Leaf spring flex

[jeep97tj]

I am putting leafs under the front of a xj on mogs and have a pair of leafs from the front of a 60 and the rear of a 79.

What ones would be better for a bit of flex. The leafs are thiner in the 60 pack but the overall lenght is a fair bit shorter than the 79pack.

So whats better thinner or longer.

Thanks

[alien]

i'd go thinner, this way you'll have a lower spring rate and better approach/departure angle... add or remove leaves to get the ride right.

[jeep97tj]

Its on 42s so ther isnt really alot of overhang out the front. Can i just run less leafs in the 79 pack to soften up?

The 79s are brand new 60s are old.

[bulldogy]

Longer springs will flex better shane just rip some out and go from there.

[lay80n]

Just be careful if you start stripping leaves from the pack, as you will get axle wrap.

Layto....

[Gheto_Modz]

ditto on the axle wrap
the portal on the mogs will magnify wrap a huge amount.
There are lots of ways to correct it tho... you can run a torque arm from the top of the diff ( if ti is spring under) or bottom if spring over to the spring mounting bolt . Of course they are to run towards the centre of the vehicle... Pirate have heaps of info on this and I will see if I can get some links for you...

Mark

[ISUZUROVER]

I am putting leafs under the front of a xj on mogs and have a pair of leafs from the front of a 60 and the rear of a 79.

What ones would be better for a bit of flex. The leafs are thiner in the 60 pack but the overall lenght is a fair bit shorter than the 79pack.

So whats better thinner or longer.

Thanks

As far as spring design goes, long thin springs are best for longevity and wheel travel. thinner springs have less of a difference in stress between the top and bottom faces of each leaf when they are bending.

However, if you use thinner leaves you need more to get the same rate. e.g. a 10mm leaf is MORE than twice the stiffness of a 5mm leaf - so you might need 3x5mm leaf to equal 1x10mm leaf.

Same goes for length. A 4' long spring will have less stiffness (more flex) than a 3' long spring of the same thickness.

So the bottom line... Longer springs with thinner leaves will flex best and last longest (but will mean more unsprung mass).

[Tojo]

you already have exactly what you need - long and thin leaves. Use the main + second (thick) leaf from the 79 pack and then add enough of the 60 series (thin) pack to suite your needs. It will take a bit of trial and error to work out. If you get to much axle wrap use the first 3 leaves from the 79 pack and add thin 60 leaves to suite. With the 79 and 60 leaf packs you have more than enough to mix and match and end up with the perfect result.

[Gwagensteve]

You'll need to be realistic with how much flex you are going to get and you will 100% need some sort of anti wrap.

Volvo set up portals with leaves but they ran anti wrap bars front and rear and very limited flex.

Mercedes set up the mog with torque tubes from day one to get around the wrap problem and have decent flex.

The bigger problem is going to be braking. you can generate far more force under brakes than you ever could under power and that force is going to trash front springs with the 5.5" of leverage from the portal box.

Steve.