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Old 03-28-2009, 05:59 PM
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Lightbulb Re: 295 50 16 tires

Quote:
Originally Posted by Bart II View Post
Can anyone tell me what the widest tire is that will fit on my GN without modification to the wheelhouses or notching the frame rails.
Specifically, what wheel size, backspacing etc.
*sigh* You and a lot of other people...

There is not a simple answer, oddly enough. And every time one is produced, some one insists that they managed to shoehorn something larger onto their car without changing a thing.

Keep in mind that the basic Regal is a car that was never designed for monster rubber, steamroller wheels, etc. So when you try to shoehorn all that under it, it really doesn't want to fit.

In addition, there are a lot of "It depends..." clauses that get added into the answer for such a question. There are many factors that have to be considered that help define the answer:
- Are you looking for a street setup, drag setup, or both.
- Will the car be lowered at all?
- Do you care about running your wheel arch trim?
- Would you consider rolling the inner lip of your wheel arch for clearance?
- Would you consider notching your frame for clearance?
- Are you considering a larger than stock wheel? (diameter and/or width)
- Is it important for you that your speedometer be correct? (it does matter to your ECM and TCC lockup patterns)
- Planning to do any hard cornering?
- Planning to do any front suspension upgrades or brake upgrades? (i.e. aftermarket A-arms and/or 16 F-body rotors, Baer brakes)
- Are you going for looks, performance, or both?

As few thoughts that might help with your questions:
- Anything much wider than a 275 on the rear on the rear will be difficult to fit.
- Lower profile wheels (short sidewalls) or drag-only setups (no high speed turns, and little rear axle swing) allow for more tire width in the rear.
- A wheel backspace greater than 4" on the rear may cause the tire to rub the frame if no notching is done.
- A wheel backspace of 3.5" or less on the rear will likely cause a tire on an 8.5" or wider wheel to rub the wheel arch trim if it is present or the lip is not rolled.
- Tires wider than 225 on the front will likely rub the frame at full lock. But only at severe lock, and that is only typically done in parking lot maneuvers.
- The stock tire diameter is ~26".
- It is possible to alter speedometer and VSS readings to account for large tire diameter changes via speedometer gear changes in the transmission.

Others, feel free to contribute.
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