I am thinking about maybe getting a set of the Thunderbird SVT 17x7" wheels for my Mark VIII. I realize that tire choices are limited. The factory car (that never made it to production) had 225/45-17 tires. Thats pretty low, and way too short compared to our factory tire height. Anyway, here are my choices:

Obviously the best choice is 245/50-17, but after looking on www.tirerack.com I could only find a few models in this size.. and they were all around $200 each!! I would even try 255/50-17, it's only 1.5% off... but I'm not sure what vendors recommend a 255-wide tire on a 7" wheel.

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
Factory:
225/60-16 5.3in 13.3in 26.6in 83.7in 757 0.0%
Choices:
245/50-17 4.8in 13.3in 26.6in 83.7in 757 0.1%
255/50-17 5.0in 13.5in 27.0in 84.9in 746 1.5%
255/40-17 4.0in 12.5in 25.0in 78.6in 806 -6.0%

And as always, please please please post pics of your 17x7" wheel/tire combo... I'd like to see the sidewall differences :)

I don't have pictures for you but I did discover something while shopping for tires on the website you mentioned. I also was looking at going to wider tires both on my MarkVIII & Trailblazer EXT. The trailblazer has P245/65R17 on a 7" wide rim and I found that going wider say 265/60R17 would require a wider rim more like 8" wide to accommodate the wider tire. Since I was not willing to replace the rims also I stayed with the original size. Now for the Mark, I also considered going wider there too but after reading all the reports on the tire I was choosing I stayed with the original size because of the 7" wide rim. I ended up buying a set of the Falken Ziex ze512's V rated due to the price & consumer reports on them. One point that users complained about that stuck in my mind was that these tires had squiggly or noodly sidewalls, but in each complaint case the common denominator was a wider than compatible tire to rim. They complained when a 245- 255 or greater tire was on a 16x7 rim or some other 7" rim so I decided to stay with the OEM size and have had no problems. There are over 400 reviews from customers on this tire and more than 90% are positive, the few negative ones are from mis-matching sizes or lead foot drivers who wore them out fast. From reading between the lines on all the reviews I determined that the OEM size was best for the OEM rim. In your case the rims are still only 7" wide and I notice when going around curves in the Trailblazer EXT with it's wider 245 tires and of course higher height that the sidewalls give when going too fast. In my final analysis I believe the manufacturer made the right tire/rim selection for this given car. I also read somewhere that enginneers when designing a new car already have the best wheel/tire selected when they design from the ground up. Why mess with it.

Well, factory is 225, and I hate it. It's way too skinny. For appearance and for handling. I doubt I will be going with 225.

Also, Sonny Day Out messaged me privately, but he had some good info. I'm not sure why he didn't post it publically to this thread... maybe its because of his embarassing addiction to the exclamation mark, but I assure you it's nothing to be ashamed about!!!!
Dear Sean ;

As the width of the tire increases , the steering/handling decreases ! ! ! You will need more caster to offset the increased width ! ! ! I have 235/55/17 Kuhmo K11 on 7" wheels and they are the maximum width that you would want for appearance ! ! ! The Kuhmos are wider that my Michelin 235/55/17s ! ! ! The Michelins look too narrow on an 8" wheel and the Kuhmos look too wide on a 7" wheel , so I plan to switch wheels and tires ! ! ! I have an ' 88 LSC with Kuhmos and an ' 89 LSC with the Michelins ! ! ! I have kumnos on my ' 97 LSC ! ! ! When I do swap , both of my MK VIIs will have the 235/55/17 Kuhmos ! ! ! I would recomend 225/55/17 Kuhmo K11s to you ! ! ! I can try to take pictures tomorrow 3/18/05 , if you want me to ! ! !

Sincerely,
Sonny

I've got 225-50-17's on mine. I had 245's before that they are really too wide for this wheel and my car drove kinda weird with them. :nos: