NCT - Have all 4 tyres to be the same?

egan007

Hi
I have one different tyre on the back right of my car. The reason being that the original are 190Yoyos each
Someone was telling me that you have to have 4 of the same tyres for the NCT
is this true?

Stephen

As far as I know, no its not. I assume though, that all 4 tyres must be exactly the same size, and will have to have more than 1.6mm tread depth.

jhegarty

egan007 wrote:

Hi
I have one different tyre on the back right of my car. The reason being that the original are 190Yoyos each
Someone was telling me that you have to have 4 of the same tyres for the NCT
is this true?

same size & type yes... same brand no...

AlienGav

You'll be fine once you don't mix either cross-ply with radial thread tyres on either the front or back of your car.

De Hipster

egan007 wrote:

Hi
I have one different tyre on the back right of my car. The reason being that the original are 190Yoyos each
Someone was telling me that you have to have 4 of the same tyres for the NCT
is this true?

did you check today's date?! :rolleyes:

egan007

Yes it's the first of April -
but he told me this last christmas.....

De Hipster

egan007 wrote:

Yes it's the first of April -
but he told me this last christmas.....

As long as all the tyres are all road worthy & of roughly the same wear type/rate - summer/winter, same dimensions (i.e. my own are 175/50 R13s) the brand & other slight variations will not matter.

ds20prefecture

De Hipster wrote:

As long as all the tyres are all road worthy & of roughly the same wear type/rate - summer/winter, same dimensions (i.e. my own are 175/50 R13s) the brand & other slight variations will not matter.

Many cars use different widths between front and rear tires. Check your handbook.

BrianD3

No, tyres do not have to be the same brand. But there are are a few things about tyre spec. to take into consideration

Ply: Cross ply tyres can be fitted on all four wheels or on the front axle only. Therefore, if crossplies are fitted on the rear axle, they must also be fited on the front axle. Also, crossplies and radials must not be mixed on the same axle. Cross ply tyres are very rare these days anyway so it's not really an issue

Size: both tyres on an axle must be the same size in terms of width and aspect ratio. The exception to this are tyres which have no aspect ratio on them, in these cases the aspect ratio is assumed to be 82 and it's allowed to put one of these on an axle with a tyre with aspect ratio 80.

As already stated, tyres on different axles do not have to be the same size. Many supercars have rear tyres which are significantly wider than the fronts. This is perfectly acceptable.

Speed rating: all tyres must have a speed rating letter on them. Any letter OTHER than A,B,C,D,E,F,G,J,K is acceptable for the NCT

Direction: tyres with directional tread patterns must be fitted the right way around. These tyres will have a rotation arrow on them which must point in the direction that the tyres will turn when moving forward. If it doesn't the tyre is on the "wrong way around"

BrianD3

unkel

ds20prefecture wrote:

Many cars use different widths between front and rear tires

That's wishful thinking

AMurphy

generally I would recommend the L&R be the same brand, type, size, ie twins.

F&R, could be different, brand & size.
However, I would also recommend not mixing Radials and "the other kind" on any vehicle. Particularly, if you do a 4 wheel rotation.

And with directionan "V" groove tyres, you have few options, so you certainly need 2+2.

If u do a 5 wheel rotation, you have no options, Quins.

eg. I use different size F&R, but exact same tyres L&R on a vehicle, and if one has to be replaced, I replace both, making the odd the new spare. F&R are different names, size and class, All radial, ie the rear is a general/M&S traction tyre, the F is a wet traction tyre.
Balance.

but then again, I don't pay 190YoYO's for any tyre, prefering to wait until something suitable goes on sale .....(in pairs for 100YoYo's).

Ratchet

unkel wrote:

That's wishful thinking

some cars can even use different size of the rim. smaller on the front and bigger on the back. Brother's car has inch difference between rims on two axes

AMurphy

Ratchet wrote:

some cars can even use different size of the rim. smaller on the front and bigger on the back. Brother's car has inch difference between rims on two axes

I think one of the souped up Chryslers (The Prowler ) were more radical than that.
Typically this idea is reserved for performance cars, our average humble family car/van not being included in that class generally.

greglo23

there is another type of tyre which is marked outside on the tyre. once these tyres are properly fitted on the rims they can be rotated with no hassles as the outside is always out. be careful if buying remoulds (mostly rubbish) as some have no speed rating on them. some unscrupulous retailers out there are selling land tyres which have a speed rating of 45 mph which they grind off.

Capt'n Midnight

Stephen wrote:

As far as I know, no its not. I assume though, that all 4 tyres must be exactly the same size, and will have to have more than 1.6mm tread depth.

you can't mix tyres on an Axel
I've had a car pass the NCT with 14" wheels on the front and 15" on the back - lost two wheels to a pothole

Seth Brundle

unkel wrote:

That's wishful thinking

Mine do and I would have thought your are also.
Mine are 235/40/17 on front and 255/35/17 on rear IIRC

tonky

Brand or tread pattern don't seem to matter. Last car went through with 4 different fitted. Once they are in good nick, seems to be acceptable.

ds20prefecture

AMurphy wrote:

Typically this idea is reserved for performance cars, our average humble family car/van not being included in that class generally.

I know of one manufacturer (can we guess who?) that used wider front tyres than rear, in the interest of neutral handling balance, and the cars thus equipped would certainly not be classed as "performance" cars.

My fronts are 180/15 and my rears 165/15.

tonky

Sounds good. Might try that. Been driving RWD cars for years and recently gone to FWD. Always liked to dig in the nose on corners and let 'er rip.
I would have thought that wider front tyres on a FWD car would make more sense, both from traction and handling on corners view?

AMurphy

ds20prefecture wrote:

I know of one manufacturer (can we guess who?) that used wider front tyres than rear, in the interest of neutral handling balance, and the cars thus equipped would certainly not be classed as "performance" cars.

My fronts are 180/15 and my rears 165/15.

FWD or Rear?.
Rims wider also or just the tyres different?. No, I'm not aware of any "car" I came across with larger F than R. Neglecting utility/construction/spec purpose vehicles.

ds20prefecture

AMurphy wrote:

FWD or Rear?. Rims wider also or just the tyres different?. No, I'm not aware of any "car" I came across with larger F than R. Neglecting utility/construction/spec purpose vehicles.

FWD, Rims are 5.5" on front, 5" on the rear, but with 165 I could get away with 5.5" on the rear. Originally the car had 180R15 and 155R15. 15" 155s are getting a little tricky to source these days.

The car is the Citroën DS (I know I know, I keep banging on about it), but I think the GS, SM and CX all used narrower tyres on the rear. The 2CV didn't, but I don't think you can get narrower tyres than it's front ones anyway!

Frankly, its a bit of a pain as the spare is 180R15, which is a bit of a squeeze in the (enclosed) rear wheel arch. The handling benefit is somewhat moot, the car weighs 1600kg and has a mere 98bhp so one is hardly likely to push the envelope. If you do, this results is massive body roll but surprising levels of grip and ultimately a little understeer.

egan007

Thanks for the replies everyone