Main Menu

Will these fit my new "R/T'

Started by MoparsNBurnouts, March 18, 2021, 04:57:41 PM

Previous topic Next topic

0 Members and 1 Guest are viewing this topic.

MoparsNBurnouts

Hey Fellas and Fellete's,

I'm new here, and just picked up a 1970 Dodge Challenger "R/T" with a 440. The wheels I want I believe will fit, but the offset they state I'm not sure about. They are 18x8 with 4.58 Backspace and a +2 Offset, the rears are 18x9.5 with 5.09 Backspace and a -4 Offset. Can't wait to drive her! Thanks in advance.
1970 Dodge Challenger R/T 440

HP2

Of course tire selection is also a factor as this width may contact spots on the wheel lip opening or leaf spring. For the wheels themselves, fronts should work fine. Rears I'm less sure of. You  should measure from the drum face to the rear spring segment to see how much room you have. Challenger leaf springs are splayed so the rear eye mount is wider than the front eye mount. This creates slightly less clearance on the rear segment.

anlauto

Factory 15 X 7 rims have a 4.5" backspacing, so I don't see a problem with the rims, but as mentioned, tire selection will come into play.
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration


shawge

 :alan2cents: I would strongly recommend taking some measurements/mock ups before dropping coin on wheels if deviating from stock widths/offsets.  These cars don't have the best tolerances so what fits for others may not fit on yours.  If you could describe what brakes (front/rear - stock disc/drum, aftermarket), the rear end (stock e-body, b-body, offset shackles, etc), and the ride height (stock, lowered, raised).  With that info the guesses of what might fit can be narrowed down.

That being said... when I was looking for wheels I scoured the e-body sites for the combos other people were using and put them in a spreadsheet.  For 18x8s on the front the backspace ranged from 4.5" to 5.5".   For 18x9.5s on the rear the backspace ranged from 5.125" to 5.5".  Very dependent on the car setup.
1970 Challenger, 451 MS3Pro EFI
Colored wiring diagrams
Wheel spreadsheet

MoparsNBurnouts

Thanks, guys. I forgot about the tires, my bad. I'm going 245/40/18 and 275/40/18, although I'd really like a 285/40/18. Think that would fit?
1970 Dodge Challenger R/T 440

MoparsNBurnouts

Also, it's all stock as far as I can tell and has front single piston disc brakes. I will be upgrading all the brakes soon though.
1970 Dodge Challenger R/T 440

7212Mopar

I think front is fine. 5" BS is standard at the rear and will leave you some room, more on the spring side than the quarter side. Your wheel has more than 5" so bring you closer to the spring by .09. It is easy to check with a measuring tape. I think 285 would also fit but not too many tires to choose from. More choice with 275.
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket


Plum70Dodge

the 18x9.5 with -4mm offset will not fit. The tire will scrub the fender lip. a lot.
You can trust me.

MoparsNBurnouts

#8
Would I have to roll the lip? I have found three 1970 Challenger's with the exact rims I'm talking about, American Racing Boss VN338's. I currently have 275/60/15 in back and 245/60/15 in front.
1970 Dodge Challenger R/T 440

MoparsNBurnouts

Will 18x8 with 0 offset and 4.5" BS, and 18x9 with 0 offset and 5" BS fit?
1970 Dodge Challenger R/T 440

7212Mopar

How can a 9" rim at 0 offset have a 5" BS?
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket


HP2

Because offset is based on centerline of the rim width from inside the bead while backspace is based off the mounting face and overall width outside of the rim.

This shows it well: http://www.gtsparkplugs.com/Backspace-Offset-Calculator.html
   

7212Mopar

I thought 0 offset means mounting pad is at centerline of the wheel. So on a 9" rim it is 4.5" which you would have 4.5" BS?
1973 Challenger Rallye, 416 AT
2012 Challenger SRT8 6 speed Yellow Jacket

HP2

Seemingly, but offset in inside the bead, backspace is outside the bead at the edge of the rim. So you have the width of the rim material and any extra lip that rolls off that edge.