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I'm new to the forum and new the the Falcon world. Just got out of the Foxbody Mustang world and bought my first falcon. A 64 hardtop. Anyways i am looking into wheels and curious of rear wheel/tire fitment. I have been reading that a 15x7 wheel with 4" bs and a 255/60 tire is the biggest i can go. I think i wanna go with torq thrust 15x4 fronts and steel 15x7s in rear with a 255/60 drag radial. Just wanna make sure of this before i go and order them. Any help would be appreciated.
 

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I have a 64 Comet and a 65 Falcon with the American racing Torq thrust 2.1 in 16x8 with 4.89" backspace in the rear i was able to fit 245-50-16. With a 15" rim I do not see you being able to go any taller then a 235-60-15.
 

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You are mistaken or have been misinformed if you think you can get a 255/60 with a 4"bs in that wheel well without consequences. Unless your intention is the jack the rear of that car up so the top of the well clears the tire. That is an obnoxious look and I do not think you really want to go there. Measure, measure and remeasure or you are going to be headed for a world of hurt. Explore the back pages there is no easy combo but with that back set you might be looking more at a 235 at best.
Ras
 

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With a standard 8 inch axle you will need a 4.5 inch backspace for a 15 x7 wheel or you will rub outer wheel well. Good luck finding a 15 x7 with that b.s.ing. I've been looking for several weeks. Actually I'm trying to find a 15 x 7 with a 5 inch b.s. and a like wheel with 4 inch for the front.
It seems that the newer wheels are now measured in metric offset which is beyond my pay grade as far as figuring out what will fit. Rather than hijacking this tread anymore than I have I will start a new one and maybe someone can educate an old dog.
 

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I found myself in the same situation last week. I can't speak for your application. Here was my solution which was quick and easy. The wheelrite tire gauge is great tool. I was able to borrow one and the process took just a few minutes. I went to tirerack and got the math formulas and converted metric to inches, i'm not a Euro. My 69 was able to take 275/40ZR/17 on a 17X9x5in b.s. rear and 225/40ZR/17 on a 17x8x4.5in b.s. front. I went conservative 255 rear, axle stops removed and 215 front. Check out the links and follow the directions. Hope this helps, TODD



Tire Tech Information - Calculating Approximate Tire Dimensions

Wheel Rite - Wheel and Tire Fitment Tool
 

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I found myself in the same situation last week. I can't speak for your application. Here was my solution which was quick and easy. The wheelrite tire gauge is great tool. I was able to borrow one and the process took just a few minutes. I went to tirerack and got the math formulas and converted metric to inches, i'm not a Euro. My 69 was able to take 275/40ZR/17 on a 17X9x5in b.s. rear and 225/40ZR/17 on a 17x8x4.5in b.s. front. I went conservative 255 rear, axle stops removed and 215 front. Check out the links and follow the directions. Hope this helps, TODD



Tire Tech Information - Calculating Approximate Tire Dimensions

Wheel Rite - Wheel and Tire Fitment Tool
That is the way to do it! I used a simple story pole made from wood and a measuring tape. Old school but got the job done. 255/40/17 in a 64.
Ras
 

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With a standard 8 inch axle you will need a 4.5 inch backspace for a 15 x7 wheel or you will rub outer wheel well. Good luck finding a 15 x7 with that b.s.ing. I've been looking for several weeks. Actually I'm trying to find a 15 x 7 with a 5 inch b.s. and a like wheel with 4 inch for the front.
It seems that the newer wheels are now measured in metric offset which is beyond my pay grade as far as figuring out what will fit. Rather than hijacking this tread anymore than I have I will start a new one and maybe someone can educate an old dog.
You are not that old, you have just been around a long time. You can pull up these conversion charts online for "Free". Google is your friend, has saved my ass many a times.
Metric Conversion charts and calculators
Ras
 

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I have 245/45-17s under my 65 right now. and they were under it before the Mini-tub and spring relocate. I think I may have removed the axle bump stops though? Will be going 295's soon.

Check your Cell phone under the Tools/ Calculator function. Some have a Conversion function as well.

And I'm still sporting a standard flip phone AKA the JitterBug by guys at work. LOL!

Jet
 

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Thanks for the kind words and info. I can figure the metric conversion part but what I'm in the dark about is the offset verses b.s. example, a 15x7 with +38 mm offset. How do you determine the back spacing. Do you deduct the 38mm(1.5 inch) from the 7 inch width?

OK, bare with me.I think I may have this figured out. The offset is measured from the center line of the wheel to the mounting surface. In above example of 38mm(1.5 inches) the mounting surface will be 1.5 inches to front side of wheel plus 3.5 inch(1/2 of 7" width) from center line to back side of wheel equals 5 inch backspacing.
Am I close to being on the right track here?
 

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Thanks for the kind words and info. I can figure the metric conversion part but what I'm in the dark about is the offset verses b.s. example, a 15x7 with +38 mm offset. How do you determine the back spacing. Do you deduct the 38mm(1.5 inch) from the 7 inch width?

OK, bare with me.I think I may have this figured out. The offset is measured from the center line of the wheel to the mounting surface. In above example of 38mm(1.5 inches) the mounting surface will be 1.5 inches to front side of wheel plus 3.5 inch(1/2 of 7" width) from center line to back side of wheel equals 5 inch backspacing.
Am I close to being on the right track here?

BS is the distance from the mounting plate and the inner edge of the rim surface.
Offset is the distance from the wheels center line and the outer edge of the rim.
You would have to take into consideration the distance between the mounting plate in the wheel and the distance to the wheels centerline when working any equation with the wheels offset.
I know it all sounds pretty daunting, but I think most of it is because of the investment involved. The last thing you want to do is drop that dime on those shinny new wheels and hydes only to find out they do not fit or rub the wheel wells.
I was not so concerned with the offset when I did my calculations. I concentrated my efforts inbound and outwards. So taking the posistion of the mounting posistion on my diff. loaded on the perches. I determined the max depth I could obtain without clearance issues then measure outward to determine the max wheel size I could get in there without issues on the other end. Offset was not even a consideration, it just eneded up being what it was. I knew I was not going to get a deep dish in there and I did want a bit of a relief.
I ended up with an 8" rim would prefer a 7" in the front so I can loose the spacers. Also take into consideration I was a non traditionalist when I set up this Falcon I run 17" wheels. Many of you Falconites frown on that.

Don't forget to take into consideration how much your tires will protrude past the edges of the rims.

I saw this on line and hope it shines some light on this topic:
"Offset Equation
Using a 10-inch-wide Niche Over Ride wheel as an example, we can easily find the offset using the backspace measurement.
Measurements needed: Wheel centerline (wheel width divided by two) and backspacing
Equation: Backspacing minus wheel centerline equals offset
Note: If the answer is negative, then you have a negative offset; if it's positive, you have a positive offset. A 10-inch-wide Niche Over Ride has a wheel centerline of 5 inches and the backspace is 6-1/2 inches
Offset: 6-1/2 (backspace) minus 5 (wheel centerline) equals 1-1/2 inches (positive offset)"

Ras
 

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Discussion Starter #12
Thanks for all the info. For now i decided to leave to steelies on back that came with car and eventually mini tub it before i spend money on wheels and tires for the rear.
 

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I have a 64 Comet and a 65 Falcon with the American racing Torq thrust 2.1 in 16x8 with 4.89" backspace in the rear i was able to fit 245-50-16. With a 15" rim I do not see you being able to go any taller then a 235-60-15.
I just put on 245 60 15 with room to spare on my 64 falcon. I am going to try 255 60 15 now. I do have 15x7 rims, and 4" BS. My axle is from a maverick which is 57", one inch narrower than a falcon stock axle, also i am changing the axle to an explorer axle that will be 56.5 after it is cut, which will give me more room.
 

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I have a 1965 Ford Falcon Sprint Hardtop. Everything is stock on it. What size wheel and tire can I run with all four the same size without rubbing. I was hoping for a 15" Cragar rim. The car currently has 14" rims on it.
 

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I'm running 15x6 Torq Thrust D's with 3.75" backspacing on my 1965 Ranchero. Tires are P195/60 front and P215/60 rear, with no rubbing under any conditions. I could run 215 on the front, but I have manual steering, so I went with a narrower front.
 
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