Just want to clarify these mods before I begin

[Derrick Adams]

I'm getting ready to purchase some wheels and lift for my 03 Mountaineer. I want to run 305/60/18s (32.5x12.5) Nitto Terra Grapplers mounted on 18x10 Helo rims with 6.88" BS. I will run adaptors to clearance the wheels as needed. I'm also not afraid of cutting and clearancing bumpers, inner fenders, fenders, etc for them to fit.

I have read that 33's will fit with the 3" body lift. So how much more clearance problems should I expect with the 10" wide rims vs. the normal 8.5"?

Secondly, since my Mountaineer has the puny hitch behind the bumper cover should I expect it to have the 3.55 gear center cases? In which case I need to source a set of larger cases to accept new ring/ pinion?

 

[The Electrician]

you don't need to change the case

only you need to change the front carrier (the object that holds the ring gear and spider gears) due to Carrier Breaks: 3.54 ratio and numerically lower / 3.73 ratio and numerically higher

Carrier Breaks means that you need to change the carrier if you changed the gear ratio between the diff break ratio due to the deference of the thickness of the ring-gears which is compensated by the dimension of the carrier

the rear carrier does not have Carrier Breaks which means that the carrier is usable for all gear ratio and there is no need to change the carrier if you want to change the gear ratio unless you want to install a selectable locker or helical LSD or any type of full carrier locker

the 3rd & 4th gen explorer shares the same differentials

the following threads are helpful

http://www.explorerforum.com/forums/showthread.php?t=317166

http://www.explorerforum.com/forums/showthread.php?t=318076

 

[Kazer]

Brandon@BTF-Fab [(http://www.explorerforum.com/forums/showthread.php?t=279667) (Phone number : 909 702 7462)]sells coil spacers for $250 shipped. those spacers combined with a 1.5" body lift (http://www.explorerforum.com/forums/showthread.php?t=312012) will net you enough lift to clear 33's

here is my truck with 2.25" front coil spacers, 1.75" rear coil spacers and a 1.5" body lift with 285/70/r17 (33") Cooper Discoverer STT's

 

[Derrick Adams]

Nice job on that ride Kazer!

 

[Derrick Adams]

Just to clarify, I do need to change my carrier in the front if my Mounty is currently equipped with a 3.55 gear ratio? If it's already running 3.73 carrier there will be no need to change it.

Also, I was wanting to go with a 4.30 gearing to add some extra pulling power and compensate for the 33" tires. I see that there is a 4.27 offered for the front and a 4.30 offered for the rear. Are these ratios close enough?

 

[Kazer]

No. Numerically the ratios can only be up to .01 different from each other. I would recommend 4.56 gears for 33s for optimum performance. I recently asked this question to a knowledgeable member on here and this is what I got

Steve,

Any increase in the size of your tires over stock numerically LOWERS your effective gear ratio. So for example, say you have 3.55 gears in your axles and you have 235/70/16 on the truck. Then you swap in the 285/75's without changing anything else. By swapping in 285/75's you are effectively lowering your gear ratio (numerically) to like 3.13. This lowers your engine RPMS in any gear...and it also lowers the torque sent to the wheels.

Now some people will say lower RPMS equals less fuel burned so better fuel economy. If the world were completely flat that might be somewhat true. Of course we deal with hills and highway ramps and stop and go driving so that isn't the case. Also, the 4.0 SOHC is a v-6 so it needs to rev a bit to make good torque. So if you numerically lower the effective gear ratio (by installing larger tires) you are making the engine work harder in all gears to get the vehicle moving and also to maintain speed on hills.

Of course you can go too high numerically on the gears also...like if you put in 4.88's with stock tires. Then your RPMs would be so high that the engine would be spinning faster than needed to maintain speed and get up hills. So it's a balance.

In my opinion, the best balance between good acceleration/torque to the rear wheels and good fuel economy on the 4.0 SOHC motor is to shoot for an EFFECTIVE gear ratio of around 3.73-4.10 with whatever tires you plan to run.

For 285/75's that would mean you need to install either 4.10 gears (giving you an effective gear ratio of about 3.61....falls a bit short of the 3.73 threshold) or 4.56 gears (giving you an effective gear ratio of about 4.02...ideal in my mind). With that said I think the 4.56's would be the best option if you are running 285/75's but of course the RPMs will be a little high if you decide to run the stock tires at all.

What you don't want is to spend all that money on gears/installation and feel like you should have geared it numerically higher...so when selecting the gear ratio, consider that old saying "don't fear the gear!"

Hope that helps!

James

Enjoy

 

[Derrick Adams]

Thanks for all the help! I have no issues in going with 4.56 gears. I'm trying to find a good balance between pulling power and fuel milage.

Right now i'm pulling down around 20mpg (highway) with the 4.6L in stock trim, but with my 6x12 enclosed trailer its around 10mpg. I personally think it's under geared right now.

Time to climb under there and hope that it has the 3.73 carrier in it already!

 

[Kazer]

No need to craw under the truck. Open your drivers door and look for the tag on the end of the door, look for "Axle" and report back here with the 2 character code that is listed

 

[Derrick Adams]

Axle code is 45

 

[The Electrician]

Axle code is 45

that means: it is open diff with 3.55 gear ratio

http://www.explorerforum.com/ntrprize/Axle.htm

 

[n.gardner]

Nice job on that ride Kazer!

x2

 

[Derrick Adams]

So an Explorer actually came with 4.10s from the factory?

 

[Kazer]

Those codes are for sport track models. They use different front differentials and solid axle 8.8s

 

[Kazer]

I have read that 33's will fit with the 3" body lift. So how much more clearance problems should I expect with the 10" wide rims vs. the normal 8.5"?

Quoted from a guy running 285/75r16's on DC-1 rims (8.5"?) with just a 3" body lift

Spacers are definitely needed though...she rubs at about 50% steer either way. It will sit in the garage until they come

3" Body Lift (no suspension lift):

looks like you should wait till you get spacers and the 3" bodylift for 285's

 

[Jwigs7]

Quoted from a guy running 285/75r16's on DC-1 rims (8.5"?) with just a 3" body lift





looks like you should wait till you get spacers and the 3" bodylift for 285's

well presented

 

[The Electrician]

I'd like to add something the spacers cause a high stress upon front upper control arm's ball joints, and the ball joints tend to fail so often. Also the lift will cause negative camber at normal ride height

The remedy: is to install BTF extended upper control arm with uni-ball joint

• The new upper control arms are longer to give you the adjustability so that your alignment can be set back to factory specs.
• They are stronger than the stock arms.
• They have polyurethane bushings for more precise handling and steering. Polyurethane bushings are much stronger and won't wear out as quickly like the stock rubber bushings.
• They have a uniball joint instead of a regular ball joint. Much stronger, better range of motion, and won't wear out as quickly like the stock regular ball joints under heavy use.

http://www.explorerforum.com/forums/showthread.php?t=312771

you can order a spacers + UCA form BTF for around 770$ shipped

For ordering PM Brandon@BTF-fab or email him jalopydriver88@yahoo.com he'll be glad to help

 

[Ronin8002]

Good info Kazer...definitely answers a few questions. I wonder what the backspacing was on those wheels?