From Michelin's UK website:

 

FOR COMPLETE CONTROL, FIT YOUR NEW TYRES TO THE REAR AXLE

Rear wheels are not connected to your steering wheel, which makes it extremely difficult to judge their grip while driving. We recommend that new tyres or the least worn tyres are fitted to the rear wheels to ensure:

 

• Better control in emergency braking or tight corners when the roads are slippery.
• Less risk of losing control of your vehicle, especially on wet surfaces
• Better road holding, particularly in difficult situations, whether your car is front or rear wheel drive

 

 

I'm guessing they've spent a few more quid on research than I have so I tend to think their advice is probably sound....

I'm told by Costco that Michelin will not allow them to put new tyres on the front unless the rears are being renewed as well. They explained about the handling issues if the rears are old and the fronts new.

GeoffH, do shop around a bit on the internet, Costco's tyre ain't cheap granted a lot of things in Costco are cheap and good quality but, tyres ain't one of them.

*If more grip is required at the rear, how comes the fronts wear thrice as fast?

*Manufacturers have a vested interest. Sure safety is a major concern but it also suits them if owners do not rotate tyres, and simply buy new tyres more frequently.

*Manufacturers advice caters for all drivetrain types. RWD cars are far more likely to lose rear grip than FWD, and the Octavia 3/Gofl Mk7's shared Electronic Control Systems which point blank refuse to let the back step out.

*In the wet, front tyres tend to cut a drier line for the rears to follow in.

 

The following video shows how hard it is to force the back end loose on a GTI 7. Check towards the 4min mark.

https://youtu.be/fuu5C0qFuVg

 

Unless the rear tyres are below legal limits there is no way an Octy's rear-end will snap out unless the car is being driven extremely stupidly. IMO the Octy has far too much rear grip. Mine just understeers, understeers, understeers when pushed.

Edited 17 March, 201511 yr by Orville

*If more grip is required at the rear, how comes the fronts wear thrice as fast?

 

The two elements of that statement/question do not go together. They are two questions.

 

More grip isn't required at the rear. But if the front has a greater grip on a given surface than the rear, then you are more likely to lose the back end sooner as the threshold of grip on the rear is lower. If the threshold on the front is reached first you are most likely to notice this effect and back off, the rear tyres having more grip will simply track as they haven't yet reached their threshold.

As for wear. Under acceleration the front driving wheels will tear into the road surface to drag the vehicle up to speed. Under decelleration the weight of the vehicle will bear down on the front wheels inducing more friction than on the rear. Over time they will wear faster.

*If more grip is required at the rear, how comes the fronts wear thrice as fast?

*Manufacturers have a vested interest. Sure safety is a major concern but it also suits them if owners do not rotate tyres, and simply buy new tyres more frequently.

*Manufacturers advice caters for all drivetrain types. RWD cars are far more likely to lose rear grip than FWD, and the Octavia 3/Gofl Mk7's shared Electronic Control Systems which point blank refuse to let the back step out.

*In the wet, front tyres tend to cut a drier line for the rears to follow in.

 

The following video shows how hard it is to force the back end loose on a GTI 7. Check towards the 4min mark.

https://youtu.be/fuu5C0qFuVg

 

Unless the rear tyres are below legal limits there is no way an Octy's rear-end will snap out unless the car is being driven extremely stupidly. IMO the Octy has far too much rear grip. Mine just understeers, understeers, understeers when pushed.

Why does rotating your tyres mean you buy less from the manufacturer? Sorry I don't follow... you buy the same number of tyres but at different times depending on whether you do or don't rotate? The manufacturer doesn't gain or lose either way?

I think what was ment was you can get better discounts on 4 tyres at a time.

I think what was ment was you can get better discounts on 4 tyres at a time.

Point taken but the discount comes from the retailer and not the manufacturer so it still makes no difference?

Is this advice for both summer and wintertyres?

Why does rotating your tyres mean you buy less from the manufacturer? Sorry I don't follow... you buy the same number of tyres but at different times depending on whether you do or don't rotate? The manufacturer doesn't gain or lose either way?

Let us suppose that tyres have not been rotated and fronts require replacement and backs are fine. Next let us suppose that the worn tyres fitted are Sport Contact 2's (or other brands of tyres that are no longer made or available). The choice to the end user will be, i) run mixed tyres front & back, or ii) buy a new set of 4. Fronts and rears rarely run out at the same times (unless rotated) and manufacturers have a habit of superseding tyres every few years. The result is that Tyre manufacturers sell more tyres.

 

Additionally, buying sets of 4 tyres often works out cheaper than pairs (Kwikfit 4 for 3 offer example).

 

Edit: last comment already mentioned by themanwithnoaim further up. I didn't spot his post until after my post.

Edited 17 March, 201511 yr by Orville

This is partially correct. The drive axle will get a "twist" in the tyre but it can be removed / relaxed.

Imagine the components in the tyre when new line up like:

IIIIIIII

On the drive axle after a while they will twist like:

\\\\\\\\\

If you kept them on the drive axle but swapped them left to right the driving of the wheels would try & force the twist in the opposite direction from:

\\\\\ to //////

this can cause problems as it is happening too quickly and can cause tread delamination (at worst) or just vibrations, etc.

If you move them from the drive axle straight back to the lazy axle without changing the direction of rotation then the twist will naturally relax itself:

\\\\\\\ to IIIIII

at the next tyre rotation to the drive axle you can swap sides & change the direction of rotation.

Don't want to sound stupid as maybe I'm missing something here but when you brake Won't you be twisting back the other way? I don't think changing the rotation of a tyre that's not a rotational one would have any real impact on its structure. Not that I rotate at all anyway.

Some interesting thoughts, particularly re new tyres on the rear, which I understand the argument for. I think for this time around I'll still swap front to back as don't want to run a mix of types until the rears run out. The fronts aren't on the limit or anything but certainly are lower than the backs. Once I've got the type of tyres I want on, then I can move rear to front as and when it needs new ones as these will be the same - although the the spanner in this plan is when I need winters!

1If more grip is required at the rear, how comes the fronts wear thrice as fast?

2Manufacturers have a vested interest. Sure safety is a major concern but it also suits them if owners do not rotate tyres, and simply buy new tyres more frequently.

3Manufacturers advice caters for all drivetrain types. RWD cars are far more likely to lose rear grip than FWD, and the Octavia 3/Gofl Mk7's shared Electronic Control Systems which point blank refuse to let the back step out.

4In the wet, front tyres tend to cut a drier line for the rears to follow in.

 

The following video shows how hard it is to force the back end loose on a GTI 7. Check towards the 4min mark.

https://youtu.be/fuu5C0qFuVg

 

Unless the rear tyres are below legal limits there is no way an Octy's rear-end will snap out unless the car is being driven extremely stupidly. IMO the Octy has far too much rear grip. Mine just understeers, understeers, understeers when pushed.

I numbered your points.

 

1) The front wears 3x as fast because it has more weight on it & does the steering, accelerating & braking.

The problem at the rear is that it lacks weight.  If the rear tyres are at minimum tread or severly aged / hardened then the rear will tend to aquaplane in wet weather or try & overtake the front wheels under severe braking combined with cornering (eg: really crap driving).  the easiest / simplest fix for this is to keep the rear tyres as new & full of tread as possible & let the fronts wear out as quickly as possible.

 

The above phenomenon was actually discovered in a New Zealand research paper commissioned by the Dept of Transport (circa 1980 or 1990 IIRC) when it was noticed that the number of single vehicle accidents had increased beyond the statistical expectation.  This was about the time that they gave up local manufacture of variouys RWD Ford Anglias & Leyland Marinas and had started buying cheap 2nd hand Jap import FWD vehicles.  The dynamics of the vehicles had changed & in many case the "like new" tyres on the rear of the vehicle were age hardened & no longer fit for purpose (but still legal).  The standard practice in the tyre retailers was to fit new tyres to the front in order to get the best wheel alignment results and save time not having to put the rears on the front.

 

2) While manufacturers do have a vested interest I don't think their recommendations would sell more units. They also have a duty of care & I'm sure they get asked about this subject often so it wouldn't pay to give information that is totally wrong.

New tyres to the rear doesn't totally preclude doing tyre rotations.  You can still move them around the vehicle with some thought & planning (as I do).  I think the tyre manufacturers aren't aiming their message at responsible folk that give a toss such as most of us forum members, they are aiming at those that would happily drive about with 8 year old tyres with 2mm tread remaining fitted to the rear.  I've seen plenty like that that are totally clueless (including some tyre vendors).

 

3) It's not about stepping out, more like stepping up (aquaplaning) although under severe braking the back end will unload quite severely.

 

4) they will, but they will do that simply because of the weight of the engine.  this also assumes that the track at the front is the same as the rear track.

 

Keep in mind that the manufacturers recommendations are of a general nature for all car owners.  Not all vehicles are as accomplished as an Octavia.  Not all owners care or even think about the dynamics of their vehicle.  eg: I tell my wife to test the ABS under controlled conditions so she knows what it feels like.  She says I'm just being a hoon and ignores the suggestion.  Then she has to emergency brake & takes her foot off the pedal when the ABS kicks in.  "I thought the brakes had malfunctioned" she says.  I'd say 90% of drivers are like her.  This is why google are developing a driverless car.

 

You've hit the nail on the head with your "no way an Octy's rear-end will snap out unless the car is being driven extremely stupidly".  The trouble is there are plenty of stupid people out there that will snap the rear end out .

 

You can't always follow the recommendations to the letter but you can get pretty close.

Don't want to sound stupid as maybe I'm missing something here but when you brake Won't you be twisting back the other way? I don't think changing the rotation of a tyre that's not a rotational one would have any real impact on its structure. Not that I rotate at all anyway.

It probably would if you braked as much as "drove" the wheels.

On my 45km commute I'd guess that the front wheels are braking for about 5% of the journey, freewheeling (no load either way) for about 40% and driving for the remaining 55%.  So 50% of the time the tyre is being twisted in one direction more than the other.  I've pulled those % out of the air but it's near the money.

 

I'm talking total movement in the tyre carcass measured in micromillimetres.  It's all bonded together as a (hopefully) single entity.  It wasn't something you could see with the naked eye on the forecourt.  You have to send the tyres to the techo boffins with microscopes, etc.

I drive a lot in mk so hopping between roundabouts probably equals out the accelerating to braking a bit more than that... Also holding a car at a set speed probably doesnt load the tyres very much at all.

Keep in mind that the manufacturers recommendations are of a general nature for all car owners.  Not all vehicles are as accomplished as an Octavia.  Not all owners care or even think about the dynamics of their vehicle.  eg: I tell my wife to test the ABS under controlled conditions so she knows what it feels like.  She says I'm just being a hoon and ignores the suggestion.  Then she has to emergency brake & takes her foot off the pedal when the ABS kicks in.  "I thought the brakes had malfunctioned" she says.  I'd say 90% of drivers are like her.  This is why google are developing a driverless car.

Hearing stuff like this makes me appreciate the (expensive) Finnish driving license requirements. Here you can't get a license without driving on a track and doing emergency breaking, avoidance etc. exercises at least for a day. (There's a second track day 6-24 months after getting your license.) So it's at least a little less likely someone gets frightened by the ABS kicking in...

Wish we had that. Also wish we had a requiement to spend time in the cab of an HGV, and spend time on a motor cycle and push bike in town.  Also wish all professional drivers had retests every few years

Back on tyres can we agree, If you don't own a garage and fit4 new tyres for every journey then everything is a compromise?  If so, can we also agree that in some situations you will benefit from new tyres on the rear, and some from new front? If so.... Then we know the choice we are making, great.  ''Guidance " from manufactures is more to help those to stupid or careless to make that informed choice.

 

Personally.....back to front, new to back is the plan. On my last car I rotated and replaced 4 at a time no difference really.

Hearing stuff like this makes me appreciate the (expensive) Finnish driving license requirements. Here you can't get a license without driving on a track and doing emergency breaking, avoidance etc. exercises at least for a day. (There's a second track day 6-24 months after getting your license.) So it's at least a little less likely someone gets frightened by the ABS kicking in...

Area of Finland ~340,000 sq km?  Population ~6 million?

Area of Australia  ~7,700,000 sq km.  Population ~ 24million

 

It's a great idea in theory (because we have some really crap drivers here) but some people live 3000km from the nearest race track.  

Area of Finland ~340,000 sq km?  Population ~6 million?

Area of Australia  ~7,700,000 sq km.  Population ~ 24million

 

It's a great idea in theory (because we have some really crap drivers here) but some people live 3000km from the nearest race track.  

The distances to a track (not a racing track, mind you, but a purpose built handling track) may be quite long here as well, though admittedly not nearly as long as they can be over there.

 

It's a common practice for a driving instructor to get a car full of pupils to the track, with them each driving the vehicle in turns on the way to and back from the track. This way they can incorporate regular driving lessons to the trip without making anyone drive for too long at one go.

 

Not all owners care or even think about the dynamics of their vehicle.  eg: I tell my wife to test the ABS under controlled conditions so she knows what it feels like.  She says I'm just being a hoon and ignores the suggestion.  Then she has to emergency brake & takes her foot off the pedal when the ABS kicks in.  "I thought the brakes had malfunctioned" she says.  I'd say 90% of drivers are like her.  This is why google are developing a driverless car.

 

I remember a number of years ago doing some skidpan training, and the instructor saying if you got a car with ABS brakes and hadn't tried them before, you should make a point of testing them out somewhere quiet to get a feel for them. He suggested trying your local supermarket car park on a Sunday afternoon (this was when supermarkets weren't open on Sundays, so their carparks were pretty much deserted). He emphasised that you should do it somewhere quiet and not to do anything too extreme - his emphasis was because apparently a previous attendee on his course had thought that the best way of trying out this new-fangled ABS thing was to go down a fairly steep hill and get to the bottom doing about 45-50 mph, and then brake for the sharp left-hander at the bottom of the hill. And to make sure that there wasn't any other traffic about, he did it at about 8am on a Sunday morning. In December. When it was about five below freezing and the road was icy. Apparently he did get to feel what it was like when the ABS kicked in. He also got to feel what it was like when his car went through a hedge at about 43mph...

Edited 20 March, 201511 yr by JJJ66

This reminded me that it's pretty impossible to get by without feeling the ABS kick in if you drive in Finland in the winter time anyway. The line where cars stop at intersections often gets polished to a mirror finish, so ABS activates any time you arrive at an intersection even a little above walking speed.