Time for new tires and rims for the 68 Dart

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RBConvert

RBConvert

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The same tires and rims are on the car since I bought it in 2012. Fronts are 15 x 6 w/ 4.0 back space steelies shod with 205/60-15 BFG. Rears are 15 x 7 w/ 4.25 back space steelies on 245/60-15 BFG. The tires are embarrassingly old and as much as I dig the steelies, I've (pretty much) decided on Torq Thrust D's, VN105. The rear tires rub the inside lip of the quarter slightly when hitting the curves aggressively. The fronts have no fitment issues.
It's been years since I picked out tires and rims and after searching and reading dozens of threads in this forum plus scrolling through scores of online sites, I now know how much I don't know about choosing tires and rims.
I think the front is sorted out: I'm staying with a 15 x 6 rim and a 205/60 or 65. Tire will probably be either a Cooper Cobra or BFG again.
The rear is where I have questions. I've done extensive measuring and in addition to the 4.25" bs, laying a flat edge across the back sidewall, it's 5.25" bs. Measuring from the face of the drum to the edge of the spring is 6.25". That gives me 1" of wiggle room, verified by the photo below. So I'm thinking I'm golden, all I need is a rim with 4.75" bs. The problem is that the 7" TT only come standard with a 3.76" bs. Up until just recently I assumed wheel manufacturers made their popular rim sizes with multiple bs' for people to choose.
Now I understand why a lot of members decided to go up to 17" and 18" rims. But I want to stay with 15s, so the obvious answer is have American Racing make me a custom offset. Is it common for people to request custom offsets? Or is it more popular to stay with standard offset and roll the lip? The problem is that with a 3.76" bs rolling the lip isn't going to help. To further complicate things, I want to go with new MT ET's 255/60-15, which have a section width of 10.1, about 1/3" wider than my BFG's.
Any suggestions, or is there something I'm overlooking?

IMG_20220117_161132.jpg


IMG_20220117_161201.jpg
 
That ruler shows 1.5" doesn't it?

Why don't you do an offset hanger at this time?

Anyhow, if you have 5.25 to the spring, aa 4.75BS plus a tire is going to be tight, and may require a spacer, but it's best to error to having too much backspacing as it is easily correctable.
 
I had to go custom off set. Running 17x7 215/45/17 (I need taller and wider) up front and 17x8 245/45/17 rear, both with 19mm offset. This was for OEM 73-up front discs and A-body 8-3/4 with BBP axles for OE BBP drums (i.e. 11x2.5, 11x2, 10x2.5 etc)

I take it your converted to BBP, how was that done?
 
dano said:
I had to go custom off set. Running 17x7 215/45/17 (I need taller and wider) up front and 17x8 245/45/17 rear, both with 19mm offset. This was for OEM 73-up front discs and A-body 8-3/4 with BBP axles for OE BBP drums (i.e. 11x2.5, 11x2, 10x2.5 etc)

I take it your converted to BBP, how was that done?
Click to expand...
Yes BBP front and rear. Front is disc brake swap from mid 70s Dart and rear is B body 8.75.
 
roccodart440 said:
That ruler shows 1.5" doesn't it?

Why don't you do an offset hanger at this time?
It does look like 1 1/2" but the angle is deceiving and the tape isn't perpendicular. And there's actually 6.
Anyhow, if you have 5.25 to the spring, aa 4.75BS plus a tire is going to be tight, and may require a spacer, but it's best to error to having too much backspacing as it is easily correctable.
Click to expand...
The pic is deceiving because the tape isn't perpendicular. I agree on the back spacing, either custom offset or rims other than TT.
 
RBConvert said:
Yes BBP front and rear. Front is disc brake swap from mid 70s Dart and rear is B body 8.75.
Click to expand...

OK, So you will need more offset for the rear wheels.

I started to look for 15" but gave up when I soon realized custom was the only way to find something that would fit without spacers and still look good. When I started to price custom wheels and tires it became obvious larger rims were not that much more to get in a custom sizes and the available tires in 15" vs 17" finding tires for 17" wheels were far more abundant, superior in tread design, speed, heat and tread wear ratings for almost the same cost. Knowing someday (and I have at this point) I would be going to bigger brakes I went with 17". The goal being my car would be safe at modern highway speeds and the way today's drivers drive like they don't know they are driving at all. Just food for thought.
 
YOu can get every offset / backspace known to man in 1/4" increments in a 15" wheel...IF...you have a 5x4.5 pattern. Mine are 11.25 wide and are 15's.
 
I haven't done enough research yet, but if you are looking only at one piece torque thrusts, try shopping the two piece. There should be more selection of b.s. And as said above, there are lots of tt copies out there that may have different b.s. available. Torque thrust m, for mustangs have lots of backspace, but I don't know if 15s are available.
You do know that ARE has a custom shop that can make you anything you want, within reason. I had some 15x12s made a few years ago, with minimum backspace. Weren't cheap then, won't be now.
As said above, I much prefer too much backspace versus too little. Too little, the tire crashes into the fender, too much bs, it rubs on the spring, but that can be fixed perfectly with a spacer.
 
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dano said:
OK, So you will need more offset for the rear wheels.

I started to look for 15" but gave up when I soon realized custom was the only way to find something that would fit without spacers and still look good. When I started to price custom wheels and tires it became obvious larger rims were not that much more to get in a custom sizes and the available tires in 15" vs 17" finding tires for 17" wheels were far more abundant, superior in tread design, speed, heat and tread wear ratings for almost the same cost. Knowing someday (and I have at this point) I would be going to bigger brakes I went with 17". The goal being my car would be safe at modern highway speeds and the way today's drivers drive like they don't know they are driving at all. Just food for thought.
Click to expand...
Thanks dano. Up until now I hadn't considered going larger than 15", preferring to keep it old school. But after diving into the research, I'm at least considering the idea.
 
RBConvert said:
Thanks dano. Up until now I hadn't considered going larger than 15", preferring to keep it old school. But after diving into the research, I'm at least considering the idea.
Click to expand...

It's tough, I originally wanted the "recall" wheel or Black Steelies with Dog dishes. But the recals that we're repopped at the time wouldn't fit and custom steelies were as much as my American Racing customs.
 
For comparison purposes, you may want to check out ET wheels. They have a Torq Thrust style wheel available in one piece and two piece with custom widths. A friend of mine has a set of Classic V on his Super Bee, and they look great.
ET Wheels by Team III Wheels
 
RBConvert said:
They are 5x4.5. To your point, it's time to start calling some manufacturers.
Click to expand...

Go to summit racing and set the filter to 15" wheel, the width you want, and the desired backspacing and you'll see more wheels than you will know what to do with.

"Measuring from the face of the drum to the edge of the spring is 6.25"

What is the measurement from the face to the quarter?

What width and backspace are you looking for?
 
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Here is an example of:
15x6 - 205/65/15 front
15x7 (4.5” BS) 255/60/15 MT drag radial rear

Stock tubs, leafs with 3/4” inboard hangers.

CFED4922-BF13-4767-9F33-3DD845BE2319.jpeg
 
Your problem is the rear axle. depending on the year, a B-body rear axle is 2-6" wider than a standard A-body. You need to know your total width to determine proper backspace for fender clearance. Your picture shows how far out the brake drum is in relation to the fender.
A-body drum to drum '66 to '72 = 57 1/2"
B-body drum to drum '65 to '67 =59 1/2" '68 to '70 = 60 1/2" '71 to '74 = 63"
 
I have a pair of 15 x 7 Magnum 500 wheels , that have a 5 1/8 or 5 1/4 backspace , made to fit an A body with a B body rear.
They are for sale , PM me if you are interested.

Frank
 
roccodart440 said:
Go to summit racing and set the filter to 15" wheel, the width you want, and the desired backspacing and you'll see more wheels than you will know what to do with.

"Measuring from the face of the drum to the edge of the spring is 6.25"

What is the measurement from the face to the quarter?

What width and backspace are you looking for?
Click to expand...
I still have to measure to the quarter.
Currently with a 245/60-15 with 4.25 bs it rubs the quarter lip at hard turns. There's about 1" space from inside tire to leaf spring so I'd like to get a 4.75" bs. That would still give me 0.50" to the spring and almost 0.50" off the inner lip. I don't see any 4.75" bs unless I move up to an 8" wide wheel (currently 7").
 
dusterdoug said:
Here is an example of:
15x6 - 205/65/15 front
15x7 (4.5” BS) 255/60/15 MT drag radial rear

Stock tubs, leafs with 3/4” inboard hangers.

View attachment 1715856402
Click to expand...
I've seen your posts in other threads as I was researching. If I remember, you also said you had plenty of room even if you hadn't done the offset. I want to run the MT ET's in the same size you have.
 
MoparLeo said:
Your problem is the rear axle. depending on the year, a B-body rear axle is 2-6" wider than a standard A-body. You need to know your total width to determine proper backspace for fender clearance. Your picture shows how far out the brake drum is in relation to the fender.
A-body drum to drum '66 to '72 = 57 1/2"
B-body drum to drum '65 to '67 =59 1/2" '68 to '70 = 60 1/2" '71 to '74 = 63"
Click to expand...
I was busy with other things this weekend (like getting my wife's Opel GT running again) and still need to get around to measuring. I'll post after I take the measurements.
 
roccodart440 said:
Go to summit racing and set the filter to 15" wheel, the width you want, and the desired backspacing and you'll see more wheels than you will know what to do with.

"Measuring from the face of the drum to the edge of the spring is 6.25"

What is the measurement from the face to the quarter?

What width and backspace are you looking for?
Click to expand...
Went on Summit Racing and filtered down to the size and bs I wanted and wound up with only 14 choices. Damn! And the only one I liked were the black steelies - same exact ones on the car now!
 
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