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Do you like my new stickers?

12K views 88 replies 11 participants last post by  FJLED 
#1 ·
Figured that's get one of the three viewer's attention.

Considering there's no other discussions occurring here, and I'm certain there will be no shortage of opinionated responses, I'll toss this in the ring for debate.

Preface with I'm mechanically challenged, when it comes to the discussion, or implementation of suspension design, theory, calculations, fabrication and installation, but I'm not a dumb ass. If the education and information is above the requesting of the members here, then I'll quietly revert back to lurking, as one of the three viewers on the FJ portion.

Attempting to determine the rear end, gearing, and locker combination, as part of an in process LT upgrade. All of the usual have been suggested, and have had many conversations with the other blue room participants that frequent this forum, but the more I delve into discussions with various vendors, the more I realize how ignorant I am.

Intend on maintaining the OEM linkage geometry, mounting locations, shock mounts, again for the previously stated lack of ability.

Let the flaming education begin. What is critical for determining what is necessary?
 
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#2 ·
銀チタン;13344305 said:
Figured that's get one of the three viewer's attention.

Considering there's no other discussions occurring here, and I'm certain there will be no shortage of opinionated responses, I'll toss this in the ring for debate.

Preface with I'm mechanically challenged, when it comes to the discussion, or implementation of suspension design, theory, calculations, fabrication and installation, but I'm not a dumb ass. If the education and information is above the requesting of the members here, then I'll quietly revert back to lurking, as one of the three viewers on the FJ portion.

Attempting to determine the rear end, gearing, and locker combination, as part of an in process LT upgrade. All of the usual have been suggested, and have had many conversations with the other blue room participants that frequent this forum, but the more I delve into discussions with various vendors, the more I realize how ignorant I am.

Intend on maintaining the OEM linkage geometry, mounting locations, shock mounts, again for the previously stated lack of ability.

Let the flaming education begin. What is critical for determining what is necessary?
:laughing:
 
#3 ·
No flaming here:flipoff2: The answer to your question has more to do with what you intend on doing with your rig and or how capable are you needing to build it. It sounds like you already have plans for the front end, so that being said desired tire size will drive most of what you will have to modify to the rear end (ie gear ratio, Ring & Pinion size, lift etc) what size and type tire are you wanting to run? Are you planning on using low range or mostly high range? Are you needing a real locker? What type of terrain/obstacles are you wanting wheel? The answer should be pretty easy after answering these questions. Feel free to respond and I'm sure we can provide you a pretty clear laundry list of mods that will have to be done to meet your needs. As far as the "3 Viewers" that is pretty sad:shaking: I spend most my time in the Comp sections and I would imagine that a lot of fellow FJ cruiserheads split time in other forums and casually drop in to here. Thanks
銀チタン;13344305 said:
Figured that's get one of the three viewer's attention.

Considering there's no other discussions occurring here, and I'm certain there will be no shortage of opinionated responses, I'll toss this in the ring for debate.

Preface with I'm mechanically challenged, when it comes to the discussion, or implementation of suspension design, theory, calculations, fabrication and installation, but I'm not a dumb ass. If the education and information is above the requesting of the members here, then I'll quietly revert back to lurking, as one of the three viewers on the FJ portion.

Attempting to determine the rear end, gearing, and locker combination, as part of an in process LT upgrade. All of the usual have been suggested, and have had many conversations with the other blue room participants that frequent this forum, but the more I delve into discussions with various vendors, the more I realize how ignorant I am.

Intend on maintaining the OEM linkage geometry, mounting locations, shock mounts, again for the previously stated lack of ability.

Let the flaming education begin. What is critical for determining what is necessary?
 
#4 ·
Thanks for your reply.*

Intended usage is mixed, but will be driven the many miles necessary just to get to the varying terrains, that consist primarily of rocks, trails and minimal high speed desert terrain.*

The OEM third is notoriously a failure point, and attempting to prevent occurrence 400 miles from home, at the same time increasing the rear track width 4" to correspond with the front. Reliability being biggest reason for replacing.*

Currently running 33"s and based on the responses from varying sources, re-gearing to 4.88s has been advised with air lockers front and rear. Front being an addition, altogether.*

I've discussed the RJ60 and it's been stated it's probably heavier than necessary, and there are lighter options offered that are "bolt on", and better suited for the purposes described. Having stated the lack of resources and capability for fabrication, "bolt on" factor has been the primary concern, and the limiter to determining, without requesting input from forums and vehicle specific vendors.*

To address the "3 viewers" comment. There's obviously a wealth of technical experience on this entire forum, and I've perused every section here in, with intention of self educating. I realize that there's little tolerance for dumbass questions, and I've spent a considerable amount of time attempting to answer the dumbass question I posed, already, to no avail. Each answer poses another question.*

I'd like to see more discussions here, in regards to the technical aspect of the specific vehicle, *but there must be an underlying fear from participation.*

I bounce between several forums, but have found the limitation of discernible information, when it comes to questions of this nature, on the others. Except for a few guys with actual experience, the respondents are quoting the pertinent information from the vendors webpage for whatever it is they were sold, and had installed.*

As stated in another thread, I'll likely win the prize for the "least meaningful contributor" which appears to be an accurate statement, but considering the lack of current threads in this section, a dumbass question may beat none at all, and pave the way for more dumbass questions from the other lurkers with the same intention I have, for the sake of audience participation.*

Make it challenging to post in every FJ thread in a day, all while enlightening those not concerned about the "do you like my new stickers?" threads waded through elsewhere.*
 
#5 · (Edited)
Without getting into too much tech:D Keep in mind I have never built an FJ, I bought it:smokin: That being said, I have built many rigs over the years and have sold them right here on Pirate. Any time you start swapping axles there is a good chance you are going to have to fab bracketry (w/exception of a Jeep) Also keep in mind you are on a slippery slope. Once you start building it will never be good enough and you will continue to throw $$$ at it:D So my .02 cents is build it right the first time, trust me it will save you $$$ later.
first off 4:88's are correct and will take you to 37's if you want later. Due to your axle width requirement, you can cross out all mini truck rear ends due to 55"-58" width depending on year. 4 Runners (96 and newer) around 60" so that would require wheel spacers (not recomended) unless you have to. The RJ is over kill for what you want to achieve. That being said, if cost really isn't a big factor, my top two choices would be a Spyder 9" (no question) or Currie 9" due to availability, weight, options. That being said, I have seen several FJ 80 Axles on here (in classifieds), with the cost factor, electric lockers, full floater, and aftermarket chromally shafts from Longfield this would be a great choice. You probably would have little fabbing to do due to simiar suspension design, it is 63.5" width vs your 64.25 FJ so you are right in there. This would be a great option and you could do the SAS later very affordable plenty of axles. Trust me, if you stay on the rocks, it is a slippery slope and you will eventually do a SAS. Do not do Coil overs in the rear, it's not worth punching 2 holes in your truck. (Been there with my 1990 Range Rover on portals and 42"s). Use the OME 418's (3" coil lift) that will clear up to 37's easily. Call Tony as Rock Equipment and get one of his buggy sway bars (it's not bolt on and will require very little welding)
FAB= None of us were born Fabricators, in the long run, you will save yourself a lot of $$$ and headache by learning to weld. Keep in mind your not building a tube buggy:flipoff2:You just need to be able to buy brackets/links and be able to weld them on. Tires=KM2 BFG (yeh, I'm sponsored by BFG) however, best choice for your application, Good Year MTR 2nd choice

I hope some of this info helps
 
#8 ·
Very much. Thanks.

Currie 9" appears to be the contender. As for the specifics, still reading. At some point, they were rumored to offer an FJ specific bolt on, but there's no indication anywhere I can find.

Every answer poses another question.

I can weld, but I'm not a welder. Have honestly never built anything but quads, but my intention since I bought was to do it myself, regardless of fuck ups. Plan to adhere to.

Thanks for the direction.
 
#6 ·
Chris as insinuated earlier on other forums the 9" LP Currie is probably your best bet for a "bolt on" axle that matches OEM geometry. It will be lighter and stronger than the HP RockJock that everyone seems to believe (on the blueroom) is invincible.

Currie is the only company that will offer a bolt on option. Any other axle provider will be requiring you to setup the mounts yourself.

However, I'd really consider doing a new rear suspension if you are spending the money on a new axle. The vast majority of folks have had their OEM rears hold up fine...the ones that I've seen break them first hand were loving on the skinney pedal and hopping.



btw - coilovers in the rear don't have to go through the body :flipoff2:
 
#10 ·
I listened, but still unclear on the specifics.

Why the LP vs. HP?

Will the drive shaft have to shorten with either?

ARBs for front and rear? Only regear front?

Is it stupid to replace the known weakest component of the drive line, in advance of even a planned redone rear?
 
#7 ·
What size CO's in the rear R U running and at what angle? I am assuming that you mounted them vertical to the axle with no inward slant! If so, how is the body roll and sidehill stability?
 
#9 ·
I'm not refering to mine (photos of mine provided below for reference tho). You could potentially fit a 12" travel 2" dia coilover without going through the interior (forward, vertical, or aft of axle...see photo below). A 14" might be possible if you push it and are willing to have a very low mount on the axle, oem ish. A wider axle makes things a bit more friendly.






Images of the coilovers on mine are below. 14" travel 2" diameter notched into the frame. Coming into the interior wasn't an issue for me since the back seats were replaced with a storeage setup anyways. It's all framed out anyways too look like oem sheetmetal below the stock interior.




 
#11 ·
銀チタン;13348116 said:
I listened, but still unclear on the specifics.

Why the LP vs. HP?
HP in the rear you are running on the coast side of the gears which isn't as strong.

銀チタン;13348116 said:
Will the drive shaft have to shorten with either?
Yes, you'll need a custom driveshaft or yours modified to the correct length.


銀チタン;13348116 said:
ARBs for front and rear? Only regear front?
ARB isn't your only option as far as lockers go if you are doing a custom rear. The front and rear axle have to run the same gear ratio, so unless you get an aftermarket axle and run 3.73's, you'll have to regear the front to match your rear. If regearing the front, there isn't much added cost to add a locker there as well (really the cost of the locker itself) since you are already pulling the dif apart


銀チタン;13348116 said:
Is it stupid to replace the known weakest component of the drive line, in advance of even a planned redone rear?
Build the vehicle as you see fit. If thats preventative so things don't break than go for it. If its upgrading when things break then go that route. I will say that your rear third isn't the weak link in the entire driveline (imo)...many more folks have blown their CVs than those tearing apart their rear third members.
 
#12 ·
OK, being one of the three I will jump in here. Dont feel like a dumb ass for
asking stupid questions. I have the baddest FJ in the world and am a technical idiot. I'll be the first one to admit that when I started building Mad Dog the first time, I thought a locker was where you stored your gear I just didnt understand why you needed two of them.
I happened to have the resources and very little time so I had almost everything done by someone else and if I didnt like the way it worked out I just had them do something else. I didnt want to know how or why I just wanted to drive it hard and fast on the toughest trails in the country.That being said I didnt really become part of the offroading community I just became known as a rich dumb ass.
Mad Dog has now been built 3 different times and is in its 4th and final as I write this but I have changed along the way and have really started learning how and why. As the 3rd build progressed I started doing some of the work myself and researching suspension geometry and calculations. I also started paying attention to my rig and how it responded in the desrt and in the rocks so that I could make sense out of roll center and antisquat and the way that the rear wheels track in reference to the front.I think it was Belly Doc who made a coment on one of these threads about how you dont really have or know the true spirit of offroading until you have done your own work. So that is what I have started doing as much as possible. I recently aquired an FJ40 that I will be building on my own and have alrady started. I am also learning to weld so I know if I can do it any one can.
Hopefully some time I can go back and post a comprehensive build thread for Mad Dog from the begaining so all can see how it morphed into what it is now. The next build thread will be from what it was at last KOH to the race build that is being done now.

I HATE LONG POSTS !!
 
#18 ·
I had good conversation with a local builder, whose a vendor here, about the rear end short term goals, and long term aspirations.*
To reiterate the short term, eliminate a potential issue, while extending width.*

After meeting, seeing, and hearing his responses to my questions, and explanations of several I hadn't known to ask, I feel comfortable with his capabilities to see this through to the end......once I determine where the end is.*

I wish I'd had the opportunity to meet with a few weeks ago before a few acquisitions were paid for, and I possibly would've gone all out on this round. *The *rear will be baby stepped into, without limiting future changes. Not too far gone. I can still do what I thought I was going to do solo, makes the necessary major revisions to the rear suspension next year (or month, who really knows), while replacing the OEM, now.*

He claimed the linkage brackets can be installed, removed, and re located without damage. They've done it before, and expressed no concern. ( that statement would kind of have me concerned under normal circumstances ). The components of themselves would remain unchanged, regardless of 3 or 4 link, or lefty addition later.*

So that puts me back to where I was, with a rear end to order in the near future.*
 
#24 · (Edited)
:laughing: The last bit wasn't neccessarily directed at you....more or less pbb in general. I want to learn dammit! (looks around and waits for someone to post up "Search :flipoff2:")


銀チタン;13367863 said:
From reading, the Dana pinion is 2" above the axle, and the 9" is 2" below.

I'm a proponent for the 9", due to the intended usage, for clarification.

Googled "Currie 9" FJC" and spent two hours perusing Air's build. Basis for the question, and I did the 2+2=4 math for the uneducated 4" difference.
Ahh...I think you are comparing a high pinon 60 axle to a low pinion 9 axle? Comparing apples to apples (LP to LP or visa versa), the pinion height to axle center difference, between the 9 and 60, should only be around an inch.

The tradeoff with the HP is better driveline angles (reduce your risk of rocks meeting driveshaft), but at the cost of reduced strength vs its low pinion counter part.



I'm not saying that a 60 isn't stronger than a 9 or can't be built stronger....or the other way around, in some situtations. However, I think it'd be better to elaborate on "why is it stronger" aspect with info on the respective axle. I only have a basic understanding compared experts on here, but from what I've seen, when you start looking at the strength to weight...things can get a bit muddy but folks seem to gravitate in a certain directions.


Chris - are you open to all axle options or only one you can get with bolt on mounts (limits the discussion to curries products)? It helps frame the context of the discussion and options.
 
#26 ·
:laughing: The last bit wasn't neccessarily directed at you....more or less pbb in general. I want to learn dammit! (looks around and waits for someone to post up "Search :flipoff2:")




Ahh...I think you are comparing a high pinon 60 axle to a low pinion 9 axle? Comparing apples to apples (LP to LP or visa versa), the pinion height to axle center difference, between the 9 and 60, should only be around an inch.

The tradeoff with the HP is better driveline angles (reduce your risk of rocks meeting driveshaft), but at the cost of reduced strength vs its low pinion counter part.



I'm not saying that a 60 isn't stronger than a 9 or can't be built stronger....or the other way around, in some situtations. However, I think it'd be better to elaborate on "why is it stronger" aspect with info on the respective axle. I only have a basic understanding compared experts on here, but from what I've seen, when you start looking at the strength to weight...things can get a bit muddy but folks seem to gravitate in a certain directions.


Chris - are you open to all axle options or only one you can get with bolt on mounts (limits the discussion to curries products)? It helps frame the context of the discussion and options.

I quote from "Currie FJ Ford 9 Axle" circa 2008. ( Google Title, if interested )

"there are two primary aftermarket gear sets for factory off road vehicles. The Dana Series for crawlers, and the Ford 9 for racers. Dana pinions are 2" above the rear axle, and the Ford 9 is 2" below. So who wants a Ford 9? It's stronger (than OEM was author's intent ) and takes sudden shock loads of high-speed runs better, but the clearance creates as issue over the rocks."

End quote

According to this same thread, the author's FJ was used for, and this was the prototype for the Ford 9/FJ "bolt on". For context, was installed on probably the most intense build I've seen for a desert FJ, to date.

I'm not one to be spoon fed, as the participants on the "other" forum know, and still yet I have multiple, impending WTS threads coming soon. So don't think I read and considered this to be the final word, it's the only information I've found anywhere about, vehicle specific.

No. I'm no longer limiting to "bolt-on" due to the previously posted meeting, yesterday. I would like to maintain the ABS/Speed Sensor functions, though.

The basic criteria is wider and reliable, on 35"s with intention of OEM linkage mounts (not OEM links), now. I don't want to limit a future rear 3-4 link, or have to replace, considering they're not giving them away.
 
#29 ·
Again, I don't know enough to argue on my own. I just read stuff like this (aware that these are not the best sources - just a bunch of anicdotal):

From Pirate:
The Dana 60 is unquestionably the most desirable steer axle currently used by rock crawlers. No matter what upgrades are performed on lighter duty units, their strength just cannot be compared to the Dana 60.
http://www.pirate4x4.com/articles/productreviews/dedenbear

http://www.fullsizebronco.com/forum/archive/index.php/t-116363.html

http://www.moparchat.com/forums/showthread.php?t=72878&page=2

http://www.stevesnovasite.com/forums/archive/index.php/t-173033.html

(I doubt last two were Hi-P though)
 
#30 ·
That is no different from folks on the blue room saying a HP rockjock is indestructable. Aside for one or two posts there is little technical comparison between them...the few that are there are far from comprehensive. I can post up links to other forums saying "go with the 9"...its better". What value does that add to this thread though without justification behind it?

I'm not arguing for one axle or the other. Simply trying to illustrate the tradeoffs I know of and better understand the ones I don't. Shafts, R&P, Locker, Housings, Design, Strength, Weight, etc.


btw - it probably would be best to keep the thread and vehicle in context, so we are all on the same page. Unless Chris is planning on doing rear stear or swapping his IFS out for a SA front the pirate link doesn't provide much insight. Rear axle & aftermarket options (not stock).
 
#31 ·
I can't argue your point. I was just saying that anecdotally I always heard that the D60 was stronger.

Chris, I think you should put a TTB in the rear (being facetious). That would be a first for an FJC though. Has anyone ever put one on the rear before? I was just thinking about it because Torchmates Ultra4 build w/ TTB in the front recently won a race.
 
#32 ·
In continuation.*

Let's assume that a bolt on product is no longer a criteria.*

Based, again, on little information a Google search produces about vehicle specific 9" offerings, and even less general knowledge, it appears that Currie (2008) attempted to offer a bolt on option for the FJ, yet I can find the product (for research, not purchase) anywhere.*

Some issues the prototype for FJ encountered were, quote*

"1. Toyota set the engine and transmission "flat", meaning it does not tilt down as in most other engine installations. *This affects the driveline geometry negatively, but has benefits in ground clearance and center of gravity.

2. The Toyota transmission output shaft sits relatively high for protection. *This increases the driveshaft angle even more.

3. The Ford 9 pinion is 2 inches lower than stock, increasing the driveshaft angle again.

4. The Dana 60 pinion is 4 inches higher than the Ford, so it does not have the angle geometry problem. *However, it still needs a new driveshaft because the pinion is a couple inches farther forward.

The first adjustment Currie tried was to lengthen my upper links by an inch. *This has the effect of rotating the axle back, pointing the pinion up and decreasing the angle. *But it wasn't enough.

All-Pro does carry adjustable uppers, but the adjustment range is intended for the stock axle. *This is true for all the adjustable lowers out there as well. *So, putting in adjustable upper and lower links would not have rotated the axle far enough in this case." end quote.*

They corrected with a new drive shaft a Double Cardon joint, and modifications to the linkages at this install. The 9 had a u-bolt yoke and the drive shaft was accommodated to mate, but it was stated the the 9 had the option of flanged, just wasnt utilized.*

Here's my questions:

Could this have some bearing on why Currie doesn't market a 9 bolt on?

Let's assume that the OEM linkage points are maintained, and the pinion angle is correctable, will the LP pose an issue, requiring the CV2 joint, regardless?*

Mad Dog, I know you hate long post, but in light of the current banter, wanted to provide the information as I read it, in it's full form, so we're all on the same page, to avoid the bullshit.*

As previously expressed, I'm technically challenged, but the issues as stated, are making sense.*
 
#33 ·
Chris - what Todd outlined there are all minor items that come with changing out axles...none of them are as "big" as his posts made them out to be. I don't see any of them stopping Currie from offering a 9" for the FJ specifically.

You'll need a new driveshaft anyways, so getting one with a CV isn't a big deal. You'll see less vibration with CV/double cardan, but it will be a pia to deal with if it fails (not as easy as reparing a singal cardan on the trail). Going with something like a Tom Wood's or High Angle driveshaft and you'll be fine for the type of trails you are planning on doing.
 
#36 ·
I've heard the term "expedition vehicle" to describe. More specifically, drive hundreds of highway miles to get to varying terrain. Primarily, see more rocks and trails, locally, but intend on traveling the desert south west.

Want to maintain the ABS functions, so maintaining stock brakes, and in the future, may (I'm frigging sure) do a 4 link and coilovers. For now, maintain the OEM linkage geometry.

Part of this process has been ensuring that the rear is permanent, for whatever suspension in finalized.
 
#37 ·
For an expedition vehicle either will work. A good expedition vehicle is about reliability. The one I was driving was supercharged with a manual on 40's. The hp rear held together fine.

If you are going to use the stock bracketry, I would go 9" as I think it would be easier to weld everything to. I'll bet Currie can put factory outers on either axle.

For what you want to do, I'd run the factory axle. Easier to get spares for if it breaks, which is still unlikely.
 
#47 ·
Communications with Currie, in regards to.


Quoting Darrell at Currie.*

"The 9 is definitely a viable option to look at, depending on what you plan
on doing with the truck. The 60 is the bigger differential in gear size,
carrier size, and just basically sheer size in everything. It is the
'stronger' of the two in almost all aspects. The one aspect that the 9 inch
beats the 60 in would be housing strength, especially a fabricated housing.
The 60 has a slightly weaker housing because of the inherent strengths you
lose when you have a steel tube pressed into a nodular center. The 9 inch
has an all steel housing with steel tubes welded in. The fabricated centers
have a 'D' shape notched into the end of them so that they index the
faceplate and basically have one continuous structure from housing end to
housing end. Both units use essentially the same axles and bearings, so
there's no real difference there. The 9 inch also has a bit better ground
clearance because it's smaller. So really, there are situations where either
would be the better choice. You just have to determine what situations you
are going to be in and choose the unit that suits that better."

Second reply, my questions are obvious.*

"The 9 is available as complete as the 60 is. I don't build them with the
axles already in there because they reuse your factory brakes. The 9 inch is
going to be smaller and lighter than the 60, typically about 40 lbs lighter.
LP is definitely stronger in the rear. The 9 inch is the only one that will
really make a difference in a truck as light as an FJC. The high pinion 60
will still be more than strong enough. What size tires are you running?"

I replied "35s". His response.*

"You could technically run the high pinion on either one of the 9 or 60, but
the high pinion 9 inch is at its limit with that kind of vehicle weight and
35 inch tall tires. The 60 would be much stronger, or the low pinion 9 inch."

"If *you're high speed running, like a desert run, the low pinion 9 inch would
be better. For slower rock crawling type stuff the high pinion 60 would be
better. "
 
#50 ·
Considering the latest information from Currie, and the nominal 40lb difference between the two completed assemblies, and takers on recommending a direction from here?
How critical is the 40lb difference?

I originally thought the axle/driveshaft could be a consideration, and installed, later adding the TC/Crawlbox, whatever, but it's potentially more of an issue later, correct?
 
#51 ·
I'm still interested to hear more on the 40lbs difference. Most quotes I'd seen previously had showed it at 100 or more and the Pirate weight chart shows 75lb difference between a 9" (225lbs) and a 60 (300lbs).

As Dave mentioned elsewhere the beauty of the 9 is being able to weld directly to the housing. The 60 nodular section means most folks truss it which potentially increases your overall height. Definitely the case on the FJC which makes it a bit difficult to manage with the upper crossmember near the gas tank.

Either one is an option (so is sticking with OEM). If I had known more when I bought mine and not simply gone on the vendor saying the HP 60 is "indestructible", I would have selected a different axle.

You'll likely need a new driveshaft if you go with a aftermarket axle...yours could be modified to work tho. If you plan ahead of time you can probably also make the driveshaft you get work with your current and final transfer case. Again not something to get too hung up on.
 
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