How much tire can I fit?

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Mopar-Man

Mopar-Man

Big Block Better Burnout
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So it is getting close to tire and wheel time for my '74 Duster. It has a Dana 60 and Caltracs, stock tubs and trimmed quarter lips. I pulled out some new 28x10.5 Mickey slicks mounted on 15x10 Welds and mocked them up. The Welds are 3.5 backspace so I knew that wouldn't work. But I have extra long studs so I can play with spacers. Hey, let's flip them over and add some spacers. Wow, they fit! So it looks like I need 5 in backspacing to run this tire.

All I see are 4.5 or 5.5 backspacing online. I spent a couple hours searching and came up empty. I do remember when I bought some Alumastars I got them in 4 in BS but I would rather not go with a pricey wheel this time. Any suggestions? I could 5.5 and run a 1/2" spacer but I don't know if that is safe.

I am trying to fit as much tire as I can back there. Also, I am sure a drag radial has way less sidewall bulge than this ET Street bias ply does so I may have more room than I think (didn't buy those tires yet!).
 
So, if the 28x10.5 slick is 12.5 section and 10.0 tread x 28 diameter a 295/55/15 that is 11.9/10.6 x 28 should fit with a 5.5 backspacing... aw hell I am goin for it!
 
my uncle runs a 1/2 inch wheel spacers on his low 9 second belvedere. probably over 10 yrs now, I'd say they are safe
 
twayne24365 said:
my uncle runs a 1/2 inch wheel spacers on his low 9 second belvedere. probably over 10 yrs now, I'd say they are safe
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The ones I got have 10 holes in them and flop around on the studs! I only use them for mockup. I would want something that fits tightly.
 
diymirage said:
find some that are labeled "hubcentric"
they will center themselves on the hub and at half an inch thick, i'd expect them to have a raised edge on the outside to allow the wheel to center on

like these (but i didnt check the register size on these)

4X HUBCENTRIC WHEEL SPACERS ADAPTERS ¦ 5x114.3 ¦ 15MM THICK | eBay
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or you could make small set of spacers that center the 1/2 spacers near perfect on ur studs, no biggie. I have 1/2" spacers on myc 68 fastback w/ 295 65 15 drag radials on it. 3 1/2" offset, 9" wheels are what I really need . I have 2, 3" offset -8" prostars, and 2- 4" offset , 8" prostars.
 
Sweet!
You are mounting on a 15" rim correct?
I also have a 1974 duster (15" rallye rims on the rear currently).
Would love to know the max tire size with spacers.
Thanks
 
Okay, so I figured out my backspacing and ordered wheels and tires. Fingers crossed I might actually know what I am doing! 17x7 (would like narrower but all they had) in front, 17x9.5 (wanted a 10 but close enough!) in the rear. 225/50/17 front Nitto Extreme 555, 275/50/17 rear Nitto Extreme 555. Rears are just a tick under 28 inches tall which is exactly what I wanted. Discount Tire has the screaming deal on Ebay right now and I saved $100 on the wheels and $100 on the tires (2 separate orders to do this). $840 for everything shipped.
 
DSCF1065.jpg
 
+8 = .315", but that's just the offset from the centerline. A 17x9" with a +8 offset has 5.6" of backspace. I use this calculator, you input the offset and it will show you the backspacing. Rounds it to the tenth though. Also a good way to compare your new combination vs. your old combination to see if it will clear, because it tells you the difference in the locations. Custom rims, rim tire packages for your ride - RIMSnTIRES.com

What we should really do is drop the US system entirely and use the SI system (metric) like the rest of the world. Only 3 countries in the world don't use the metric system- the US, Liberia, and Burma. There's company for you :rolleyes:. It's not even "our" system, we adopted it from the British and just never got rid of it. Won't happen though. For the average person it's a big change with no real benefit, just confusion about how fast you're going or how far you're traveling. Anyone that works in the scientific fields already uses the metric system, as the US system is a colossal pain in the butt to use with any kind of engineering, physics, mathematics etc. Fastest way to guarantee an engineering calculation will be wrong is to put everything in US standard. Biggest culprit is our use of weight instead of mass. A pound on Earth is not a pound on the moon, because a pound is weight and includes gravity. A kilogram on Earth is a kilogram on the moon, because it's a mass measurement, a kilogram doesn't include the force of gravity. Anytime you have something listed in pounds you have to divide out the acceleration due to gravity to get a unit called "slugs", and carry around a bunch of conversion factors. Almost guarantee's you'll make a math error somewhere.
 
72bluNblu said:
+8 = .315", but that's just the offset from the centerline. A 17x9" with a +8 offset has 5.6" of backspace. I use this calculator, you input the offset and it will show you the backspacing. Rounds it to the tenth though. Also a good way to compare your new combination vs. your old combination to see if it will clear, because it tells you the difference in the locations. Custom rims, rim tire packages for your ride - RIMSnTIRES.com

What we should really do is drop the US system entirely and use the SI system (metric) like the rest of the world. Only 3 countries in the world don't use the metric system- the US, Liberia, and Burma. There's company for you :rolleyes:. It's not even "our" system, we adopted it from the British and just never got rid of it. Won't happen though. For the average person it's a big change with no real benefit, just confusion about how fast you're going or how far you're traveling. Anyone that works in the scientific fields already uses the metric system, as the US system is a colossal pain in the butt to use with any kind of engineering, physics, mathematics etc. Fastest way to guarantee an engineering calculation will be wrong is to put everything in US standard. Biggest culprit is our use of weight instead of mass. A pound on Earth is not a pound on the moon, because a pound is weight and includes gravity. A kilogram on Earth is a kilogram on the moon, because it's a mass measurement, a kilogram doesn't include the force of gravity. Anytime you have something listed in pounds you have to divide out the acceleration due to gravity to get a unit called "slugs", and carry around a bunch of conversion factors. Almost guarantee's you'll make a math error somewhere.
Click to expand...

I just saved that website in my Favorites! Thank you.
 
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