Demon tire/wheel decision??

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northeastmopar

northeastmopar

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OK, so I was looking at the American Racing torque thrust black wheels for my Demon. I am thinking about the following
Rear wheel 18" x 9" with a +24 offset?
Front wheel 17" x 8" with either a +30 offset or a 0 offset?

Rear tires either a 285-45-18 which would be 28" tall or a 255-50-18 which
is also 28" tall.
I have the large bolt pattern axels and an 8 3/4 rear with 3:55 gears. The motor being built is a 416 stroker with a 727 tranny and about a 2900 stall billet converter. The car is for street use with a run or two at the track. I really do not want to move the springs other than maybe that 3/4" kit thaty Dr Diff sells which is only actually a 1/2" gain.
Anybody here familiar with my concerns regarding which would be the best fit. I am understanding that a 28" tire is about all I can put under. I should also add I have new ESPO springs coming. I ordered the heavy duty with a 1" higher build.
 
That rear wheel 18X9 is going to have 6" back spacing a little to much for stock spring location on a stock width "A" body drum to drum rear end. But it will be close you might be able to use a spacer to get the wheel out a little and it might work.

The fronts I'm guessing probably need the +30 thats about 5.5" back spacing. It's going to be close to the tie rod ends on the inside. Are you using the 73+ disc brakes?
 
zhandfull said:
That rear wheel 18X9 is going to have 6" back spacing a little to much for stock spring location on a stock width "A" body drum to drum rear end. But it will be close you might be able to use a spacer to get the wheel out a little and it might work.

The fronts I'm guessing probably need the +30 thats about 5.5" back spacing. It's going to be close to the tie rod ends on the inside. Are you using the 73+ disc brakes?
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How about I use the 255-50-18 on the 18" x 9" wheels? It has a tire width of about 10 1/4" vs the 285 which is 11"? Also, if I did go with the 285 and I moved the springs in the 1/2" with the kit, would that help. Just looking for all my options to try and be safe.
 
northeastmopar said:
How about I use the 255-50-18 on the 18" x 9" wheels? It has a tire width of about 10 1/4" vs the 285 which is 11"? Also, if I did go with the 285 and I moved the springs in the 1/2" with the kit, would that help. Just looking for all my options to try and be safe.
Click to expand...

On "A" body cars I have had that were stock. I would run into the tire rubbing on the front spring clamp at about 5-1/2" from mounting surface on rim to tire section bulge. Your wheels will have 6" of back spacing but very little if any tire bulge.

If you used the spring offset kit I think it would work. When you start getting this tight of clearances it's best to use any size wheel installed then start taking measurements and doing a little adding and subtracting just to be safe.
 
The 285/45/18 is a oddball size not very common. Might consider a 285/40/18 much more common size and better pricing available. only about an inch shorter
 
zhandfull said:
The 285/45/18 is a oddball size not very common. Might consider a 285/40/18 much more common size and better pricing available. only about an inch shorter
Click to expand...

I would really like to keep the height at about 28". If offset is a problem, I could downsize the rims to 17" if that would help, but I really want the 28" tire in about a 10" to 11" tire width.
 
Stay With 17''. 18's, 19's 20's ETC. Cost A Lot More Money. Usually The Bigger And Wider The Rim The More Expensive For The Proper Size Tire To Fit It JS.
 
17x8" rim with +30 offset is a backspacing of 5.6", that should be about right. With a 17" rim it will put you pretty close to the tie rod ends, but you should clear.

18x9" with a +24 offset is 5.9" of backspace. With a stock 8 3/4 you'll need spacers, its not going to fit. If you do the offset hanger/shackle kit it'll buy you ~1/2" per side, but it may still might not be enough, it'll be close.

The reason I say that is I test fit the 17x9" rims I have on my Challenger on the back of my '74 Duster. They've got 275/40/17's on them and a 5" backspace. They hit the springs without a spacer. :violent1: With a 1/4" spacer everything cleared by just a touch less than a 1/4", but that works out to only 4.75" backspace on a 17x9". Now, my Duster still has a BBP 7.25" rear end in it, and I've heard they're a little shorter than the 8 3/4's. The number I usually hear for the 8 3/4" rears is about 5.5" of backspace, which means you'd just squeak by if you go with a 1/2" offset kit. But when you're cutting it that close, it will come down to body assembly tolerances-ie, it will work on some cars but not others. Just hope your car isn't one of the cars with the rear axle offset by a 1/4" one way or another.
 
72bluNblu said:
17x8" rim with +30 offset is a backspacing of 5.6", that should be about right. With a 17" rim it will put you pretty close to the tie rod ends, but you should clear.

18x9" with a +24 offset is 5.9" of backspace. With a stock 8 3/4 you'll need spacers, its not going to fit. If you do the offset hanger/shackle kit it'll buy you ~1/2" per side, but it may still might not be enough, it'll be close.

The reason I say that is I test fit the 17x9" rims I have on my Challenger on the back of my '74 Duster. They've got 275/40/17's on them and a 5" backspace. They hit the springs without a spacer. :violent1: With a 1/4" spacer everything cleared by just a touch less than a 1/4", but that works out to only 4.75" backspace on a 17x9". Now, my Duster still has a BBP 7.25" rear end in it, and I've heard they're a little shorter than the 8 3/4's. The number I usually hear for the 8 3/4" rears is about 5.5" of backspace, which means you'd just squeak by if you go with a 1/2" offset kit. But when you're cutting it that close, it will come down to body assembly tolerances-ie, it will work on some cars but not others. Just hope your car isn't one of the cars with the rear axle offset by a 1/4" one way or another.
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Would I be better off with say a 17" x 8" on the rear and a 17" x 7" on the front and using a different width 28" tall tire. How would that fill the openings? I don't want to be toooo close to anything and I guess based on other posts here, to spend 612.00 for one tire would be way out of price range for the build.
 
That is the problem with the bigger wheels the tires are not really that tall, the average sizes are about 25 to 26". I like the taller tires to especially on the rear of car.
 
zhandfull said:
That is the problem with the bigger wheels the tires are not really that tall, the average sizes are about 25 to 26". I like the taller tires to especially on the rear of car.
Click to expand...

Would I be better to look at 15" or 16" wheels to find the 28" tires???
 
northeastmopar said:
Would I be better off with say a 17" x 8" on the rear and a 17" x 7" on the front and using a different width 28" tall tire. How would that fill the openings? I don't want to be toooo close to anything and I guess based on other posts here, to spend 612.00 for one tire would be way out of price range for the build.
Click to expand...


The 9" rim out back isn't a huge problem, with offset springs and the right backspace it should be fine. An 8" rim out back would be easier, 4.25" to 4.5" backspace usually works pretty well with the stock length axle.

An 8" rim on the front isn't bad either really. Usually 5.5-5.7" backspace is where you should be, but some of the lower ball joints are a little different with the steering arm, some give more tie rod clearance than others. A 7" rim is a piece of cake. Your other option would be an 18" rim up front too, because the the tie rod fits inside the rim and you can run a lot more backspace.

My recommendation would be to find your tires first. Some sizes are a lot more popular than others, you'll notice they're cheaper and there's more selection. A 285/40/18 is an oddball size, you'll have a lot more selection in 275 or 295.
 
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