here...well..except for me...i have one leaf spring car, it was built in 1932. It has four new tires and I tend to avoid the rain with it.

The testing wasn't conducted with older solid axle and leaf spring cars.

It was, however, conducted by European tire and automobile manufacturers. And I own a few European cars, one of the which doesn't even have springs...

So perhaps you should consider the advice instead of dismissing it through presumption...

 

[Astro14]

Originally Posted By: lubricatosaurus
Originally Posted By: Quattro Pete
.Some car manufacturers specifically advise against tire rotations.

I've seen that too. I guess the philosophy is, if you're getting uneven treadwear, then get a proper alignment! To me its a matter of whether or not your front tires (steering) wear a lot on the outside due to turning hard a lot; then you probably should rotate.


Generally, the high performance cars, often with a staggered set up. BMW comes to mind...

Mercedes still recommends rotation, but the same side of the car only, to maintain rotation direction...

 

[chrisri]

Astro14,
I'm not being snobby, but you guys do still drive cars like Crown Vic in great numbers. RWD commercial vehicles (pick up trucks) are used for personal transportation, and are equipped with powerful engines, and aren't limited in speed, yet they do not handle as good as modern cars.
Most of cars over here are normal, modern cars. Light commercial vehicles are limited to 90 kmph, and are driven by professionals.

Astro, I drive for a living, 19 years now. 100-150k per year in various conditions of this continent. The fact that I'm driving for a living doesn't mean I'm brilliant at it. I'm not. But I do spend a LOT of time on the road so I would like to think that I'm average driver.

I know what is recommendations from various associations, and logic why they recommended what they recommend. I understand physics enough to know how rear end lift at highway speed results. This is the reason why I said any tyre on the car,regardless front or rear, should be in good condition.

There's, like in other things in life, other side of the medal.
On most European motorways (continental) there are no standing water. Not even in a heaviest rain. They are designed that way. In this conditions with tyres that are road legal danger for aquaplaning is minimal.
Now try braking from modest speed of 90kmph with older, but still legal tyres up front, and with new tyres on front axle. Difference is staggering.

I guess things are more regulated here when it comes to tyres. I have 5 vehicles and every year I have to put snow tyres from 15.11-15.3 to be able to drive outside of city limits. (no snow here in the city until you go to the mountains).

Anyway, thanks for advice, I know you mean well.

 

[CapriRacer]

Just an FYI:

I used to work for one of the major tire companies. Every year we would put on a track day event where we would demonstrate our new products. Included in that day was an event where we demonstrated WHY new tires should go on the rear.

The set up was there were 3 identical cars. One with new tires all around. One with new tires on the rear, shaved tires (4 /32nds) on the front. And one with new tires on the front, shaved tires (4/32nds) on the rear.

We had the people attending the event drive the cars - no stunt drivers involved. They all drove each vehicle at 45 mph around a large paved circle, where part of the circle include a patch with water flowing over the surface - about 1/8". That speed was easy to maintain, but a bit uncomfortable.

We usually did the demonstration with small, short wheelbase FWD cars because they were cheap and easy to find, and they would spin very quickly - thereby enhancing the effect. But we have done it with full sized RWD cars as well - it was just rough on those cars.

The vehicle with 4 new tires went through the patch of water like it wasn't there. The vehicle with the new tires on the rear experienced hydroplaning on the front, but after it left the water, it could be saved.

But the vehicle with the new tires on the front would spin almost immediately and you could not recover from the spin. And it would do it all but itself, with no help from the driver.

Please note: The demonstration was purposely set up to get the car to spin on its own - just like in the Michelin video Michelin video - Install Two New Tires on the Rear Axle. Some folks think that video is staged, but it isn't. The driver in the Michelin video is reacting what he is feeling - and that feeling occurs before the car visually loses control.

Some folks were able to prevent the car from spinning by driving too slow, or by straightening out the steering wheel before entering the water, but otherwise the car spun.

 

[lubricatosaurus]

CapriRacer, great write-up! If you drive long enough, you might experience that first hand. I have a few times. I don't think people have a decent understanding of Newton's laws of motion they can visualize, but it can bite you in the rear.
Bottom line: Spinning is always to be avoided.

A related corollary to all this is that you want higher grip tires in the back if you're mixing brands in the summer time. For example, using an all-season touring tire on the front, with something like performance BF Goodrich g-Force tires on the back will keep you from spinning in the dry. ..... And of course make sure the g-Force's there have deeper tread for the wet.

 

[gfh77665]

Originally Posted By: bbhero
Actually, when I had my better tires rotated up front recently... May seem strange but I had far less hydroplaning incidents with the better tires on the front. I felt much more uncomfortable with the front end losing traction than if the back end got out of shape.


I have refrained from this subject so far, but I would now like to add I agree with you. I drive on pancake flat highways that are usually usually straight as an arrow. With this in mind, the rear wheels track almost exactly in the path of the front wheels. If you notice, water is mostly cleared from the paths, so the back tires have all most nothing to cut through.

 

[Astro14]

Originally Posted By: chrisri
Astro14,
I'm not being snobby, but you guys do still drive cars like Crown Vic in great numbers. RWD commercial vehicles (pick up trucks) are used for personal transportation, and are equipped with powerful engines, and aren't limited in speed, yet they do not handle as good as modern cars.
Most of cars over here are normal, modern cars. Light commercial vehicles are limited to 90 kmph, and are driven by professionals.

Astro, I drive for a living, 19 years now. 100-150k per year in various conditions of this continent. The fact that I'm driving for a living doesn't mean I'm brilliant at it. I'm not. But I do spend a LOT of time on the road so I would like to think that I'm average driver.

I know what is recommendations from various associations, and logic why they recommended what they recommend. I understand physics enough to know how rear end lift at highway speed results. This is the reason why I said any tyre on the car,regardless front or rear, should be in good condition.

There's, like in other things in life, other side of the medal.
On most European motorways (continental) there are no standing water. Not even in a heaviest rain. They are designed that way. In this conditions with tyres that are road legal danger for aquaplaning is minimal.
Now try braking from modest speed of 90kmph with older, but still legal tyres up front, and with new tyres on front axle. Difference is staggering.

I guess things are more regulated here when it comes to tyres. I have 5 vehicles and every year I have to put snow tyres from 15.11-15.3 to be able to drive outside of city limits. (no snow here in the city until you go to the mountains).

Anyway, thanks for advice, I know you mean well.


"I'm not being snobby, but you guys drive old, weird cars, unlike we do in Europe..."

That about right?

So what?

European manufacturers did the test on European cars and came up with the result: if you only mount two new tires, it's safer to put the new tires on the rear.

So, you're distracting yourself by vehicle difference, when, in fact, those differences don't matter. The simple fact is that you, in Europe, with your cars, that you drive, as a professional driver, are safer mounting two new tires on the rear.

Your European manufacturers, Michelin, Continental, etc. recommend that.

 

[Astro14]

Originally Posted By: gfh77665
Originally Posted By: bbhero
Actually, when I had my better tires rotated up front recently... May seem strange but I had far less hydroplaning incidents with the better tires on the front. I felt much more uncomfortable with the front end losing traction than if the back end got out of shape.


I have refrained from this subject so far, but I would now like to add I agree with you. I drive on pancake flat highways that are usually usually straight as an arrow. With this in mind, the rear wheels track almost exactly in the path of the front wheels. If you notice, water is mostly cleared from the paths, so the back tires have all most nothing to cut through.


Pancake flat, arrow straight, South Texas roads are an anomaly. They aren't representative of the vast majority of roads in America...

Or Europe...

 

[edwardh1]

michelin has a recommendation, can't recall what it is. rear I think

 

[Quattro Pete]

Originally Posted By: edwardh1
michelin has a recommendation, can't recall what it is. rear I think

Yes, rear. Their video was posted earlier in this thread.

I don't recall a single tire manufacturer that recommends otherwise.

 

[krzyss]

C&D in their winter tire testing did mix and match scenario testing. Winter in front, AS in back and the other way around.

From pictures it seems that they used previous generation Ford Focus (FWD).

They managed to get better time on snow driving course with front winter tires but they claim that the car spend most time sideways. With winters in the back and AS in the front the car was slower but easier to control.

Krzys

 

[gfh77665]

Originally Posted By: Astro14


Pancake flat, arrow straight, South Texas roads are an anomaly. They aren't representative of the vast majority of roads in America...

Or Europe...


Of course. Thats why I elaborated. I know the difference very well. I have driven some of the highest roads in the high Rockies many times, like Mt. Evans auto road and Pikes Peak.

Back to the tires, I believe in my circumstance, best tires go on front.

 

[Oldmoparguy1]

CapriRacer,
this issue pops up every few months and it is always a furball. I have never understood the controversy. In todays world, I rotate my tires and replace them in sets of 4, so, I don't get into these either/or situations. I've driven since age 13, legally from age 16. That's 65 years. Back in my salad days, I bought used tires, 1 or 2 at a time, always the best ones on the front, because the fronts wore out first. I never had problems, never spun out is the rain, because I always drove below the limits of my equipment and the local conditions. I have studied those videos and for the life of me, I can not understand why the cars spin out. It makes no sense. Finally, I believe I understand, the test is designed to fail. If I were driving the test, I would not spin out. No matter what kind of test you set up for me, I could drive through it without losing control.

Do you know why?????

 

[CapriRacer]

Originally Posted By: Oldmoparguy1
CapriRacer,
this issue pops up every few months and it is always a furball. I have never understood the controversy. In todays world, I rotate my tires and replace them in sets of 4, so, I don't get into these either/or situations. I've driven since age 13, legally from age 16. That's 65 years. Back in my salad days, I bought used tires, 1 or 2 at a time, always the best ones on the front, because the fronts wore out first. I never had problems, never spun out is the rain, because I always drove below the limits of my equipment and the local conditions. I have studied those videos and for the life of me, I can not understand why the cars spin out. It makes no sense. Finally, I believe I understand, the test is designed to fail. If I were driving the test, I would not spin out. No matter what kind of test you set up for me, I could drive through it without losing control.

Do you know why?????


First, let me state that the preferred practice is to rotate tires regularly and frequently. That results in relatively even wear and the issue of where to put new tires is completely avoided.

It's also the safest way because you don't have one end of the car out of balance with the other end. Both ends would be equally prone to hydroplaning - and you would sense that and slow down.

- BUT -

If you don't rotate tires regularly AND you have a FWD car, you will wind up with the front tires worn out first - by a significant margin. This should be avoided if you can.

But I am going to disagree with you, OldMoparGuy. You can NOT follow the instructions of the demonstration and avoid the spin. The demonstration is purposely set up to make it happen - every time. It is also setup to show the difference - as the car with the new tires can drive through the water, but you can't with worn tires.

The demonstration could have been set up to make EVERY car spin out, but that doesn't demonstrate why one way is better than another. It could have also been set up to avoid the spin completely - again, that would not show the difference.

Yes, going slower or driving straight through the water will avoid the spin. Just as anticipating the spin and applying steering input BEFORE the car starts to spin. AND, more water and higher speeds will cause problems for the other cars as well. But the point is to show that there ARE differences.

 

[Oldmoparguy1]

Thank you CapriRacer. The tests are designed to fail! It's a political point. "We know better, do it our way". This demonstration could be used as a teaching moment, "see what happens? Be aware of your tires and your driving conditions."

And yes, I could do it and not spin out.

 

[HerrStig]

Originally Posted By: chrisri
Originally Posted By: Astro14
Your opinion is wrong. It seems instinctively true but is specious. We are not talking about hot laps on a track in exotic performance cars, on which you base your arguments. We are talking about safety in the real world in which the threat is loss of stability.

Testing has shown that even professional drivers, on a track, who know the loss of traction is coming, will lose control of a car that hydroplanes at the rear. They are able to maintain control of a car that hydroplanes at the front.

A regular driver on the street will not do better.

So, put the good tires at the rear.

We cover this every two months at BITOG. Bottom line: what you think you know about traction, stability and tires is not true. Put new tires on the rear.


I am a professional driver. I never experience rear end aquaplane, either in FWD car or a RWD van or track. Even on motorways' with Autobahn speeds. In practice it simply doesn't happen in Europe. Maybe because we do not drive cars with chassis and RWD cars with rigid axles on leaf springs with 'all season ' tyres? Maybe we just drive slow? Who knows?
Maybe WE don't drive those cars any more either, for about the past 20 years.

 

[rslifkin]

Originally Posted By: Oldmoparguy1
Thank you CapriRacer. The tests are designed to fail! It's a political point. "We know better, do it our way". This demonstration could be used as a teaching moment, "see what happens? Be aware of your tires and your driving conditions."

And yes, I could do it and not spin out.


Exactly. In a realistic scenario where the worse set of tires isn't trashed but is just a little more worn than the better set, you should never be put into a situation as severe as the demos.