Depends on whether you prefer under or over steer. I get why it's recommended the new ones go on the rear, but personally I prefer the rear to let go first.

Under/over steer is not as simple as 2mm more tread-depth on one end.

The biggest factor is how you are driving, the second factor is the road conditions, the third how the suspension is setup.

If you are getting the back end out on public roads, then you are driving like a knob. Tyre rotation doesn't even come into it.

Yes I have spun a car on public roads. I know the exact cause. I was driving like a knob.

I went to pass a car while heading into a set of corners in heavy rain and they sped up. Instead of backing out (like I should have) I sped up, completed the passing but entered the corners at roughly twice the recommended speed.

I got around the the first corner with the tail out. But I was unable to shed enough speed coming into the second, tighter, corner. I was on opposite lock and the back end of the car kept coming around.

It stopped with me facing the way I came on the other side of the road.

Edited 22 June, 201312 yr by Kiwibacon

Sorry but I disagree.

If your car does spin you won't be able to do anything about it. "Knowing what to do in a spin" doesn't come into it. Even in F1, when you spin you spin. You're off the side of the track and into the tyre wall.

Like I said earlier, many people have a fantasy about the rear end just drifting out in a graceful manner and them being able to control it. It doesn't usually happen like that. If the back end lets go it will be sudden and unexpected and you will be off the road backwards before you've realised what happened.

The advice about tyre placement applies to everyone, the cautious as well as those who like to push their luck, the experienced and knowlegeable as well as the inexperienced. And people are not always as knowlegeable as they might like to think, as the misunderstanding of what "slip angles" are all about demonstrates.

However it is advice. It is not a rule and it is not law and many people do not follow the advice - some because they are unaware of the advice, some because they disagree with it. Fair enough - your choice!

Oh I don't know, if you are simply "pushing on" then I guess the back end could be slid out in a controlled manner (I can't confirm this as I am steady eddy), however I agree that if you hit a patch of diesel or oil then it's game over regardless of how good a driver you are.

I have to say that I've had the back end step out in snow an ice (in a 4wd) a few times and have been able to catch it, so it's not impossible.

Some people here aren't half talking rubbish. The reason for recommending new tyres go to the rear is to give most grip at the rear. I expressed my PERSONAL PREFERENCE that I like it the other way around. That's all. How this lead to F1, slip angles, and driving like a nob, who knows. And it's obvious some people have never experienced a car sliding but seem to know exactly what happens when it does. Having a preference of over steer doesn't mean I drive everywhere sideways either.

Some people here aren't half talking rubbish. The reason for recommending new tyres go to the rear is to give most grip at the rear. I expressed my PERSONAL PREFERENCE that I like it the other way around. That's all. How this lead to F1, slip angles, and driving like a nob, who knows. And it's obvious some people have never experienced a car sliding but seem to know exactly what happens when it does. Having a preference of over steer doesn't mean I drive everywhere sideways either.

I'm afraid that liking oversteer (I doubt that you would like a car which really did oversteer and was therefore unstable - I suspect that your preference is actually for a car with much reduced understeer) is not the same as having a car where the rear end is likely to let go first.

Understeer / oversteer is about "slip angles" and that misleading term (the tyres are not slipping, the tread is distorting) is what confuses many people. It is not the same thing as which end will let got first in freak conditions.

As an extreme example: if you had bald but properly inflated tyres on the front and tyres with plenty of tread but with only 10 psi on the back, then it would oversteer horribly but if you cornered very hard on anything but a perfectly dry, clean surface, it is almost certain that the front would lose grip first and the car would just stop cornering any tighter and would scrub itself to a standstill.

Do it the other way round and the car would normally understeer in a very reassuring, boring way. But if you hit slippery conditions while cornering hard, the back end would let go first and the car would spin, with you having no control of it at all.

If you spin a car on public roads you are either driving like a nob (which I was when I spun my Morris Monor) or you have been unlucky enough to encounter freak conditions. And yes, this does happen and it is, by definition, unexpected. I know of several drivers - some very experienced and skillful, some very experienced and cautious - who have lost control of their cars when they certainly were not driving like nobs. Some have had the car roll, some have gone off backwards and some have just ploughed on into a ditch.

And like I said, one very experienced driver I know who went off backwards had put the more worn tyres on the rear as he always did, like I always used to. He doesn't do so now, and neither do I.

Obviously you are free to put your least-worn tyres at which ever end you prefer, and live with the consequences which are most likey to be - nothing. I just hope that you are like most drivers and never encounter the freak conditions which some of my friends have.

But don't confuse the issue by talking about understeer and overster, which is a different matter.

Edited 22 June, 201312 yr by Stuarted

got pulled by VOSA today in my tanker and asked them if its best to fit new tyres to rear?

he said they use to advice people to fit new onto front but now its new onto rear and to swap tyres round after every 6 months to get even wear.

Was going to swap mine round but....never check them and they are down to the markers

check my truck every day ...tyres/oil/ect....but never check car for anything,just leave it until it goes in for a service so getting some goodyears on and having wheels done black

Think what you want mate, but don't try to tell me what I mean or what I know.

Think of it with the weight transfer as well, its simple laws of physics & no pub argument can contradict those

We all know the front of the car lifts under acceleration & dives under heavy braking & the principle with the tyres is similar but less extreme

If you are driving your car & you start to loose grip at the front the natural reaction is to lift off or some oiks even brake either way you transfer weight onto the front wheels pressing them harder onto the road regaining some control, or the oik who brakes if to hard may loose the rear

If you are driving along & you start to loose grip at the rear and you lift off the power let alone brake the weight is transferred forward & your rear tyres now have less downforce onto the road so less grip & as they are already sliding away the slide speeds up & you are quite possibly going to spin

If you don't believe me find a large EMPTY roundabout WITH CLEAR VIEWS down all access roads, drive round until you feel you are on the limit & then lift off & you will feel the tendency of the front of the car to turn in & the back to step out, REMEMBER to lift off gently the first couple of times to get a feel for it & also don't hug the inside of the roundabout as the car will have a tendency to turn in. I have witnessed a youngster in a saxo start to loose it on a roundabout, lifted of suddenly & ended up parked on the roundabout, nothing apart from his pride damaged

got pulled by VOSA today in my tanker and asked them if its best to fit new tyres to rear?

he said they use to advice people to fit new onto front but now its new onto rear and to swap tyres round after every 6 months to get even wear.

Was going to swap mine round but....never check them and they are down to the markers

check my truck every day ...tyres/oil/ect....but never check car for anything,just leave it until it goes in for a service so getting some goodyears on and having wheels done black

Which seems to reinforce some opinions on here that if you are going to run different tread depths then best to back, but it is equally as acceptable to rotate and wear all four equally and change all 4 at once.

Think what you want mate, but don't try to tell me what I mean or what I know.

I don't wish to be antagonistic , but if i recall correctly it was you who first metioned understeer and oversteer:

"Depends on whether you prefer under or over steer. I get why it's recommended the new ones go on the rear, but personally I prefer the rear to let go first."

I will not offend you by suggesting that you do not fully understand what understeer and oversteer are, what causes it and what slip angles are.

But for the benefit of others reading this who do not understand these things as well as you do, I feel I ought to point out that understeer and oversteer are not about which end lets go first when tyres eventually lose their grip, although the two things can often go together.

In particular a tyre with less tread may well lose its grip before one with little or no tread, particularly if the surace is not dry and clean. However the amount of tread on a tyre will not affect whether the car understeers or oversteers.

As you (but not necessarily everyone reading this) will know, "understeer" simply means that the car turns a bit less sharply than you expect when you corner, so you simply tighten the steering slightly to maintian your line. "Oversteer" means that the car turns slightly more sharply than you expect when you go round a corner and you need to turn the steering wheel back very slightly in the opposite direction to allow for this. Reversing the direction you have turn the steering wheel (even very slightly) each time you go round a corner is tedious and tiring and is why cars are designed to understeer - some (the more sporting ones) very slightly, the more utilitarian ones rather more which makes them more stable and more relaxing to drive.

How much a car understeers depends on the difference between the slip angles of the rear tyres compared with the slip angle of the front tyres, and the "slip angle" (which is a misnomer - the tyre is not actually slipping, it is merely twisting or distorting) of the tyre is merely the angle between the direction the tyre is pointing and the direction it is actually travelling.

It is not about skidding, drifting or sliding. Once the tyre has actually lost its grip and is sliding or skidding, a different situation prevails, but that should be irrelevant to sensible driving on the road.

The slip angle depends on, among other things, the design of the tyre (mainly the stiffness of its carcase), the air pressure in it and the load on it - but not the amount of tread it has. In fact, a less worn tyre with more tread may have a very slightly (barely detectable) greater slip angle under given conditons than an otherwise identical tyre with hardly any tread on it, since there is slightly less rubber on it to twist and distort.

If you want to alter the degree to which you car understeers, the simplest way is to alter the tyre pressures. Soft tyres flex more and have higher slip angles so having soft front tyres will make your car understeer more. Another way is to add or stiffen one of the anti-roll bars. An anti-roll bar transfers more of the weight onto the outer wheel when cornering, and the more load there is on a tyre the greater its slip angle will be. So fitting a stiffer front anti-roll bar will increase the slip angle of the outer front tyre and the car will understeeer more. Correspondingly, fitting a rear anti-roll bar (or a stiffer one) wil reduce understeer and make the car's handling more neutral.

One small detail: another factor which affects slip angle is the camber of the wheel. Negative camber (top leaning inwards) will reduce the slip angle and negative camber (top leaning out) will do the opposite. Which is why the very early Hillman Imp (remember those?), which had most of its weight at the back due to its overhung rear engine but which was desgned as an everyday utility car had massive positive camber at the front and front tyres running at far lower pressure than the rears to try to elimiate the otherwise inevitable (but highly undesirable, in such a non-sporting car) risk of oversteer.

This is yet another reason why correct wheel alignment (camber as well as toe-in, on the rear as well as on the front) is essential for pleasant relaxed driving even when driving at modest speeds and cornering gently.

If you don't believe me, go and read it up in a reputable textbook. But I presume you knew all this anyway.

Safe driving, which ever end you choose to fit your new tyres!

Edited 22 June, 201312 yr by Stuarted

I presume that interlocking tread blocks are designed like that to reduce the slip angle then?

And there was me thinking the slip angle was all to do with how to approach a slippy bend. Sorry - that tangent again! Just one member trying to inject a little something to defuse the tension...

Stuarted, I get the point you're making, I do, but let me clarify what I was originally trying to say. The discussion was about the recommendation to put the newer tyres to the rear, and the reason for that is about what might happen on wet roads as in the video that has been linked. In conditions such as those, where one end the other may slide mid corner, my preference is for the rear to go first. Unless you are going way too fast, it will not result in an instant spin as has been suggested. Perhaps most people's automatic reaction would be to panic and get off the throttle or even brake, but it would not be mine. I feel more comfortable with the idea of correcting the rear than drifting out towards oncoming traffic.

I know that simply swapping the tyres around will not completely transform the balance of a car and make it prone to oversteer. That's not what I was suggesting. I was merely saying that when considering the argument for which end to fit the new tyres, I would go with the front.

The real difference it makes is small anyway, and as has been said, driving style and the overall vehicle set up will have the greatest affect on whether it under or oversteers. A few mm of tread difference won't really make much difference at all if any, and most people will never even get to find out any difference it makes anyway.

Just a point on the video, I think the results are exaggerated for effect, and I don't believe for a second that VBH would not be able to stop the rear of the car sliding in the example shown.

Stuarted, I get the point you're making, I do, but let me clarify what I was originally trying to say... (etc.)

I largely agree with what you say. I think the possible confusion can arise from the use of the words "understeer" and "oversteer" which are often used inappropriately and sometimes misused even by supposed "experts".

If you prefer to fit the more worn tyres on the rear and the less worn ones on the front, that is your choice. Your car and you are the driver.

As you have stated, however, this will make it more likely that it will be the rear end and not the front which will let go first in extreme circumstances such as freak road or weather conditions or when the driver may be “pressing on” or when (to use that wonderful expression) he is “driving like a nob”.

If the car behaving like that in the extreme is indeed what you prefer, then so be it – your choice. But it is worth noting that, particularly in the kind of conditions described above, this will not necessarily result in a graceful tail slide and could result in the car spinning or changing ends very quickly indeed, and the car going through the nearest hedge backwards.

As you appreciate, despite popular confusion over the matter, this is not really the same thing as over-steer or under-steer, which are a description of how the car responds to steering input during normal everyday driving conditions and (as you say) is mainly influenced by factors other than tyre tread depth.

Edited 22 June, 201312 yr by Stuarted

Stuarted, I get the point you're making, I do, but let me clarify what I was originally trying to say. The discussion was about the recommendation to put the newer tyres to the rear, and the reason for that is about what might happen on wet roads as in the video that has been linked.

The problem I have with that video that keeps being linked to these threads, is that it was completely staged, to the point where even despite their best editing efforrs you can see where the driver cranked on the steering wheel to throw the car into oversteer.

This suggests to me, that even with the most worn tyres on the rear, on a flooded roundabout, they were unable to get the car to oversteer as they claim it would. So they had to throw it into a slide.

In short. It's complete *******s.

I am also curious as to the UK spelling of "nob" vs "knob".

My comments about the inadvisability of fitting the more worn tyres to the rear were not based on any video (some of which may indeed be staged) but on

(1) the published advice of tyre and car manufacturers and

(2) the experience of skilled, well-informed, high-mileage divers I know who always used to put the less-worn tyres on the front (like I used to do) but have been startled to discover, in unexpected circumstances, what can sometimes happen if you do.

I will add that videos commentries can sometimes add to a common misunderstanding of the words 'oversteer' and 'understeer' by using these words to describe which end of a car loses grip first in exteme conditions, which is not really a correct use. Strictly speaking, understeer / oversteer describes how a vehicle responds to steering input in normal, everyday driving when the tyres have not lost adhesion.

As for the spelling of 'nob' - dunno, I just copied the spelling used by other posters in this thread. I am tempted to ask if there is a video about this somewhere!

Edited 23 June, 201312 yr by Stuarted

As you have stated, however, this will make it more likely that it will be the rear end and not the front which will let go first in extreme circumstances such as freak road or weather conditions or when the driver may be “pressing on” or when (to use that wonderful expression) he is “driving like a nob”.

I believe what you are referring to is called driving "enthusiastically".

And its "nob" because knob could be confused with something not-rude.

I believe what you are referring to is called driving "enthusiastically".

Indeed so. (Been there, done that.)

And I think this is much of the point.

In the days when I would have misguidedly put the less-worn tyres on the front (simply because those are the wheels which always provide the steering and most of the braking, whether the car is front, rear or all-wheel drive) I also used to have a mental picture of the rear letting go, me promptly applying opposite lock and a graceful tail slide ensuing.

That delusion was enhanced by experiments with deliberately pushing the tail out (where safe to do so) in snowy or other similar conditions. A skid pan can also provide similar experiences. And I had naiively assumed that is similar to what would happen in real-world conditions, even if the rear end let go accidentally - i.e., suddenly and unexpectedly.

The experiences of various unfortunate friends, who had gone off the road backwards when the rear let go unexpectedly, demonstrated that this "apply opposite lock and enjoy a tail slide" image is not neccessarily what would happen in real life, and I think I may have worked out why.

Our experiments are usually at relativley low speed, in very slippery conditions - often, not much more than a brisk walikng speed. Whether on snow, ice or a kid pan, the surface chosen is deliberately a very slippery one so that the exercise can be carried out at low speed - usually not much more than 10mph or so. After all, we don't want to wreck our cars!

However in the real world, when the rear end lets go absolutely unexpectedly, we are likely to be travelling much faster - 30, 50 or even 70mph. Let's say just 50mph. That is 5 times faster than we were travelling at when experimenting. The energy of a moving object is proportional to the square of its velocity, so we are now having to cope with a situation where there is 25 times as much energy suddenly to dispose of, or suddenly available to throw our car in an unwanted (and unpredictable) direction.

Under these high-energy conditions, things are likely to happen very fast indeed, much faster than in our "practice" sessions and almost certainly faster than we will be able to cope with. F1 drivers are travelling even faster still, so even the world's best drivers, when the back end lets go, spin off.

This "instantly-off-the road", "Good heavens, what on Earth happened there then?" is exactly how my unfortunate (albeit experienced) friends described it, and is exactly what happened when I spun. You find yourself facing the other way or through the hedge before you even realise anything is about to happen. It really is almost instant.

So this is why, nowadays, I have changed my policy. I now take the latest, up-to-date advice of car manufacturers and tyre manufactuers, and although best of all is to have all tyres the same, if there is any significant difference in tyre wear, I put the best ones on the back.

This "instantly-off-the road", "Good heavens, what on Earth happened there then?" is exactly how my unfortunate (albeit experienced) friends described it, and is exactly what happened when I spun. You find yourself facing the other way or through the hedge before you even realise anything is about to happen. It really is almost instant.

From someone I know who put winter tyres only on the front wheels of their car (against my advice), I heard the same thing. They got to a corner, then were backwards in a ditch the next moment.

A slide that happens on the road, and an F1 driver loosing the rear are totally different. F1 drivers are driving to the absolute maximum and at much higher speeds, in vastly different vehicles. Racing drivers in general are also correcting slides ALL the time. The fact that they fail to do so once in a while is just due to the fact that they are pushing so hard.

The advice around fitting the best tyres to the rear is to address which end breaks away first in the circumstance such as those in the posted video. In those cases the slide is perfectly controllable. A car will not suddenly go in to a massive spin. The advice is what it is, purely because most drivers who have never experienced a slide before, will react better to the front going than the rear. It's just about giving the average driver the best chance of not crashing.

If you're fitting the best tyres to the rear because you think it will prevent suddenly losing the rear and spinning off the road when you're driving at warp 10, then you're kidding yourself. Those extra few mm of tread on the rear will not prevent the spin under the circumstances in which it happens. Those people who have experienced sudden massive spins and gone off the road backwards would have done so regardless whether the rear tyres had deeper tread than the front or not.

It would be interesting to see the difference swapping the tyres around makes to stopping distances in the wet. I suspect that would show you're better off with the newer tyres on the front.

There are experts, and there are forum members who know better. I would go with the advice of people who get paid to make the decision to put new tyres of the rear.

The police cars at work are supposed to be taken out of service if the new tyres are put on the front. If its serious enough to ground them, its good enough for me.

The police cars at work are supposed to be taken out of service if the new tyres are put on the front. If its serious enough to ground them, its good enough for me.

I find that pretty ridiculous. What about rear wheel drive cars that have different size tyres front and rear so they can't be swapped around. Are you supposed to always fit new rears if new fronts are fitted? What about once the rears start to wear, and they wear faster than the fronts. Now the rears have less tread than the front again, and they're the driven wheels, AND they're wider so more prone to aquaplaning.

I see the reason for the recommendations, under steer is safest. However some points of view seem to be that having more tread on the front than the rear is outright dangerous, and that's just absurd.

The problem I have with that video that keeps being linked to these threads, is that it was completely staged, to the point where even despite their best editing efforrs you can see where the driver cranked on the steering wheel to throw the car into oversteer.

This suggests to me, that even with the most worn tyres on the rear, on a flooded roundabout, they were unable to get the car to oversteer as they claim it would. So they had to throw it into a slide.

In short. It's complete *******s.

I am also curious as to the UK spelling of "nob" vs "knob".

Of course it was over egged as it was a TV show segment, but the effect is still the same. The worn tyres break away quicker than 'good' tyres.

As for driving like a knob, it's easy to drive over a patch of oil or whatever on a motorway where the weight of the car stops the front breaking away completely, but starts to. By the time the lighter rear hits it all bets are off as to what will happen. It could start a full blown spin, especially if one side has complete grip at all times, or a wobble which the driver themselves turns into a spin by over correcting.

It happens quite a bit, without need to 'drive like a knob'

New tyres on the rear for me.

There no safety benefit to having a car with lots of tread on one end and little on the other. There is also no monetary saving to be made either way.

absolute nonsense of course there is...

This is a recurring theme from you lot "down under" i had a debate about this on another forum guy was from Sydney he said the same thing as you.

People who rotate tyres are just tight!

absolute nonsense of course there is...

This is a recurring theme from you lot "down under" i had a debate about this on another forum guy was from Sydney he said the same thing as you.

People who rotate tyres are just tight!

So how does having mis-matched tyres improve safety or even save money?

Of course it was over egged as it was a TV show segment, but the effect is still the same. The worn tyres break away quicker than 'good' tyres.

In the video they couldn't make the overly worn rears break away as they said they would. They had to resort to tactics they didn't use in the control run. They proved themselves wrong and made a mockery of their test.

It's like ARB putting out a video showing how much weaker the chinese lockers were than their own. Most people (me included) wondered why you'd pay double to get the 8% stronger ARB one.

As for driving like a knob, it's easy to drive over a patch of oil or whatever on a motorway where the weight of the car stops the front breaking away completely, but starts to. By the time the lighter rear hits it all bets are off as to what will happen. It could start a full blown spin, especially if one side has complete grip at all times, or a wobble which the driver themselves turns into a spin by over correcting.

It happens quite a bit, without need to 'drive like a knob'

If you hit a patch of oil, tyre rotation isn't going to make any difference to the outcome. You've just unwillingly lubricated your tyres.