75 series front springs in 60 series (1 Viewer)

[wedgetail]

There is talk about this conversion - supposedly you use extended shackles and 75 series front springs in the front a 60 series for better flex and comfort.

But I haven’t heard it first hand. Has anyone here got
Any experience of it? Do you use regular or lifted 75 springs? What length shackles and what lift do you end up with?

My brother has an hj60 he’s left in my care for the moment and want to spruce it up a bit. Rear is very healthy measuring 2-3” lifted but front looks sagged at 1” and will be fitted 285s or 33s.

 

[NookShneer]

Looks like it could be done with the CS006F. The leaf is going to be 40mm longer on the shackle end of the pack meaning that your Axle will stay in the same place but you will need a longer shackle for the front. You will be lifting the front in the process.

It would have about the same ride as a heavy 60 set-up and you could remove a leaf to reduce that.

 

[dbleon]

Bump to see if anyone has tried this setup

 

[dbleon]

@lcwizard

Any input on this would be greatly appreciated

Interested how these longer springs might play with the shackle reversal kit since the (longer?) Mohave springs are NLA. I’ve seen some talk about the aftermarket 60 springs being too short to work well with the SR

Trying to lift the front a bit to clear larger tires I don’t really want to cut the fenders or go SOA either

There is a thread on the 55 forums where guys are running the 75 series springs with good success

 

[cruisermatt]

Bump to see if anyone has tried this setup

I think this is pretty popular in Australia, I've known about this for years and definitely read about it on here a bunch of times. I think @CruiserTrash just did his as well

 

[CruiserTrash]

Thanks Matt, yes I did this earlier this year.

@dbleon Going to HZJ75 springs with my shackle reversal was a great choice. The problem with the 60 springs and a shackle reversal is that the shackle angle is dead vertical or a few degrees forward even. The resting shackle will move either direction with less force when it’s at about 30-45 degrees laid back, so at vertical it’s going to take a lot more force to get it started moving - equating to a harsher ride. I got Dobinsons springs and they’re ~1.5” longer, the ride on the road is great and the flex on the trail is fantastic. Each pack came with 7 leaves and I removed 2. The center pin keeps the axle in the same location as stock.

current shackle angle

Height/stance with 33” KO2s - I could easily fit 35s and have plenty of room for flex (I’d want to regear the diffs first, and I may as well install a locker … for me going 35s is bigger project than just buying the rubber so I keep the 33s for now)

When I did the front springs I had already put 60 Series Dobinsons springs on the rear with 6” shackles and the resting shackle angle is almost vertical. I definitely get far more flex and a better ride up front, although the rear isn’t terrible and improves when loaded down. Maybe in the next year or two I’ll find some longer rear springs and do the same thing on the back. Hard to justify when I just bought them 12 months ago.

Front droop

Front stuff - not quite to the bump stop though

 

[4runner2FJ60]

@CruiserTrash So the 75 series lifted springs with the shackle reversal for the front and just the long shackle in the rear? Or if you did over would you get the matching 75 series springs for the rear? How is steering and did you add caster shims? THANKS!

 

[cruisermatt]

Thanks Matt, yes I did this earlier this year.

@dbleon Going to HZJ75 springs with my shackle reversal was a great choice. The problem with the 60 springs and a shackle reversal is that the shackle angle is dead vertical or a few degrees forward even. The resting shackle will move either direction with less force when it’s at about 30-45 degrees laid back, so at vertical it’s going to take a lot more force to get it started moving - equating to a harsher ride. I got Dobinsons springs and they’re ~1.5” longer, the ride on the road is great and the flex on the trail is fantastic. Each pack came with 7 leaves and I removed 2. The center pin keeps the axle in the same location as stock.

current shackle angleView attachment 3488202

Height/stance with 33” KO2s - I could easily fit 35s and have plenty of room for flex (I’d want to regear the diffs first, and I may as well install a locker … for me going 35s is bigger project than just buying the rubber so I keep the 33s for now)


When I did the front springs I had already put 60 Series Dobinsons springs on the rear with 6” shackles and the resting shackle angle is almost vertical. I definitely get far more flex and a better ride up front, although the rear isn’t terrible and improves when loaded down. Maybe in the next year or two I’ll find some longer rear springs and do the same thing on the back. Hard to justify when I just bought them 12 months ago.

Front droop


Front stuff - not quite to the bump stop though

You should drill your axle spring perches and move your front axle forwards 1.5-2” and your rear axle back like 1”. You would really like it
60’s do well with a little more wheelbase

 

[dbleon]

Great info @CruiserTrash

Looking at your rear shackle angle it looks like you could benefit from the 75 springs in the rear as well?…

Thinking about going in this direction

 

[CruiserTrash]

@4runner2FJ60 @dbleon I have no idea how long the rear 75 spring packs are relative to the rear 60 leaf packs. Yes I could benefit from extra length but I'm not sure it's as easy as assuming all 75 springs are longer than 60 springs, you'd have to check datasheets and such. This truck is a daily driven rolling project, it's never done, so for now I decided that I spent the money on the rear springs so I'm gonna run them for a while and live with it. Maybe in a few years I'll swap them out, but they work pretty well for now and I have all sorts of other things to get to first - currently I'm rebuilding a t-case and transmission, I have a spare 2F torn down and need to get the block to the machine shop, I eventually want 4.11 or greater diff gears, I'm going to try to DIY repair the little wheel well and c-channel rust, etc, etc, etc.

@cruisermatt brings up a fair point - all of this measuring and guessing can be avoided by just buying 60 Series springs, then cutting mounts off and rewelding them to the frame in the desired position. I was personally looking for a more "off the shelf" solution. And fwiw I get zero rub under any conditions except full stuff in the left rear touches the inner fender ever so slightly. 25s would be a different story I bet.

 

[cruisermatt]

That is not what I was suggesting, drilling the axle perch like this would be a TON easier. I would do this in addition to your 75 front springs.
Would cost nothing other then effort

 

[cruisermatt]

You do NOT want 75 rear springs on the rear of a 60. Theyre a 1-ton style truck spring with a bunch of overload leafs. I have a 75 here right now and could measure the length, but would make more sense to just get a custom main leaf from Alcan or Deaver and mod your existing spring pack.

 

[dbleon]

That is not what I was suggesting, drilling the axle perch like this would be a TON easier. I would do this in addition to your 75 front springs.
Would cost nothing other then effort

View attachment 3488679

Would doing this change the caster/pinion angle? Any ill affects to clamping on the leaf spring off “center”? I’m trying to wrap my brain around this but I’m running a little slow this morning

 

[dbleon]

You do NOT want 75 rear springs on the rear of a 60. Theyre a 1-ton style truck spring with a bunch of overload leafs. I have a 75 here right now and could measure the length, but would make more sense to just get a custom main leaf from Alcan or Deaver and mod your existing spring pack.

Some of the 55 guys are running the 75 spring in the rear IIRC. I think they are pulling leaves

I’m mostly interested in the longer spring for two reasons

1) to allow for bigger shackles/ more lift and keep a good shackle angle for ride quality

2) for a smoother ride (I’ve read that longer springs will inherently ride better due to the physics of the spring blah blah) some mumbo jumbo, but I’m sure it’s way more complicated than that

 

[cruisermatt]

Would doing this change the caster/pinion angle? Any ill affects to clamping on the leaf spring off “center”? I’m trying to wrap my brain around this but I’m running a little slow this morning

That is going to vary spring to spring depending on the arch, which direction you’re going, etc. in the case of @CruiserTrash 60 I can just look at it and tell it would be fine.

 

[cruisermatt]

Some of the 55 guys are running the 75 spring in the rear IIRC. I think they are pulling leaves

I’m mostly interested in the longer spring for two reasons

1) to allow for bigger shackles/ more lift and keep a good shackle angle for ride quality

2) for a smoother ride (I’ve read that longer springs will inherently ride better due to the physics of the spring blah blah) some mumbo jumbo, but I’m sure it’s way more complicated than that

Yep, all that is correct. It’s not more complicated then that.
I wouldn’t base anything for your 60 off 55 tech. Totally different ballgame

 

[CruiserTrash]

@cruisermatt Sorry I guess I missed when wheelbase became part of the conversation or how that's relevant. I'm ok with the wheelbase I have anyway - wheels are centered in arches, no appreciable rub, etc. Folks are have fact cut spring hangers and moving them to change the shackle angle on some of these oddball applications fwiw.

@dbleon I'm currently in a fight between my caster angle and driveline angle. I've realized that without cutting and turning the axle (essentially rotating the knuckle balls and spring perches relative to the diff), I'm not going to get things perfect. I've resigned myself to a decent caster angle and a not-so-great driveshaft angle for now. I'll eat u-joints but that's manageable. My truck handles great on the road and I don't want to change that. Maybe one day far down the road I'll buy another front axle and do all that work.

 

[cruisermatt]

It was merely a suggestion based on my experience and your setup

 

[dbleon]

I’m trying to decide which direction to go. I see 4 options for what I’m trying to accomplish.

Right now I have the following:
2” Ironman lift (medium)
1.75” body lift

Weight: front ARB with winch
Vortec swap (-200 lb?)
Dual batteries and compressor setup (future)

1) give up on large tires, forego my dream of running the big boy trails, and resign myself to fire roads and camping in designated spaces

2) throw longer shackles on there and live with the horse-and-buggy ride

3) Shackle reversal with longer springs and shackles front/rear

4) Remove body lift, re-work drivetrain mounts (Lower it) and go full bore SOA

 

[CruiserTrash]

@dbleon What size tires do you want to run and what kind of trails do you want to do? SOA and 40s or other highly involved builds will get you far, but it's not like 3-4" of lift and 33s limits you to "fire roads and camping in designated spaces". I guess maybe folks need clarification on your goals to give good advice. Is this a dedicated wheeling rig? A family camper? A hunting truck? What's the terrain like near you - rocks, mud bogs, tundra?