FJ40 & FJ60 Diff Conundrum - Advice needed

[RAY185]

I know theres been alot of talk recently about diff swaps from 60 to 40 and I understand whats involved (well I'd like to think I do anyway).

I have a wrecked FJ60 bought for parts to swap into my FJ40. I had every intention of putting the 60 diff housings under the 40 to gain both more track and to utilise the front disc brakes (40 currently has drums all round). I also intend on using the 60 series power steering.

I'd like to hear from people who have installed the 60 series diffs into a 40. Does the wider track make a profound difference to stability in off camber situations when compared to the original track width?

I am having second thoughts about the diff swap becuase I just dont have the time its gonna take to do it. If the gains are significant I can be talked into it though. My thoughts are to just do the brake disc swap and power steering conversion and sell whats left over. Bigger offset wheels can always give me a little more track in the long run but from what I have read it just doesnt seem worth it to gain the extra 3" track width by going to a 60 diff housing. (can someone confirm that it really is only 3" as I could well be mistaken)

[pcman]

im curently fitting 60 diffs under my 40 specifically for the extra width
i hate how the 40 is tippy with the skinny diffs
also 60 diffs mean you can run a wider tyre with no clearance issues

acording to factory specs its onlt 2.75" wider however mesuring it up against my 40 diff it was 4" difference


its really not a huge job to fit them i recon it could be done in a weekend

rear just chop the spring perches off and weld them back in the correct spots
front just outboard the spring perches even reusing the old perches isnt a huge task

mine is a little different tho the vehicle wont be road driven ever as its being turned into a rock crawler for comps only so im doing a shakel reversal at the same time aswell s spring over so ive got my work cut out for me

[bad_religion_au]

is "only" 3 inches difference significant? i'd say so, otherwise 1, and 2 inch wheel spacers wouldn't be sold, and rim flips wouldn't be popular.

they say for every 2 inches you go up, go out 1 inch (i think that was how it went) so effectively, you can go up 6 inches after the 60 diffs go on...

i'll tell you when i'm done doing my 60 diffs

[RAY185]

Thanks for the replies. I understand there is a gain in going wider even if it really is "only" 3", the question is how much of a gain. Is there anyone on this board that has actually done the conversion and wheeled it so they can report? And surely it would be a cheaper and easier option to gain the extra 1.5" each side by buying a bigger offset rim or having yours modded to suit? Again, I am not ruling out the conversion, just making sure its worth my time and the associated hassles of having the 40 off the road and taking up useful working space as it will be a long project.

Ray

[shorty_f0rty]

hey Ray.. want my 2c?

i figure moving spring hangers/outboarding and all that seems like a pretty big job that could put stress on the chassis where it wasn't intended (possibly i dont know), obvious DOT issues, and a permanent mod.

if its only 3" then wouldn't 1.5" offset rims have the ssame affect? granted they will put more stress on your bearings n stuff.. but its an easy fix... its relatively cheaper than doin the above.. maybe look at playin with your spring packs so you length wheelbase and lower cog but allowing for your current big rubber and with offset rims your where you want to be?

definately go the 60# steering.. let me know how you go getting the box on the chassis (i want to do this soon too).. and go for disks up front.. you wont look back!

probably nothing new here for you but thought id share anyway!

cheers,

Andrew

[STIKA]

i have done it, with a front shackle reversal at the same time

I cant say i have realy noticed any difference in stability, at first the i thought the shackle reversal was a waste of time. Then i fitted torque bars and it has definatly inproved the vehicles climbing ability

[RAY185]

hey Ray.. want my 2c?

i figure moving spring hangers/outboarding and all that seems like a pretty big job that could put stress on the chassis where it wasn't intended (possibly i dont know), obvious DOT issues, and a permanent mod.

if its only 3" then wouldn't 1.5" offset rims have the ssame affect? granted they will put more stress on your bearings n stuff.. but its an easy fix... its relatively cheaper than doin the above.. maybe look at playin with your spring packs so you length wheelbase and lower cog but allowing for your current big rubber and with offset rims your where you want to be?

definately go the 60# steering.. let me know how you go getting the box on the chassis (i want to do this soon too).. and go for disks up front.. you wont look back!

probably nothing new here for you but thought id share anyway!

cheers,

Andrew

Andrew you have echoed my thoughts precisely and I think this will be the way to go unless someone else who has done it has some convincing advice to sway me.

i have done it, with a front shackle reversal at the same time

I cant say i have realy noticed any difference in stability, at first the i thought the shackle reversal was a waste of time. Then i fitted torque bars and it has definatly inproved the vehicles climbing ability

Yeah a shackel reversal may be on the cards in the future, although I will have to do some research on this too as there seems to be alot of conflicting results from what I have read. So in your opinion from your experience would you say that it is not worth the time/effort to fit the 60 diffs merely to gain off camber stability?

Anyone else have some advice here?

[bad_religion_au]

hey Ray.. want my 2c?

i figure moving spring hangers/outboarding and all that seems like a pretty big job that could put stress on the chassis where it wasn't intended (possibly i dont know), obvious DOT issues, and a permanent mod.

if its only 3" then wouldn't 1.5" offset rims have the ssame affect? granted they will put more stress on your bearings n stuff.. but its an easy fix... its relatively cheaper than doin the above.. maybe look at playin with your spring packs so you length wheelbase and lower cog but allowing for your current big rubber and with offset rims your where you want to be?

definately go the 60# steering.. let me know how you go getting the box on the chassis (i want to do this soon too).. and go for disks up front.. you wont look back!

probably nothing new here for you but thought id share anyway!

cheers,

Andrew

how about....
don't outboard the spring hangers, instead narrow the perches on the diff..that way your using factory hangers = similar stresses on the chassis.

that will give you more travel from whatever springs you put in it both because of more leverage and springs, and also because for every inch of travel at the spring, you get more at the wheel due to the length increase.

adding spacers is more stress on bearings and sh!t, and really, aren't that much cheaper than a pair of 60 diffs. not to mention difference in scrub radius and all that technical steering sh!t, and it's extra maintanence, both wheelbearings and it's an extra set of lugnuts to work with. where 60 diffs are set and forget... gotta be a reason why you can DOT approve 60 diff swaps, but not wheelspacers.

now if you want more width, and you added spacers, where do you go from there? if you want more width on the 60 diffs... add spacers.

[RAY185]

hey Ray.. want my 2c?

i figure moving spring hangers/outboarding and all that seems like a pretty big job that could put stress on the chassis where it wasn't intended (possibly i dont know), obvious DOT issues, and a permanent mod.

if its only 3" then wouldn't 1.5" offset rims have the ssame affect? granted they will put more stress on your bearings n stuff.. but its an easy fix... its relatively cheaper than doin the above.. maybe look at playin with your spring packs so you length wheelbase and lower cog but allowing for your current big rubber and with offset rims your where you want to be?

definately go the 60# steering.. let me know how you go getting the box on the chassis (i want to do this soon too).. and go for disks up front.. you wont look back!

probably nothing new here for you but thought id share anyway!

cheers,

Andrew

how about....
don't outboard the spring hangers, instead narrow the perches on the diff..that way your using factory hangers = similar stresses on the chassis.

that will give you more travel from whatever springs you put in it both because of more leverage and springs, and also because for every inch of travel at the spring, you get more at the wheel due to the length increase.

adding spacers is more stress on bearings and sh!t, and really, aren't that much cheaper than a pair of 60 diffs. not to mention difference in scrub radius and all that technical steering sh!t, and it's extra maintanence, both wheelbearings and it's an extra set of lugnuts to work with. where 60 diffs are set and forget... gotta be a reason why you can DOT approve 60 diff swaps, but not wheelspacers.

now if you want more width, and you added spacers, where do you go from there? if you want more width on the 60 diffs... add spacers.

Yes I agree with the idea of relocating the spring perches on the 60 diffs rather than outboarding the hangers, thats a definate plan IF I go ahead. I would never put wheel spacers on to gain track. I intended to buy wheels with a bigger offset or have my wheels cut and rotated to get the required offset. The idea is that I can sell these 60 diffs (minus brakes) to cover any cost for rims and the vehicle can always be returned to its original track width by fitting some cheap standard rims. Wheel bearings are IMHO a very small trade off for the hassle saved by not doing the diff swap. I really appreciate your ideas/advice though, keep em coming!!

[midi73]

I have never heard of people outboarding the hangers. Everyone moves the mounts in on the diffs. And if you know someone who can move the perches on the diff then it is not a very big hassel at all Just cut and weld 4 mounts then bolt it all in. Would prob only cost a couple of hundered to get it done then bolt it all in yourself.
The only hassel is moving the front RH perch because the pumkin is more offset, but people have done it. I am looking into it at the moment for my BJ 73.

[midi73]

i have done it, with a front shackle reversal at the same time

Could you give me some info on doing the shackle reversal I am keen to do this as well.

[Shorty40]

Do the 60s man. One of the best things I did to my 40. The stability was quite noticeable

You can see the difference between standard and modified. "Standard" was sprung over 40s diffs with 35s on 15x8. Modified was sprung over 60s diffs with 38s on 15x8.

[RAY185]

Those pics look like the track has been increased by alot more than 3" overall. Have you used offset rims or is it just the bigger rubber giving it that illusion?

[Shorty40]

Sorry mate. I thought I put it in my post. They are flipped 15x8s.

I will find a pic when I still have the same 35s on it

[RAY185]

Sorry mate. I thought I put it in my post. They are flipped 15x8s.

I will find a pic when I still have the same 35s on it

Great, thanks for that, if you could give me an idea on how much offset you gained by flipping your 15x8s I'd appreciate it, and if you could tell me who did it and how much it cost I'd appreciate it even more!

Also just for the record, it looks fuggen awesome with the 60 diffs and flipped rims.

[Shorty40]

The flipped rims give between 2" and 3" each

I got all my work done at M&M Custom engineering. Can't remember exactly but the flip job cost around $50 per rim.

Thanks for the compliment

[RAY185]

The flipped rims give between 2" and 3" each

I got all my work done at M&M Custom engineering. Can't remember exactly but the flip job cost around $50 per rim.

Thanks for the compliment

2" to 3" each!! Thats awesome, so tell me again why I'd want to bust my guts sticking 60 diffs under it to gain 1.5" each side when I can have my rims flipped and gain 2" to 3" each side and have the option of going back to standard by fitting standard rims? You said the stability gain was quite noticable but was that noticed with the 60 diffs alone or a combination of that and the flipped rims? If my maths are correct you have gained overall 3.5" to 4.5" each side so that would make a huge difference to off camber confidence. Thanks again for the info, keep it coming!