15 x 7s, what size would you run on a 68 four door dart ?

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Cruisingram

Cruisingram

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I just bid and won 4 15-7 cop wheels with lugnut covers off ebay- should be here by March 6th, Later that weekend, operation suspension upgrade begins LOL.

Looks like I have nearly everything I need. I am switching to the BBP obviously. I have a Dana 35 from a wrangler going in the back. I have new torsion bars and adding 1-2 more leafs to the HD springs I already have on the back.

Now, last thing I have to buy, I think, or last big thing- is the tires.

One of the biggest reasons I am going with 15s is because of ground clearance- I live on a bumpy road and sometimes lava rocks try to kill my oil pan- have been succesful once!

I am looking on Amazon to get some tires, or may go to my local place, but looking in the direction of these:

https://www.amazon.com/Cooper-Cobra-GT-All-Season-Tire/dp/B004QGZOB4/?tag=fabo03-20

My question is- any risk of rubbing anywhere?
 
Those are likely going to be too tall and little too wide on the 7" cop rim for the front of that car. Depending on the offset of the wheels you may also have problem in the back.

There are a lot of threads you should take the time to search on this site that cover “what size tires"? Or "how big of a tire can I go" etc….

Good luck
 
By the math, a 215/70-15 is about 26.85 tall.
And yes it will bolt on, but you will not be able to steer to full lock as the tire will rub , depending on the Backspace in at least two places, First is the bottom front corner of the fender, and second is possibly on the frame rail.
If you run any non-stock offset wheel, and a taller than stock tire, then the Scrub-radius will cause the tires to pull.
You might have had better luck by using the stock wheels and tires but just raising the ride height.
IIRC the stock tires were about 24.5 tall
Since you are not afraid to change things; and
the wheels are already purchased, and
the T-bars are on the way
I suggest a 225/60-15 at about 25.6ish tall
If required;
The checking rim for a 225 is 6.2. The 7.0 is already at 79% section-width, so that should be fine for a 225/60.
The fenders are easily trimmed,
The ride height can easily be adjusted,
The steering stops can be welded,
However, if the tires are coming from the mainland, I suggest to buy just one, and make sure they fit on both front and rear. Then make a decision. Or maybe you can find a junk tire kicking around your neighborhood.
I bought a Milodon roadrace pan. She has bump-outs sideways but is till a bit below the K-member. I just built a skid-plate, and bolted it on, took me like an afternoon. Now my car can fly! Speed bumps here we come.
Maybe you can build a plate too.
 
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Cruisingram said:
I just bid and won 4 15-7 cop wheels with lugnut covers off ebay- should be here by March 6th, Later that weekend, operation suspension upgrade begins LOL.

Looks like I have nearly everything I need. I am switching to the BBP obviously. I have a Dana 35 from a wrangler going in the back. I have new torsion bars and adding 1-2 more leafs to the HD springs I already have on the back.

Now, last thing I have to buy, I think, or last big thing- is the tires.

One of the biggest reasons I am going with 15s is because of ground clearance- I live on a bumpy road and sometimes lava rocks try to kill my oil pan- have been succesful once!

I am looking on Amazon to get some tires, or may go to my local place, but looking in the direction of these:

https://www.amazon.com/Cooper-Cobra-GT-All-Season-Tire/dp/B004QGZOB4/?tag=fabo03-20

My question is- any risk of rubbing anywhere?
Click to expand...

How are you converting to BBP in the front?

How wide is the Dana 35 from mounting surface to mounting surface?

With the 73+ Mopar BBP brakes your 15x7’s with a 4.25” backspace will work with up to a 225/60/15 on most cars. You may also be able to run a 215/65/15, which is right at 26” tall. That’ll be the tallest you can pull off most likely, and it will be tight to the front corner. But if you’re using a different disk brake conversion that may not be accurate.

In the back I’d have to know how wide that Dana 35 is. The taller tires you linked originally will fit, but only if the axle is the right width for those cop wheels.
 
I used the 15x7 cop car wheels to check the fitment of 225 60 15s on my 68 dart. I then bought Centerline aluminum wheels with the same offset.
I have green bearings on the 8 3/4 with 4.5" axles and 73 up disk brakes up front. All cleared fine. Front fenders being the closest point. The dana 35 can't be much wider than an 8 3/4 with big bolt pattern axles though or tires will rub on outer wheel lip.
My experience mimics what was previously stated. I do not see the cooper cobras in the 225 60 size on the link?
 
72bluNblu said:
How are you converting to BBP in the front?

How wide is the Dana 35 from mounting surface to mounting surface?

With the 73+ Mopar BBP brakes your 15x7’s with a 4.25” backspace will work with up to a 225/60/15 on most cars. You may also be able to run a 215/65/15, which is right at 26” tall. That’ll be the tallest you can pull off most likely, and it will be tight to the front corner. But if you’re using a different disk brake conversion that may not be accurate.

In the back I’d have to know how wide that Dana 35 is. The taller tires you linked originally will fit, but only if the axle is the right width for those cop wheels.
Click to expand...
I have a 73 duster front disc set up. The 35 Is exactly the same width as the dart bolt surface to bold surface. So maybe I just just be safe with a 205?
 
Roughly 3/4" taller and 3/4" narrower than a 225 60 15. I think they would clear on my car. Front bottom edge of fender being the closest point.
Being a local shop they will likely mount a tire and let you check fitment. A local tire shop did that for me when I got mine.
 
72bluNblu said:
They’re 26.4” tall, so they may not clear the front corner.

26” tall is pretty much the limit unless you’re running a really skinny tire, or really high on the ride height.
Click to expand...
Dart seems tighter than a duster/dart sport and the best I could do with about 1/3-1/2" of clearance was a 215/65r/15 on my duster which is 26" tall. This on a 15x6" Cragar 5 spoke with about 3 3/8" backspacing and narrower than the cop wheels. To the OP, height is the main issue and you should listen to bluNblu here.

Also, to the OP, have you searched the endless threads on ‘what tire size’ can I use. All of this has been talked about at nauseum and you WILL find the answer there. In fact, just search bluNblu’s posts as he’s often one of the main contributors one these threads. The back of a dart sedan is definately tighter than of a duster/dart sport too. The planets would have to align to fit anything larger than a 27" tall by 10" wide tire on a 7" rim with perfect backspacing.
 
72bluNblu said:
How are you converting to BBP in the front?

How wide is the Dana 35 from mounting surface to mounting surface?

With the 73+ Mopar BBP brakes your 15x7’s with a 4.25” backspace will work with up to a 225/60/15 on most cars. You may also be able to run a 215/65/15, which is right at 26” tall. That’ll be the tallest you can pull off most likely, and it will be tight to the front corner. But if you’re using a different disk brake conversion that may not be accurate.

In the back I’d have to know how wide that Dana 35 is. The taller tires you linked originally will fit, but only if the axle is the right width for those cop wheels.
Click to expand...
if it's out of an XJ, it's 60.5" drum to drum. Everything I've seen, YJ and TJ wrangler axles are the same width (60.5"). I have an XJ one in my garage I was going to put in my duster, but it does limit tire size unless you go high offset wheels, so I'm looking at picking up a ranger 8.8, which is 58.5" wide.
 
4mulas said:
Dart seems tighter than a duster/dart sport and the best I could do with about 1/3-1/2" of clearance was a 215/65r/15 on my duster which is 26" tall. This on a 15x6" Cragar 5 spoke with about 3 3/8" backspacing and narrower than the cop wheels. To the OP, height is the main issue and you should listen to bluNblu here.

Also, to the OP, have you searched the endless threads on ‘what tire size’ can I use. All of this has been talked about at nauseum and you WILL find the answer there. In fact, just search bluNblu’s posts as he’s often one of the main contributors one these threads. The back of a dart sedan is definately tighter than of a duster/dart sport too. The planets would have to align to fit anything larger than a 27" tall by 10" wide tire on a 7" rim with perfect backspacing.
Click to expand...

The backspacing is pretty important, with a little extra backspacing you can get taller than 26”. And it’s also a height/width thing, the wider the tires are the less height you get. So some of the drag racers run quite a bit taller than 26”, but they’re super narrow tires that sit in from the edge of the fender.

The Dart clearance changed, in ‘72 the wheel opening got longer by almost 2”, with 1” being in the front. So a ‘72 dart can actually run a taller tire than a ‘71. When I swapped over from my ‘74 Duster fenders to ‘71 Dart fenders I found the front corner clearance on my 275/35/18’s was pretty close to the same, it would be more individual car specific than model specific I think. Ride height is also a HUGE factor for clearance at the front corner.
michiganpat said:
if it's out of an XJ, it's 60.5" drum to drum. Everything I've seen, YJ and TJ wrangler axles are the same width (60.5"). I have an XJ one in my garage I was going to put in my duster, but it does limit tire size unless you go high offset wheels, so I'm looking at picking up a ranger 8.8, which is 58.5" wide.
Click to expand...

Ok, so that’s great information. The 68-70 B-body rear I run is 60.125”. And when I had cop wheels (15x7” with a 4.25” backspace) I was totally maxed out to the quarter with a 225/60/15. So if the XJ is wider, even that little bit would mean a 225 would be out.
 
michiganpat said:
if it's out of an XJ, it's 60.5" drum to drum. Everything I've seen, YJ and TJ wrangler axles are the same width (60.5"). I have an XJ one in my garage I was going to put in my duster, but it does limit tire size unless you go high offset wheels, so I'm looking at picking up a ranger 8.8, which is 58.5" wide.
Click to expand...
I had to go look and remeasure to be sure- but my YJ is 58", wich is about a half inch narrower than the A body? Spring pads are identicle spot, only wrong side of the axle. Looks like I am going with the cooper 205s, so fitment should be pretty good.
 
Cruisingram said:
I had to go look and remeasure to be sure- but my YJ is 58", wich is about a half inch narrower than the A body? Spring pads are identicle spot, only wrong side of the axle. Looks like I am going with the cooper 205s, so fitment should be pretty good.
Click to expand...
the stock 7.25" in my duster is 57 1/8".

YJ being 58" opens up more possibilities, if I can find a rear from one. TJ's are easier to find. do you know if the TJ's are the same width as a YJ rear?
 
took a straight piece of wood and held it down with 2 lugnuts on each side to clear under the pumpkin/shock plates, measured with a tape measure, and subtracted the wood thickness.
 
michiganpat said:
the stock 7.25" in my duster is 57 1/8".

YJ being 58" opens up more possibilities, if I can find a rear from one. TJ's are easier to find. do you know if the TJ's are the same width as a YJ rear?
Click to expand...
I do not honestly know but can actually find out- I have 11 jeeps, and my TJ is my daily driver, but I would have to have the rear tires off it- I don't have a spare rear end for that laying around- I bought the jeep cheap because the 35 was wrecked, but got another one off Oahu, been driving it since 2017. I am pretty sure the TJs are wider.
 
michiganpat said:
took a straight piece of wood and held it down with 2 lugnuts on each side to clear under the pumpkin/shock plates, measured with a tape measure, and subtracted the wood thickness.
Click to expand...

What year and SBP or BBP 7.25”?
 
1976, small bolt pattern. original axle (our family has owned the car 33 years, 2nd owner, it turned over 50000 miles on the way home from buying it from the original owner, who was 83 in 1991)
 
Cruisingram said:
I do not honestly know but can actually find out- I have 11 jeeps, and my TJ is my daily driver, but I would have to have the rear tires off it- I don't have a spare rear end for that laying around- I bought the jeep cheap because the 35 was wrecked, but got another one off Oahu, been driving it since 2017. I am pretty sure the TJs are wider.
Click to expand...
everything I've found online it said the TJ's were 60.5" d-t-d, but I thought I also found that YJ and TJ axles were the same width....of course, I found enough stuff online saying XJ rears were 59.5" that I felt OK picking one up w/o checking first, but the D35 from one I picked up was 60.5". maybe there's a width difference between the danas 35's and corporate 8.25's in XJ's?
 
michiganpat said:
1976, small bolt pattern. original axle (our family has owned the car 33 years, 2nd owner, it turned over 50000 miles on the way home from buying it from the original owner, who was 83 in 1991)
Click to expand...

I believe you, I just wanted to confirm some of the details. Because the stock BBP 7.25's are absolutely not that width, the housings are narrower and the WMS-WMS is substantially narrower than even a SBP 8 3/4. Your measurement is the same as a SBP 8 3/4, but that would require a totally different housing width than the BBP 7.25's.

The BBP 7.25's are well documented at a WMS-WMS of 56-3/4", and a housing width of only 51.5". I had one myself and confirmed, and you can look up any number of wheel/tire threads with people fitting wheels that would fit an 8 3/4 with BBP axles not being able to run the same combination on a BBP 7.25 or 8.25 (same width as the BBP 7.25's).

I do not have good measurements for a SBP 7.25 of any year, haven't ever had one myself and most people don't bother to run big wheel/tire combos on them. Based on the wheel fits I have seen I suspected they were probably closer to SBP 8 3/4 width than the BBP 7.25's, but with body tolerances such as they are I wasn't 100%.
 
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