Odd tyre - should it be changed?

[rustleg]

Just taken delivery of a used (Sept 2008, 12500 miles) C Class C220 CDI diesel and when I got home I discovered the nearside rear tyre was different from the other 3. It is a Conti Sport Contact 2 whereas the others are Conti Premium Contact 2. Also these 3 are marked MO whereas the Sport Contact isn't. (Didn't know about MO until I read the manual)

The only reason I looked was that I thought I could hear excessive road noise from the nearside rear on the way back from the dealership. Could this be the cause?

More to the point do I have a case for complaint and expect them to change it? One issue is that I read somewhere else that the ESP might not work correctly if there is some problem with the tyres. They are all the same size 205/55 R16 V.

In fact looking more closely the other rear tyre is quite worn - down to about 3mm in places. Would it be reasonable to expect better on a newly bought used car? Looks to be about 6mm on the fronts so maybe they've been changed - could be the only original tyre is the worn rear offside? Doesn't sound so good after only 12.5k miles.

This is my first Merc - I like the car - hope my enthusiasm isn't going to be spoiled.

 

[Xtractorfan]

Conti's tend to get noisy as they wear down, as long as the tyre is the same size and legal then you dont have a case regarding the person who sold the car to you and it wont make a difference to the ESP.. Check your spare it may be a mach for the others..

 

[rustleg]

The spare is one of these emergency only tyres, not a substitute for a normal tyre.

 

[Xtractorfan]

Right apologies just noticed its a 08 reg..

 

[canute]

Not sure I can answer your question but I can tell a few stories!

I had the same thing on my 220 CDI Coupe, I just bit the bullet and bought two new tyres the same as the the "good ones" and put them on the rear (Dunlop SPs BTW), next time I will change all 4 or replace the fronts if they wear quickly.

As for ESP, I once replaced two tyres at a time on my old A class (the suppliers only had 2 in stock so I had to wait a week for the other two). When driving down a hill (loaded, I was taking the inlaws to the airport) I braked heavily on the hill and both the car and ESP went crazy. It could have been coincidence but I felt that the ESP didn't like the different style and wear tyres. The car had never been that twitchy before or since after I replaced 4 at a time.

Personally I'd change it, but more knowledgable people than me might advise otherwise.

 

[teddycatkin]

My advice --change the two rears to match the fronts now -get exactly the same -
You will then have peace of mind and know you are driving on 4 good tyres.

 

[rustleg]

Thanks for the responses. Yes I have decided to buy 2 new tyres for the rear for peace of mind.

Incidentally do people rotate their tyres? I've had front wheel drive cars for many years now and normally I'd just put the best tyres on the front whenever replacing tyres. Is this good practice with Mercedes?

 

[rf065]

Incidentally do people rotate their tyres? I've had front wheel drive cars for many years now and normally I'd just put the best tyres on the front whenever replacing tyres. Is this good practice with Mercedes?

That advice is outdated, best tyres always go on the rear, no matter front or rear wheel drive.

Russ

 

[rf065]

If you bought the car from a Mercedes dealer, it should be part of the used car inspection that there is sufficient tread. I would ask them to replace the tyres.

Russ

 

[rustleg]

Thanks Russ (incidentally also my name!)

I found the inspection sheet, so I went out and made my own measurements - I have a gauge and I have tested it is accurate.

The sheet readings were as follows (my readings in brackets)

Position Inner Centre Outer
NSF "New" (7 7 7)
NSR 4(5) 6(5) 4(5) - this is the "rogue" tyre
OSF 4(5) 5(5) 3(5)
OSR 4(3) 4(3) 4(3)

I suppose the readings are arguably close enough except for their offside front.

The dealer said their policy was to supply a new tyre if the reading was below 3, although they haven't yet come back with a comment about the odd "rogue" tyre.

So far as wear is concerned there isn't a good match between the 3 normal tyres, I have 777 555 and 333. Looks like I should replace 2 tyres and match the 777 with the 555.

Or maybe buy one tyre and match it with the 777, putting the 555 and 333 on the front. Wait a few months and then buy another.

Whichever way the match on the fronts is not going to be close. Does this matter?

Maybe I should go silly and buy 3 tyres - at least I'd then have a good set all round. Pity the spare is one of these 50mph emergency tyres as otherwise it would probably be much simpler.

Any thoughts on this would be appreciated as I'm getting confused now.

 

[canute]

Personally, I'd buy two new tyres.

Change the "rogue" and the tyre with inconsistent wear for the new ones, then put the new ones on the back axle.

Replace the front two when needed (6 months? whatever), then swap them to the rear.

And so on.

That is my plan for my car, I had a similar problem to you, two good and one reasonable Dunlop Sp, one badly worn (outer toe wear) Pirelli.

If you really want to really take it seriously, have a search around the forum and you will find out that some cars wear tyres differently to others, so by swapping around every couple of months you might get more consistent wear.

W203 Coupe's wear fronts on the edge and rear tyres in the middle apparently.

 

[teddycatkin]

IT LOOKS LIKE IT NEEDS TO BE THREE NOW !
Seeing as you just got the car -get the 3--ask to kkeep the other good one when its off the rim and store it as a spare--chuck the others?

 

[rustleg]

Noticed that the car's manual says put new tyres on the front. Therefore surprised that people are saying they should go on the rear.

Still waiting for a definitive answer on whether they will replace the rogue - waiting for the manager to return from somewhere. Judging by their response on this there's no way they'll cough up for the 3mm tyre.

Looking at the Protyre site (where I'll probably go for the tyre) it says

The legal tread depth for a Car or Van tyre in the UK is 1.6mm across three quarters of the tread width around the full circumference of the tyre.
However the wet weather performance of a tyre decreases dramatically when the tread depth is below 3.00mm

Think I'll go for 2 tyres keep the 7mm and 5mm ones. Now just a question of best tyres on front or rear. Any further comments on why the manual says front would be welcome.

 

[rf065]

Now just a question of best tyres on front or rear. Any further comments on why the manual says front would be welcome.

Whoever wrote it did not do their homework & relied on incorrect information.

http://www.tyresafe.org/news-and-events/detail/motorists-get-their-tyres--back-to-front--/

Russ

 

[turbopete]

only reason i can see for putting new tyres on the front of a rwd car is to allow them to 'bed in' more gently ie to not have accelleration forces forced through them by being on the drive axle. however ive got to admit that i was always told to put the best tyres onto the drive axle ie your rear axle!

 

[jberks]

Put them on the front, you increase the chance of oversteer (whichever wheels are driven) or rather, to be more accurate, you don't decrease it. Put them on the back, you increase (don't decrease) the chances of understeer.

Given that oversteer is far more dangerous and less progressive (and hence predictable) than understeer, and most drivers can't cope with oversteer, it stands to reason that the official advice is to always put new tyres on the rear.

I don't think which wheels are driven really comes into it, except that with RWD, the potential to oversteer is much greater, so it becomes more relevant. Plus, on a fwd, the rear tyres get almost no wear, so its a good policy to rotate the rears over to the front when the fronts wear out rather than let them sit on the rear until you have to change them, still unworn, 6 years later due to cracked sidewalls.

 

[EireJames]

Of course this Tryesafe crowd who are "...... the new name for the Tyre Industry Council" would be keen on getting folks to buy tyres more often, so by putting new rubber on the rear on fwd cars and then switching it up front when the fronts wear would be good for tyre sales. No doubt they may be technically right too but there motive for doing the research is no doubt driven by selling tyres. Lots of older front wheel front wheel drive cars are not oversteer prone anyway. Although I have found newer models to be a bit more inclined to go sideways.