Mix 'n' match FJ40/55 FZJ80 axle hybrid (1 Viewer)

[serenity]

I've been discussing this over in the 40/55 tech area and it was suggested you guys might be a better sounding board for my ideas.

I have a bone stock 55 and an 80 that will become a parts cruiser. My plan is to cut off the 55 knuckle balls and run the 80 series units that will give me a larger birf, stronger steering components and of course disc brakes.
I want to keep the width as close as possible to a factory 55 setup as my 55 has a FF rear end that I will make calipers adapter plates for to run the 80 series rear brakes.

I've found that I can buy fj40 30 spline inners as well as fj80 30 spline birfs from trail gear. I'm wondering if these could be used to mix and match, so I can avoid having to purchase custom length 80 series inners.

Longfield Toyota 30-Spline Inner Axle Shafts - Trail Gear

Longfield FJ80 Birfield, 30 Spline Chromoly, Gun Drilled - Trail Gear

 

[mr jits]

I'd go with custom length RCV inners over any of the trail gear products. Stronger, true lifetime warranty, and not much more expensive than one of their supersets. I'd also upgrade to the 300m material; you will never need to buy another axle

I've been discussing this over in the 40/55 tech area and it was suggested you guys might be a better sounding board for my ideas.

I have a bone stock 55 and an 80 that will become a parts cruiser. My plan is to cut off the 55 knuckle balls and run the 80 series units that will give me a larger birf, stronger steering components and of course disc brakes.
I want to keep the width as close as possible to a factory 55 setup as my 55 has a FF rear end that I will make calipers adapter plates for to run the 80 series rear brakes.

I've found that I can buy fj40 30 spline inners as well as fj80 30 spline birfs from trail gear. I'm wondering if these could be used to mix and match, so I can avoid having to purchase custom length 80 series inners.

Longfield Toyota 30-Spline Inner Axle Shafts - Trail Gear

Longfield FJ80 Birfield, 30 Spline Chromoly, Gun Drilled - Trail Gear

set for your 40 as long as you keep tire size to 40" or smaller.

 

[mudgudgeon]

set for your 40 as long as you keep tire size to 40" or smaller.

Serenity is not likely to be contemplating a tie anywhere near 40"
In most states in Australia, anything bigger than 33" tyre (possibly less for a 40) is not street legal without an engineer certifying the vehicle. And the rules are policed

 

[serenity]

I'd go with custom length RCV inners over any of the trail gear products. Stronger, true lifetime warranty, and not much more expensive than one of their supersets. I'd also upgrade to the 300m material; you will never need to buy another axle

set for your 40 as long as you keep tire size to 40" or smaller.

Serenity is not likely to be contemplating a tie anywhere near 40"
In most states in Australia, anything bigger than 33" tyre (possibly less for a 40) is not street legal without an engineer certifying the vehicle. And the rules are policed

Mudgudgeon isn't wrong! I'll be running skinny 33's, probably a 255/85r16 and no more than a 2" sua lift. Front will most likely remain unlocked but I'd like to put an e-locker in the rear. Hardly hardcore I know. However this section probably has the most knowledge on modified axles.

Would I be better off running a custom length rcv axle with 24 splines and use my factory 80 series birfs? The birfs have probably less than 30,000km on them as my 80 is factory part time.

 

[mr jits]

Mudgudgeon isn't wrong! I'll be running skinny 33's, probably a 255/85r16 and no more than a 2" sua lift. Front will most likely remain unlocked but I'd like to put an e-locker in the rear. Hardly hardcore I know. However this section probably has the most knowledge on modified axles.

Would I be better off running a custom length rcv axle with 24 splines and use my factory 80 series birfs? The birfs have probably less than 30,000km on them as my 80 is factory part time.

I'm pretty sure RCV doesn't make a 24 spline option. Go with the 30 spline upgrade and don't look back.
Posting from my phone so I couldn't see your location. You will "never" break an RCV with a 33.

 

[mudgudgeon]

I think if you put a locker in the front, you'll be fairly hard pressed to break factory birfs on skinny 33s too, unless you're rough on them.
I've broken one in the 3200kg 105, on 35s (315 muddies), deflated to 12psi, on full lock, doing a front dig to try and get out of a bind, so I was giving it some stick.
That was the original birf with close to 300k km on it

 

[LAMBCRUSHER]

Having narrowed a rear fzj 80 for my 55, can I suggest leaving the length on the housing? The wheels needed to clear the disc will have deeper back spacing netting in only 3" wide track overall... hth

 

[serenity]

Having narrowed a rear fzj 80 for my 55, can I suggest leaving the length on the housing? The wheels needed to clear the disc will have deeper back spacing netting in only 3" wide track overall... hth

I'm not planning on shortening the housing at all, just cutting off the 55 knuckle balls and welding on the 80 series ones. Then running a 55 inner and 80 outer. I've checked my 55s stock 16" steeliness on my 80 and they fit fine so no calipers clearence issues. Overall track width should only depend on the location of the WMS on the hub.

 

[chesshircat]

I don't think you want to use the 80 series balls, they steer from the bottom and behind the axle so you would need to change the steering on your 55. if you are getting aftermarket axles you defeat the purpose of upgrading to 80 series birfields. Get RCV's for the 55 and don't look back, you'll never break them. then find any cruiser or mini truck disk axle and convert yours to disk. I have been away from the cruiser seen for a while so i think what im saying is correct. I've never seen a 55 but im guessing its like a 40 drum? Do you wheel the 55 hard? If not i would not worry about upgrading the axles just convert to disc

 

[69LC]

I'm not planning on shortening the housing at all, just cutting off the 55 knuckle balls and welding on the 80 series ones. Then running a 55 inner and 80 outer. I've checked my 55s stock 16" steeliness on my 80 and they fit fine so no calipers clearence issues. Overall track width should only depend on the location of the WMS on the hub.

I was planning to do something similar, but learned that the 40/55/6x inners have a different splines at the inside of the birf cage. I think the 80 has a unique 24 spline whereas the others share 27 spline count. So if i understand correctly to do the 80 knuckles on another cruiser housing require custom inner shafts. I have asked RCV if they do 80 birfs and they do. They can also build the custom inner.