Wondering if it’s possible to fit 18s on a P400 using spacers to clear the brake caliper (I.e. without grinding down/replacing)? Are there any problems which may arise using spacers?

 

Yes. But the spacers would probably need to be at least 5-6" wide to clear the calipers.

Something along this sort of spec.

Lots of trimming of the wheel arches and the fenders too most probably to off set the rubbing from the wider stance and turning arc of the wheel.

 

I read a Facebook post where a guy fitted LR3 wheels (I think I found them - linked below) on his P400 using what looks like 20-30mm spacers, unless the offset on those requires larger spacers which wouldn’t be immediately obvious. His vehicle certainly didn’t look like the image above. I wonder if anyone else has tried.

https://www.autorimshop.com/18-oem-w...RoCQmMQAvD_BwE

 

Having fitted 18's to my P400 I know that an 18" wheel will need to be positioned as I have outlined if it has any chance to fit on the rear wheels with unmodified calipers. It's not going to happen otherwise. Won't matter what the wheel type is. The size of the caliper is constant and internal radius of the wheel won't differ significantly from brand to brand. 20-30mm won't even come close. No chance.

 

I was thinking of answering along the same lines. Your pic killed it, tho.

 

Oh, Lord! Please do not let any Defender end up like this...

 

and no way is someone fitting 30mm spacers without a whole lots of work to extend and install longer wheel studs. There is a thread somewhere in here on someone doing just that. looks like the whole wheel assembly needs to come apart. Yes i know you can use a spacer with additional outbound lugs but if you are using your 18's for serious offroad fun two sets of lugs per wheel is nothing more than additional failure points.