Time for new wheels and tires

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Markzilla88

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My wife and I just picked up a 72 Demon that currently has drag tires on it, with the fronts being only 4” wide. We need to replace all 4 tires with radials. I was looking at a few members rides and combinations and am in need of direction on how to find the right combo for us. We like the look of 14” wheels up front and 15” wheels in the rear, but I’m afraid of them rubbing. Is there any way to measure exactly what the tolerances are on the car? (Posted picture is just for an idea of what it looks like currently but I’ll get a better shot tomorrow of it from the side)

B846A987-30E7-457B-ADE1-23AA60E843E9.jpeg
 
My71 duster is pretty much the same car as your demon. Rears are 15x8 with a 4.5" backspace and a 275/60/15 fits no rubbing. A 255/60/15 fits well on an 8 " wheel as well, nice sidewall to it. Fronts are 15x6 with a 205/70/15 no rubbing at all.
 
My wife and I just picked up a 72 Demon that currently has drag tires on it, with the fronts being only 4” wide. We need to replace all 4 tires with radials. I was looking at a few members rides and combinations and am in need of direction on how to find the right combo for us. We like the look of 14” wheels up front and 15” wheels in the rear, but I’m afraid of them rubbing. Is there any way to measure exactly what the tolerances are on the car? (Posted picture is just for an idea of what it looks like currently but I’ll get a better shot tomorrow of it from the side)

View attachment 1715405133

What do you mean by drag tires?

What's wrong with bias ply?

I've never heard of 4" wide front tires. What size and brand are they?

I'm further confused by you seemingly wanting to improve handling yet running a 14" front and 15" rear.

Is the car big bolt pattern or 5x4"?

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Now in my humble opinion.... you have a nice set of wheels. If I were to do anything, which depending on your answers above I may not, I may wrap them I new rubber. 14's don't belong on the car. They don't belong on anything other than a resto and are a waste of time and money. 14 front/15 rear is awful and a stagger IMO doesn't look good on these cars. But alas.. it is your time and money. But clearly by the picture you could spend it more wisely.
 
My wife and I just picked up a 72 Demon that currently has drag tires on it, with the fronts being only 4” wide. We need to replace all 4 tires with radials. I was looking at a few members rides and combinations and am in need of direction on how to find the right combo for us. We like the look of 14” wheels up front and 15” wheels in the rear, but I’m afraid of them rubbing. Is there any way to measure exactly what the tolerances are on the car? (Posted picture is just for an idea of what it looks like currently but I’ll get a better shot tomorrow of it from the side)

View attachment 1715405133


5 Lug - Wheel / Tire Combination Measuring Tool Gauge * Fitment Tool Gauge | eBay

This works well
 
Yes you can measure- Google how to measure wheel backspacing. 205/70/14's are nice up front with a six inch wheel. Out back 8" wheels are perfect. You can do 4.5 or 4.25 backspacing. 245 /60/15 or 255/60/15 tires fit really nice. Some guys will chime in and say you can do 275's out back, but they are too big unless you make some modifications. You can call a wheel company like Crager and they will help you choose the right size too
 
The current set up is up front is Mickey Thompson sportsman’s 26x7.50-15 LT and rears are Mickey Thompson ET Streets P235/60R15. It’s been upgraded to 5x4.5 all around and has 73 discs up front now as the drums were done away with. I was in the understanding that more of a contact patch upfront would help handling and control of the car. My wife will be driving it as well so I want to set her up for success. The car is manual steering so that’s new to her as well. Is there truly a big difference in handling between a 14 and 15” wheel up front, or was that comment just your personal preference?
 
I'm looking for tires as well, I've also read through pretty much every wheel and tire thread.

What you will come to find out with all your Mopar decisions is they are all like picking a woman. They all look and sound nice and you don't fall in love with one of them until you just pick one.
 
The current set up is up front is Mickey Thompson sportsman’s 26x7.50-15 LT and rears are Mickey Thompson ET Streets P235/60R15. It’s been upgraded to 5x4.5 all around and has 73 discs up front now as the drums were done away with. I was in the understanding that more of a contact patch upfront would help handling and control of the car. My wife will be driving it as well so I want to set her up for success. The car is manual steering so that’s new to her as well. Is there truly a big difference in handling between a 14 and 15” wheel up front, or was that comment just your personal preference?
generally speaking, yes the wider tire patch will improve handling. As for rim size affecting it, the larger rim with the same over tire height will have a reduction in side wall flex. That said, make sure if you're running modern tires that the alignment is configured for it. The published specs are for the original factory type compounds from the 60s. Not suitable really for modern radials and those compounds.

If you want a good handling setup, look up using the search feature some of the posts by @72bluNblu or @roccodart440 or even @Jim Lusk . All very knowledgeable when it comes to getting the most out of these old torsion bar cars.
 
I'm looking for tires as well, I've also read through pretty much every wheel and tire thread.

What you will come to find out with all your Mopar decisions is they are all like picking a woman. They all look and sound nice and you don't fall in love with one of them until you just pick one.
yep and then they'll nag at you as well. :lol:
 
yep and then they'll nag at you as well. :lol:

Shoot that's no lie. I spent all that time doing the wheels yesterday (and only finished the front face of the wheels) and my wife comes out and says "I thought you were just going to have them sand blasted?" Pfft
 
Shoot that's no lie. I spent all that time doing the wheels yesterday (and only finished the front face of the wheels) and my wife comes out and says "I thought you were just going to have them sand blasted?" Pfft
shoot, my wife nags when I do the dishes, too much water, too much soap, not enough rinsing, not enough soap. I swear they pull them aside in healthclass and teach them how to torture their future husbands
 
The current set up is up front is Mickey Thompson sportsman’s 26x7.50-15 LT and rears are Mickey Thompson ET Streets P235/60R15. It’s been upgraded to 5x4.5 all around and has 73 discs up front now as the drums were done away with. I was in the understanding that more of a contact patch upfront would help handling and control of the car. My wife will be driving it as well so I want to set her up for success. The car is manual steering so that’s new to her as well. Is there truly a big difference in handling between a 14 and 15” wheel up front, or was that comment just your personal preference?

I run 26x7.50's. They have a section with of 6.3" and that is on a 4" measuring wheel.

Which ET Street? They make 4 different varieties including radials. THe only one worthy of true street use os the ET Street S/S.
While there is nothing wrong with bias ply tires, you do not ever want to mix the 2 together on a car.

It's good that it's been upgraded to 5x45.". That gives you nearly endless wheel options.

I run mine with those fronts on it and my wife has driven it many times. Honestly, unless you make some suspension and chassis changes It doesn't matter. I've never run out of front tire under braking or cornering but I don't corner the car hard. I just drive normal.

Being manual steering, a bigger front tire exacerbates the increased steering force required, albeit mostly at slower speeds. That is also something you can change in the future fairly easily.

There is definitely a difference in handling from 14's to 15's, 2 fold.. One is the very limited tire selection with 14". The 2nd is the increased sidewall height.
 
Just so you know the 73-up widen the front track around 3/8" per side. Keep this in mind as you may need more positive offset in the front.
 
shoot, my wife nags when I do the dishes, too much water, too much soap, not enough rinsing, not enough soap. I swear they pull them aside in healthclass and teach them how to torture their future husbands

maybe u need to b like me and not do dishes at all !
Not house broke !
 
maybe u need to b like me and not do dishes at all !
Not house broke !

I'm with you! My wife used to nag when I did chores around the house. I told her why would I help do house chores if you're going to nag .I could instead not do anything and play with the cars while getting the same nagging. Ill chose the 2nd option every time .
 
I run 26x7.50's. They have a section with of 6.3" and that is on a 4" measuring wheel.

Which ET Street? They make 4 different varieties including radials. THe only one worthy of true street use os the ET Street S/S.
While there is nothing wrong with bias ply tires, you do not ever want to mix the 2 together on a car.

It's good that it's been upgraded to 5x45.". That gives you nearly endless wheel options.

I run mine with those fronts on it and my wife has driven it many times. Honestly, unless you make some suspension and chassis changes It doesn't matter. I've never run out of front tire under braking or cornering but I don't corner the car hard. I just drive normal.

Being manual steering, a bigger front tire exacerbates the increased steering force required, albeit mostly at slower speeds. That is also something you can change in the future fairly easily.

There is definitely a difference in handling from 14's to 15's, 2 fold.. One is the very limited tire selection with 14". The 2nd is the increased sidewall height.

I have heard and read about mixing radials and bias ply tires all my life , and know the tire manufacturers don't recommend it . I have mixed them over the yrs. on 2 hemi cars, hot sbc`s , a 440 coronet , vega , pickups , and now my barracuda , switched back and forth and cant tell any diff .
Maybe if I drove like a teenager , did the road race thing when I was young, don't do it now , mostly hi way and straight line speed . ??????
 
I'm with you! My wife used to nag when I did chores around the house. I told her why would I help do house chores if you're going to nag .I could instead not do anything and play with the cars while getting the same nagging. Ill chose the 2nd option every time .

maybe u need to b like me and not do dishes at all !
Not house broke !

I just put headphones on and turn up the music really loud, can't hear the nagging if I'm deaf
 
I have heard and read about mixing radials and bias ply tires all my life , and know the tire manufacturers don't recommend it . I have mixed them over the yrs. on 2 hemi cars, hot sbc`s , a 440 coronet , vega , pickups , and now my barracuda , switched back and forth and cant tell any diff .
Maybe if I drove like a teenager , did the road race thing when I was young, don't do it now , mostly hi way and straight line speed . ??????
is wonder if the difference would be if you had say 1 bias and 1 radial up front, vs having different types front vs rear
 
Look up any post in this forum by 72blunblu. Invaluable knowledge. Recently helped me with tire/wheel combo for my 73 Sport with disc brakes.
 
Mark- with manual steering wider tires up font may be harder to steer.
 
The current set up is up front is Mickey Thompson sportsman’s 26x7.50-15 LT and rears are Mickey Thompson ET Streets P235/60R15. It’s been upgraded to 5x4.5 all around and has 73 discs up front now as the drums were done away with. I was in the understanding that more of a contact patch upfront would help handling and control of the car. My wife will be driving it as well so I want to set her up for success. The car is manual steering so that’s new to her as well. Is there truly a big difference in handling between a 14 and 15” wheel up front, or was that comment just your personal preference?

It's not really that there's necessarily a big handling difference between having 14" and 15" wheels up front, it's the tire selection. There are very few tire sizes, and very few brand and compound options for 14" rims. Selection for 15" rims is still better, although the tire selection for 15" rims is pretty limited too nowadays. Pretty much down to whether or not your want to run BFG T/A's or Cooper Cobra's. Both are all season tires with a pretty hard rubber compound, and are pretty mediocre compared to modern tire performance standards. But unless you're willing to go to 17" or 18" rims they're about the best you'll do for a street tire, and they have the "classic look" with blackwalls and white lettering.

In the front with 73+ disks you should be able to run up to a 225/60/15 on a 15x7" rim with a 4.25" backspace without any trouble. You might have to make a slight adjustment to the lower front fender to bumper brace depending on your ride height. With manual steering that still shouldn't be too difficult to manage, especially if you have the standard 24:1 manual ratio. Even the fast ratio 16:1 shouldn't be an issue with 225's and the typical caster you can run up front with the stock suspension, and the car should feel much better planted in the front. More importantly you'll have better stopping power with more traction up front, and the front end will be less likely to understeer or "plow" with a rapid steering input than it would be with the 4" skinnies you've got up front now.

In the back you haven't mentioned yet what rear axle you have, it makes a difference. Factory A-body axles are not all the same width, the BBP 7.25" and 8.25" rear axles are 56 3/4" wide at the wheel mounting surface (also sometimes called drum to drum). 8 3/4" axles are 57 1/8" if they're still SBP, if they've been upgraded to BBP axles they're more like 57 13/16". Which makes a difference in the amount of backspace you'll need, especially if you run wider tires.

Measuring your car in the back is fairly simple, all you need is a tape measure and some kind of straight edge. A carpenter's square if you have one large enough works as well. Put the straight edge across the wheel mounting surface (the face of the drum at the studs, not on the center register) and then measure back the spring. Repeat and measure out to the quarter lip. You'll have to rearrange the straight edge in between as you want to keep the tape perpendicular to the spring and then the quarter for an accurate measurement. On a Demon with the stock spring locations and uncut quarters you should end up with about 12" from spring to quarter lip. How that's split will depend on the axle width, but with the right backspace fitting a 275/60/15 is usually no problem at all. For reference, a 275/60/15 is 11" wide at the section width. Which means, properly centered in the wheel well, there should be a 1/2" to the springs and a 1/2" to the uncut quarter, which is more than enough even on a car that has been lowered from stock. A 255/60/15 is a piece of cake, leaving ample clearance everywhere assuming you run the right backspace.

If you happen to have an A-body 8 3/4 with BBP axles, the typical set up is a 15x8 with 4.5" of backspace, which typically works well with a 275/60/15. That axle should give a WMS to spring distance of ~6", which also means the WMS to quarter should be ~6". Tire is 11" wide, so 1" of tire hangs over the edge of the rim. Backspace is 4.5", so add 1", you get 5.5" of wheel which gives you a 1/2" clearance. Front space on the wheel is also 4.5", so you guessed it, 1/2" clearance on the quarters.

Here's a post I wrote awhile back, in response to TF360, showing 12 different members' cars, with pictures of their cars and links to their threads, showing how they run 275's on uncut and unmodified Demons/Dusters/Dart Sports. I didn't even include my own car in that list, it fit 275's just fine when it was stock. I know there's more, but I only listed examples that specifically mentioned being unmodified.

Demon Rear Wheels

Excuse me while I go change my undies

Funny, that's the same exact thing you'll be saying if you get caught out in the rain with those replica PolyGlas tires.

They do look pretty though.
 
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