quote:Originally posted by Bianchito:
...I have NOT A CLEAR IDEA on wheels and tires parameters...Can someone explain me the concepts here...
FB, I hope you didn't think I had forgotten about your original question!
I figured the pictures I've posted would help you to understand the considerations in fitting a new wheel/tire package into the Pantera, at least on the rear. It just so happens you asked your question the same week I was fitting my new wheels onto my car for the first time. I also hope the pictures may entice you into thinking bigger than 17" wheels.
Positioning the tire within the wheel well is accomplished by a wheel parameter known as "off set" or "back spacing". If you are purchasing a wheel/tire package designed specifically for the Pantera, then this parameter should not be a consideration for you, it will have already been engineered.
In my situation, I was building a wheel/tire package for the rear wheels that had not been attempted before, so I worked with somebody experienced with fitting tires & wheels onto the Pantera, to develop the new specification. I must say, he positioned the tire within the rear wheel well perfectly.
The tires most Pantera owners install in the rear of their cars are so wide, that positioning them near the outer edge of the fender is not a consideration, placing the tire within the wheel well so that it doesn't rub on the inside or outside is the consideration. The tire moves inward as the suspension deflects upward.
On the front the wheel needs to be centered the same as the factory spec to maintain the factory "scrub radius". Some people would like to place the tire outward as much as possible because they think it "looks" better, but this is not advised. Not only does this alter the scrub radius, it will also cause the tire to rub the outer fender lip during spirited cornering.
In general, we fit tires onto Ford era & GTS Panteras that are 24" to 25" outside diameter on the front, and 26" to 27" outside diameter on the rear. Wheels widths will run 8" to 9" on the front, and 11" to 12" on the rear. The exception being the original 15" Campagnolo wheels, in which case you are limited to a 8" wide front wheel and 10" wide rear wheel.
The owners of GT5 & GT5-S cars have other difficulties in sizing modern wheels & tires for their cars, because the factory installed 23.9" diameter front tires & 24.5" diameter rear tires on those cars.
The diagram below illustrates the relationship between the terms "off set" and "backspacing".
cowboy from hell
