Will these fit my new "R/T'

[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.

[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.

[shawge]

  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.

[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?

[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.

[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.

[Plum70Dodge]

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

[MoparsNBurnouts]

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.

[MoparsNBurnouts]

Will 18x8 with 0 offset and 4.5" BS, and 18x9 with 0 offset and 5" BS fit?

[7212Mopar]

How can a 9" rim at 0 offset have a 5" BS?

[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?

[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.