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18x11 Wheel and what backspacing?

9K views 44 replies 13 participants last post by  Ba mustang 
#1 ·
I am looking at upgrading to 18x11 wheels and 315/30-18 tires. The exact sizes are negotiable, but I'm wanting to be at or very close to those sizes. If I utilize the stock wheel hub placement (not looking into arm extensions or a wider rear end), what offset or backspacing is needed for these wheels? If I go with 0 offset, it looks like I'll have about 6" of backspacing, is that too much? Will that rub? Or do I need to look into negative offset wheels to get that backspacing number lower?
 
#3 ·
Yes, on a '65 coupe. I am planning on modifying the fenders and lowering the car too. I am moving away from the stock look as I modify the car.
What am I missing that makes this happen?
Is 11" just too wide without major suspension modifications?
What is the back spacing on the stock 15x7 wheels?
 
#6 ·
This is a good start as far as inside clearance, but beyond that, you've got some fender/quarter panel hacking to do, as well as some sort of flare solution. I doubt you're going to find anyone here that's going to have personal experience with how to fit the dimensions you're looking for. This one falls in the category of so custom, you're going to have to figure it out for yourself.
 
#5 ·
I am looking at upgrading to 18x11 wheels and 315/30-18 tires. The exact sizes are negotiable, but I'm wanting to be at or very close to those sizes. If I utilize the stock wheel hub placement (not looking into arm extensions or a wider rear end), what offset or backspacing is needed for these wheels? If I go with 0 offset, it looks like I'll have about 6" of backspacing, is that too much? Will that rub? Or do I need to look into negative offset wheels to get that backspacing number lower?
EDIT: just saw you post about your year...

Check out mike maier inc. His track car ol’ blue has 305’s on all corners, if I remember correctly. That’s who I would look for with advice on big tires for the 65 chassis.

Definitely will take some fab work

Sent from the interwebs... where else?
 
#7 ·
Mike's car is the inspiration, but I don't have the funds to go full tilt and build a replica of his car. I know Mike has done a lot of custom work on his car and he specializes in suspension, but I'm not finding any info on the black magic he used to make his wheels fit (18x11 and 315/30).
 
#12 ·
Not a 65, but for reference I am running 18x10 with 5.5 inch backspacing on my 70 Mach 1. The axle hub to hub width is a bit narrower than stock at 57 3/4 inches. I am running at Total Control Products 4-link with coil overs, so the leaf springs are gone. I currently have 285/35-18 NT05 tires, but looks like I can go to a 295 and that is it. No mods to wheel well beyond pounding the pinch weld seam out of the way in places and rolling the fender lip. With mini-tubs, maybe a bit wider, but not much.
 
#13 ·
Don’t use Mike Maier’s Old blue with the small flares as an example. The front spindle was chopped down to allow more wheel hanging inside. Mike has said that ultimately it was a failed experiment. You will need big wide flares to do 305s on a 65/65.
 
#14 ·
I may have posted my questions hastily. After digging a little more and reading through everyone's comments, I may have been over zealous with that massive wheel and section width. I also don't have 750HP to turn those big wheels anyways. :)
I am pulling back to a more realistic 17x9 with something in the mid 200s for width. I'll keep an eye out for a maximum backspacing of 4.75" and I'll be careful not to go too far in the other direction with back spacing as I don't want to mess with the dynamics of Scrub Radius and the like. I do plan to add flares so I want something wider than normal, but I'll need to keep all that in check.
 
#15 ·
make sure the rim clears the uca lock to lock at full droop. If you can get a 2 piece 18" rim thats not been welded together so you can play with the back spacing. I was lucky enough to have Phil Smith do that with 17" when he owned PS wheels back in the 90's. I trailered my 65 down to his shop. I have my own custom uca's and 17's so my measurements would not work for you. You should be able to get a tad more back space with 18's.
 
#23 ·
Google “clinched flares”
They sell a wide range of bolt on flares that you will have to trim to fit...
 
#25 ·
Look on google or Facebook for a guy from Norway named Magnus Marthinsen. I believe he is running 315s on his. I believe the car is now black, but it was once the same color as my tractor, New Holland Blue
 

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#35 ·
I wish there was more info about the fenders on this car. Replicas don't have the flares as high up the fender and quarter panels like Mike's car. Also, Mike's flares are aluminum shapes, all I seem to find are either fiberglass units or generic flares that don't really identify the distance they stick out. That Magnus guy in an earlier post said he uses massive wheel spacers to get the clearance (which helps me a little), but I wish I had more info.
 
#37 ·
You are correct, and I had no delusion that it's that easy. However, my questions is more on the details of how much was removed, what are some of the dimensions, and where can I source the same stuff. I'd rather use metal flares, but it seems the stuff I can find is super generic.
 
#38 ·
However, my questions is more on the details of how much was removed, what are some of the dimensions, and where can I source the same stuff. I'd rather use metal flares, but it seems the stuff I can find is super generic.
That’s why I said this in my first post:

I doubt you're going to find anyone here that's going to have personal experience with how to fit the dimensions you're looking for. This one falls in the category of so custom, you're going to have to figure it out for yourself.
 
#40 ·
All caps yelling and not even a link?

I looked it up and all I see are generic and very different photos stolen from Google. May be a fine product but I find their marketing approach flawed at best, dishonest at worst.

 
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