Ultimate wheel/tyre fitment thread

I think the issue is it is partly confusing to grasp your concept! That and one man's strech will be another man's death wheel.

I think I get your idea though. So I'll get the ball rolling:

-MGB GT. You have a few choices here. If you have the Sebring arches and are lowered you can do the following:
8J x 15" - 225/50R15s work as do the 55 profiles. 215/55R15 isn't a bad shout either and can give a nice amount of stretch. I've seen some people use 215/60s on an 8J in this application previously

That's on 215/60s



-Ford Ka/Potentially other MkIII Fiesta derived cars like the Puma etc.

For handling the 14s and 15s win. The rolling radius is the same and you can get some great tyres in those sizes. So, the sizes

7J x 16" on 195/40R16s
7J x 15" on 195/45R15s ET30; the rears will just begin the touch the rear arches if you put two people int he back.
6.5J x 14s on 185/55R14s
13s on 185/60R13s ET36. Some do fit 175/50R13s to get a lower profile as well as less offset and better arch clearance. But IME it can make the ride more figity and it can throw off your rolling radius quite a bit. That and your arch gap gets bigger.

-Triumph Stag.
These left the factory on 5.5J x 14" GKN 5 spokes on initially 175R14 rubber and then 185R14. Unfortunately many were not drilled straight and thus many Stags out there tend to have almost incurable vibration issues; it is one reason why many are on Minilites. Several people fit on 185/70R14s or 195/70 because they are cheaper and to be fair it can give a nice ride still! Many are on Minilites that are 6J. I've been in and tried a few combos. A great combo is the following:
6.5J ET33 on a 205/60R15 or 195/65R15 tyre. I had the latter and this drives very nicely indeed and certainly to my eyes gives the Stag a more purposeful look. 7J would be nice but it would be too close to arch rubbing territory on stock arches I fear. That and ET33 is pretty close to the inside of the struts as it is up front!
16" wheels would be awesome on a 205/55R16 but I doub many would commit to that in the Stag world.

Cheers guys - it's actually a simpler concept than that!

Example question it could answer:

What does a 235 45 18 look like on a 7.5j wheel?

What about a 245 40 18?

Not so much about the car! I'm about to buy 4 tyres for minimum £200 and i don't want to buy them and regret the size choice. Unfortunately - the internet loves skinny tyres, and stretching them over wide wheels. It's difficult to find info on the opposite! Which is why i thought it might be cool to build a wheel/tyre database.

Totally get this. Tyrestretch mentioned above do exactly this, in a nice, searchable format, but that doesn't mean we can't build up a large reference guide here too.
The only downside is that it won't be anywhere near as orderly, sortable or searchable as the one that already exists.