Running 39.5 Iroks on Toyota Axles? Should I go to 1 tons? (1 Viewer)

[mybluetoy]

I know that this has been asked a few times over because I have searched and read and saw, but I could not get the precise answer I was looking for. I have stock FJ40 axles and would like to run 39.5x13.5x15 Iroks. Just want to know if I'll be breaking all the time, axle shafts, pinion, transfer case output shafts, or drive shafts? I would go to after market dirty 30s or longfields for the axle shafts, heard great things about both but would I be breaking these as well? I want to be able to try any obstacle that I might come across. Either I go this way or I go with the wide ass one tons, Dodge Dana 60 and a Chevy FF 14 bolt. Really like how strong the one tons are but really dislike the width. Thanks for any and all advice.

 

[yzftaco]

I think this depends on how the driver wheels their rigs.. With Longfields and Chromo's (in the rear)

Someone who is a finesse driver will last a long time..

Someone who just can't keep their foot out of the throttle no matter when.... You're going to break even with 1tons (eventually)

 

[chicago]

What he said!!!!^^^^^
what else do you an on having in place like lockers, crawl boxes etc?
Just 39s you WILL be using the throttle w/ out the above items.
I'd def. Up grade to superaxles and polys.
You can cut the 1 tons down too. Just FYI.

 

[mybluetoy]

I did hear about narrowing the axles, I'll look into that because as of now I have stock transfer case and tranny, so yes it will be all throttle (355 sbc) where needed. I like to crawl over things, rocks fallen trees, but sometimes you need the extra horses. Just hate going out and after a day of playin, not hard core, but just playing, I have witnessed many break axle shafts and out put shafts to. Thanks.

 

[chicago]

Just out of curiosity, why jump right into 39's?
Seems the money could definitely be used elsewhere and more effectively on your rig, like lockers just as an example. You might Find you don't need tires that big.

Just a thought.

 

[BDSeff1fitty]

Just out of curiosity, why jump right into 39's?
Seems the money could definitely be used elsewhere and more effectively on your rig, like lockers just as an example. You might Find you don't need tires that big.

Just a thought.

This.

I have found that i am able to do everything i want right now on 35's, the limitation is my gearing and lockers which i'm going to partially be taken care of over the holidays.
My best suggestion is to wheel a couple times before deciding on the next upgrade if you have't already.

 

[69LC]

John,

If you do go 1 tons, you will have to change your tcase too. That's why I suggested shortening the right side of that 73" wms 14-bolt. It could be set to whatever width you want or to match a narrower D60. You can also change out the dually hubs for srw hubs with no other mod. There is an axle builder in Cedar Springs who could supply the shortened shaft.

For everyone else, John's brother is his primary wheeling influence and he breaks longs, Toy knuckles and anything else that gets between him and the terrain. Also, the biggest reason for the taller tires is ground clearance. We have quite a season for mud in Michigan.

John has my very first attempt at a prototype set of hinges. I had to give him a bump.

Matthew

 

[mybluetoy]

Matthew is right, about the ground clearance issue. I went out with my brother and some friends, all had 39.5 to 46" tires and I had 35" tires, they had to pull me through mud that they crawled through, I had to winch over obstacles that they drove right over, basically I was an anchor that day and there were many other days like that. Oh and that day was an easy trail day here in Michigan. I am tired of being that guy in tow. I don't want to lead I just want to keep up.
Matthew I may call you about the narrowing of that axle, also if any of you guys like to take your full doors off with ease and switch out to tube doors or half doors, 69LC has some very nice hinge replacements for you.
I'll keep you all posted as to what I do end up doing, thanks for the advice and please keep it coming, haven't done anything yet.

 

[chicago]

Ah. Mud...
Not into it, want no part of it (unless I absolutely have to) and know nothing about how to wheel in it.
Fortunately for me, where I live I don't have to deal w/ it that much.

 

[mybluetoy]

I really don't like Mud myself, but it does come up often on the trails here, I have to travel quite a distance to get mountainous terrain, North, South, East, or West. We have hills, sand, mud, and some more rocky terrain towards and in the UP of Michigan, but that's it. Some of the off road parks have imported rocks or dug them up and made some cool trails, but nothing beats mother natures work, IMO! Went to Morning Wood off road park in Saulte Sainte Marie this October and well, it was amazing (Crawl Mag Plug, It is featured in their magazine with the blue FJ40 on the cover). If I travel that far, I do not want to break on the trail, would rather spend time wheeling than wrenching in those types of terrain, I can wrench at home. Hope this gives a better understanding of what it is I would like to do.

 

[cohoslider]

37 on Toyota axels gears and low first is a super good combo but any bigger full size is less breakage in the long run

 

[hellbent40]

i would say research..
are you building a trail rig or a rig that you can drive to the trail...

if its going to be a trail rig try researching here and pirate

but as far as upgrading the stock landcruiser axles i would invest money in lockers and upgraded chromo shafts... i did just the birfs on mine just because i am running a tire thats about a 36inch tire... inner shafts should handle it... but your pinion might not... if its still a course spline...

 

[mybluetoy]

I blew ou my rear pinion this past summer and bought one out of a 1978 with fine spline. I was running 35" BFG m/t. And yes this will be a trail rig.

 

[fj40forlife]

There are tons of people here that wheel with 40" on there Toyota mini truck axles. I just got a set of 39.5 iroks for my fj40, was going to run my fj60 axles I go under my rig but everyone talk me in to going one ton. The fj40s a little heaver then mini trucks. Plus I have the one ton laying around already.

 

[hellbent40]

i see in your sig that your still sua...
so whats your list of upgrades going to be to put one tons in it then..
SOA... 4 link rear and 3 link front????
to bad you cant find a set of mog axles... and keep it sprung under... always wondered if anyone has ever done that...

curious in what direction your going to go with this..

 

[mybluetoy]

39.5 are on my toy axles, drove around some easy trails, I was in 2wd and crawled through spots where I needed 4wd before with my 35s. Love the way it looks and rides with these on, but I know that sbc with those tires will chew up toy axles. The 4.10s I have now seem fine. If I need a lower ring and pinion I'll get them in the 1 tons.
Yes I am still SUA

List of mods I'll be making:
Dodge Dana 60 up front, 14 bolt FF SRW in the rear, 4.10 to start
Looking to 4link the front, SOA in the rear for now, 4-link rear later
Coil springs up front to start then later on I'll some air shocks
Some leaf springs in the rear
Stretch the front 4" to 6"
Stretch the rear not sure yet, will wait on that for now
hydraulic assist or may just go full hydraulic
I'll be using 1 1/4" hiems from EORP
Shave the 14 bolt might use C&C hubsto narrow the 14 bolt and maybe narrow the long side of the Dana 60
For now leave the stock tranny and transfer case in, but I am thinking of either th350 or th400 and would like an Atlas but that's way out of the budget, for now.

There is more, but this is just off the top of my head. This is a lot to do and I have some help from brother who built a bad ass buggy and our friend Matthew, 69LC here on Mud, knows a thing or two. Looking forward to this project, will definitely do a build thread at some point, it will be slow due to shortness of funds for this project and time as I am a full time college student, all year, summers included.

 

[lcwizard]

out of curiosity, how's your turning radius with a stock front end? If 35's touch the front leaves at full lock
39.5's must be a bitch in tight corners.
We used to run 42's on a 40 in the warn/bfg rock crawls and 37's in ARCA ( their rules limitation).
We shortened a Dana 60 front to a 62" track by shortening only the passenger side and did the same to a Dana 60 rear.
This allowed us to have the offset rear and ran an FJ60 transfer which is a huge strength improvement.
With a 62" track up front 42's just clear the leaves at full lock.
This is an economical solution. We shortened the axles ourselves by cutting a few inches inside the knuckle and sleeving with DOM

 

[mybluetoy]

No issue with touching the leaf springs with the 35s or the 39.5s I think my backspacing is quite low, around 2" to 3" of back spacing. Looking forward to friday when the project begins.

 

[shelfboy1]

when you ran the 35s were you locked up and were they good 35s and were they truly 35 " tall.usually the difference in height isnt that much and can be made up for with a little throttle.

 

[mybluetoy]

They were newer K2 BFG Mud Terrains, tread was great! No locker up front, I did not want to build it for small tires, I want to be able to take my FJ40 anywhere with the lease bit of worries. Not sure if that answers your questions.