245/60/15's on 15X8 rims

[68 Coronet RT]

Yeah that's about what stock should be.

255's are out. You only have 10.75" to work with then on the "tight" side. Even assuming a 255/60/15 is only a 10" section width when it's on a 15x7" that isn't going to work. If you gave the quarter a 1/2" of clearance you'd only have a 1/4" to the springs, and that's not enough.

I would say a 245/60/15 is as big as you can go unless you trim the quarter lip or install 1/2" spring offsets. And 15x7's with 4.25" of backspace won't work. The math to center everything up on the side with less clearance gives you a 15x7 with 4.65" of backspace, so, what I would probably do is order a set of 15x7's with a 4.75" backspace and a set of 1/8" spacers. It will be right about 3/8" to the springs with that backspace, you can play with the 1/8" spacers if it's too tight on the springs.

Thanks for the info, kinda stuck between a rock and a hard place. I have had my rims ( 15X7 ) on order since the beginning of December and they are due to be shipped any day. If I special order some with more back space I might have to wait till the end of June to get them, that's not an option right now. Going to have to live with it. Most likely go with a 235/60/15 really not much difference in width, but would really like the 245's oh well !!

 

[Wayne Brown]

On your Coronet? They can handle 15x8's easy and the 255's work well on 8" wide wheels/ I have 255's on 7" wide and they work ok. View attachment 1715147175 View attachment 1715147177

Not sure who sees what when I send this. I'm upgrading pretty much everything on '71 Swinger. Wheels next on the docket. Went from 14 X 4 BP wheels to now (needs to be 15" wheels) because if disc brake upgrades. I'm getting regular ole' steel rims for now $$$$$ but would like to put a wider if not the widest tire in the rear. New 8 3/4 rear coming with wilwood disc conversion on rear. Front is the package from Performance Online. The ? is how wide should the 15 X ?? steel rim be? Going with the 15 X5 or 15X6 for a skinnier tire look in front. How wide rim?, How large Backspacing?, for a good wide tire on the rear. And..... Any Boneyard leads since this is not my final answer? aka when I hit Lottery will have customs done....

 

[Wayne Brown]

..The attachment photo of the blue dart with the rallye wheels is the look I wanted to start out with but the 3" center bore needed for the new front rotors seems to be an issue View attachment 1715147175. Taking things slow but I really don't need to spend the same money twice...so I am going to go with steel for now.

 

[rrvolare]

255-60-15 WILL FIT .... you need to measure correctly to get the proper clearance ............Been there and done it with SBP centers welded in 15 inch rings ..... so why would they not fit with BBP 15 X7 wheels ????

 

[72bluNblu]

255-60-15 WILL FIT .... you need to measure correctly to get the proper clearance ............Been there and done it with SBP centers welded in 15 inch rings ..... so why would they not fit with BBP 15 X7 wheels ????

Not all Darts have enough space for 255/60/15's. They will fit some Darts, not others. I've seen the measurements from cars that don't have enough room to do it without cutting or rolling something. The dimensions and measurements are right in this thread, the math doesn't work. You say to measure to get proper clearance, but if the measurements come up short you just can't get the clearance unless you start cutting. How do you figure you can get the clearance when the measurements tell you there isn't enough space?

These cars were not all the same from the factory, I've seen differences in the quarter measurements that are different by almost a 1/2". Some cars have enough room for 255's, some do not.

 

[68 Coronet RT]

Not all Darts have enough space for 255/60/15's. They will fit some Darts, not others. I've seen the measurements from cars that don't have enough room to do it without cutting or rolling something. The dimensions and measurements are right in this thread, the math doesn't work. You say to measure to get proper clearance, but if the measurements come up short you just can't get the clearance unless you start cutting. How do you figure you can get the clearance when the measurements tell you there isn't enough space?

These cars were not all the same from the factory, I've seen differences in the quarter measurements that are different by almost a 1/2". Some cars have enough room for 255's, some do not.

72bluNblu
Made some adjustments to my Dart in hoping to get the 255/60/15 on a 15X7 rim. From the face of the drum to the quarter panel lip I now have 5 inches on each side and 6 inches to the springs on each side. I'm also in the process of installing Mopar Performance Super Stock Springs to raise the rear end 2 inches. Hoping this works.

 

[toolmanmike]

I noticed you mentioned you are switching rears with disc brakes. I would recommend that you install the rear end first and measure for the correct width and offset wheels. The disc brake rear may have different dimensions than the 8 3/4 in my blue Swinger. Better to be safe than sorry.

 

[rrvolare]

I have yet to hear a 15 X 7 inch wheel will not fit in the rear with correct off set... and i know that 255 60 15 tires fit ....

 

[68 Coronet RT]

I have yet to hear a 15 X 7 inch wheel will not fit in the rear with correct off set... and i know that 255 60 15 tires fit ....

The rims I'm looking ( 15X7 ) at have a 4.25 backspacing

 

[72bluNblu]

I have yet to hear a 15 X 7 inch wheel will not fit in the rear with correct off set... and i know that 255 60 15 tires fit ....

Of course a 15x7 will fit with the right backspacing. Not arguing that at all. What tire will fit is a different story.

As far as what you know about 255's, you know they fit your car. And a few others no doubt, there's a few in this thread. But that doesn't mean they'll fit every car, because they're not all the same. Here's some folks that have encountered cars that either couldn't fit 255's, or had to trim the quarter lip to do it. On 15x7's too.

My old setup on my '69 was 255/60-15 on back. Fit like a glove on my car. My buddy tried them on his '69 and they wouldn't fit. Not even close. I'm not sure how some guys are getting 275s on their car but it seems to work for them so...

I am running 255/60R15's on 7" steelies with 4.5" backspacing. Driver's side fit perfectly...passengers side rubs a little bit so I had to trim about 1/8" off the inner fender lip. Fronts are 205/65R15 on 6" steelies

On my Dart, I was able to fit a 245/60/15 on a 15x7 with a 4 1/4 inch back space. 1969 Dart.8 3/4 rear. I can just fit a finger between the tire and the leaf spring. And between the tire and the fender.

On the white car in my avatar, I had 245/60R-15 on 7" rims and I was 1/8" clearance on the quarters. I had used Moser axles when I switched over to the 5x4.5 lug pattern.

Thanks for all the Help guys! I got my wheels and tires on and it looks great. I had to shave 1/2" of my inner fender lip and put ESPO +2 springs on and I have plenty of clearance!
For anyone else having the issues I was see below for sizes.

rear- 15x8"mopar cop wheels with 4.5" BS wrapped with a 255x60x15 BFG
Front 15x7"Mopar cop wheels with 4.25"BS wrapped with a 215x65x15 BFG

Bought my wheels from Summit Racing because they had these sizes in stock.

These are all from this one thread 1969 dart wheel and tire size?

1/8" clearance to the quarter won't work, it WILL rub eventually. One finger width isn't enough either, unless someone's got a 1/2" thick finger. And then there's the "fits on one side, rubs on the other" issue. These cars are not all the same, not even from one side to the other. Axle housings are sometimes offset by a 1/4", wheel wells/quarters can be off by as much as a 1/2", even side to side.

The rims I'm looking ( 15X7 ) at have a 4.25 backspacing

Like I said earlier, that's not enough. 5" to the quarter, 6" to the springs. A 15x7" rim is 8" wide outside lip to outside lip. A 255/60/15 has a section width of 10.2", a 245 is 9.8". So that means you have 1.1" of tire overhang with a 255, and .9" with a 245.

4.25" of backspace means 3.75" of front space. So, 3.75 +1.1" is 4.85". That means you'd have .15" of clearance to the quarter, and that's not nearly enough. It would also mean you have .65" to the springs, which is plenty. Even if you assume the 255's section is squeezed down on a 15x7" and call it 1" of overhang you still don't have enough room. Even with a 245 you'd probably not get away with the 4.25" of backspace, it might clear most of the time but if you did any kind of serious driving or loaded up the trunk or back seat I bet it would rub.

What you want, if you want to run 255's, is a 15x7" with 4.5" of backspace. That's the ticket on your car with BBP axles and brakes. Even for a 245 that would be what you really wanted for backspace.

 

[toolmanmike]

Of course a 15x7 will fit with the right backspacing. Not arguing that at all. What tire will fit is a different story.

As far as what you know about 255's, you know they fit your car. And a few others no doubt, there's a few in this thread. But that doesn't mean they'll fit every car, because they're not all the same. Here's some folks that have encountered cars that either couldn't fit 255's, or had to trim the quarter lip to do it. On 15x7's too.











These are all from this one thread 1969 dart wheel and tire size?

1/8" clearance to the quarter won't work, it WILL rub eventually. One finger width isn't enough either, unless someone's got a 1/2" thick finger. And then there's the "fits on one side, rubs on the other" issue. These cars are not all the same, not even from one side to the other. Axle housings are sometimes offset by a 1/4", wheel wells/quarters can be off by as much as a 1/2", even side to side.



Like I said earlier, that's not enough. 5" to the quarter, 6" to the springs. A 15x7" rim is 8" wide outside lip to outside lip. A 255/60/15 has a section width of 10.2", a 245 is 9.8". So that means you have 1.1" of tire overhang with a 255, and .9" with a 245.

4.25" of backspace means 3.75" of front space. So, 3.75 +1.1" is 4.85". That means you'd have .15" of clearance to the quarter, and that's not nearly enough. It would also mean you have .65" to the springs, which is plenty. Even if you assume the 255's section is squeezed down on a 15x7" and call it 1" of overhang you still don't have enough room. Even with a 245 you'd probably not get away with the 4.25" of backspace, it might clear most of the time but if you did any kind of serious driving or loaded up the trunk or back seat I bet it would rub.

What you want, if you want to run 255's, is a 15x7" with 4.5" of backspace. That's the ticket on your car with BBP axles and brakes. Even for a 245 that would be what you really wanted for backspace.

Right you are! My passenger side is tight. I can't slide my finger tips through the gap between the tire and the 1/4. The Drivers side is not a problem. If I had weak saggy springs I would be cutting tires or grinding clearance.

 

[rrvolare]

Correct... if you had WEAK SAGGY springs there will be an issue .. and why are we sticking with 4.5 backspace ... you can get different back spacing .. like i said with CORRECT back space ... 255-60-15 will fit

 

[toolmanmike]

I have 4.25 backspace. A 1/4" isn't much but it might be rubbing or not. I have a little room on the inside. The 4.25 b/s was a 'off the shelf' wheel.

 

[72bluNblu]

Correct... if you had WEAK SAGGY springs there will be an issue .. and why are we sticking with 4.5 backspace ... you can get different back spacing .. like i said with CORRECT back space ... 255-60-15 will fit

Man I'm tired of this. No, with the "correct" backspace you still can't fit 255's on every Dart. That's just BS. Yes, with the correct backspace you can fit 255's on some Dart's. Maybe even most Dart's. But not all Darts. Capsmash all you want, it's just not true. I posted examples of guys that had rubbing, that had to cut and roll the quarter lip on one or more sides of the car. The examples I posted also showed they had the right backspace. Just do a search, there's posts all over this board of guys that can't fit more than a 245 on their Dart even with the correct backspacing. There just isn't enough room on every Dart that ever left the factory. Some have shifted axles, some have body tolerance discrepancies, it's just how these cars were built.

Why am I recommending the OP use a 4.5" backspace? Well, do the math. 4.5" backspace, 1.1" of tire overhang, that's 5.6". He has 6" to the springs. That only gives him .4" of clearance. Now let's do the front space. 3.5" of front space, 1.1" of tire, 4.6". Why, that's .4" of clearance. It's almost like I meant to center the wheel in the wheel well! And realistically, the section width will be squeezed down slightly on a 15x7", so he'll have the 1.2" of clearance he needs on both sides.

Can you run the clearance to the springs tighter than that? Sure. You could go with 4.625" of backspace if you wanted, you might or might not need a small spacer. Probably not. If you went 4.75" you'd need a spacer, but if you were thinking of going disk brakes later and don't want to buy new rims that might not be a bad idea, run the spacers until you do the disk conversion, most of those add about a 1/4" to the track per side.

But the "correct" backspace for the measurements that 68 Coronet RT is giving me? I'd say it's 4.5". I might go 4.625" for custom rims, but I like to err on the side of too much backspace and correct with a spacer if I have to. But some folks don't like messing with spacers.

I have 4.25 backspace. A 1/4" isn't much but it might be rubbing or not. I have a little room on the inside. The 4.25 b/s was a 'off the shelf' wheel.View attachment 1715155764

Right, but you have SBP axles and brakes. The BBP conversion widens the track width about 5/16" per side (smidge more), from 57 1/8" drum to drum to about 57 13/16". So actually, the extra 1/4" of backspace on the wheels for the BBP axles and brakes we're talking about should give a touch more clearance than you have.

 

[dogbreath]

how about the summit wheel vintiques ralley wheels in 15 x 8 with the 4.625 backspacing.

 

[toolmanmike]

how about the summit wheel vintiques ralley wheels in 15 x 8 with the 4.625 backspacing.

15x7's just barely fit.

 

[68 Coronet RT]

how about the summit wheel vintiques ralley wheels in 15 x 8 with the 4.625 backspacing.

All ready purchased the Wheel Vintiques mag 500's 15X7 4.25 backspace not here yet, installing the Mopar Performance Super Stock springs and looks like I'm going to buy 245/60/15's for the rear. I would like the 255's but just not worth the hassle of buying the offset shackle kit for less than a half inch tread.

 

[72bluNblu]

how about the summit wheel vintiques ralley wheels in 15 x 8 with the 4.625 backspacing.

15x7's just barely fit.

15x8's will fit, but probably not with 255's. At least not if you're counting on that little bit of sidewall squeeze you'd get by putting them on 15x7's. You could probably run them with 245/60/15's, but, those fit just fine on 15x7's. A 7" rim is actually the "measuring rim" for the factory specs listed for a 245/60/15. So there isn't much of a point.

Also, you have to pay attention to what you're doing with the backspace. A 15x7" with 4.625" of backspace has an offset of +16. A 15x8 with a 4.625" backspace has an offset of +3. What that means is that you moved the centerline of the rim a full 1/2" outboard with the 15x8 compared to the 15x7. If you want the centerline of the wheel to end up in the same place, the 15x8 would need a 5.125" backspace. Of course it gets more complicated if you start considering whether or not the section width is getting squeezed down or stretched out.

All ready purchased the Wheel Vintiques mag 500's 15X7 4.25 backspace not here yet, installing the Mopar Performance Super Stock springs and looks like I'm going to buy 245/60/15's for the rear. I would like the 255's but just not worth the hassle of buying the offset shackle kit for less than a half inch tread.

It's still going to be very tight to the quarters with the measurements you have.

According to the math, even with 245's on 15x7's and 4.25" of backspace you're only going to have like .35" to the quarter lip if you've got 5" from quarter lip to wheel mount. That's not much, even with super stock springs. But with stiff springs and the raised rear end height it might work. The math is all 2D, I'm assuming that the widest part of the tire's section width is at the spot where you measured- the worst case scenario. If you raise the quarter lip above the widest part of the section width, how much clearance you actually have depends on how much spring travel you get running around on the road.

 

[roccodart440]

It doesn't seem like a big deal to me to have to trim the lip or roll the quarter. I always kind of took that as a given.

One thing worth mentioning is you can't roll the quarter lips if you run the factory wheel well trim. You have to trim.

 

[cpearce]

My 69 Swinger with all new springs, bushings, hangers, shackles, and shocks will not take a 255 60r15. I have a stock width sbp 8 3/4. I had 245 60 r15 on 15x8 with 4.5 BS and it was very tight and often rubbed on passenger side wheel lip. I then switched to 235 70r15 which are also very tight. I currently have 15x7 with 4.25BS being painted. This car has never been wrecked or bent it just has tight wheelwells. Blanket statements like "THIS WILL FIT YOUR CAR" are risky. Our 71 Scamp has more room than my 69 Dart, also has sbp 8 3/4.

 

[68 Coronet RT]

My 69 Swinger with all new springs, bushings, hangers, shackles, and shocks will not take a 255 60r15. I have a stock width sbp 8 3/4. I had 245 60 r15 on 15x8 with 4.5 BS and it was very tight and often rubbed on passenger side wheel lip. I then switched to 235 70r15 which are also very tight. I currently have 15x7 with 4.25BS being painted. This car has never been wrecked or bent it just has tight wheelwells. Blanket statements like "THIS WILL FIT YOUR CAR" are risky. Our 71 Scamp has more room than my 69 Dart, also has sbp 8 3/4.

Did you mount the 235/70/15's on the 15x8 rims ? I thought about the 15X8 but there just isn't enough room for the 245's. I'm installing the Super Stock springs as soon as my new rear hangers get here and with the height they will give me the widest part of the tire should be below my wheel lip

 

[cpearce]

Did you mount the 235/70/15's on the 15x8 rims ? I thought about the 15X8 but there just isn't enough room for the 245's. I'm installing the Super Stock springs as soon as my new rear hangers get here and with the height they will give me the widest part of the tire should be below my wheel lip

Yes, here is a photo of 235 70r15 on 15x8 wheel.

 

[68 Coronet RT]

Yes, here is a photo of 235 70r15 on 15x8 wheel.
View attachment 1715156049

Are you running the stock leaf springs ? I wanted the 15X8's but there just isn't enough room. I really won't know how much room I have until my spring hangers get here and I get it together I also have air shocks so I can get a little more out of it. I'm hoping the springs will raise it almost to the top of the tire which should give me the clearance I need.

 

[cpearce]

Are you running the stock leaf springs ? I wanted the 15X8's but there just isn't enough room. I really won't know how much room I have until my spring hangers get here and I get it together I also have air shocks so I can get a little more out of it. I'm hoping the springs will raise it almost to the top of the tire which should give me the clearance I need.

Stock height springs from 383 GTS, new though.

 

[roccodart440]

@cpearce You mind telling us why you wouldn't want to put a 245 or a 255 on an 8" wheel?

Considering the minimum recommended wheel width for a 255 is 8" (max 9.5) and for a 245 it runs from a minimum 7" to a max 8.5", you must know something the engineering world does not?