went to change rear tyres today & thought i'd put one new tyre on rear & take tyre off spare & put one im takin off on spare then if it gets stolen they aint got a new tyre, but when we took the spare off it was only 19" not 20".
so i phoned guy salmon wakefield who told me they put 19" spare as the 20" wont fit under car,then i thought if it aint same size it will the diff up when used,unlless its 50 profile instead of 40 but in that case the 20" will fit under car as the 20" 40 is same size as 19"50.
any one any suggestions why they dont fit 20" spares..?

Think it's the wheel width that is the clearance issue underneath the rear.

But could be wrong, not a lot in it between the 19's and 20's, 1/2 inch I think.

mmm yes did'nt think about the width,yes thats what it will be.

They don't fit 20s because they are cheap (Land Rover, not your dealer...) There is virtually no difference in overall "rolling" circumference between a 19" fitted with 255/50/19 and a 20" fitted with 275/40/20. Both will fit no problem in the spare wheel well (the 20" may hang out a little more since it's a hair wider, but hardly noticeable), and since the circumference is the same you will be just fine running that 19" as a temporary spare without fouling up transmission / differentials, etc. AFAIK, they have always put in 19s with 255/50 tires (over a black rim with ugly yellow sticker? At least that's the way my 2006 came) on RRS fitted with full size spares, regardless of whether you have 19 or upgraded 20" as running wheels.

You are lucky you get a full size spare at all actually, since 2007 Land Rover has been fitting compact spares on every trim Sport (HSE and S/C) here in North America, to save a few extra bucks. Real handy if you get a flat while off-road.

I think FFRR are the only Land Rovers still getting an actual matching rim and tire as spare wheels. 

Don't beat around the bush Umbertob.

Land Rover are Cheap.

That's got to be the post of the day. And I couldn't agree more.

And there was me giving LR the benefit of the doubt.

When I think of Gaydon, I keep getting flashbacks to old films like Carry on At Your Convenience. (For Umbertob - Low budget Classic English Comedy Film)