Xc60 Tyres
 

Quite by chance noticed today the tyres on my fwd 2015 xc60 are different front to back

235/65R18 on the front to 235/60R18 on the back , can only assume previous owner was told by the fitters this was ok

Anyone have a view please ?

Well it's wrong. For 18" wheels should be 235/60. Is this on a FWD or AWD?

Your rolling circumference is going to be greater on the front. Could put your speedo out.

FWD , 235/65R18 on the front , 235/60R18 on the back

It's not factory (all tyres were same size) but it's not illegal or dangerous either, as long as the tyres are match on the same axle and do not foul the bodywork or chassis.

As said above, if the larger tyres are on the front it will make your speedometer read less.

You could swap the front and rear wheels over so that your speedo won't be out.

My understanding is that this would be illegal. Speedometers may over-read (ie indicate you are going faster than you actually are) by something like 5% (might even be 10%, I'm not certain) but may not under-read at all (ie indicate you are at the speed limit, whereas you are actually speeding). That is one reason why so often you see cars driving at a few mph below the speed limit - car manufacturers err on the safe side, and routinely slightly over-read, so the driver often assumes incorrectly that he/she is driving at the limit whereas in fact is driving below it (easily checkable with a GPS on a straight and level road). You should ensure the tyres on the front are no larger than whatever the car is meant to have per the owners handbook.

Er, no.

Speeding illegal, yes. Non factory size tyres on car (that match across axle and do not interfere with bodywork) completely legal.

He means driving without a working speedo (for any reason). Not sure how you would ever get caught though!

Good evening sir just pulled you over to ask if I can borrow your car to go for a spin and check your speedometer is accurate? - Not likely to ever happen in the real world.

Swap front and rears sounds like the best solution providing they clear chassis ok

I’ll look to return to standard when the rears wear out !

It is illegal in the UK to have a speedometer which is not reading within the permissible tolerance. If your tyre sizes take you out of that margin then yes, illegal. I had exactly this debate once with a tyre installer, who was worried that my winter tyres/wheels which he was fitting, which had a slightly smaller radius than the summer tyres/wheels being removed, were outside the allowed tolerance, till we checked the vehicle handbook which showed which sizes are approved to keep within the permissible speedometer regulations (and of course, not interfere with the bodywork).