10" on a stock 73 Duster?

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Hi folks,

Could I run a 295x50x15 rear tire on a Cragar V5 15X10" on my stock 73 Duster 340 without any mods?

Cheers.
Without a lot more info , my guess would be.... probably not!
First thing we would need to know : what backspace on the wheels? (and i dont mean that damn "offset"bs)
Next, 8 1/4 or 8 3/4. (Large or small bolt pattern)
Next, how much ridiculous seventies ***-way-up-in-the-air stance are you willing to put up with?
 
I did on mine it's a 74 but I crawled underneath there, with a tape measure, to check it out first, and it has super stock Springs. Billet Specialties wheels also
 
Without a lot more info , my guess would be.... probably not!
First thing we would need to know : what backspace on the wheels? (and i dont mean that damn "offset"bs)
Next, 8 1/4 or 8 3/4. (Large or small bolt pattern)
Next, how much ridiculous seventies ***-way-up-in-the-air stance are you willing to put up with?

The Cragar info says 3.75” backspace.
I believe I have a 8 1/4” and small bolt pattern.
I like rake.
 
Okay. To fit a ten under the fender of most a or B mopars, you would need at least a five inch backspace, 5.5 would be better.
So, those wheels with that tire will stick outside the fender a couple inches. So to keep from cutting them up with your fender, plan on jacking up the rear of the car about four or five inches from where it likely is now.
In other words, don't. My opinion only.
 
Oh , and for the rear end....
An 8 3/4 will have a smooth backside, and a small bolt pattern
An 8 1/4 will have a bolt-on rear cover, and a large bolt pattern.
And I'll bet that cragar is a large pattern wheel only.
 
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'73 with 295/50R15's, 15" Cragars 10" wide (stock backspace whatever that is), ESPO +2" springs in stock position. About 1/2" clearance inside from leaf springs . 8 3/4 BBP.
 
View attachment 1716058127'73 with 295/50R15's, 15" Cragars 10" wide (stock backspace whatever that is), ESPO +2" springs in stock position. About 1/2" clearance inside from leaf springs . 8 3/4 BBP.
How far do they stick the tire past the wheel well? Reason I'm asking is because I've got a big bolt pattern 8 and 3/4 in my 74 with 295s on it with an 8-in wheel
 
Can't put a tape measure on it right now, but it's basically the sidewalls that poke out on those 50's. Not a ton, and no, the *** end isn't 5" up in the air. Hope these are helpful.




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Duster in Driveway.JPG
 
This walk around video gives you a pretty decent view:


Can't put a tape measure on it right now, but it's basically the sidewalls that poke out on those 50's. Not a ton, and no, the *** end isn't 5" up in the air. Hope these are helpful.




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Those stick out about the same as mine..nine... I've got quite a bit of room in the leaf springs still those rims are 320 bucks a piece they came off my buddies 71 340 4spd #s Cuda, as soon as they went on. Backset off by 1/2"....
 
I have a 69Barracuda fb which has about the same tubs as the Duster. It is lowered to be level at the rockers, with the lowest part of the K-member at 6 inches from the road. It has the offset rear spring hangers, which run about flush with inner walls of the tubs.
In this configuration, 325/50-15's on 10s still allow normal straight-line driving. But I can't corner at much over 20/25 mph as the body slides over to rub on a big old lump, that each wheel well has in it, that defys my every effort to pound it out. The lump is smooth so it's not cutting the sidewall.
But the 295/50-15s (BFGs or Cobras) on 10s do not rub, and I can drive the nuts off the car with no issues.
Interesting factoid, my 295s on 10s, IIRC, measure a tic over 13inches after mounting, which is actually 330mm, or there abouts.
The branded size on any Passenger car radial is determined on a checking rim that is 70% of the branded size; so for a 295, 70% is 206.5, which is 8.13, so an 8 incher would be used.
So then, a 295 on an 8 is supposed to be 295 +/- 5mm. But on a 10inch wide rim, which IMO is still too narrow, that is 2 inches wider; this 295 is gonna be less than 50mm/more than 25mm , wider. At a measured 330, this is 35mm wider so 1.4inches. So you gotta figure this into your equation when ordering your custom-backspace wheels.
Furthermore; generally .5 is the recommended minimum sidewall clearance.
At my lowered rideheight with nearly flat springs that each of which has an extra full-length main leaf, and mounted on Poly bushings, body side-shift is minimal. I can get away with just .25 inch. So you gotta figure that in as well.
I can't give you a backspace cuz my rear end has been narrowed to fit a standard 4.5" backspace wheel. Please note, at the tread, and about 2 inches down over the sidewalls, these 295s are still inside the wells, both sides. This the only legal way in Manitoba, to run them without flares. If a cop pulls me over, it won't be for tires sticking out too far.
 
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Thanks for all the info guys, I think I may be more confused than before! ahaha.
I currently have the stock 14" Rally wheels, are they small bolt pattern?
 
up here, 1973 was a transition year.
>if the car came with slanty, it got the small bolt pattern
>If the car came with a V8 and disc brakes it got the 4.5bc
>If the car came with a V8 and all drums....... IDK

If your car came with Rally Wheels, it's east to tell;
> the early sbc Rallys had a small centercap that resembled a Mexican Sombrero.
> The later BBP Rallys had a bigger and IMO, more attractive cap that was notched around the lugnuts.
 
Okay, V8 and disc is what I have, so 4.5bc. So it looks like I could use the Cragar V5's as they are 5 x 4.5 in. Bolt Circle?
Could I run the following without any mods?

225/60R15’s on the front 15x7 rim
275/60R15’s on the back 15x7 rim
Both have 3.75" Backspace.
 
Okay, V8 and disc is what I have,
Yeah but was it born with those?
that 73 is now 50 years old, a lot couldda happened since then.
If the 340 is original, my guess is that the car is set up with the 4.5BC : but it's just a guess.
Notta chance would I run 275/60s on 7s on the street. Rule of thumb, back in the day, was to run a rim that is at least as wide as the tread. But with radials, that's a bit shy. 275s need a minimum 8.5 to survive on the street.
If you install them on 7's they will just burn off the centers. If you reduce the tire pressure until they wear a lil better, you could be down to in the range of 20/24psi. Have you ever run 15x28" tall tires at 20/24 psi on the street With a jacked up azzend?
Warning;
slow down for the turns.....
IMO that's a bad idea.
Jack up the car, remove a rear wheel, set a square against the drum tight to it, then measure from the drum to whatever is closest to it, in both lateral directions. Usually the outer wheelhouse lip will be closest, but it could be the spring.Then you do a lil math. If it's really close, then you better also check the other side; the axle could have dropped in, NOT centered, right from the factory.
Another option is to mount any 15" rim, measure it up, then correct for the known backspace of the checking rim, then order what the math says will work, commensurate with the chosen tire width; ie don't try to put a 275/60-15 on a 7"wheel, lol.

I for one, won't commit to saying anything will or will not fit, cuz if it doesn't, It's you who pays the price; and I will be less popular with you than if I just don't commit, lol..
 
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Yeah but was it born with those?
that 73 is now 50 years old, a lot couldda happened since then.
If the 340 is original, my guess is that the car is set up with the 4.5BC : but it's just a guess.
Notta chance would I run 275/60s on 7s on the street. Rule of thumb, back in the day, was to run a rim that is at least as wide as the tread. But with radials, that's a bit shy. 275s need a minimum 8.5 to survive on the street.
If you install them on 7's they will just burn off the centers. If you reduce the tire pressure until they wear a lil better, you could be down to in the range of 20/24psi. Have you ever run 15x28" tall tires at 20/24 psi on the street With a jacked up azzend?
Warning;
slow down for the turns.....
IMO that's a bad idea.
Jack up the car, remove a rear wheel, set a square against the drum tight to it, then measure from the drum to whatever is closest to it, in both lateral directions. Usually the outer wheelhouse lip will be closest, but it could be the spring.Then you do a lil math. If it's really close, then you better also check the other side; the axle could have dropped in, NOT centered, right from the factory.
Another option is to mount any 15" rim, measure it up, then correct for the known backspace of the checking rim, then order what the math says will work, commensurate with the chosen tire width; ie don't try to put a 275/60-15 on a 7"wheel, lol.

I for one, won't commit to saying anything will or will not fit, cuz if it doesn't, It's you who pays the price; and I will be less popular with you than if I just don't commit, lol..
I'm the same way AJ I take a framing square, and start checking it out with a tape on my back now if you've got an old tire and rim that helps even more! And, Yes Sir, note (in other posts, even this one) I say " what works on my car".... I may give a few measurements, I tell you what Rim I've got, I definitely always tell you "I have super stock Springs", but that car, being a 74 (w/ 8 3/4"), who knows what actual width it is who knows what it came out of I'm not too worried about checking it out cuz it works for my needs all I can do is try to help people out with some ideas
 
I keep hearing folks talking about SS springs. I know they are better for traction but do they give a guy more room for larger tires as well?
 
I keep hearing folks talking about SS springs. I know they are better for traction but do they give a guy more room for larger tires as well?
Only in height. Not width. With the fender moved up, a wider tire can be used. But it wider can be used. The tire size is only approx 26-3/4 in diameter but they’re 12 - 12-1/4 inches wide depending on who makes them. They’re all close in size but not the same.

The wheel lip is the biggest item to avoid. Not so much the springs though that can be easy to come in contact with. The SS springs move the body up a good bit in order to fit a taller tire. A Duster holds a 28 inch diameter wheel without hitting the car body up front. There’s a lot of room behind the tire. If you kept the tire narrow like a stock tire, you can really go up in diameter.

The wider tire can be a problem if the springs do not hold the car up high enough. The wheel lip can touch the top of the tire. I don’t think this is a problem with the SS springs.

I just installed a set of 275/60/15 Nitto 555 on a 8.5 wide wheel. They fit right in there with stock springs on a ‘74 Duster, 8-1/4 rear.
Their 27.99 diameter and section width of 10.98.
See below;
Nitto Tires 107830 Nitto NT 555 RII Tires | Summit Racing
 
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up here, 1973 was a transition year.
>if the car came with slanty, it got the small bolt pattern
>If the car came with a V8 and disc brakes it got the 4.5bc
>If the car came with a V8 and all drums....... IDK

If your car came with Rally Wheels, it's east to tell;
> the early sbc Rallys had a small centercap that resembled a Mexican Sombrero.
> The later BBP Rallys had a bigger and IMO, more attractive cap that was notched around the lugnuts.

A body 73 to 76 - if the car had 4 drums, it was 4" bolt pattern. 73 to 76 with disc, 4.5" bolt pattern.
 
just to re-itterate;
I know for a fact that 295/50-15s on 10s will fit into/inside/between the inner and outer walls of the tubs, at almost any ride-height. I say almost because there is a bulge out near the top of the wheel opening, that can contact the outer sidewall when the tire, on jounce, moves up into that area . So I mean if you intend to jump your car, or if your springs allow a lotta body-roll, you gotta keep that in mind....... lol.

But on the factory-width A-body rear-end,
> it will take a custom backspace wheel that IMO looks poorly because the spider is out so far; Here's a guess/6.5". AND
> more than likely, the springs will have to be moved inboard, which is really not that big a deal, and when you do it, you can simultaneously correct your pinion-angle, and move the axle back a tad. AND
on my Barracuda, I had to trim the outer wheel house lip. Actually, I just folded it up a lil
>So then, to use any common 10" Period wheel, which mostly come in a nice 4.5bs, the rear end has to be narrowed some 2 inches per side, AND the springs moved. After I did this, the tubs even accepted 325/50-15s
I can almost guarantee you, that after you do this, you will never be sorry. Especially if you have a 360 or a stout 340, which will just burn up 275s at the rate of one pair every summer, if they even make it that far.
Furthermore, when you are powersliding on city streets, 275s do not have enough sideways rubber for a controlled slide, AND they don't have enough sideways rubber to brake if you lift throttle. Thus, there is an excellent chance that you will spin out, if you do stoopid stuff. In traffic, this is more than just embarrassing. Whereas:
295/50-15 BFG/Cobras are very predictable below 30/35 mph. In mid-slide, if I see it going bad, I just lift throttle and let the tires bite. The car will lurch oddly then head in whatever direction the front wheels are pointing, so be alert. In worst-case, I lock everything up, and the car comes to a nice sideways sliding stop.
But if there is no saving it, I crank the steering wheel the wrong way and mash the gas, which swings the back end around until the car is pointing to where I want it to go.
Here's the deal:
with 275/60s or with 275/50s
Everything happens faster, and somewhat unpredictably, and as a 50/55 year old at the time, sometimes (many times), the car was no longer on the road, when it came to a stop. I cannot count the number of times. To say this was frustrating, doesn't even come close.
So here's what I spent;
>For the stock-width rear end;
245s on 8s, 255s on 8s, 275s/60 on 8.5s, 275/50 on she same 8.5s which were not wide enough, so I went back to 275/60s on the 8.5s; and a few broken or bent wheels; Ok that's 5 summers.
> after I narrowed the rear end:
295/50-15s on 10s, and the offset spring perches.
These tires have traction only the first few weeks, then she's into the hard stuff. After that they will slide very nice and they'll go for Three summers in total, two if you lite 'em all the time. I keep a spare set in my shop at all times.
> As you can see, narrowing the rear, in the long run was not only the right thing to do, but was also waaaaay cheaper, and above all; Safer.
BTWs,
>with discs on the front/ 10" drums on the rear, , after you do this, you can get rid of the brake-proportioning valve, and finally have some decent stopping power. and
> as your rear ride height goes up, your car will experience more body roll in the turns. This means that on one side of the car, the body will tend to move towards the inner wall, while the other side will simultaneously tend to move towards the wheel lip. If you run SS springs, your azzend will be high enough that this will not be an issue. But be warned, not everyone likes the ride of those babies. and, they will shift weight OFF the rear tires, towards the front, which even with the 340 T-bars, you will feel.

Ok, bottom line;
I'm NOT telling you that you have to narrow your rear end.
Maybe you don't drive like I do.
What I'm saying is that;
if you do drive like I do, then
for optimum tire life, and
a safe driving experience,
the best things I ever did, was to bite the bullet and narrow the rear-end, AND move the springs.

Happy HotRodding.
 
Awesome info AJ, I appreciate your time on my question. I have decided not to go the 10” route and I have ordered a set of 8x15 and a set of 7x15 Cragar V5’s from Summit. 5x4.5.

I am thinking 275/60 on the rear and 205/70 on the front. I think that should fill in the gaps quite nicely, so to speak.
 
Awesome info AJ, I appreciate your time on my question. I have decided not to go the 10” route and I have ordered a set of 8x15 and a set of 7x15 Cragar V5’s from Summit. 5x4.5.

I am thinking 275/60 on the rear and 205/70 on the front. I think that should fill in the gaps quite nicely, so to speak.
I ran 205 /80s front of my 66 Satellite. Dug those tires I couldn't find that size for my Duster so I ended up with 215/ 60/15
 
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