What size tires will fit on stock dart 15" wheels?

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1970dartcustom

1970dartcustom

of the Moore clan
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I need to know for my build (1970 dart) what size tires will fit without rubbing on the front and back (I know the back may be wider, but I need to know the widest for both). The rear springs/rear mounts have been moved in a little to add a little room in the back by the previous owner...
Also, I am probably gonna use Wheel Vintiques Rallyes 15x8 smallbolt that have a backspace of 4.625 offset +3mm in the back and the same wheels up front but 15x7 Rallyes with 4.25 backspace offset +6mm...
Will those fit (even the wheels)? What about tire size on those wheels?
Please help!:banghead:
 
I am having a lot of trouble finding out what tires will fit on my dart... I am going to order 15x8 rallyes for the back with 4.625 backspacing n +3mm offset, n 15x7's for front with 4.25 backspacing n +6mm offset...

I think these wheels will fit, as the rear end mounts/springs have been moved in a bit making a little more room for the rear wheels, but I am not sure exactly how much width was gained, as the previous owner was the one who did the alteration...

Can anyone tell me what will fit with these wheel sizes as far as tires go?
And am I off base with these wheel dimensions?:rolleyes:
 
Your rim dimensions aren't bad. The 15x7's in the front are about right on, you can go a little wider with a little more backspace but you can't do much more because of clearance on the 15" rims. With a 15x7 and a 4.25" backspace you should be able to run 225/60/15's, although you might have to make some minor adjustments on your fender to bumper braces.

In the back you might want some more backspace for 15x8's. The one's you suggested aren't "bad", but they may not get you to your maximum tire size. But that depends on your rear axle. If you have a 7.25" rear, the +3 offset will be pretty good and you could probably run 245/60/15's. If you have an 8 3/4, you might want to go with a +6 offset, even with the SBP. Again, that should let you run a 245/60/15.

You mention the springs may have been moved? How much? Is it a 3/4" mopar spring offset?

Generally speaking, a 245/60/15 should fit most Dart's of that era with the stock spring location with careful backspacing. 255/60/15's are possible on some cars, but others need some trimming on the quarter lips to make those work. With a 3/4" Mopar spring offset (which is really only a 1/2" spring offset, just like Dr. Diff's) you can run 255's on pretty much any '70+ Dart, and most cars can clear a 275 with that offset. To get more than that you'd need the 3" relocation and a mini-tub.
 
its an 8 3/4 rear, and I think it is a 3/4 inch mopar spring offset... what size in front will work without altering anything???
 
Honestly the 225/60/15 should work with the SBP front. I ran 225/60/15's on my '74 Duster on 15x7's with 4.25" of backspace, all I needed to do was adjust the front fender corner to bumper braces to their maximum. But with the SBP brakes you should have more room than I did with the '74 BBP disks, by a good 5/16" or so since that's about what's added to the track width with the later brakes.

Looking at that list I don't see a 225/60/15. The 215/65/15 would be closest, but keep in mind that although that tire is narrower, it's also taller. Again, it should work with that backspace, but every car is a little different. You shouldn't have to cut anything, but some adjustment might be necessary.
 
I would hazard a guess that 15" tires will fit.
 
on overall diameter on the list for the P245/60R15 it says 26.54.
on overall diameter on the list for the P215/65R15 it says 25.98.
So, that means that the rear tires will still be .56 higher than the front?
Also, going by each size's recommended rim width, it looks like 7's all around will still fit both...
So, you think this would work? Or am I missing something?
Thank you so much for your help...
 
Also, I'm running 383 with 8 3/4 and 727... lots of HP on those rear tires... will 8 inch tread be sufficient?
With 3/4 offset springs n such, you said +6mm offset was good which is what the 15x7's are...
the list says I can fit P255/60R15 on a 15x7 wheel and the tread width would be 8.2
 
1970dartcustom said:
on overall diameter on the list for the P245/60R15 it says 26.54.
on overall diameter on the list for the P215/65R15 it says 25.98.
So, that means that the rear tires will still be .56 higher than the front?
Also, going by each size's recommended rim width, it looks like 7's all around will still fit both...
So, you think this would work? Or am I missing something?
Thank you so much for your help...
Click to expand...

Yup, rear tires would be taller. Not an issue unless you're planning an autoX car or road races, but then you wouldn't be looking at 15" rims.

The 15x7's in the rear would be a better fit because of the +6 offset. With an 8 3/4 that would be the minimum I'd use, even with a SBP set up (BBP adds to the track width). But that's for a car with the stock spring locations.

1970dartcustom said:
Also, I'm running 383 with 8 3/4 and 727... lots of HP on those rear tires... will 8 inch tread be sufficient?
With 3/4 offset springs n such, you said +6mm offset was good which is what the 15x7's are...
the list says I can fit P255/60R15 on a 15x7 wheel and the tread width would be 8.2
Click to expand...

How much hp is "lots"?

The problem is that you can't fit a lot of tire back there. You probably need more, but you can only fit so much. On a Dart with the stock spring locations you only have about 11" of room between the quarter and the springs. If you figure a 1/2" of clearance on each side, now you're down to 10". If you consider that has to be the widest part of the tire (the section width) then you're down to an 8" wide tread, and that's with only a 1/2" of clearance all around.

What I said was that a +6 offset on a 15x7 was ok for a SBP 8 3/4 with the stock spring location. That's the minimum I'd use, and only because of the SBP axles. That's not considering the spring offset. You need to confirm if you have a spring offset. If you do, you can run bigger tires than the 245's, but you'll need more backspacing to do it.
 
I'm running 15x6 on the front with 205/65/15s and 15x8 0n the back with MT Sportsman S/R LT 26x10R15 on the back.Can't remember B/S what ever the standard is for 15x8 sbp.Picked them up at Summit not a special order.No rubbing issues,but it is pretty close on drivers side as my rear end isn't centered real well. The wheels Wheel Vintiqes steelies.If your using them and running dog dishes you'll have to grind the nubs that hold the cap.Not stamped deep enough and the caps pop off real easy.Unless they've changed their dies.
 
midlife89 said:
I'm running 15x6 on the front with 205/65/15s and 15x8 0n the back with MT Sportsman S/R LT 26x10R15 on the back.Can't remember B/S what ever the standard is for 15x8 sbp.Picked them up at Summit not a special order.No rubbing issues,but it is pretty close on drivers side as my rear end isn't centered real well. The wheels Wheel Vintiqes steelies.If your using them and running dog dishes you'll have to grind the nubs that hold the cap.Not stamped deep enough and the caps pop off real easy.Unless they've changed their dies.
Click to expand...

Backspacing is everything, and there is no "standard".

A quick look at Summit shows that they have the Wheel Vintiques steelies in SBP and 15x8 in both 4.5" and 4" backspacing. Of the two I'd wager you have the 4.5" backspacing, which isn't ideal but might work on some cars with the SBP. Of course, they also offer the sbp rallye rims in a 4.625" backspace, which would be better, and they certainly could have offered the steelies in that backspace at some point as well.
 
1970dartcustom said:
I need to know for my build (1970 dart) what size tires will fit without rubbing on the front and back (I know the back may be wider, but I need to know the widest for both). The rear springs/rear mounts have been moved in a little to add a little room in the back by the previous owner...
Also, I am probably gonna use Wheel Vintiques Rallyes 15x8 smallbolt that have a backspace of 4.625 offset +3mm in the back and the same wheels up front but 15x7 Rallyes with 4.25 backspace offset +6mm...
Will those fit (even the wheels)? What about tire size on those wheels?
Please help!:banghead:
Click to expand...

Depends on front wheel hubs (disc or drum brakes?). If you're running KH disk brakes, the front tread could be wider. The front track on a BBP A-body is wider with factory disks than with drum brakes.

I converted both the 72 Demon and 73 Mordor to factory BBP DBs and installed 15 inch wheels. The 72 has cop car wheels, 235/60 tires; the 73 got Magnum 500s, 205/60 . Specs on the wheels were the same 15x7 & 4¼ backspace. The 235s are tight with the wheel opening up front and the leaf spring (stock loc.) in the rear. No problem with bumps going straight. Lean it over in a hard turn and the fronts sometimes catch the inside of the fender (not the lip) on a bumpy turn. Think I'll drop to a 225/60 when it comes time to replace the 235s. The 205s are no problem anywhere.

Hope the info is helpful.
 
so i think I can fit 4.5 backspace steely 15x8's with 255/60r15's on my 1970 dart with a 3/4 inch spring offset on an small bolt 8 3/4 rear end set up... Right?
and upfront, with smallbolt disk brakes, I can fit the 15x7's with 4 inch backspace steelies with 215/65/r15's??? Or can I go wider than that???
I am sorry, I am having trouble with this, thanks for your help...
 
I had a pair of 215/65/15 laying around and I tried them but had rubbing issues fronts are 15x6 w/3.75 bs. 255s might be a little tall to fit,I guess it depends on how high your rear of your car sits,mine is pretty much stock ride height.
 
here are 225/60-15 on a 15x7 wheel and 4 1/2" backspace. if i did it again i'd go 4 3/4 backspace..

*NOTE: front is 73-up disc brakes. rear is stock abody 8 3/4 housing using big car large bolt pattern axles and brakes.



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Is your car still factory SBP or converted to LBP and disc's up front? As others have said this will affect what offset you need to buy. In the end a rim, large square and tape measure help a lot or a Percy's wheel rite.
 
dano said:
Is your car still factory SBP or converted to LBP and disc's up front? As others have said this will affect what offset you need to buy. In the end a rim, large square and tape measure help a lot or a Percy's wheel rite.
Click to expand...

I agree with Dano. Can you buy a single (or a pair) 15 X 7 wheel and bolt it on the rear without a tire. Measure off that wheel and draw a diagram showing how much clearance there is to the spring (front and rear of the spring ) and to the outer wheel lip and inner fender. Measure both sides of the car! They probably will not be equal. Expect up to 1/2" difference per Mopar Performance.

I do not have personal experience with early 70's Darts but it looks like Joe's car is what you have. Pat attention to what he says. Looking at his pics, you have an advantage because of your spring offset. That's good but look past the spring to the top of the tire and notice the clearance to the inner wheel well. Not much.

Fact...Factory Chrysler 15 X 7 wheels have 4-1/4" BS, no matter the style. These typically fit.
A good rule of thumb is to keep wheel width within 1/2" of tread width to get good tire performance. If you want 8" tread, an 8" wheel is perfect. Do what you can to use the 8" wheel even if it means ordering a custom offset. I don't know how that affects trim ring fitment on Rallyes.
My opinion is that a 215-65 on a 15 X 7 front wheel may be a little tall without trimming the lower fender lip. A 215-60 is a little shorter and gives more clearance. As mentioned already, it's not just the width, the diameter is equally important.

P.S. Nice looking car Joe.
P.P.S. poly bushings in the rear shackles will take out some of the rear side-to-side movement if your tires are close to the body.
 
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