I'm finally getting ready to install an 01 Expo rear axle - no biggy there as far as install, but, I also have a set of 08 Expo chrome wheels that I'd like to run.

Will the extra width of the Expo axle be sufficiant to compensate for the lack of offset on the 08's wheels? I am not a fan of spacers but will use them on the front for daily use (offroad, I'll swap back to my current wheel/tire) if I don't have to use them on the rear.

 

fyi explorer axle is .75" wider per side than the ranger axle. I am not sure what offset those wheels are though.

 

i cant see a difference in the width on my axle but it was wider

 

So far all I've been able to find on the 08 wheel is that it's a 44mm offset. I haven't been able to confirm it though.

I knew about the .75/side, I'm just trying to figure out if it's enough to run the new wheels without spacers and not have them make the back of my truck look like it's on stilts.

 

whats your stock wheel offset?

 

i think stock is 3.75 and it shouldn't change the look much i didn't notice a difference

 

Arent the new rims a different bolt pattern? I thought they changed it when they went to an independent rear suspension.

 

^^^ i think your right i think they went to 5x5.5

 

pretty sure it didnt change

 

ZeBeard: I'm told the stockers are 12mm

The new Expo wheels have the same bolt pattern as the Ranger. I've already had them on my truck but they make it look like it's on stilts due to the different offset.

 

No, it won't compensate for the offset, they'll still look inset. The Expo rear compensated for the Mustang 24mm offset quite nicely though.

 

44mm-12mm is a 1.25" difference but im not sure in which direction.

so if its the right direction then they would still need a 1/2" spacer

 

Proper wheel offset is based on where the centerline of the wheel bearings are in relation to the mounting surface where the rim mounts to the axel. This is so that resulting centerline of the wheel is even with the centerline of the wheel bearings. When the centerlines of the wheel and wheel bearings are offset from each other (not even) a torque is applied to the bearing which results in premature bearing wear and failure. The more offset these two centerlines are, the faster this will happen.

The wheel offset has nothing to do with axel width.

That said, I have no idea what the offset is that you are looking for. I only know it has nothing to do with the axle width.

 

Thanks Zebeard.

icthusrulz: thanks for the "for dummies" tutorial. It gives me more to think about.

 

actually from the total question he is asking its got everything to do with axle width

 

Ok.

He's got an explorer axel that requires a given backspacing based on the design and location of the bearings to the mounting surface for the wheel. I'm not seeing how that relates to axle width other than possibly for axle identification purposes.

Now if you want to match the width between the wheels to the stock axle, then you can pick the backspacing to do so. The further this backspacing is from what the axle was designed for, the more quickly the bearings are going to wear. Now, practically speaking you can deviate "slightly" from the backspacing the axle was designed for without any "significant" difference in bearing life.

I'm not above being wrong. Am I missing something here?

 

Dan...you're way over thinking this... 110k on the stock bearings with heavy 15x10 wheels and 35x12.50 tires on wheels with a 4" backspace....been running stuck out steel wheels and oversize tires since about 40k. not a peep from front bearings and the rears are still in perfect shape. I'm not saying your wrong, because well...you are right. But the OP isn't going to be running a 15x15 wheel with 2" backspace on 40x14.50" tires...

For what the OP wants, wheel mount surface to wheel mount surface has alot to do with what he wants...a decent fitting OEM explorer wheel on a Ranger.

 

It seems you have more experience with this application than I do. I guess Ford added quite a bit of safety margin when they designed their wheel bearings. Got any ideas about what ranges of what a given deviation in backspacing will get you in the way of bearing life?

Improper offset will also cause some additional bending loads to be experienced by the axle itself, which can cause a fatigue failure, but such a small amount of backspacing is probably poses no real problem.

Have you had any ill effects from additional backspacing on your front wheel bearing?

 

Some of the confusion here is that I'm a landscape architect not a mechanic. I know what I want to accomplish regarding my Ranger unfortunately, I may not express myself clearly and/or use the wrong terms to descibe what it is I'm after.

Now that I feel I have a decent grasp on wheel offset, I'm going to go ahead and run with my plan. I'll be driving x-country in a couple weeks, I'll check for any signs of wear when I get to my destination.

 

I guess my whole point is...MANY MANY MANY people run different offset/backspaced wheels with much larger heavier tires....and they don't seem to go through parts like you suggest. I'm not saying you don't know your stuff, because it seems as though you do. In my opinion, if someone can get over 100k on stock front end components on a 4wd, that's pretty good...add the larger wheel tire combo, and I think it's pretty dang good. I'm basing my statements by my experience on my own truck over the past 70k that I've owned it....90% of those miles were on aftermarket low backspace number and larger tires. I don't not agree with you...larger, heavier rolling setups and less backspace wheels do add some extra wear, just not as much as you are making it seem, espicially for a little explorer stock wheel compared to ranger stock wheels.

I've not had any ill effects yet on the front bearings/hubs(I was talking about that as well in my previous post) in the 110k they've been on the truck. No growling, no moaning, no whining. They do have 110k on them, and have had the 10" w/ 4" bs and 35x12.50 for almost 50k now, so I think for good measure, I'm going to replace those when I replace the outer TRE's(since they need them now...stockers still there).

 

You had mentioned that your rear wheel bearing had held up fine. I was curious how the front end was holding up. I wasn't trying to argue, I was just curious.

And the bending thing was something that could theoretically become a problem. I even said that probably shouldn't be a problem. It seems that experience confirms that.

So does anyone know what amount of backspacing starts to significantly break things, or is it so much that it really doesn't matter?

 

The biggest thing to remember here, is that positive offset, yes, will cause "more" wear to suspension components. But the Explorer wheels have negative offset. So he needs the longer axle to compensate. No extra wear on the suspension components with the Expo wheels, therefore, that whole argument is a mute point in this thread.


To the op, I think if anything, you may need to run a spacer with the new Expo wheels, seeing as they have so much negative offset.