Backspacing? 38.5"x15" tires and no lift, Chero WT

[Hammer]

Ok, I have a deal on a set of 38.5" boggers.
I will be either running no lift, or about 3-4" lift, depending on clearancing issues.
I will be using M715 front fenders on the 78 Cherokee widetrack. And making my own rear fenders to resemble the M715 fenders.

What kind of backspacing do I need?
This is a testing phase, so I won't mind 'some' rubbing. And I can limit the steering stops a little if need be.
But I don't want to severly limit it or have big chunks or rubber flying!

I searched and most backspacing questions are for smaller tires and more lift.
And I KNOW there are members here who have close to what I am describing.

[Hammer]

Oh yeah, stock widetrack Dana 44 axles for right now.
And I know they won't take abuse with these tires for long. But it won't see much 'abuse' until it gets the 1 tons. Mainly just simple trail riding in the near future.

[AlsChopShop]

that will probably work if you are running m715 fenders. stock widetracks can run 37's if the flares are cut off.

Al

[Hammer]

Yeah, not too worried about the size of the tire for clearing the fenders, I am concerned on the amount of backspacing and how close that will get me to the inner fenderwells, springs, etc.

Just found out that the rims that come with the tires have 4" backspacing.
10" wide rim.
They are nice rims, good to resell when I am done messing around with them. But not if they will kill me for rubbing on stuff.

So how would this size tire work with a rim with 4" backspacing?
What is stock, about 3 5/8" or so?

[Stuka]

You will have no room for flex, but they will fit. As for back spacing, whats the width of the tires?

[Hammer]

Tires are 38.5x15.5x15 Boggers on 15"x10" rims with 4" backspacing.

I am not worried about the flex part. If they don't have enough room, I will put the lift on it.

Just trying to keep it as LOW as possible. That's why I want the M715 style fenders.

I figure that when I do the spring over for the 1 ton axles, I will have a lot more room. Maybe too much.

[Stuka]

Well, you should know in order to use 15" wheels on 1 ton axles you need to get out a grinder and run 2.5" back spacing.

As for back spacing on only 10" wide wheels, I would run at a minimum 3". Any more and you may not clear the springs.

[Hammer]

Yeah, I thought I would have problems with the 4" backspacing.
Not sure the deal will go as well without the rims as a package deal though.

I have no plans on keeping these tires when I go with the 1 tons.
I already have the axles and the H1 rims.
I am just trying to do one step at a time so I can keep driving this.
And I don't have all the other peices ready for doing the 1 tons swap.

[Hammer]

How bad would the tires get into the springs anyway?

[Stuka]

Well, you would have to adjust your turn stops out up front, not sure on how close they would be in back. I know a NT with 8" wheels and 12.50 tires comes about 1/2" fromt hitting the rear springs (sitting level).

[Hammer]

Just went and looked at the current tires on it.
33x12.5x15
Rim might be a 10", hard to tell.
The inside of the rim sits about flush, or maybe slightly covering the rear drums.
And about 2.5" to 3" of clearance between the tire and rear spring.
Didn't feel like pulling a rim off to measure back spacing right now.

BUT, NT width is what, 61" WMS to WMS? and Wide tracks are 67" WMS to WMS?
3" on each side does help.

I am looking at 38" tires for height. But I am finding the different ones from 12.5" wide, to 14.5", 15", 15.5" and up.
I would LIKE the wider tires, but the narrow tire would cause less problems for now.
Right now, if I put 38x12.5" tires on my current rims, I wouldn't have many problems until they were fully stuffed. They would rub the indents in the rear fenderwells for the seat belts are.

[Hammer]

Might have found some 15"x10" rims with 2" backspacing.
That would solve a lot of problems, and they are pretty cheap as well!

[Stuka]

In bac, NT's at 57.5 and WT's are 60.5

[AlsChopShop]

yeah, i'd agree on the 3" or less backspacing for that wide of a tire. those 2" backspaced rims will clear it for sure, but put more stress on the bearings and your front tires will have to 'roll' in turns causing a lot more stress on the steering box. you may also have more problems keeping them out of the front fenders on turns because of that 'roll'.

but hey, go for it!

Al

[Hammer]

Man, I didn't think it would be this hard to find a set of used 38" tires! At least ones that fit without TOO much trouble.
I have a line on two sets now.
38.5 x 12.5" x 15", so they are narrow enough. Just tall.

Other set is 38.5" by 14.5"(I think), but they are on 15"x12" rims with 3.5" backspacing.
That would get me closer to optimal. Not the exact backspacing needed, but the wider rim will keep more of the tire further out, and keep it from rolling as much.
Here's a couple pics of the ones on the 15x12" rims.

http://images.craigslist.org/01010401020201040020070908838a726809aad6bf1d001e96 .jpg
http://images.craigslist.org/0101080103110104072007090866275ae1fab31ef53c00a372 .jpg

[Mikel]

Years ago, I thought of doing the exact same thing - Take a friend's Cherokee NT, put M715 fenders up front and make similar fenders for the rear. Big tires with room for articulation and no lift. But I got distracted with other projects :o

Good ground clearance with a low center of gravity is the way to go! :thumbsup:

[Hammer]

Yeah, I have wanted to do this for years, and I now finally have a good canidate vehicle. It's a widetrack, but the rear pass flare is rusted. But the rest of the body is in good shape! Heck, even where that rusted flare meets the body is in good shape!

I have a nice big sheet of metal waiting to make the rear fenders. I have the M715 front fenders. I just need the tires now.

I basically plan on running these tires on this setup for a while to see how this size of tire, and amount of lift, will work with the m715 fender setup.
When I decide on what tire size and lift I need. I will swap in the 1 tons and whatever tires I can fit (thinking a 39.5" tire should be perfect!)

[baja]

Hamer,

I have run my 78 Chief WT for a few years with the set-up you are talking about.
4" lift and 15x39.5-15 TSL's on 10" wheels with I think 3.5" back-spacing.
I cut my front fenders out as far as I could and well past what an M715 fender will give you. Just about to the bottom of the hood.

Do my front tires rub? Yes, at back of the inner fender in front of the firewall where there is a bracket that holds the inner fender to the firewall. The inner fender is smooth there and I replaced the original bolts with some button head cap screws, so as not to tear the tires up.
(People have reported seeing tire smoke coming from the front tires when turned and spinning the tires in mud, I also had a sever rear main seal leak at the same time though, so who knows:rolleyes:)

Do the front tires hit the front springs or frame? Yes on the springs, just enough to make noise at full lock, and don't forget that this size of TSL's have huge lugs.

Another point of tire contact was right behind the front turn signals where the trailing edge of the front vailance panel meets up with the front of the inner fender. I did some trimming and bending and got a little clearance but still rubbed, then I removed the lower vailance completely including the turn signals and did a little more bending and pretty much eliminated that contact area.

I would be carefull about going to wheels with less than 3.5" of back space as then the tire will swing farther front to back as you turn, and will interfere more with the body.

When the tires rub the backside of the inner fenders, I don't ever notice. And 35" tires with no lift will rub the same place too.
When they rub the area behind the turn signals, the whole front clip jumps around and it sounds awful.
When they rub the springs, it is usually only at full steering lock and full suspension stuff on one side, like steering hard right with the drivers side fully stuffed into the fender. Pretty much only the extremes.

I mostly only play in the mud as thats the main thing we have around here, maybe throw in some rocks and logs. I did high center a fair amount, but with the tranny x-member being basically flush with the bottom of the frame and the nice gat tank skid plate that is on our rigs I never damaged anything on the bottom.
I loved the set-up, a 4" lift is not complicated and requires no other mods to anything in the suspension or drive train. With the springs I was running, I could get 780 on an RTI ramp and I later found that my rear shocks were limiting rear droop.

Go for it.
You'll love it.

baja

[Hammer]

GREAT info!
I am going to get those 38.5" tires for now. 14.5" wide, 12" wide rim with 3.5" backspacing.
I figure I will proably be putting that lift on it ASAP.
I put a lift on my last chero WT, not a big deal really.

The way I figure it, these rims/tires/axles are just a 'test phase' until I put in the 1 tons. I will learn everything I can with them, and try and get as close to perfect when I put the 1 tons in.

How is your rear clearance with those tires? How much did you trim? Up to the inner fenderwell on the rear?

I still want to keep a functional rear seat in the chero. That might mean using bucket seats instead of the bench seat so I can cut the inner fenderwells up.

[orangecherokee]

PM trickc. he knows quite a bit about the low stance and larger tires.

[baja]

GREAT info!
I am going to get those 38.5" tires for now. 14.5" wide, 12" wide rim with 3.5" backspacing.
I figure I will proably be putting that lift on it ASAP.
I put a lift on my last chero WT, not a big deal really.

The way I figure it, these rims/tires/axles are just a 'test phase' until I put in the 1 tons. I will learn everything I can with them, and try and get as close to perfect when I put the 1 tons in.

How is your rear clearance with those tires? How much did you trim? Up to the inner fenderwell on the rear?

I still want to keep a functional rear seat in the chero. That might mean using bucket seats instead of the bench seat so I can cut the inner fenderwells up.

On the rear fenders I basically projected the inner wheel well out through the outer quarter panel.
I knocked off/cut off the rear outer flare and seperated it from the outer inner fender (rust does most of this for you).
Then I cut out the outer inner fender in one big piece and aligned it up on the outside of quarter panel where it would be if it came straight out and traced a line following it's shape.
Trimmed the outer quarter panel to line, and welded in a piece of 12 gage steel flat stock about 7" wide in the shape of the arch made by the inner fender/trim job. This piece of flat stock went from the remainder of the inner fender out through the rear quarter panel and was welded all around.

It gives perfect clearance for up to a 40" tire. And you do not have to do anything to the insides of the Jeep, you can keep the stock rear seat and all related parts.
One thing I did rub on in the rear was when fully articulated, the inside lugs would make contact with a piece of metal that captures the plate that the rear outer seat belts are bolted into on the rear inner fenders.
So I ground it off and tapered the piece the seat belts bolt to. I mostly had this problem with a narrow track rear axle, a wide track Cherokee rear axle might not be a problem and a J-truck rear is not a problem at all.

Here's a couple picks.
baja

[1x1_Speed_Craig]

On the rear fenders I basically projected the inner wheel well out through the outer quarter panel.
I knocked off/cut off the rear outer flare and seperated it from the outer inner fender (rust does most of this for you).
Then I cut out the outer inner fender in one big piece and aligned it up on the outside of quarter panel where it would be if it came straight out and traced a line following it's shape.
Trimmed the outer quarter panel to line, and welded in a piece of 12 gage steel flat stock about 7" wide in the shape of the arch made by the inner fender/trim job. This piece of flat stock went from the remainder of the inner fender out through the rear quarter panel and was welded all around.

It gives perfect clearance for up to a 40" tire. And you do not have to do anything to the insides of the Jeep, you can keep the stock rear seat and all related parts.
One thing I did rub on in the rear was when fully articulated, the inside lugs would make contact with a piece of metal that captures the plate that the rear outer seat belts are bolted into on the rear inner fenders.
So I ground it off and tapered the piece the seat belts bolt to. I mostly had this problem with a narrow track rear axle, a wide track Cherokee rear axle might not be a problem and a J-truck rear is not a problem at all.

Here's a couple picks.
baja

Nice looking setup there, baja. :thumbsup:

Craig

[Hammer]

On the rear fenders I basically projected the inner wheel well out through the outer quarter panel.
I knocked off/cut off the rear outer flare and seperated it from the outer inner fender (rust does most of this for you).
Then I cut out the outer inner fender in one big piece and aligned it up on the outside of quarter panel where it would be if it came straight out and traced a line following it's shape.
Trimmed the outer quarter panel to line, and welded in a piece of 12 gage steel flat stock about 7" wide in the shape of the arch made by the inner fender/trim job. This piece of flat stock went from the remainder of the inner fender out through the rear quarter panel and was welded all around.


That was my EXACT plan for doing the rear fender. The inner well is already a very nice shape and I plan on copying it exactly. Just extended it past the body sides.
Only hard part looks like getting the cut in the body perfect so the flare will seal up to it (or at least very close).


One thing I did rub on in the rear was when fully articulated, the inside lugs would make contact with a piece of metal that captures the plate that the rear outer seat belts are bolted into on the rear inner fenders.


I have that rub spot as well, that is why I mentioned clearance on the rear.

Either way, thanks for the pictures! That is exactly what I needed to see. It gives me a great idea of how tall it will sit with the tire heigh and lift together.
Still very low, but fairly decent belly clearance (especially considering these things are 4x4 station wagons!!! )

[Hammer]

Baja, what axles are those you are running in that?

[baja]

Baja, what axles are those you are running in that?

Front is a standard old FSJ Wide track DANA 44, converted to 5 on 5-1/2 bolt pattern with Ferd hubs and Power Lock differential.

The rear is a J4000, DANA 60-2 with rear disc brakes and welded rear differential.

Thinking/planning/trying to put a Chebie DANA 60 front in it but I do not want to give up the stance or ride either.

baja

[Hammer]

Do the ford hubs change the width of the axle?
Man, that is asking a lot of a 44 to run those tires with a power lock.

[baja]

Do the ford hubs change the width of the axle?
Man, that is asking a lot of a 44 to run those tires with a power lock.

The hubs do not change the width much if at all.
The 44 holds up suprisingly well, as long as I use Spicer brand u-joints.
Also I'm pretty good at changing axle shafts out on the trail too.
I've had more problems with the outer shafts twisting off than with u-joint/knuckle joint failure.
But I only have a few more sets of extra axle shafts left for this front end so I will be going to a 60 front sometime soon.

[baja]

Nice looking setup there, baja. :thumbsup: [quote=1x1_Speed_Craig]


Thanks Craig, I've been diggin' your CJ10 project too.
Sure wish I could've gotten my hands on that extra tub you had.
baja

[Hammer]

First step, putting M715 fenders on the front.
With the 38" tires, I am not sure how close I will be clearance wise.
But this picture shows what stock suspension and the M715 front fender looks like with a 33" tire.