Another Wheel and Tire Question

[PickleJar]

I've been scouring the threads and can't quite find what I'm looking for.

So I'll try asking it this way:

This is what I would like to do...

Bronco will be stock body height (will consider 1 inch lift, either or), with a stock suspension. The suspension is all new so no sagging. It will be uncut front and back. I would like to run a 30" tire on a steel wheel, which so far I have confirmed will fit.

What I'm trying to figure out now is proper width and back space for the wheel, and the width of the tire. It is a '76 so it has the larger parts on steering axle.

What would be an ideal for fittment setup, width wise, for a 30" tire on a stock 76 bronco?

I've looked at Wheel Vintiques series 62, but don't know what width to go with, and I haven't found all the different options to test fit with.

If someone out there could tell me what their running on their stock 76/77 Bronco: tire size, wheel size, b/s that would be super awesome...

Thank You

 

[PickleJar]

For Example, would this work:
30x9.5x15 tire
15x6 wheel (how much backspace)

or

30x9.5x15 tire
15x7 (how much backspace?)

or

29x8.5x15 tire
15x6 or 15x5 (How much Backspace?)

 

[RM70]

I'm using a set of refurbished oem 15x5.5 wheels on my 70 with the 30" tire.

 

[PickleJar]

Looking for a stance like this, but its a 76, not 66...so need to know specifics on needed wheel...those 7.00-15 are 30 inches x 7.9 inches

https://offroadaction.ca/2021/01/01/jeff-leslies-1966-ford-bronco/

 

[DirtDonk]

You can use either the 6" or 7" wheels with 9.50" wide tires. The maximum backspacing for yours is to be no more than 3 5/8" and, depending on the wheel's actual rim profile/cross-section shape, might be better with 3 1/2" backspacing. But many have used 3 5/8" and had no fitment issue. Not sure how the Vintiques would differ from stock in that area though.

Since you're going with a 15" diameter wheel, you're physically limited to this backspace because of the tie-rod end clearance issue you mentioned. Not that they're larger, but the steering arms where the rod ends mount are angled further outward so are closer to the wheel edge than earlier styles.

The '66 in the link looks like it has 5.5 or 6 inch wheels max. Since they're stock I think that was the only choice. Either 5 or 5.5 inch with 6 inch wheels coming later?
If you want closer to that look, stick with 6" wheels I would say. Maybe see if you can get some info from the original restorers that might know what backspace the original wheels had. It's probably been mentioned here before, but i don't remember what it might be.
Ford was not only using the tie-rod clearance as their criteria, but also handling/steering so their backspace/offset was chosen for that reason too, if not only for that.

Paul

 

[PickleJar]

Thank you Paul, I’ll keep digging. I’m going to try to go a good salvage yard this week and grab some specimens for test fitting. If all goes well I will take pictures of different wheels being mounted and post them for everyone else to see the differences.

Thanks again

 

[ajordan73]

RM70 - is your Bronco lifted? If not, I'm assuming the 30" tire fits okay. Specs would indicate that a 30 inch tire uses at least a 6 inch rim. The originals are 5.5 inch. I'm trying to determine a good size for a 73 stock unlifted and I would prefer something bigger than the P215/75/r15 that is apparently a replacement for the G78-15. Years ago, a tire dealer tried putting on a L78-15 but it rubbed on the rear fender lip. My axle is 4.11 so a larger diameter might be preferable.

 

[DirtDonk]

Hey ajordan, welcome to posting! I see you've been here awhile, but figured I'd say hey anyway.

Even though the original tires were approx. 28" it seems 30" tires fit without issue in most cases because lots of people have used them on uncut Broncos over the years. As you've probably noted, the wheel offset/backspacing is critical no matter what the size of the tire is, so the more tucked-in the wheel is, the more clearance you typically have for the tires.
Where did your L78's rub? Front or back?

Taller tires, just like wider tires, will eventually hit something in the front. At some point the tire will rub the radius arms when you turn fully. This is not a big deal, and if the noise bothers then you can adjust the steering stops to compensate.
If it rubs on the little overlapping lip of the inner fender skirt/apron where it meets the body tub (rear side of the front wheel opening) it can be trimmed down by almost an inch without anyone ever knowing it. Those that chose to simply hammer it into submission were still successful in clearing the tire, but even a new-to-broncos person will see the obvious bent metal. But a clean trim leaves it completely invisible to any but the most Bronco-centric person.

If it was in the rear, if rubbing the upper edge of the opening then it's all about wheel offset. If it rubbed on the leading edge of the wheel opening where it tucks in slightly around the rocker panel, then that's the tire diameter-vs-lift issue. Best not to trim if you want it to look stock still. Most that have that issue will move their rear axle back an inch or so to add clearance at that tight leading edge.

A 9.50 tire is perfectly fine on a stock 5.5" wheel. But these days most of the larger tire chains won't mount a tire on a wheel where the size is not specifically listed in the manufacturer's chart. But smaller tire shops will still be happy to do it.
And if you have not checked yours yet, you should verify that you have the early 5.5" size, or the later 6" size. Pretty sure Ford upsized them at some point.

I went the 32x11.50 route myself, which was very popular back in the day. But I had 7" wheels and cut rear fenders so clearance was not an issue. I still rubbed in the front, but rather than just trimming the lip I wanted flares to match the rear. Except on Stroppe Baja Broncos I prefer the fully cut look vs the rear only look.
Even with 1.5" of lift I still rubbed on that lip. And no amount of lift will stop a taller tire from rubbing a radius arm during a tight turn, so I adjusted the stops. That way even though I knew it wasn't hurting anything and I could release the steering wheel slightly to stop the rubbing, I preferred to not have to think about it during tight turns.

Back to your question, I've never personally fitted a 30" tire to a stock height, uncut Bronco. So I can't help you with exact experiences. Just what I've seen here and there over the years.

Paul

 

[RM70]

RM70 - is your Bronco lifted? If not, I'm assuming the 30" tire fits okay. Specs would indicate that a 30 inch tire uses at least a 6 inch rim. The originals are 5.5 inch. I'm trying to determine a good size for a 73 stock unlifted and I would prefer something bigger than the P215/75/r15 that is apparently a replacement for the G78-15. Years ago, a tire dealer tried putting on a L78-15 but it rubbed on the rear fender lip. My axle is 4.11 so a larger diameter might be preferable.

No it is not lifted but I eventually plan on doing a 1" body lift.

 

[jckkys]

I played for years with tire/wheel combinations on my single owner '77. The OE wheels were not ideal. The rim comes so close to the tie rod ends that wheel weights get knocked off or at least get grooved. I went with Kelsey Hayes 15"X8" steel wheels for 70s Dodge Ramchargers. They have a 4" backspace that clears wheel weights by about 1/8". I gave up on the silly uncut thing, because chains couldn't be used with the L78X15 tires, even tho that combination was OE and worked without chains. The whole uncut idea as being somehow desirable proved to be garbage. By '73 when I bought my first Bronco most on the road were cut. The original wheel well didn't look right on the '64 F100s where the design originated either.