MO Tyres

[RonFleet]

I've just fitted Michelin CrossClimate tyres to my W205 after a chat with Michelin. They told me that the MO designation didn't mean that the tyres were any better than non-MO tyres, just that they'd been approved by Mercedes after joint development work. They also said that they will not be designating the CrossClimate tyres with the manufacturer OEM approval letters.

 

[RonFleet]

Just to clarify while there is a valid question as to how MO tyres are different to no-MO - if at all - but clearly any tyre officially sold in the UK that meets EU regulations and the manufacturer's specifications in terms of size, load, speed rating etc, is both legal and safe to use.

The only real question is simply whether there is any actual advantage in buying MO tyres... not if it is illegal or unsafe to drive on non-MO tyres as such.

Tyres are a consumable. As markjay says, so long as they are the right size, speed and load rating as per the vehicle manufacturer's specifications and meet the EU legislation, what's the problem?

 

[HB]

I contacted my insurer Aviva about upping the rears from 285 to 295, due to more availability and being a bit of a poseur, and they said they weren't interested in tyres for insurance purposes.

Yes.

When I bought my wife the 212 350 cdi recently ( from Mercedes Edinburgh) , it had one Conti 2 N3 rating with a 93 load index. All the others were Conti 3 97 load rated MO spec. The dealer said this was fine, I said not. They said ask your insurance company, if they say change it, we will.

I asked the insurance company about this and they said, as long as it has passed it's MOT, it is fine with us.

 

[C240Sport97]

Yes.

When I bought my wife the 212 350 cdi recently ( from Mercedes Edinburgh) , it had one Conti 2 N3 rating with a 93 load index. All the others were Conti 3 97 load rated MO spec. The dealer said this was fine, I said not. They said ask your insurance company, if they say change it, we will.

I asked the insurance company about this and they said, as long as it has passed it's MOT, it is fine with us.

I would not want a car with one tyre with a different load rating from the other 3. I doubt MBUK would agree with the dealer.

 

[190]

Having one or more tyres with a higher than necessary load rating may be safe enough for an MOT pass but it's not a good idea in terms of the impact that a stiffer construction will have on ride comfort. I presume that if the higher load rated tyre is inflated to the same pressure as the others it will have less deflection. That can't be right either in terms of ride or grip.

 

[HB]

I would not want a car with one tyre with a different load rating from the other 3. I doubt MBUK would agree with the dealer.

Yes Sean exactly my thoughts ( I bought 2 new rears the following day anyway)

I did speak to MBUK and agin they said, if the dealer passes them as fit and tha car has passed its MOT, there is nothing for us to be concerned about.

They don't really care.

TBH I got such a good deal on a very good car so a £150 tyre was not an issue for me.

 

[markjay]

Arguably it is not conclusive, i.e. are Conti 2 and Coni 3 same 'type'? But if you show this to the dealer they will need to address this question.

 

[190]

The insurance company using the MOT as an excuse is interesting as the MOT for cars doesn't involve a check on speed or load rating of the tyres.

 

[400ixl]

I have seen an example where a manufacturer has specified a particular tyre not to fit as it had found handling issues with that tyre.

There may be specific cases out there which is why you should read the handbook of the car to check really.

There is also the difference between advice and law. The insurer needs to take a balanced view if it is not law. Unlikely they would invalidate unless they was a very clear written reason which is unlikely.

That image markjay is interesting as it could raise a concern. They are also advising against the industry which recommends always fitting the best tread to the rear wheels of a car be it FWD or RWD. Not sure on AWD so could be for that.

 

[whitenemesis]

Yup, have always been advised to fit new tyres to the rear wheels ....

 

[uumode]

In the small print of my PCP terms and conditions I need to fit MO tyres.
Don't think my insurance small print included this.

 

[190]

The reason new tyres are advised on the rear wheels is to ensure that any imbalance of grip produced by the new tyres results in the vehicle understeering which is considered safer than oversteering into a possible spin.

Oversteer is much more fun though. Understeer is no fun at all.

 

[telu]

Presumably following the backlash over increased premiums for winter tyres, they are now (sensibly) looking only at different/larger wheels but not tyres...

On a related note, the need to notify the insurer regarding modification is one thing, but the driver is still responsible for ensuring that the vehicle is safe and roadworthy at all times. The fact that the insurer is not interested in tyres does not give drivers a carte blanche to fit whatever tyres they wish... in the event of a claim, having incorrect tyres fitted to the vehicle can in principle be used by the insurer to avoid pay-out if they can convince that the car was unsafe or not roadworthy (though they will probably require something more substantial than an increase from 285 to 295).

That makes sense...