71 'Cuda Setup - 315/60 or Bigger?

[Carlwalski]

OK guys, I'm pretty much set on getting a 528ci Hemi for the 71 'Cuda. To make the most of this huge elephant, I need to get as much of that to the ground and get a good launch as well. It will have a 5-Speed Keisler behind it so that's not going to helping grip matters upon launching any easier.

I LOVE the look of "Filmsergeons" car below. (I think) he's running 315/60/15x10" rims on BFG Radials. I have 15x10" cop rims that I really, really, want to use. I want the biggest I can stuff in there but without having to mini-tub, although I would consider it (possibly). I definitely won't be doing a full tub. The rear end I will order eventually will be a B-Body Dana 60 for that extra 2"? of clearance. I'm undecided yet if I will keep the leaf springs. Chryco suggested I look at ladder bar and/or a floater system & retain the leaf springs or eliminate the leaf springs and add 1 cross member & use coil over shocks & a pan hard breather. I'm not sure what all that means but it sounds OK? LOL. I also like the look of Chip Foose's Challengers set up. Minus the chrome rice though...... 

What would be involved with getting 325's or possibly 335's in there? They are massive tyres, I know, but it will help the traction, not all of it, but it definitely won't hurt the traction. Does anyone know what a 15x10" limit is for tyre sizes?

Thanks lads, I'm a bit up in the air with the set up I'm looking for but please feel free to offer some street style set ups. The car will be a custom/clone 1971 'Cuda so correct is out the window, just want an aggressive looking street machine that will handle and grip well.

[HemiDog]

First of all, if you are going that big with the wheel/tire combo, you won't be using the 3/4" spring relocation kit.  In fact, you might consider ditching the leaf springs for a different setup (ladder bars, 4 link, ).  If you are going to use leaf springs you will have to use the 3" relocation setup.
The advantage of using the b-body rear is that the spring perches are in the correct position for use with the 3/4" relocation kit and you gain roughly an inch in the offset of the rim.  If you have the rims you going to use, you need factor in the the offset of those rims, along with the knowledge you are wanting to tuck the entire tire in the wheel well.  Since this is the case, I will bet you will need to cut down a b-body rear end and definitely cut off the perches. Then cut the axles or buy custom ones.  Buying the b-body rear, gains nothing for you.  You want to order a custom new custom dana 60, or know that you are going to modify a old dana 60.  To do that you will need to mock up your wheel/tire combo and suspension option in the car and measure for the dimensions you need.

I am sure there are others here that can explain it all better.      Cheers! 

[Carlwalski]

Thanks Hemidog, a little over my head I'm not ashamed to admit but it will eventually mean something to me.
So, if I order a custom made rear end from Dr Diff or likewise I maybe able to get a 325 in eh, sounds interesting.

Will a 315/60 tyre on a 15x10" cop rim with 5-1/2" BS fit in with a 1" relocation kit and a Dana 60 rear? It would have to be very close! Perhaps 325 or 335 is a little too big. I'm totally lost when it comes to rear end suspension parts like leafs etc. Gear ratios fine, diffs a little better but the whole leaf, ladder and what-not gets me every time.

[HP2]

Verify what tires you have available before you get too worked up about it. Granted, you may have more choices in your locale, but I haven't seen any of those sizes in 15", unless you are talking drag radials which are going to be plenty tall to go along with the width.

Check the inside dimension of your wheel well sinc eyou don't want to do any tubbing. This will confirm how much you can actually stuff in there. Just guessing, I would think there is room for a 305 or 315, but custom backspacing may be the only way to get it in there. Sidewall bulge also become a factor with spring locations as a 5.5 back space rim may fit, but once you put a tire on it it may contact the rear spring segment.

[HemiDog]

I was able to stuff 285/45/18 in my wheel wells without mini tubing.  On a Cuda, I would think going any bigger in the overall diameter and width would be pushing tolerances to the limit.  I mounted the tire on a 18x10 rim with about 5.8" backspace and a b-body rear.   I have about a half inch between the tire and spring with the 3/4" relocation kit and another 1/2" between the fender lip and tire.  I would think you are fine with that rim and the b-body rear.  It is just a matter of finding out what rubber to wrap it in.

The wheel/tire combos in the pictures are way bigger than what I am running.  That Foose car probably has a 20x15 rim under it. 

When people are talking to you they might be referring to a Chally and not a Cuda.  I believe the Chally has more room to work with, so make sure.

[Carlwalski]

Cool, thanks guys great info.

Stockton or Vintiques make a 15x14" Cop style wheel with a 8" back spacing. The more BS means the more the rim will sit in towards the diff center, correct? A 5.5" BS will sit out towards the fender more? Correct? BFG makes a 315 but only for a 17 rim and with a 35 profile. Tyres, I can get what ever you can, I'll import them myself so that's not a worry. I'll end up saving more If I get them myself. Yupe, I knew the 'Cuda had less room as I put the same wheels on the Cuda as I did on Lucy and it was a "little" less room, not much at all and you couldn't tell by looking you just knew, if that makes sense. lol

[nivvy]

I hate to disagree with HEMIDOG  but you can get 325/50/15's in there with a 3/4 relo kit...

I have a b body rear - 3/4 relo kit and SS springs

15*10 rims with 5 inch backspace...

all you need is a thin wheelspacer on the passenger side ... I forget what size mine is....

the pics shown are with no wheelspacers and I have 1/2+ clearance to the springs and 1 1/4 to the lips..... the tires in the pic are 28*12.5*15 MT's which has a 12.6 section width.... the MT 325/50/15's have a section width of 13.1 so that is only 1/4" inch difference on each side of the tire and I gain 1" tread width and I have 1 1/4 to the wheelwell lips...so the 325/50/15's go 1/4" closer to the spring I just add the 1/4' wheel spacer to get the needed 1/2 clearance and the 1/4" to the lip I loose plus the 1/4" whell spacer leave me with a little over 1/2" needed clearance to the wheelwell lips.... 

I did trim the wheelwell lips a little... and also a cuda may be different than my challenger ...

FYI the MT 315/60/15's have a section width of 13.4 which is wider than the 325's and each have a tread width of 11"'s ..

[Carlwalski]

Whoa that is great info and photos mate, there is hope!!!

I have 15x10" with a 5-1/2" back spacing, will that make it easier to get a setup like yours or harder?
What do 28*12.5*15  equate to in "315/60" type terms?  What are "SS" springs, I'm guessing Superstock? If so, what is the difference between them (SS) and stock springs?

Based on what your combo is and what you know, will the following combo fit or come very close?

B-Body Dana 60
3/4" or 1" spring relocation kit
15x10" rim with 5-1/2" BS
Wheel spacer perhaps on both sides.


Dumb question, but what does a wheel spacer do/look like? Where does it sit?
Is it a piece of metal with the same lug nut configuration that slides between the wheel and hub?

Oh, and 325/50 sounds definitely like me!!

[nivvy]

Here is my reccomendatios.... yes the 5 1/2 backspace will pose a problem as it set you 1/2 closer to the spring.... to get that back DR. DIFF makes a 1 1/4 offset shackle as opposed to the 3/4 ... so you should be fine.... but I reccomend calling him as he is a rearend expert as to where the spring perches are on a dana 60 as opposed to my 8 3/4 which Im sure you could move in if you had to ... I added a link to his website below... 28*12.5*50 equates to 295's and yes SS are superstock springs and mine are the 3400lbs ones and mounted on the upper hole of the spring hanger to make it sit lower....the car actually sits lower now than the pic as I have put a battery in there...

http://members.aol.com/doctordiff/

also is a pic of MR. Gasket wheelspacer...you just put them over the studs and slide the wheel on to put the wheel further away from the spring (you need longer studs if using spacer)... you may not even need one with the dana 60 and 1 1/4 relo shackles ... 

[conv340]

One thing to add. How high or low is the car going to sit? What is the target hight? One of the reasons that you get several people that say they can fit different tires onto the same car is the hight of the car. There's a lot more to rub if the car is slammed! 
   I would thing the first car "Filmsergeons" would have to have been mini-tubed and a 3" relocation to sit like that.

[Carlwalski]

Thanks a heap for the replies guys, I can't say thank you enough. Yeah, sitting height is not at the top of the list yet. For me, getting the desired tyre size and suspension set up is my main rear end concern. Once we get the 528ci Hemi down here with the car acid dipped and prepped ready for metal work we're going to do some pretty decent body stiffening, using the XV kit and our own pieces to give this 37+ year old body some strength. Otherwise with 700hp+ on tap the engine will basically starting tearing the seams from the car over time, plus ride & handling will be improved ten fold.


 

[nivvy]

Filmsergeons tires are 30" 's in diameter and it looks lower than actually is.... so the tires goes higher up in the wheelwell and has a section width of 13.4 as opposed to the 13.0 of the 325/50's and each tire has 11" 's of tread so why not go with the 325/50's ... when using a tape measure from the ground to the wheel lip my car is 26.5 inches ... 

[Carlwalski]

Thanks guys for all the input.


I found a rather useful tire height chart that is helping me a lot, I highly suggest keeping it your favorites folder.
http://www.sstire.com/tireheights.html The thing is, I have 28" tires in there now (275/60/15) and height wise it's perfect. So For the height I know I have to go no higher than, say, 28" to be on the safe side. If you view the chart the following tire sizes and wheel combos are what I can have. I will obviously look at the width once I've got what size I can get in height wise and fabricate to accomodate. I may end up doing a minor mini tub or what not but still have the back seat etc.

The highest/widest 15" rim/tire combo I can have is = 305/50 @ 27"
The highest/widest 16" rim/tire combo I can have is = 295/50 @ 27.61"
The highest/widest 17" rim/tire combo I can have is = 335/35 @ 26.23" or 305/45 @ 27.81"
The highest/widest 18" rim/tire combo I can have is = 345/35 @ 27.51

I know there is plenty more to factor in but height wise I can get some decent numbers in without touching the top of the wheel well. Problem is finding 18" rims I like and I really (at all costs) don't want to get "big" modern wheels.  Hence the reason I stopped the chart above at 18, 17? Possibly. Stockton make the wheels below (painted in full black) from 15x6 through to 17x10 so it could be possible. Another problem that is strictly looks is I like white writing showing and those sizes no one (I know of) makes them. I was thinking perhaps Hoosier or similar? Any thoughts?

[nivvy]

hmmm............interesting site .... the MT 325/50/15 is 28" tall and 13" wide with 11" tread with....... thats my vote ...     lol

[Carlwalski]

I'll go have a look at the M/T site. What is the formula for working out the USA to metric conversion?
All I kept finding from searches were the 26" or 28" heights, I get confused when I see 31"x12.5" etc....