Some Questions and your thoughts

[getlost4x4]

alright i have an 06' jeep commander with a 4.7L V8, 5 speed automatic tranny, and 2.71 low range in my T-case.

you may have seen it.

this is from last weekend when we buried it in mud

i'm very interested in making it more capable as an expedition rig. now for me i'll probably never be gone more then 1 week at a time, but never the less i want to be prepared.

Here is how it is set up now:

*3" of lift using OME springs and ford f150 springs out back
*Bilstien shocks
*On Board Air Compressor (I need to add a tank, regulator, dryer, and auto shut-off)
*32" BFG KM2's
*Storage system that replaced the 3rd row of seats
*Rear Diff. Protection
*Rear Tire and Jerry Can Carrier
*Front Winch Bumper and Skid Plate
*T-Max 9000# winch
*JK Rubicon Wheels
*1.5" Wheel Spacers
*HD Upper Control Arms (IFS CRAP Suspension)
*Cobra CB
*Garmin GPS 60csx
*yellow top optima battery

everything works great except the front suspension because its IFS, it makes tons of noise, and basically drives me crazy because i cannot get gears or lockers for the front axle. I may be able to fit an ARB air locker in the rear but no one knows for sure (8.25" dodge axle specially built for commander and GC's)

Here is what i think would really improve my Commander:

*35 Gallon Fuel Tank
*JK D44 axles front and rear with 4.10 gears and commander brakes
*3-link suspension front and rear, coil springs and separate shocks(no coilovers)
*exhaust system


i am very happy with my jeep. it has 65K miles on it and has never had a problem. the biggest problems to me are the lack of aftermarket support for the axles and suspension.

 

[winkosmosis]

There's a thread on a Commander on the Pirate4x4 expedition board. I would link, but the server is down right now. You'll have to search when it's back up.

Why does your IFS make noise? Is it the CV joints? I think I would prefer an IFS vehicle for expeditions, because the ride is better, especially compared to a lifted solid axle vehicle. No worries about control arm angles causing harsh ride.

I'm not sure if your axle is 100% compatible but there is an Auburn ECTED locker for the 8.25. I don't see the point in outdated compressed air lockers when there are simple electric ones. Sometimes people stick with old tech for no reason other than it's what they're used to.

http://www.4wheelerssupply.com/?manufacturers_id=33

 

[Hilldweller]

How about a D60 rear, D44 front, 37" skins, and 4.88 gearing?
Long wheelbase vehicles have always hung me up on their break-over angles rather than articulation range. Downhill inertia on a heavy truck can be ponderous too.

 

[winkosmosis]

Doesn't the Commander have a shorter wheelbase than the 4 door JK? :sombrero:

 

[Root Moose]

Here is what i think would really improve my Commander:

*35 Gallon Fuel Tank
*JK D44 axles front and rear with 4.10 gears and commander brakes
*3-link suspension front and rear, coil springs and separate shocks(no coilovers)
*exhaust system


i am very happy with my jeep. it has 65K miles on it and has never had a problem. the biggest problems to me are the lack of aftermarket support for the axles and suspension.

I'm with you! But you already knew that.

Why three link? (I'm assuming you mean three link plus a Panhard versus a radius arm plus Panhard setup)

Here's my thought on this: An XK will never be a really extreme rock crawling machine. It's too big and and requires cutting lots of sheet metal to do the extreme stuff.

Your intention is an expedition truck, right?

I say do four link if you can make the packaging work. Your going to sell this suspension after you have it prototyped?

Why four link? Because it is one more than a three link.

I have no technical basis for this but in my mind for a truck that will see lots of highway miles a four link is more "balanced" from a forces point of view. One side is not taking more forces than the other side. Does that make sense? Call BS on it if you want.

Also, the four link will be able to keep deflection to a minimum with respect to brake and dive forces across the chassis. An expedition truck will be using rubber bushings in the suspension. If the third link is on one side of the chassis it will control deflection on that side well enough but due to the nature of a solid axle the other side will be more out of the desired movement range because that side of the suspension is not being controlled by the fourth link. It creates a yaw and twist force on the axle at highway speeds (at least in my mind it does!). Does that make sense, follow what I'm trying to say?

If you plan to sell a kit in the future you'll have a lot harder time doing it with a three link. Four link looks obvious to people (customers!) that don't eat/breathe/sleep off-road buggy design. Three link... not so much.

A four link will flex more than enough for an expedition style rig.

Anything you do to get rid of the IFS parts the better IMO. Solid axles are more robust. No question.

I like that you want to use standard coils and shocks.

You want the best on-road ride you can get for expedition use, right?

I'd design around a 33" tire. It's a "standard" of sorts. Maybe 285/75-16 (or ~equivalent 17") makes more sense these days.

Can't go wrong with the JK axles IMO. It's a no brainer in a cost/performance ratio kind of way.

Hey, you asked.

 

[Root Moose]

Just another quick thing to think about - when you are sorting out the antis - try to keep close to OEM style values (IIRC ~30%). That's what people are used to driving. Buggy builds typically use some crazy values and I've often wondered how they would behave in a road car. Probably scary at the limit.

Roll steer is another parameter to play with. IIRC you don't want very much at all.

It might be useful to take some measurements and calculate how all these parameters are setup from the factory on your XK. I can scan and forward some of the diagrams and calculations from Milliken & Milliken if you want (PM me).

 

[getlost4x4]

It will not be a rockcrawler. i'm not really into that anymore. i just love driving and hitting trails. There isn't anything that extreme around here anyway.

i think 33" tall tires would be the largest tire i will ever run.

I do not plan on selling this as a kit. I have actually quit my business because the economy really sucks, shipping ran me into the ground, and its a pain in the ******** to run a fabrication business. i'm also going back to school in the fall for business administration. i'm going to work on my BA and masters.

the wheel base of the commander is about 110". It works great off road with approach and departure angles. The only thing i really need to build is a rear bumper.

i don't like the ifs because its weak, the cv joints are starting to sound bad. the squeaking is coming from the control arms. the front end is just about dead. i use this thing off-road about half the time. the ifs is the weak link

i think using the radius arm style suspension front and rear with a panhard bar. its a good proven design, and i'm not looking for tons of wheel travel.

 

[getlost4x4]

i had no idea there was an etec for the 8.25. the only problem is if it will fit my axle. the new 8.25 is a lot different then the old 8.25" axles. It does not use c-clip.

that thread on pirate is my commander.

There's a thread on a Commander on the Pirate4x4 expedition board. I would link, but the server is down right now. You'll have to search when it's back up.

Why does your IFS make noise? Is it the CV joints? I think I would prefer an IFS vehicle for expeditions, because the ride is better, especially compared to a lifted solid axle vehicle. No worries about control arm angles causing harsh ride.

I'm not sure if your axle is 100% compatible but there is an Auburn ECTED locker for the 8.25. I don't see the point in outdated compressed air lockers when there are simple electric ones. Sometimes people stick with old tech for no reason other than it's what they're used to.

http://www.4wheelerssupply.com/?manufacturers_id=33

 

[Root Moose]

i think using the radius arm style suspension front and rear with a panhard bar. its a good proven design, and i'm not looking for tons of wheel travel.

Radius arms have worked on G-Wagens, Land Cruisers and Land Rovers for eons. It'll be fine under a Commander. The only real thing to look out for is to try to get the arms as parallel to the ground as possible when at loaded ride height.

Make sure you post lots of pics. I may follow you down the road.

 

[getlost4x4]

i'm going to have to start saving pennies (school loans) and get the axles. i just need to figure out suspension arms, springs, steering box, and some other crap.

i have a tank designed for the gas. i want to get rid of the stock tank and install my tank behind the rear axle. this would distribute the weight better then having it where it is now.

i need to design some other crap as well. hopefully i can start gathering parts this year. i have some crap i need to pay off first. the business has just killed me financially.

we are moving to a different town with much cheaper rent. i'm also getting into student housing, its a condo and all utilites are included in the price. i'm looking at saving $400 / month or more on rent and utilities. this will be a big change. i'll still have a garage atleast.

 

[Root Moose]

I don't know if you are going to have much time to work on this with school and all. Condo corps are a PITA with respect to people that wrench in their laneway too. Make sure you are discrete and secretive about the whole thing or one of your neighbors will rat you out. I'm not joking...

Sorry to hear about the business. I was hoping it would work out for you. I'd love to see the XK have more support from the aftermarket. Sometimes it's more convenient to buy than build.

Have you considered doing an auxillary tank to start? In Australia there is a company or two that makes an aux tank for the XJ that fits in that space behind the transfer case front output. It's not a huge spot for a tank but it has the advantage of being relatively easy to prototype without disturbing the regular tank. Obviously I've never looked under a XK so I don't know if that makes sense as an option - I guess you'd be doing the converse if the existing tank is in front of the axle.

For the axles, maybe get a junk yard D30 front an D44 rear (open) to get the prototyping ball rolling. I've seen them locally cheap, must be the same there. Worry about getting locked axles after you finish school and get working again.

 

[getlost4x4]

i have started designing an AUX tank in AutoCAD. i just need to get the money together for metal. it will be cut from 1/8" aluminum, have baffles and a fuel pump to pump fuel forward to the original tank.

i lived in these condo's about 5 years ago. i worked on my toyota in there before. i know the the guy that runs those very well. he doesn't care as long as i leave it clean when we leave.

 

[dirty Bakers]

Is that a chain saw? I have like Comanders since they came out.

 

[getlost4x4]

yes thats my chainsaw on the back. it makes cutting wood for fires very quick and easy. it was my wifes grandfathers. i just did a carb rebuild on it and gave the carb a tune up. the chainsaw is about 30 years old and was built by craftsman it has a 14" blade.