15x8 w/ 4.5” BS on front/good handling size?

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standup303

standup303

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Never thought I’d be the guy asking about tire size lol… but here I am…..

Hoping to hear from some who have 15x8s in front. Majority of the wheels I like are 15x7 4” BS or 15x8 with 4.5” BS. Will 15x8 4.5” fit on the front? I know the 15x7 4” BS won’t fit. What tire size would I be looking at? Thank you.

Also would like to make this a 2 parter. I want to set this car up as a cruiser. Currently have front runners and I feel like the pull all over the road. What’s an ideal size to make a well handling car? Just street cruiser, occasional mountain twisties. Not going to be auto crossing it.
 
On the front of what car?

If A-body I think you’ll find an 8 or 8.5 will be too wide. Causing tire rubbing issues on the bottom corners of the fenders. I think you’ll find 7" to be about as wide as you’d want to reasonably go. Even 6 or 6.5 if anyone makes a 6.5

If you’re running front runners right now anything will be a handling improvement.
 
4mulas said:
On the front of what car?

If A-body I think you’ll find an 8 or 8.5 will be too wide. Causing tire rubbing issues on the bottom corners of the fenders. I think you’ll find 7" to be about as wide as you’d want to reasonably go. Even 6 or 6.5 if anyone makes a 6.5

If you’re running front runners right now anything will be a handling improvement.
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Oops it’s on a 69 Dart. I see 15x5 3.75” backspace in a few I like. I need to measure the front runners I have now. They are fairly skinny.
 
If you’re looking for more of a street use set up I’d look for 15x6. Selection should be better. Also stick to that 3.75" ish back spacing too. About the biggest tire you’ll fit is 215/65r15 maybe 225/60r15.

There are many many threads on this if you do a Search.

This car is 215/65r15 fronts on a 15x6

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let's start with what brakes/front end do you have, because the later 73~76 disc set up adds width up front.

but generally, you should be able to get a 5~8" rim up there if you're not going for max tire and the car isn't excessively lowered.
 
8" will be tight. proper backspace may get them on there. have to measure carefully.

I'm running a 15x7 with 4.5 backspace and a 225/60-15 tire. firs well, doesn't hit anything on our 70 dart. if o did it over I'd got 4.75 backspace.
 
junkyardhero said:
let's start with what brakes/front end do you have, because the later 73~76 disc set up adds width up front.

but generally, you should be able to get a 5~8" rim up there if you're not going for max tire and the car isn't excessively lowered.
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It’s big bolt pattern with QA1 upper/lower and Wilwood discs I forget the disc size.
 
standup303 said:
It’s big bolt pattern with QA1 upper/lower and Wilwood discs I forget the disc size.
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15x7 rims, 225/60/15 with 4.25" minimum backspace. 4.75" best, 4.5" bksp better. Watch the very front fender lip at bottom.

For rear is the car is low, same size. I have 245/60/15 on 15x7 4.25" bksp small bolt pattern on my 68 Dart it rubs the outer fender lip. car is stock ride height.

3.75 bksp on a 6" to 8" wide rims kills fender clearance.
 
standup303 said:
It’s big bolt pattern with QA1 upper/lower and Wilwood discs I forget the disc size.
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well... that makes it a little trickier. basically, anybody that gives you a rec for what fits on their car with stock suspension you can disregard. or maybe use as a very loose guide.

so you've got the increased track width of the BBP spindle, and i *believe* the wilwood adds some to that as well, with the hub pushing the WMS out even further.

i'd hazard a guess that 3.75 BS isn't going to come near enough to make happen what you want to make happen, unless you're thinking of running a 205.

i hate saying this, but i'd try and find somebody that's got the same set up and see what they're running. from there you could at least make a better educated guess, or have some hard numbers that you could play with.

i usually say 4.25 minimum BS (which is stock) is where you want to start, with more being better. but i think at 5-ish you start to get very close to the tie rod end and possibly the upper ball joint with 15's & 16's so you need to go bigger to clear those and then run more BS and you can tuck in some fat meats.
 
autoxcuda said:
15x7 rims, 225/60/15 with 4.25" minimum backspace. 4.75" best, 4.5" bksp better. Watch the very front fender lip at bottom.

For rear is the car is low, same size. I have 245/60/15 on 15x7 4.25" bksp small bolt pattern on my 68 Dart it rubs the outer fender lip. car is stock ride height.

3.75 bksp on a 6" to 8" wide rims kills fender clearance.
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Yup!

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15x7 with a 4.25" backspace (or more if you can find it) is about the best you'll do, as others have already said. 225/60/15 is about the max unless you find a wheel with more backspacing, but you'll run out of clearance to hard parts before you get to 5" of backspace.

An 8" wide rim on the front of an A body really requires a 17" or 18" diameter rim to actually make use of the rim width. With a 15" rim you can't run enough backspace before running into interference with the brakes/control arms to to actually use the 15x8" for a tire you couldn't just as easily put on a 15x7.

Now, a 17x8 with 5.6" of backspace and a 245/45/17 all day long, maybe even a 255 on some cars.
 
I tried some 15 x 7.5 slot mags on the front of the beater a few weeks ago…4.75 back space… they hit the upper A arms… maybe a steel wheel would work clear….

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Thanks for the input everyone. Sounds like I need to get measuring. Wheel choices are super limited seems like they never have enough backspace.
 
standup303 said:
Thanks for the input everyone. Sounds like I need to get measuring. Wheel choices are super limited seems like they never have enough backspace.
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I'm curious. Why do you think 15x7 with 4" backspace WONT work? I thought that was a fairly universal fits-everything wheel.
And, what style of wheel are you looking for? Slots? Lightweight wheels to match the rears, only wider? Steelies? Five spoke?
More info please.
 
67autocross said:
I tried some 15 x 7.5 slot mags on the front of the beater a few weeks ago…4.75 back space… they hit the upper A arms… maybe a steel wheel would work clear….

View attachment 1716271860
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The original poster has QA1 UCA’s. Those give about 1/4” or so more clearance.

Also, they may rub at full droop. So need to check at ride height.

Then you can put 1/16”, 1/8”, 3/16” spacer to fine tune the clearance (front and rear)

But you are right full cast rim can reduce clearance. Especially old rims. The welded center to spun aluminum hoops have more room.
 
33IMP said:
I'm curious. Why do you think 15x7 with 4" backspace WONT work? I thought that was a fairly universal fits-everything wheel.
And, what style of wheel are you looking for? Slots? Lightweight wheels to match the rears, only wider? Steelies? Five spoke?
More info please.
Click to expand...

A-bodies are a tight. That 1/4” additional backspace is very helpful if you are trying to squeeze 225/60/15 up front.
 
33IMP said:
I'm curious. Why do you think 15x7 with 4" backspace WONT work? I thought that was a fairly universal fits-everything wheel.
And, what style of wheel are you looking for? Slots? Lightweight wheels to match the rears, only wider? Steelies? Five spoke?
More info please.
Click to expand...
I have 15x7 4” BS with 225/60/15 on the rear now. I bolted them to the front and they are definitely going to hit the fender.

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autoxcuda said:
The original poster has QA1 UCA’s. Those give about 1/4” or so more clearance.

Also, they may rub at full droop. So need to check at ride height.

Then you can put 1/16”, 1/8”, 3/16” spacer to fine tune the clearance (front and rear)

But you are right full cast rim can reduce clearance. Especially old rims. The welded center to spun aluminum hoops have more room.
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If it was a case of me really wanting to use them I would have figured it out…the real problem is still the lack of decent 15 inch tires
 
standup303 said:
I have 15x7 4” BS with 225/60/15 on the rear now. I bolted them to the front and they are definitely going to hit the fender.

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What's the gap between you inside rim and the outward edge of the upper control arm?

Lots of factors and stack up going on here: QA1 UCA's, QA1 LCA's, willwood brakes. Makes it tougher to draw comparisons.
 
33IMP said:
So, it's a tire height/width problem, not a 15x7 wheel problem. (But I do like a 15x7 with 4 1/4 or more bs).
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exactamundo.

15x7 is standard cop wheel (with 4.25 BS) and fits wonderfully, but you can't go much wider than 215 depending on ride height and aspect ratio.

but then the issue is that with the smaller diameter rim you can't get much more backspace because you'll get into the tie rod or upper control arm/ball joint.

when you add in the 73~76 spindle that increases track width things become even tighter, especially with the darts, vals and narrow body cars.
 
70 dart converted to large bolt pattern.. stock style brakes . 15x7 with 4.5: backspace and 225/60-15 tires all the way around.. like i said if i were to do it again i'd 4.75 baclspace..

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67autocross said:
I tried some 15 x 7.5 slot mags on the front of the beater a few weeks ago…4.75 back space… they hit the upper A arms… maybe a steel wheel would work clear….

View attachment 1716271860
Click to expand...
On the factory front end, 3.75 bs is about all you can use, before the wheels get into the upper bjs with 15s....... and/or the rubber gets into either the strutrods, the frame-rails or the fenders.
BUT IMO,
almost worse is that as the center of the wheel moves outboard of the design centerline, this creates a scrub radius that tends to manifest as wandering in a straightline, which for a streeter is the death-knell of long-distance cruising. Even a half-inch is annoying by 40mph or so. Which is why I went back to a 7.5" wheel, and a factory-height tire.
but, the backspace of 3.75 on a 7.5 wheel, (which is 8.5 from outside to outside) pushes the wheel centerline about a half inch to the outboard of the design centerline, and so, my car does wander some, on the hiway. To combat that, I pump up to pressure to 32, from the usual 28psi, in the 235/60-14s.

BTW
I love those lightweight slotmags, and have accumulated several sets of various offsets and widths. and,
They are easy to repair after I curb them ...........
and I seem to have curbed a few.
Those slotmags are about half the weight of a similar-sized steel wheel; and, in town, that makes quite a difference when bouncing thru potholes and hitting speed-bumps.
I get quite a kick when launching over speed bumps at speed, while watching some joker crab-walk his lowered tuner-car over same bump. I give him a lil burp on the throttle as I leapfrog the bump, for a dual 3" canons wake-up call, lol.
But I digress.

Nice-looking car. I had one like that in 1970, except PantherPink/or whatever Dodge called it..... Worst handling car I ever owned ........... but it sure was fun learning to drive it.
 
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