Just got my Sierra (wooo yeahhhhh, will post pics soon) and it came with some 31" Muddies ($1000 worth) on Sunraisers and some 215/80's on the stock rims which are pretty much dead.
It had the muds on when I picked it up last night and even with the 4AGE 20v, it's speed was nothing special at all. As I'm primarily using this car for on road with just weekend trips offroad I'd like some good road tires that will help me save on fuel while giving me better acceleration from the 4AGE. As the current ones are bald, I've been considering options. I read all of the tire threads (truly) in the Sierra bible and it helped me a lot. I also used the tire calculator in there to work out diameter in inch of the 225/75 variant tires to get a good comparisson.
Using my new knowledge and checking on available road based tires, I'm guessing that I should go a 195/80 R15 or a 225/70 R15, both which work out to be just over 27" according to the calculator found here http://www.miata.net/garage/tirecalc.html.
Now I know that stock tires would probably be best, but as I have a better engine I'm happy to go slightly larger so the car is capable off road as well as giving me a tiny bit higher gearing for the highway driving which is most of what I do. For the heavy trips I'll put the muddies on but for the one off, I'd like something that can handle a little bit of offroad.
So are the above tires good ideas? Would either be better than the other and in what respect? Should I go smaller or larger? Wider or thinner? Tire gurus, help me out
