I'm trying to figure out what would be the best look and fit for my '67 Riv - does anyone know if any of the Coy C-5s or Torq Thrust II sizes will fit the car with the appropriate backspacing? If so - pictures? What's the largest size I can get while avoiding tire rub? I'd take it to a wheel/tire shop, but the engine is currently out, haha. http://www.coyswheel.com/coys.html http://www.americanracingwheelsinfo.com/American_Racing_Torq_Thrust_II.htm -Bryce
First see if the wheels are centered in the wheel wells, if that is the case then you will want to keep the wheel centered to give you the max. amount of room. Next remove a wheel and measuring the width and backspace of the wheel, that can give you a reference of what backspace you need. The backspace is the distance from the back of the rim to the back of the wheel where it bolts to the studs. Lets just say you have a 15x7" wheel (this will measure 8" wide on the outside as the 7" is the inside width) and you have a 4" backspace. This means you have a possitive 1" offset. So if you go with a 15x10 wheel you would need a 5" backspace to keep the rim to keep it centered. They sell kits to help you measure for max size wheels but you can do the same with some plywood and a measuring tape. I build a circle the same diameter as the tire I want to use and then I drill 5 holes and mount it on the wheel studs. I just take a chunk of 1/2" plywood put a nail in the center and use a string with a pencil on the end to trace a perfect circle of whatever diameter I want, just keep the string taught and you have a nice circle. Then a jigsaw to cut it out, add your 5 bolt holes and you are good to go. From there you can measure all around to see your clearances to see what width tire you can fit. This is especially important on the front as the clearance when at full steer is limited. If you are staying close to stock offset, diameter, and width there is not much need to do all the above... The reason to do all that is to max out the width and or diameter without wasting hundreds or thousands on the wrong wheels and tires. I would go with a slightly conservative tire size and keep it the same on all 4 corners so you can rotate them. For sure stay within about 1" of the factory diameter or you will rub even without really wide tires. I would guess something like a 16x8 wheel with a 245/60/16 would work well and look nice. http://www.tirerack.com/tires/tires...tireModel=Radial+T/A&partnum=46SR5RADTARWL2V2 Note that this above tire has a 26.6" diameter which should be close to stock, and the section width is just under 10". So if you rig up the plywood like I do then you can measure from the plywood at full steer to see if you have room for the 10" wide tire. Just keep in mind the offset and how that will move the center of the tire in towards the inside of the fender if it is a possitive number and it would move the tire out if it was a negative offset.
Great breakdown, thanks! Hopefully I'll have time to check everything in a week or two when I'm home.
I bought my 68 Riviera with 20x10s in the back and 20x8s in the front. Unfortunately, I get some rubbing at full turn in the front and have had some rubbing in the rear too. Part of this problem in the back is due to the heated coil springs but I am slowly working on that. This combo looks great but I don't know what to do about a spare tire now and am trying to find a 20" space saver tire somewhere to mount on either end in case of a flat. Good luck with your selection. ~ Eric
