165/65/14 and 165/70/14

[Red Estate]

MOT gideline state ' Note: Tyre with aspect ratios of 80% and 82% are almost indentical in size and can be safely mixed in any configuration on a vehicle". not quite understand but if i have 65 series on front left and 70 on front right both are almost new. will it be ok for MOT test sir?

[Philip Chidlow]

I wouldn't. But I'm not an MOT inspector... depends on how they're feeling towards the vehicle in general I guess...

[Tim Leech]

I thought they had to be matched axle pairs but can differ front to rear, talking of tyres, if you wanted some fatter rubber on your BX but cant afford alloys a set of Xantia 14" steelies with 185/65 R14 tyres (turbo d or 2.0i) fit fine.

[jonathan_dyane]

It depends how observant the tester is, by rights it should fail, but if he is slipshod and doesn't spot it or a bit tardy you might get away with it...

You're spare isn't a legal 165/70 by any chance is it? If so bung it on for the test.

[RxBX]

MOT gideline state ' Note: Tyre with aspect ratios of 80% and 82% are almost indentical in size and can be safely mixed in any configuration on a vehicle". not quite understand but if i have 65 series on front left and 70 on front right both are almost new. will it be ok for MOT test sir?

The simple answer is NO

Link to tyre MOT acceptance:-
http://www.ctyres.co.uk/tyre_info/Tyres&MOT.html

Another Link:-
http://www.motuk.co.uk/manual_410.htm

The only thing you can get away with is the Speed Rating to be mixed i.e. 'T' and 'H' rated but as Roverman has pointed it's best to have at least a matched pair to each axle so that you vehicle handling characteristic's when driving and steering from left to right especially at speed are the same !
Also I would NEVER fit lower speed rated tyre's to what is recommend by the vehicle manufacturer, but obviously its okay to go greater then recommended.
If your not 'au fait' with Speed Rating for tyre's check it out on this link :-
http://www.ctyres.co.uk//tyre_info/Speed_ratings.html

As it states "For MOT requirements in this country, it is not necessary to fit a tyre with a speed rating to match the original vehicle fitment or the maximum speed of the vehicle."
But I am aware that in some European Country's it's actually a legal requirement that the each axle set must have the same make/type/size fitted, if not you can get fined (I'm sure that may apply to the UK soon as there always changing thing's to improve on safety) !
So if your taking your car abroad check this out prior to going to and thro' the the country/s your traveling to and of course check what's fitted to you vehicle (Also Don't forget your warning triangle in case of a roadside breakdown) !

[Red Estate]

they are two good 70 s on rear and spare and two 65 s on the front (all came with the car like that) in which one on the front is running low near legal limit. after reading that MOT note about 80% and 82% aspect ratios got me confused. so, i have set of MOMO arrow with new 195/50/15 on its way hope it would fit to rear arch of my estate without to much drama and then MOT it.

[jonathan_dyane]

they are good 70 s on two rear and spare and 65 s on two in the front

Ah, well, as Tim stated, provided each end is shod with a pair of the same aspect ratio, and they're legal, they will pass.

(It is aspect ratio isn't it? Or is that televisions...)

[jonathan_dyane]

(No, that was televisions wasn't it. Profile is the one...)

[kiwi]

This is an interesting one and I was discusssing this with my mechanic last week as well.

Seems that NZ rules are catching up with the UK at last!

The interpretation is this

You can have 65 to the Front and 70 to the rear but not 70 front and 65 rear (commonsense really)

But all the tyres must be of the same speed and load rating ie 82H etc

You can not have a mixed tread/brands on any axle but you can have differant tread/Brands on a seperate axle.

Basically I have Firestone on the Front and Michelin on the rear! I put the same question as you have to him because the TZS has now got 165/65 all around and the TRS 165/70. The problem I have is my snow chains dont fit the larger TRS tyres so I wanted to do a mix.

Yes I had run a mix before and the regulations say I can do that now! It is however a bit frustrating as I have two single tyres with differing tread patterns that have 6mm and I can not use them for anything but a spare. Which is interesting as what happens if you get a flat? Apparently same rule as those space saver Tyres as being to get you home at a lower speed .

The BX though is great in that situation though it tends to balance out the slight differance in tyre size.

Best advice here is just take it in and if it Fails get a couple of Tyres!

[jonathan_dyane]

This is an interesting one and I was discusssing this with my mechanic last week as well.

Seems that NZ rules are catching up with the UK at last!

The interpretation is this

You can have 65 to the Front and 70 to the rear but not 70 front and 65 rear (commonsense really)

For RWD cars perhaps, but not necessarily for FWD. For many years DS's (and possibly early CX's) left the factory with smaller rear tyres...

[kiwi]

This is an interesting one and I was discusssing this with my mechanic last week as well.

Seems that NZ rules are catching up with the UK at last!

The interpretation is this

You can have 65 to the Front and 70 to the rear but not 70 front and 65 rear (commonsense really)

For RWD cars perhaps, but not necessarily for FWD. For many years DS's (and possibly early CX's) left the factory with smaller rear tyres...

I would rather have the standard sized tyre to the front and the larger at the rear even in a FWD.

Another valid reason for having the Correct tyre size according to manufacturers specs to the front is the Speedometer reliability

[Way2go]

I would rather have the standard sized tyre to the front and the larger at the rear even in a FWD.

Probably unimportant on the BX as the majority of braking effort is on the fromt anyway!

[RxBX]

Probably unimportant on the BX as the majority of braking effort is on the fromt anyway!

Or hopefully on the FRONT

[RxBX]

--

[kiwi]

I would rather have the standard sized tyre to the front and the larger at the rear even in a FWD.

Probably unimportant on the BX as the majority of braking effort is on the fromt anyway!

Not just the speedometer accuracy but I was thinking about the handling on corners. When I got the TRS it had a completly wrong size tyre on one wheel didnt really notice it while driving because of the suspension.

Although can guarentee if had an accident with none compliant tyres can guarentee getting a rocket. Besides that I am a bit more Conscientiousness of driving safely to have left it like that for someone else to point out it was wrong

There are 4 bits of palm sized rubber keeping you on the road you got to get them right.