Hi Guys, Buick fan from the UK here. I've got a 64 Special Wagon and I'm looking to put 17" wheels on. I've currently got 15" wheels with 205/60 on the front and 225/60 at the back. I can't afford to go any wider at the back because with 5 passengers I'm getting a little bit of wheel rub at the back, although the rest of the time it's fine. Is there anyone out there with a 64 Special Wagon who can advise on what tire size will fit? I've been told 205/45 or 205/50 front, and 225/45 or 225/50 at the back. I'd like to get as much sidewall as I can, but I'm not going to find out if they fit until I put them on so I need to get it right! I'm looking at Ridler 645s or 695s, both of which have 4" backspace. Thanks for any help or comments.
What you need to do is measure your current wheels and back space. If it is rubbing at the back, look and see how much room you have inboard. If there is room, you can increase the back spacing to move the entire wheel/tire inwards. What you want is to center the wheel/tire in the wheel well. Rim size whether it be 15", 16", 17" or whatever really doesn't affect anything. The back spacing and rim width are what you are concerned with. I would think that more back spacing is going to solve your problem, 4" will not be enough. As far as tires go, the lower the aspect ratio goes, the shorter the side wall relative to the section width. You want to keep the overall tire wheel height as close to stock as possible so as not to affect your speedometer calibration, and effective gear ratio. It is easy to calculate the tire height, you just need to do some conversions from English to Metric and then back to English. Take your back tire for instance, currently P225/60R-15. There are 25.4mm to one inch. That makes a 15" rim 381mm. The side walls are 60% of the section width (225mm). That makes the side walls .60 X 225 = 135mm. Two side walls and the rim is tire height, 2(135) + 381 = 651mm/25.4 = 25.63". Now for the 17" wheels, let's look at a P225/50R-17. the 17" rim is 431.8mm. The side walls are 50% of 225mm. That makes this wheel/tire height 656.8mm/25.4 = 25.86". The P225/45R-17 would be a shorter tire than that. I would find out what the stock tire height was on the 64 Buick Wagon, then see what your current back spacing was on your 15" wheels, measure and see if you can move the wheel inboard with more back spacing to fit a wider taller tire if need be.
http://www.vintagecarconnection.com/vintage_tire_size_conversion_chart.htm Near as I can tell, your wagon came with either 6.50-14's, or 7.00-14's or even possibly 7.50-14. Depends whether it was a 4100, 4200, or 4300 series. That makes the wheel/tire height somewhere between 24.74" and 25.85" tall.
Many thanks for the advice and information guys, that's much appreciated. I'll get the tape measure out!
