If you want to fill wheel wells without rubbing fender lips or modifying the suspension ...
Anything wider than 255 will not fit in the spare wheel well, and will rub the sidewalls against the inner rear fender lips (the ones you can't see from outside unless you get UNDER the wagon).
To fit a 255/70R15 in the spare wheel well of my wagon I had to deflate it first.
When I needed a spare, reinflating it before installing it was a pain in the ass.
Fix Until Broke is generally correct about 29" tall tires being the tallest tires that can fit without modifications.
235/75R15 is 29" tall, and is the OE tire size for Cadillac Fleetwood limos.
(There's a thread where he explains what he had to do to install 31" tall tires.)
255/70R15 - 5 tire options (several ISSF members use without issue, classic meaty fatass tire)
255/65R16 - 8 tire options
255/60R17 - 4 tire options
255/55R18 - over 50 tire options
255/50R19 - over 50 tire options
255/45R20 - over 50 tire options
255/40R21 - 8 tire options
18" wheels will cause less suspension stress than 19" or 20" wheels.
Anything wider than 255 will not fit in the spare wheel well, and will rub the sidewalls against the inner rear fender lips (the ones you can't see from outside unless you get UNDER the wagon).
To fit a 255/70R15 in the spare wheel well of my wagon I had to deflate it first.
When I needed a spare, reinflating it before installing it was a pain in the ass.
Fix Until Broke is generally correct about 29" tall tires being the tallest tires that can fit without modifications.
235/75R15 is 29" tall, and is the OE tire size for Cadillac Fleetwood limos.
(There's a thread where he explains what he had to do to install 31" tall tires.)
255/70R15 - 5 tire options (several ISSF members use without issue, classic meaty fatass tire)
255/65R16 - 8 tire options
255/60R17 - 4 tire options
255/55R18 - over 50 tire options
255/50R19 - over 50 tire options
255/45R20 - over 50 tire options
255/40R21 - 8 tire options
18" wheels will cause less suspension stress than 19" or 20" wheels.