All very true, and in fact I also had probably the same 225/45 Yomama tire on my old car once... another size is 215/45, which probably survives here and there as a replacement tire for the front of the old Acura NSX (!)-- for me, I try to stick with widely available tire sizes, just so if I have, say, a road hazard issue, I can get the tire replaced quickly. I've used 205/45 16, and it worked very well, on my old '85-- right now, I'm using 205/50 16 on my '89-- a curiosity about the XR is that they went from a 14" wheel and a ~23" diameter setup to a 15" wheel and a ~24" setup without changing anything else. Kind of weird. But if you stay somewhere close to that range, with something that fits the wheel well, and a wheel with the right offset, you will be OK. There just isn't much room unless you do some flaring and/or use coilovers up front. The rear is more forgiving. I have staggered the tire sizes F/R, and it looks good, but unless you tune that out with maybe a larger rear anti-roll bar, the car will push. I understand why people go to 17" wheels, as there are scads of tires in that size, but don't forget that wheel camber varies with suspension movement, so if you go towards rubber bands, your chances of lifting the edges of the tread increase. I try not to go much below 100mm of sidewall.Mike McCreight wrote: ↑Tue Nov 28, 2017 8:33 amDepending on tire manufacturer, (sizes vary more than women's clothing...) and offset, (millimeters count) a 215 50 16 may fit, but I wouldn't count on it. I'd imagine there would be spring perch issues. Probably body interference as well. Coil-overs will help, spring perches and inner fenders can be sliced and diced.
I had a set of TSW Hockenheim R that were made by TSW specifically for the Sierra, (no offset stamped, sorry...) and a set of Yokos in 225-45-16 were a PERFECT fit. Sadly, that size is gone, except for a few examples, mostly Auto-X oriented. https://tires.tirerack.com/tires/225%2045%2016
and some street tires by brands you've likely never heard of.
The Cossies worked well with 205/50 15, and although we've come a long way in 30 years, the suspension design remains the same, so whatever choice you make should take that into consideration.