Chevy Impala SS Forum banner

1996 Buick Roadmaster wagon wheel & tire size

2483 Views 29 Replies 8 Participants Last post by  ayilar
Hi! I'm new to this forum and just purchased a low-mileage '96 Buick Roadmaster wagon. I want to get some Torq Thrust II wheels (or something similar) but don't know whether to go with a 16", a 17" or an 18" (figure on them being 8" wide). I want the wheels/tires to fill the wheel well for a modern version of the classic look. The wagon will be a cruiser and I have no intention right now to modify the suspension. Which diameter wheel is BEST supported by the aftermarket? What is a reasonable width to look aggressive but not rub the fender lips? What offset should I look for?


1 - 6 of 30 Posts
The stock diameter for a wagon is about 28 inches. Any substantial deviation from that will cause about 3 mph per 1" of tire diameter (larger diameter will cause the speedometer to be off slow). You can use any combination of wheel/tire that will give you the 28" diameter. For instance, a 17" wheel with a 255-60-17 tire will be about 28" in diameter. Tires are light, wheels are heavy, and a taller sidewall will give you a smoother ride. Make sure you have the stock +6 mm offset, or you may run into rubbing issues. An 8" wide rim on the front, with the +6 mm offset, will be fairly close to tubbing the outer tierod end. At 8.5" wide with +6 mm offset, you have about 1/16" of clearance at the tierod end, and must use tape-a-weights to balance the wheels.
  • Like
Reactions: 1
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.
I have run Impala wheels with 255-50-17s on the rear, and they do not rub anywhere.
Thanks for all of the input! I'm not really inclined to go any larger than an 18" wheel. I presume the 255 width works well with an 8" wide wheel? The deciding factor, then, for me would be the wheel size which has the most support/options from the tire industry. Like I said, I don't want any rubbing issues and my main goal is to have a classic looking wheel with a wider tire (with a real sidewall for ride/handling) and to keep the wheel well from looking "empty".

Remember that the offset must be +6 mm, or they will have clearance issues.
  • Like
Reactions: 1
If you change the offset, you put the centerline of the tire at a different position vs. the steering components, which puts additional stress on the steering components. It also changes the arc that the wheel/tire takes in the wheel opening, and can cause interference when simultaneously turning and compressing the suspension, especially when using a wide wheel/tire combination. If you lower the car, it is further aggravated. Should you use drop spindles, they push the wheel 1/2" out, so you must have a +18 mm offset to return the wheel to its original position. 0 offset will also move the rear tires closer to the body and can cause interference, especially because the bodies of these cars are notoriously crooked on the frame.
If you want to maximize your tire options, staying with the stock offset will be your best choice.
The +14 offset could limit your turning radius. The tire is closer to the frame in the front, and since the OEM tires tend to hit the frame at hard turning angles, the wider tire/rim setup with the additional +8 offset would place the tires 3/16 closer to the frame. You can always put a 3/16" or 8 mm spacer behind the wheel if you use longer studs.
Mine hit both the frame and anti-roll bar with a 235-75-15 on stock OCC rims.
1 - 6 of 30 Posts