Hi Lads

I am sure this question has been asked before ,but I can't find anything when I search.

At present I am running 22" wheels and tyres on my Sport ,I have the standard spare wheel under the car , If this spare wheel and tyre is a different overall diameter than the 22" wheels and tyres I am running on the car, Would I be able to use this in an emergency or is it going to throw up Faults or worse cause damage to the Transmission ?

Cheers Jock

Best thing to do is remove the spare and see how much of a difference there is. I would think that it would certainly cause problems yes. I run 20's on mine and had a standard 19 spare changed it for a matching full size. Do you want to take the risk ? I would personally get a matching spare 2008 G4 RRSport TDV8 current
2009 TDCi 90 current
2018 Discovery 5 HSE lux current
1994 Dakar current

Surely the overall diameter is the same, the larger rim just having lower profile tyres? Even then, it would only be suitable as a 'get you home' spare.

Thanks for the reply lads

I will have a look at both wheels and tyres and compare both sizes ,think there are a few sites on the Internet where you can compare tyre sizes to find out the exact difference. Will try and get the sizes on Monday when I am off. I think mine will also be the original spare.

Not sure if a 22" would go under the car so would need to look into that too. I did think that it could possibly cause problems but its one of those things that tends to slip your mind.

Cheers Jock

My full size spare fits under the car it's tight but it does fit 275/45 20 is the size 2008 G4 RRSport TDV8 current
2009 TDCi 90 current
2018 Discovery 5 HSE lux current
1994 Dakar current

Thanks Camelrock

I will also check the Diameter of your spare against the diameter of my 22" wheel and tyre and that should also give me an idea if its going to fit under the car.

Cheers Jock

Hi lads just thought I would post an update

Checked out the tyre sizes on the Internet . Tyres on the car are 285 /35 /22 which are diameter 29.85" (758mm).
My spare is 255 / 50 /19 diameter 29.04" (738mm).

Going by the calculator 22" is 696 Revs/mile against 19" which is 716 Revs/mile.

So 20mm difference in diameter ,I am trying to source a 22" spare at present and hopefully might just get it under the car going by the diameter of Camelrock's spare 275 / 45 /20 which is 29.74" (756mm) diameter.

Cheers Jock

If outside diameters of tyres are this different, how does the speedometer/milometer cope if you change all the tyres?