Backspacing on 17x7 fronts and 18x8 backs

[challengergary]

Planning on doing a staggered set up on my 70 Duster restomod. The fronts will be 17x7 and the rears will be 18x8. Front suspension has Hotchkis tubular UCA's, Hellwig sway bar, and Baer disc brakes. Rear will be stock width 8-3/4" rear with disc brakes. What would the best backspacing and/or offset be for the fronts and rears? Tire size recommendations?

 

[challengergary]

Heard back from the supplier. Wheels are 0 offset. so 4" back space on fronts and 4-1/2" backspacing on rears. These should work correct?

 

[dano]

I have 17x7/17x8 on my Dart and +19mm offset worked fine but I have less room then you do. I have 13"/11.6" Dr. Diff brakes. Does the Baer kit use the A/B/E disc spindle? A lot of Demon, Duster, Dart Sport guys got 18x8 and 18x9.

Its really going to depend on where you brakes set the track. I'd install those then measure and not assume.

 

[challengergary]

Not sure what spindle it uses. Bought a whole front end including k-member from a guy that went back to stock.

 

[mayhem]

I'd install those then measure and not assume.

What he said. Let us know what you find out.

 

[challengergary]

Snowpacolyse has delayed my wheels Should have been here yesterday but now no date showing on UPS.

So, next question - what size tires should I put on these?

 

[mayhem]

Snowpacolyse has delayed my wheels Should have been here yesterday but now no date showing on UPS.

So, next question - what size tires should I put on these?

What size wheels, backspace and offset did you buy?

 

[challengergary]

17x7 fronts - 0 Offset with 4" backspacing
18x8 backs - 0 offset 4.5" backspacing

Tire size recommendations?

Wheels are finally arriving today!!

 

[mayhem]

17x7 fronts - 0 Offset with 4" backspacing
18x8 backs - 0 offset 4.5" backspacing

Tire size recommendations?

Wheels are finally arriving today!!

Sorry, I have no experience with 17" & 18" wheels/tires.

 

[challengergary]

Christmas in January!!!

 

[72bluNblu]

17x7 fronts - 0 Offset with 4" backspacing
18x8 backs - 0 offset 4.5" backspacing

Tire size recommendations?

Wheels are finally arriving today!!

In the back you should have no issues going as wide as will fit on an 18x8” wide rim, so, 255/45/18’s. That’s a 27” tall tire too, if you step down to 255/40/18’s those are 26” but there supposed to be on an 8.5”. The car itself has room to take a wider tire but the 8” wheel shouldn’t.

In the front it’s going to depend on what spindles you’ve got and that brake kit, if you’re at a 73+ disk brake track width you probably should have gotten more backspace. A 225/50/17 may work, if that track width it 73+ or wider you may have to go 205 or 215 depending on your ride height.

 

[challengergary]

In the back you should have no issues going as wide as will fit on an 18x8” wide rim, so, 255/45/18’s. That’s a 27” tall tire too, if you step down to 255/40/18’s those are 26” but there supposed to be on an 8.5”. The car itself has room to take a wider tire but the 8” wheel shouldn’t.

In the front it’s going to depend on what spindles you’ve got and that brake kit, if you’re at a 73+ disk brake track width you probably should have gotten more backspace. A 225/50/17 may work, if that track width it 73+ or wider you may have to go 205 or 215 depending on your ride height.

Would 255/50/18 be too much tire for the back? I like a little more sidewall. Is a 28" tire too big for the wheel well?

 

[72bluNblu]

Would 255/50/18 be too much tire for the back? I like a little more sidewall. Is a 28" tire too big for the wheel well?

It shouldn’t be, but that’s pretty close to the limit. Depending on your rear springs it may be necessary to space your front hangers back to clear the lower front corner of the quarters.

I have 27.1” tall tires on mine, 295/40/18’s, but I have springs with a 1/2” longer front section so it centers the wheel in the quarter opening. Plenty of room on mine.

 

[challengergary]

In the back you should have no issues going as wide as will fit on an 18x8” wide rim, so, 255/45/18’s. That’s a 27” tall tire too, if you step down to 255/40/18’s those are 26” but there supposed to be on an 8.5”. The car itself has room to take a wider tire but the 8” wheel shouldn’t.

In the front it’s going to depend on what spindles you’ve got and that brake kit, if you’re at a 73+ disk brake track width you probably should have gotten more backspace. A 225/50/17 may work, if that track width it 73+ or wider you may have to go 205 or 215 depending on your ride height.

Looks like 225/45/17's are a lot more common than 50's. Do you think the close to 1/2" sidewall difference will matter much or should I stick with the 50 series? The 45 series will be 24.97" tall and the 50 series will be 25.85" tall

 

[challengergary]

Went with 225/50R17 for the fronts
255/45R18 for the rears

Should be here Wednesday!

 

[72bluNblu]

Went with 225/50R17 for the fronts
255/45R18 for the rears

Should be here Wednesday!

Nice!

Just for future reference the 225/45/17's would have been fine. I try to keep them between 25" and 26" tall in the front, more than 26" and you get interference issues and less than 25" just looks too small to me, most of the ones I run up front are 25.6" or so.

 

[challengergary]

Just what I wanted!! Thanks for the help guys