Tyre sizes

With all the other things i've been looking at i never really checked my tyre sizes. I noticed today that my rear tyres are 255,60 R18's while the front are 255,55 R18's. Is this within tolerances and would it have been done for a reason or mistake?

Illegal

dont think so - tiz if across an axle tho.

What. Two tyres in the same axel are taller than the other two

Don't think it's illegal, just think it's not a good idea, especially if you off-road and lock the diffs ..

Could this be the cause of a slight drone i've noticed when doing about 50mph. I've doube checked and treble checked the pressures and played around with them but its always been there. More importantly could it have damaged the auto box in any way.

defender300td1 said:

What. Two tyres in the same axel are taller than the other two

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That isn't illegal. The Lotus Elise uses smaller front wheels to the rear wheels. As do many other sports and super cars.

It is only illegal if you have mixed axles. Left and right tyres need to be the same, front and rear don't.

ragsyrandell said:

Could this be the cause of a slight drone i've noticed when doing about 50mph. I've doube checked and treble checked the pressures and played around with them but its always been there. More importantly could it have damaged the auto box in any way.

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Probably won't help the noise. Different tyre sizes will work the diff more than usual and can possibly wear them out more. I would doubt it'd hurt the gearbox though as although it's connected it's also fairly isolated from the diffs and wheels.

Thanks all. I think i'll change them anyway to make sure.

Yes seems I was wrong thought if I car was fitted like that , seems not

My spare's different from any others on the Landy .. though the main tyres are identical

How would 'they' get away with emergency wheels nowadays if it were illegal?

Paul D said:

Probably won't help the noise. Different tyre sizes will work the diff more than usual and can possibly wear them out more. I would doubt it'd hurt the gearbox though as although it's connected it's also fairly isolated from the diffs and wheels.

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I imagine the ABS/TC won't like it much either, since the front wheels will be rotating much faster than the rears.

Paul D said:

My spare's different from any others on the Landy .. though the main tyres are identical

How would 'they' get away with emergency wheels nowadays if it were illegal?

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The emergence wheels are the same in inches never thought about it .

defender300td1 said:

The emergence wheels are the same in inches never thought about it .

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No they aren't.

It is quite common that space savers are far smaller than the normal road wheels.

They are a temporary solution to get you to the nearest garage. They are also designed for reduced speed, a lot of idiots drive at 70+ using them. They are rated for no more than 50.

Bix said:

No they aren't.

It is quite common that space savers are far smaller than the normal road wheels.

They are a temporary solution to get you to the nearest garage. They are also designed for reduced speed, a lot of idiots drive at 70+ using them. They are rated for nor more than 50.

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I'm confused yep they are thinner but tallness and roundness if a wheel of the same size has to be on the same axel
The surly say it was 16 inch and of the correct height?? As say 135/5516

defender300td1 said:

I'm confused yep they are thinner but tallness and roundness if a wheel of the same size has to be on the same axel
The surly say it was 16 inch and of the correct height?? As say 135/5516

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You are right, a space saver wheel should be the same rolling circumference as the main wheel albeit a different Rim Size and thickness

Saint.V8 said:

You are right, a space saver wheel should be the same rolling circumference as the main wheel albeit a different Rim Size and thickness

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Thank you well said

defender300td1 said:

I'm confused yep they are thinner but tallness and roundness if a wheel of the same size has to be on the same axel
The surly say it was 16 inch and of the correct height?? As say 135/5516

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You would think so, but I've come across a lot of vehicles with space savers where the space saver was smaller than the main road wheels. It seems really common on luxo barges and 4x4s. Little hatch backs and the like there are only a few mill in it. I've seen 2" difference on a Merc E-Class.

Hmmmm maybe that is an illusion due to a different rim size and profile...no law in the land would allow different diameter/circumference wheels I am sure....as that is just plain dangerous!

Saint.V8 said:

Hmmmm maybe that is an illusion due to a different rim size and profile...no law in the land would allow different diameter/circumference wheels I am sure....as that is just plain dangerous!

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for emergency wheels its what you would think wouldn't you I know they are thinner but a different Circumference...