E-Body Tire Combos

[tommyg29]

before making a big mistake I'm taking the wheels off again today to remeasure very carefully. I forgot that adding the backspace and frontspace together will add up to 1/2" to 3/4" more than the width of the wheel. The wheel size is measured from the inside lips of the wheel, and backspace is measured to the outside; about 1/4"-3/8" on each side.

[PlumCrazyChris]

I've posted this before, but here is a link to a site (I have no affiliation with the site) that lets you compare different tire sizes and rim sizes.  Its very cool.

http://www.bigcustomwheels.com/rt_specs.jsp

good luck sizing your rims and tires.

Chris

[tommyg29]

Thats a great calculator. Ive been using it and it seems pretty accurate.
Just measured my rears. They are 3.5" backspace and after careful review, I think I need the custom 4-3/8" backspace. I could go to 4.5" and use a small spacer if it rubs the spring, but
I believe a 275/50-17 with the 17x9.5 TTIIs will barely fit my car both inside and out.
My fender lips have the stainless trim screwed into them, but if necessary I could grind about 1/8" off them too.
I know they arent popular, but do they make 1/8" spacers?

[ShelbyDogg]

When you measured your backspace and frontspace, does it add up to your stated wheel width and backspace?     

When ordering your wheels, most manufacturers measure to the inside of the wheel lip, where the tire will mount.

This could make a big difference when you order your wheels.  Maybe you can go by a custom wheel place and have them try on a wheel of known dimensions, then measure off of that.

I fitted my challenger 15x10s-295-50s under my cuda with my offset springs and b-body rear and everything fit without hitting the lip or sidewall.

[cudazappa]

When ordering your wheels, most manufacturers measure to the inside of the wheel lip, where the tire will mount.

Manufacturers use "offset" now on rims rather than backspace.  http://www.tirerack.com/wheels/tech/techpage.jsp?techid=101

Backspace could vary based on the width of the "lip" where the tire rests/wheel weights mount.

I don't like shim spacers in general, but the 1/8" thickness should still allow the rim to locate on the center register.

another option is to test fit late model mustang rims in the back with a bolt on spacer.  I've fitted 17x8 rims all around on my challenger that are actually for a mustang but I'm using bolt on spacers to bring me back to a 0 offset.  I'm actually looking for another set of mustang 17x9s because that's what I've found is the best fit.  I've test fitted an 18x10 with 285/40 and 5" backspace (-13 offset), but i would have been better with 5.5" (0 offset) but that was about the MAX I could fit on a stock sprung Challenger.

[tommyg29]

I understand the offset and backspace are measured to the putside lip, where the wheel width is measured to the inside, so there is about 3/4" to 7/8" total difference with most wheels.

I measured the clearance from the mounting plane of my drum to the closest point of the leafspring and it came up 5-3/8". So about a 4.5" backspace ought to do it for me with a 275 tire. Problem is there is VERY limited selection for a 17" rim, unless you go to a 40 series, which I think is too low. I wanted a 50 series to give a slightly softer ride, and I think it will look better.
Any suggestions?

[moparstuff]

Hello Guys,

 I'm currently running 245/45/18 in the front and use a 4.6 inch backspaceing. I have a different inner fender well gaping from the outside of the tire to the inside of the fender well. The left side has all the room in the world and the right side is tight. It's about a half inch differnece. My measurment is taken from the outside of the tire to the inside of the fender lip. The car is straight (according to alignment machine) and suspension is new. Did anyone have any similar issues when putting on wide tires?

Maybe its necessary to run differnet offset from right to left?

[ShelbyDogg]

Some are a little different from side to side. I noticed when putting on quarters that you can wided it a little before welding.  Have your quarters been touched?

[moparstuff]

The rear quarters have not been touched. The front fenders are goodmark. Its more noticeable in the front but the space issue exist in the rear as well. Looks like the whole body sit closer to the right side than the left. The car comes up sqaure on alignment machine and chassis machine. Even looked at the K-Frame and looks to be bolted in sqaure.



 Strange Stuff.

[PlumCrazyChris]

I'd say your fenders are just out of alignment when they where installed.  There is a lot of play in those things.  I got my car painted and the doors and fenders were rehung and they look great, but there was about a 2" gap when I tried to install the front valance panel.

good luck,
Chris

[Road_Runner]

OK, lets get a tire/tyre size combos thread started. Too many wasted threads about one topic.
Chryco if you or Ross or someone could sticky this topic that would be good.

Post what rear end you have, tire size, wheel size + back spacing etc
Also any mods or relocation kits that were needed to fit your wheel combo along with photos, definitely PHOTOS.


I'll go first:

1970 Dodge Challenger R/T
8-3/4 SureGrip

15x8" Rallyes Rear with 275/60 BFGoodrich Radial T/As
15x7" Rallyes Front with 245/60 BFGoodrich Radial T/As

Chrysler Rallye wheels: 56 Series purchased from www.jegs.com All wheels have a 4-1/2" (4.5) Back Spacing.
Rear trim rings leave a 1" gap due to the wheel being 8" and repro/OEM rings only available in 7" sizing.

No rubbing, no relocation kits, no worries. 

Cheers,
NZ440R/T

This is exactly the tire/wheel combination I'd like to run on my 73 Barracuda, but in this thread I've seen questions about whether there is a difference in the wheel well clearance between Barracudas & Challengers?  Also, does this vary by model year or is it the same for all 70-74 models?  Any help would be greatly appreciate!

Thanks, Jim

[ShelbyDogg]

This combo should work with all e-bodies. I'm pretty sure that the 15x7 have a 4" backspacing like the stock rallyes. 275x60x15 is a common rear tire that many put on.

[Road_Runner]

This combo should work with all e-bodies. I'm pretty sure that the 15x7 have a 4" backspacing like the stock rallyes. 275x60x15 is a common rear tire that many put on.

This combo calls for 7" wide on front & 8" wide on back, still good?

Thanks again, Jim

[ShelbyDogg]

Yes, 7" and 8" is good.

[Road_Runner]

Yes, 7" and 8" is good.

Great. Thanks again.