Looks like the time has come to soon replace both front tyres, after about 14K miles. (Conti Ecocontact)
As far as I know the legal limit is 1.6mm over 75% of the tyre. But I suspect that replacing the tyre when it gets to 3mm over 75% would be more sensible (as recommended by Continental)
From the advice of this group, new tyres should be fitted to the rear (putting the existing rear tyres to the front, and fitting the new tyres to the rear)
Should the rear tyres be moved to the front, keeping the same side (i.e Left rear, to Left front) or should they be crossed over? (i.e Left rear, to Right Front)?
I assume that as the tyres is not being removed off the wheel, than the wheels would not need rebalancing when being moved rear to front.
Tyre wear is as follows:
FL 2 4 3 3 FR 4 3 4 2 (average 3.125mm)
RL 6 7 7 7 RR 7 7 7 6 (average 6.75mm)
Above tread depths as as on the car (i.e front left depths are 2mm on the outside, 3mm inside - Front Right 2mm on outside, 4mm inside)
Does the wear pattern look reasonable? Is it normal for the outside of the tyre to have slighly higher wear than the inside.
Assuming that the tyre started with 8mm, is it usual to show the ratio of wear re front vs rear tyres (approx 2800miles per mm on the front, and 11200miles mm on the rear - i.e fronts wear 4 times quicker than rears)
How often should tracking/suspension geo be checked? When changing tyres, or when there is a problem with wear? Would it be needed in my case?
TIA
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Pete
Front tyres on FWD cars will always wear much quicker; coupled with PAS, a heavy engine up front and some awful British roads the wear will be increased.
The outer edges tend to wear a little more, especially the NSF as this tyre takes the load when negotiating roundabouts etc (think about it...)
What car do you have?
Looking at your wear figures (works really well!) your car would appear to have some degree of toe-in; I'd get it checked and any adjustment should be towards the toe-out setting, if you see what I mean.
I've always fitted any new tyres to the front of a vehicle, going against advice given here! It just seems the logical place to put them, that's all!
Tracking should be checked/adjusted as and when necessary; remember you should check your tyres weekly? Then any abnormal wear can be picked up on early......
MG-Rover Questions? Click on www.mg-rover.org
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You are right about the outside edge wearing a little bit more (as it has to travel a greater distance than the inside edge)
As you say, the NSF will also get more wear, and this wheel would usually travel further then the OSF due to roundabouts. Quite logical if you think about it.
The car is a Mercedes A140 (i.e Front Wheel Drive, PAS/ESP/ABS etc)
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Just come across the ATS Euromaster site,
ATS recommends:
Balancing: Each time a wheel is fitted, or when wheel are swapped to a different location.
Geometry: After a violent shock, after abnormal tyre wear, diminished road holding, at least once a year.
Does this seem reasonable?
Looks like I therefore need, two new tyres (fitted to back), all wheel rebalanced, and geometry checked/adjusted!
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Pete,
I agree with David L's points. Your wear pattern is similar to that I see on loads of FWD cars here.
If you must move the old rears to the front I would balance them. Wheels will go out of balance over time and it isn't that noticeable on the rear, but it will be when you bring them forward.
Like David I will fit new tyres to the front on FWD cars because it gives the handling and braking balance that I want, and the one I still believe to be the safest in 99% of circumstances.
To prise the lid off this particular can again......somewhere I have read the perfect description of the "new to front or rear issue" but sadly can't remember where. Anyway broadly speaking it says.....
There is a very common understanding that when fitting two new tyres to a car the new ones must always be fitted to the front. Sadly this is wrong and the following rules should apply.
Front Engine & FWD - New tyres on the front.
Front Engine & RWD - New tyres to the rear (*).
Rear Engine & RWD - New tyres to the rear (*).
(*)If there is a doubt that the old tyres left on can't do the job in the front position they shouldn't be on the vehicle.
I think there is far more common sense in that than the previous blanket statements.
David W
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I'd rather lose the back end in a corner than the front end.
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Yep, same here JC
MG-Rover Questions? Click on www.mg-rover.org
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I have now received a reply from Continental (see below)
It suggests that rebalancing of the rear tyres is not required, nor any reason to check tracking unless uneven tyre wear is being experienced.
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My response to your questions is as follows :-
1)Changing the wheels form back to front and vice-versa at appropriate intervals is recommended. In certain cases changing them crosswise can be also advantageous so as to reverse their sense of rotation (does not apply to diagonal tyres). However the instructions given in the vehicle manual should be followed when rotating the tyres.
2)If the balancing of the tyres was done correctly the first time then there should be no necessity to rebalance the wheels. As the properties of the wheel assembly have not changed.
3)If there are no significant signs of uneven wear (i.e. shoulder wear) then again I see no reason why you should have tracking checked
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Continental also recommend putting the new tyres at the rear. Check out
www.driveradviser.com/tyre/faq.shtml#q7
www.tyres-online.co.uk/techinfo/rotation.asp
The top link is from Contis site. The bottom link also gives advice on how to rotate the tyres. I've spoken to friends in Chassis Engineering at motor OEMs in the Midlands and all agree - newest tyres on the back.
As I understand it, it has to do with weight transfer under braking. Under heavy braking the weight of the car shifts significantly to the front. In wet conditions the reduced weight on the rear makes the tyres more prone to losing their grip or aquaplaning. Even if you think you are braking in a dead straight line this can cause the car to spin very quickly. This is made very much worse if the car is on a split coefficient surface - ie more grip on one side of the car compared to the other.
It is for this reason that ABS systems treat both rear wheels as one - ie if one loses traction then the ABS controls the braking on both wheels to equalise the braking in an effort to stop the car spinning, or at least slow the spin enough to allow the driver time to apply steering correction. This is gradually being superseded though by the latest traction control and EBD systems.
To illustrate the weight transfer situation remember how easy it was to lock the rear wheel on your bicycle, yet nearly impossible to lock the front? The physics is the same on your car.
Another good reason to put the new tyres on the rear is to prevent them becoming too old (years wise) - they could become more prone to blow outs if they get too old.
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"As I understand it, it has to do with weight transfer under braking. Under heavy braking the weight of the car shifts significantly to the front."
But surely any cars prone to this have brake proportioning valves to allow for weight shift??
I thought we had this all settled in previous postings. Isn't it a fact that putting the best tyres on the rear reduces the chances of understeer-induced skidding, this being far more difficult to control than oversteer skidding?
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No maybe I am all wrong but:
with simplifying the maths
New tyres on front have 8mm of tread,
Old rear tyres have 7mm of tread.
Therefore rear tyres are worse than front (incorrect according the the general concensus)
However the front will wear quicker, so it about 3000 miles tread depth will be even, and beyond that mileage the rear tyres will once again be the best tread,
Now the only thing to watch out for is the rear wearing so slowley that it perishs before it wears out..
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I do and always will put the new rubber on the driven wheels, the augments on this and other threads do not apply to me, the only cars i have ever had the back end come round on were rear drive. I now only have front driven cars or as now four wheel drive, never rear wheel drive "the drivers choice".
How do you manage to get the back out on a front drive car? its something i have never managed to do, yes i've had cars go sideways and even on two wheels. All i can assume is maniac driving will do this, if all four tyres have decent tread depth where is the problem?
Experts are constantly being proved wrong, remember eggs are good for you?
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I was unlucky enough to experience oversteer in a FWD car - my old Fiesta, a '96 1.4 with ABS and traction control. Damp road, one-way right-hand bend, bus pulls out ahead, foot off throttle and bob's your uncle I'm suddenly facing the wrong direction after clouting a lampost on the way! To say I was caught out and shocked that the rear broke away is putting it mildly...
Following that incident the fresh rubber goes at the back which I've recently done on my current Focus 2.0. Rear wheels (with part-worn rubber) swapped to front, no re-balancing, no tracking, no problems!
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Ver few cars have a proper brake proportioning-one that adjusts to the load;what most have is a valve that controls the line pressures to the back end when the pressure in the front lines gets too high in an effort to stop the rears locking up.
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Dizzy
Brake proportioning valves are a fairly simple system which go only some way to preventing rear wheel locking, as they limit the maximum braking effort at the rear. With very worn tyres or a slippery road the calibration of the system may still allow too much braking effort, and only an ABS system will cope with all the variations in tyre and road conditions.
In fact putting the best tyres on the rear reduces the likelihood of oversteer (not understeer) which is what you have if the rear breaks away - and it's generally thought this, for most people, is the more difficult to control.
FWD cars typically understeer because the front tyres are dealing with steering and drive. The normal scenario when front grip reaches the limit is for the front to run wide (understeer)The natural reaction of lifting off the throttle in those circumstances allows the front tyres more grip and tends to recover the situation - but can, if the back is getting near to the limit, cause the back of the car to break away. The sensation of a FWD car breaking away at the rear is uncommon and likely to catch drivers very unawares. For these reasons it's recommended to have the better tyres on the rear, as this reduces the chance of the rear tyres losing grip.
Regards
John S
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John S - very well explained.
The problem (and confusion) has been brought about by the widespread use of FWD. In the Morris Minor and Ford Cortina days, most drivers knew what "the back feeling light" felt like.
Now, Joe Bloggs, who has only ever driven FWD, just changes his front tyres when they wear. 3rd set on front, nearly bald back, diesel on roundabout - disaster.
(Like a 1970's 911 I drove - understeer, understeer, OVERSTEER)
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The final conclusion is that the majority of people recommend new on rear, but some disagree. There doesnt appear to an overwhelming reason tho why one is better than the other, so its down to personal choice mainly.
With regard to my vehicle (Mercedes) the car is fitted with ABS, EBD, ESP etc which assist in correcting any skid wherever it should occur (front end, rear end etc)
On my vehicle rotation of the wheels is not a recommended service item (unlike other RWD mercedes models)
I posted this question on the MB owners association forum, and received a reply from a very well respected independant MB specialist (i.e MB trained) who advised:
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"This is what you need to do. First the best tyre should be on the steering axle. So thats the front. Forget what any body else tells you.
When the tyres are fitted they will be balanced, as a matter of course. The edge of the front tyres look a little worn. But more than likely caused by the power steering.
There is a lot of thing ATS recommend. But then again they want your money.
If you decide to have the aligment checked. If its not MB , make sure they no what to do in the event they find something a little more than usual. Most of these places can't check it properly let alone adjust it properly"
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does that imply you've found a web site for Continental ? If so where ? I've only ever found bike and motor bike sites for them.
John
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