I don't want to re-invent the wheel

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Coyote Jack

Coyote Jack

Member #55, I'm old
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I am going to 15 inch wheels all around on my Demon. I am pretty sure with a spring relocation, ( which I have had for a few years and never got around to), that I can go with a 15x10 with 5.5 inch back spacing. It's the fronts where I am stumped. I want to run a tire with about a 185 to 205 width. What will work in a 15 inch wheel as far as a width and backspacing for the front on my Demon?

I am going to stay with American Racing Outlaw 1's if I can.

Jack
 
I ran a 245/50-15 on an 8"Rally, on the front of my lowered Barracuda. It was very tricky, with a lot of finessing.
The current wheel is a 7" with a 235/60-14, which is a bolt-on and go deal. I think it is a 3.75bs, but it's been a lotta years since I looked.
I'm pretty sure you could run a 235/50-15 no problem, also on a 3.75bs.
Others will chime in

As for the rear, and with the spring relocation. 15x10s will physically fit in there, but the bs is critical. I run the standard 4.5bs but the rear has been narrowed about 1.5 per side. The math thus says you would need a 6"bs to tuck the wheels in to match my install.
At 5.5 you will have lots of clearance to the inside, but may have to get creative on the outside. In fact, I would test fit them before I went thru the trouble of relocating the springs
This is not that big a deal, cuz you can always narrow the rear atta later date. At least you can drive it with SS springs.

If you have the KH 4-piston calipers, you will have to be careful with wheel selection as not all will clear the calipers, in stock form.
 
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I just bought 15 x 6 sbp cragars for the front with 195 60R15 tires. I think the wheels have have 3 3/8 back space. Mine has front disc conversion, so I was a little worried about fender clearance on top. Fit good, except I wish i had gone to 70 series instead as the 60s in that width are pretty short and I could have used a little more ground clearance.
 
Coyote Jack said:
I am going to 15 inch wheels all around on my Demon. I am pretty sure with a spring relocation, ( which I have had for a few years and never got around to), that I can go with a 15x10 with 5.5 inch back spacing. It's the fronts where I am stumped. I want to run a tire with about a 185 to 205 width. What will work in a 15 inch wheel as far as a width and backspacing for the front on my Demon?

I am going to stay with American Racing Outlaw 1's if I can.

Jack
Click to expand...

4-4.5 backspace with a 205-215 tire and 15" rim is about perfect.
 
TB
That 15" steel Rally of mine, at 4.5BS, rubbed on the Upper BJ, at near full droop, and the BJ ripped all the wheel weights right off, at ride height. The caliper rubbed in a few places too, which I had to correct. And the tire rubbed on the frame at full lock, and on the strutrod the other way.. In my application, the 4.5bs was right at the limit, if not slightly over,lol..
This was on a 68 Barracuda with the KH 4-piston calipers and the suspension lowered about 1inch. The Demon should be the same situation.
As I recall you have a 73 up Dart which with the slider caliper system, has a slightly wider front track; about .375 as I recall. So the 4.5 may work on yours, or if you already have it then it does,lol. Am I wrong?
 
My car is a 72 Demon with what I believe to be a 73 or 74 front disk system, single caliper.

The 15x6 with a 3.5 inch backspacing sounds about right. The tires I would be looking at would be a 70 profile. This is no corner carver, it likes a straight line. lol

Interesting comment on the rear back spacing. My current rear wheels are 15x8 with a 4 inch backspacing, tires are 275-60-15, so it does make sense that a 15x10 and a 6 inch backspacing would put the outer side of the tire, new tire will be 325-50-15, in the same place I have currently.

Jack
 
Those 325s fit in my 68 as well, with some judicious reshaping of the inners, in strategic spots, with the bfh...... but I had to slow down for the turns,lol.

A 325 on a 10 has only a very small section width more than a 295 on a 10.
This is because they are measured on a checking rim of 70% of the branded size.
So a 295 is checked on an 8" rim. When you put it on a 10, the section width grows by about .6x 2(25.4)"=30mm or to about 325.
And a 325 is measured on a 9" rim. Put it on a 10 and it grows by about .6x1(25.4)=15.2mm, or to 340. This makes them only 15mm apart or about .6 inch difference in section width, and only half of that to the inside where it counts.

The problem is; I have to run my 295s at 24psi to get even treadwear out of them. And the 325s at 20/22. When cornering at 20/22 the tire rolls over onto the sidewall and puts the Comp T/As into the inner fenderwell. The 295s do not roll as far with 24psi, and they never rub. The 325Comp.T/As have pretty soft sidewalls and are easily damaged.So I save them for shows.
Cornering at these low pressures can be a little disconcerting at first.The rear rolls over and steers the car a bit more than I expected; it took a bit of getting used to. It doesn't do it if the tires are spinning, so most of the time............
 
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For my fronts I use 205/70-15 on 7'' rims, you could go lower but then the headers usually don't like it as much.
 
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leblanc said:
For my fronts I use 205/70-15, you could go lower but then the headers usually don't like it as much.
Click to expand...
This will go in no problem on any wheel. The checking wheel is a 5.5, but I would try to put it on something a lil wider, like a 6 or even a 7. Sevens work well on my S. And on the wider wheels you can run a lil more pressure.
 
If you want them tucked in nicely you need a 15X10 with a 7.5" backspacing. I had 325-50s on the Barracuda, springs moved in, in the stock wheels on a 15X8.5" Centerline with 4-7/8" backspacing but the rims were to narrow and I ended up switching to a 275-60
 
This trying to find a wheel for a decent price that fits is starting to get old fast. All the off the shelf wheels are deep dished and will not fit the rear. Backspacing and offset are killing me. Why can't they have just one standard way to measure them and call it one name. Anything decent looking costs a fortune. rant rant rant

Jack
 
Stock rear and big bolt pattern. Jimjimjimmy has a Duster and runs 15x10 with 5.5 backspacing with a Nitto 325-50-15 and his just fits in the wheelwell with offset spring hangers so that is what I have been looking for. I have seen the car in person many times.

Jack
 
They will fit on 4.5bs too, which is a standard bs on most 10"rims. Then you just narrow the rear to fit them. After that any 15x10 off the shelf 4.5bs will fit. Narrowing the rear is not a big ticket item. And IMO the deep-dish wheels just look so much more at home on our classics; subjective I know. Plus, almost any smaller-than-10 wheel will instantly fit.
The thing is 325s should really be on 12s, so you can run decent tire-pressure. On 10s you will be down at around 20/22psi to get them to run flat on the road. Even my 295/50s have to run at 24psi on 10s to get decent treadwear outta them. And yes, my 295s rollover onto the sidewalls on every turn, sometimes I see the scuffmarks over an inch high. It will be worse at 20/22 with 325s
And the real insult for me was that my car was not perceptibly quicker with 295/50s than with 275/60s. And those I could run at 28psi, with little to no roll-over. I coulda saved some money and just got me some Caltracks.Or ladderbars. Or SS springs, or something,lol.
What I really need is 285/57-15s,on 10s,lol.
But I gotta admit 325/50s look really good under there.

Here's a bit of trivia;
A 325 is only a 325 on the designated checking rim....... which is 70% of the branded size. So in this case 70% of 325 works out to a 9" rim. If you mount it on a 10" rim, the section width will grow about 50% of the increase; in this case about a half inch or 13mm. So now it's a 338. But this also affects the profile spec, cuz the height does not change. So in this case the profile becomes 52.83%. so that gets you a 338/52.83-15. But tire companys will round this to 335/55-15. And when they do that, the checking rim will be just 9.23;which rounds right back down to a 9incher,lol
The point is that the 325/50-15 itself may be a victim of rounding. It might actually be a 320.1/51-15 mounted on a 9" checking rim.
So what says you
Well the 295 might also be a victim of rounding. The checking rim is an 8. When you install it on a 10 it will grow in section about 1" or 25mm. If the 295 was a rounded down number from 299.9 then it will now be a 324.9 on the 10" rim. Of course the profile will now be 47% leaving you with, dare I say it, a 325/45-15 after rounding.
Of course this does not affect the part that counts, the part that touches the road. And a 325 will always be wider.........than a 295.
The point is this; if you don't actually need the extra treadwidth, then you can make a 295 look almost like a 325
Jus saying......
 
AJ/FormS said:
They will fit on 4.5bs too, which is a standard bs on most 10"rims. Then you just narrow the rear to fit them. After that any 15x10 off the shelf 4.5bs will fit. Narrowing the rear is not a big ticket item. And IMO the deep-dish wheels just look so much more at home on our classics; subjective I know. Plus, almost any smaller-than-10 wheel will instantly fit.
The thing is 325s should really be on 12s, so you can run decent tire-pressure. On 10s you will be down at around 20/22psi to get them to run flat on the road. Even my 295/50s have to run at 24psi on 10s to get decent treadwear outta them. And yes, my 295s rollover onto the sidewalls on every turn, sometimes I see the scuffmarks over an inch high. It will be worse at 20/22 with 325s
And the real insult for me was that my car was not perceptibly quicker with 295/50s than with 275/60s. And those I could run at 28psi, with little to no roll-over. I coulda saved some money and just got me some Caltracks.Or ladderbars. Or SS springs, or something,lol.
What I really need is 285/57-15s,on 10s,lol.
But I gotta admit 325/50s look really good under there.

Here's a bit of trivia;
A 325 is only a 325 on the designated checking rim....... which is 70% of the branded size. So in this case 70% of 325 works out to a 9" rim. If you mount it on a 10" rim, the section width will grow about 50% of the increase; in this case about a half inch or 13mm. So now it's a 338. But this also affects the profile spec, cuz the height does not change. So in this case the profile becomes 52.83%. so that gets you a 338/52.83-15. But tire companys will round this to 335/55-15. And when they do that, the checking rim will be just 9.23;which rounds right back down to a 9incher,lol
The point is that the 325/50-15 itself may be a victim of rounding. It might actually be a 320.1/51-15 mounted on a 9" checking rim.
So what says you
Well the 295 might also be a victim of rounding. The checking rim is an 8. When you install it on a 10 it will grow in section about 1" or 25mm. If the 295 was a rounded down number from 299.9 then it will now be a 324.9 on the 10" rim. Of course the profile will now be 47% leaving you with, dare I say it, a 325/45-15 after rounding.
Of course this does not affect the part that counts, the part that touches the road. And a 325 will always be wider.........than a 295.
The point is this; if you don't actually need the extra treadwidth, then you can make a 295 look almost like a 325
Jus saying......
Click to expand...

Your really trying to mess with my head now aren't you AJ? LOL

Jack
 
Jusalilbit ; I guess I'm busted.
I seen you were a fellow Cannuc, and from my favorite Province,so I know you guys out there are pretty cool. I mean you have to be, cuz you spend most of your winters shoveling and all
 
Getting a rear narrowed around here is not real easy by the way. This is really a back water area of North America. The only person close to me that could do it died last year.

Jack
 
I suspected you were wanting to avoid that. I did too, but in the end it was one of the better mods to my car.
I sent my stuff down to Moser's
It cost a bit for the shipping, but it came back perfect. They also removed the C-body perches,straightened it, shortened the C-body axles, and resplined the ends for me. That was 14 years ago and pushing 100,000 miles
 
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