Fj60 leafs and a shackle reversal on an FJ40 (1 Viewer)

[cooksflips]

Hey Yall,
Just looking for some opinions here on swapping fj60 leafs onto a 40 and doing a shackle reversal. Currently im running SUA with lifted springs, 33 inch tires, and lockers, flipped rear springs. I really like this set up but I have some stock fj60 springs, 6 inch shackles and was thinking about going for the swap and maybe doing a shackle reversal at the same time. So I am wondering if anyone has any input from moving from one set up to the next and if so if they liked the improvement in ride quality ..... or if im not goin to find much improvement considering i already have a flipped rear leaf.
SHackle reversal or no while im there ?
Fj60 leafs much improvement over 40 leafs with a flipped rear ?
Bad idea using orignal stock fj60 leafs ?

 

[Bluegrass40]

Subscribed.... I have a similar setup and a set of 60 springs sitting around.

 

[franklin40]

honestly i think you’ll get a lot of variable opinions about shackle reversal. i had one on my 40 (with bds springs for a 40) and i didn’t like it. i decided to go spring over instead with a flat spring. i haven’t driven it yet because i’m still building but i have a friend with soa and it is great.

from my experience and trying to understand leaf spring mechanics my impression is that a shackle reversal makes sense for a high arched spring that will flatten when compressed moving the shackle backwards as does the axle. it’s less harsh than the axle moving forward into the obstacle. with a relatively flat spring though when it compresses it actually arches the spring making it shorten and moving the axle forward just like a stock sep up would negating the benefit of the reversal. mine had arched springs but still rode rough but i think that was partly due to the crappy springs being too stiff. fj60 springs are longer (and a bit wider) so you’d have to move hangers around anyway so reversing them would be easy to do at that time. they also will ride a bit softer i believe. if they’re already quite flat then i might just consider running them with the shackle up front. i get that doing a soa is more work with possibly needing a cut and turn but it will also ride better than a sua with long shackles and a reversal but both will have a similar lift in the end. i’d just go soa if you want that much lift. that’s my 2 cents though. you might get different advice from someone with exactly the set up you are looking to do.

 

[White Stripe]

Rear fj60 springs installed on the front and rear of a fj40 should give significantly better ride and flex. You will have to move the hangers around when putting them on the front. I would think you would want lifted springs though and not stock unless you are doing a spring over conversion. The front springs from a fj60 are useless for anything to do with a fj40 application.

 

[cooksflips]

honestly i think you’ll get a lot of variable opinions about shackle reversal. i had one on my 40 (with bds springs for a 40) and i didn’t like it. i decided to go spring over instead with a flat spring. i haven’t driven it yet because i’m still building but i have a friend with soa and it is great.

from my experience and trying to understand leaf spring mechanics my impression is that a shackle reversal makes sense for a high arched spring that will flatten when compressed moving the shackle backwards as does the axle. it’s less harsh than the axle moving forward into the obstacle. with a relatively flat spring though when it compresses it actually arches the spring making it shorten and moving the axle forward just like a stock sep up would negating the benefit of the reversal. mine had arched springs but still rode rough but i think that was partly due to the crappy springs being too stiff. fj60 springs are longer (and a bit wider) so you’d have to move hangers around anyway so reversing them would be easy to do at that time. they also will ride a bit softer i believe. if they’re already quite flat then i might just consider running them with the shackle up front. i get that doing a soa is more work with possibly needing a cut and turn but it will also ride better than a sua with long shackles and a reversal but both will have a similar lift in the end. i’d just go soa if you want that much lift. that’s my 2 cents though. you might get different advice from someone with exactly the set up you are looking to do.

Good info, I really like the low center of gravity i currently have and i really dont want to end up sitting any higher. I currently have plenty of room with the 33's and i wouldn't mind even sitting a little lower. Are you not happy with the shackle reversal because of the lift of it or because of handling characteristics ?

 

[cooksflips]

Rear fj60 springs installed on the front and rear of a fj40 should give significantly better ride and flex. You will have to move the hangers around when putting them on the front. I would think you would want lifted springs though and not stock unless you are doing a spring over conversion. The front springs from a fj60 are useless for anything to do with a fj40 application.

The front springs do seem to be worthless, only 4 leaves in them. I was thinking with the flat springs and the 6 inch shackle (pin hole to pin hole ) I would be sitting pretty nice to run 33s with cut fenders.

 

[franklin40]

i didn’t like the handling. it was a lot of work for little gain

Good info, I really like the low center of gravity i currently have and i really dont want to end up sitting any higher. I currently have plenty of room with the 33's and i wouldn't mind even sitting a little lower. Are you not happy with the shackle reversal because of the lift of it or because of handling characteristics ?