I am toying with the idea of replacing front springs that measure 14.5mm with that of rear springs that measure 16.2mm thickness. From what I can measure, the upper turret is the same size as well as the seat cup for lower mounting is the same for front and rear.

Can anyone tell me in their experience if the rear springs are heavier tension strength than the front?

I get that the front springs are supposed to bear the weight of the motor and provide responsive suspension. But what about the rear springs and supporting +300lbs in the cargo area plus 2 passengers?

Anyone with actual experience with this that knows for certain the difference between the rear and front coil springs. And crass folks that say "stock factory engineered specs should be observed" can stay out of this thread. Thanks!

 

Different springs from the same manufacturer have different spring rates.
Different springs from different manufacturers have different spring rates.
Spring rates will be different between front and rear springs.
Different springs will provide different amounts of lift, and will depend on the load carried.
Basically there are a lot of variables involved.
Here is a list I obtained from RTE.
RR1-2 = 2" Coil 330/375 rate
RR1-3 = 3" Coil 330/375 rate - Current Production(REAR)
RR1-5 = 5" Coil 330/375 rate
RR2-2 = 2" Coil 189 rate
RR3-1 = 3" Coil 285/325 rate
RR3-2 = 3" Coil 285/325 rate
RR3-3 = 3" Coil 285/325 rate
RR4-1 = 2" Coil 225 rate
RR4-2 = 2" Coil 225 rate
RR4-3 = 3" Coil 245 rate
RR4-3P = 3" Progressive Coil 200/320 rate - Current Production(FRONT)
RR4-5 = 5" Coil 255 rate

 

Appreciated fishEH. I have stock rover springs and will not be purchasing new. so whatever the rate is on my springs, in a general sense I assume the thickness of my rear springs effect the short progression or rigid feel.?.?.?

If I read the numbers right, the progression on load bearance in the front is gradual vs the rear being more rigid. Basically the progression in the front is designed for comfort and strength vs rigid strength in the rear.

Is this way off? Will I bear load of my 600lb diesel motor and maintain higher lift using rear springs on the front.

Anyone else care to chime in???

 

Rear springs are typically a heavier rate than the fronts. I know the front has the engine, but as you stated the rear is designed to hold the cargo, passengers, fuel and a large chunk of the body. So if you compare the rates Brett posted.

For example take the 3" springs
3" Rear Coils are 330/375 lbs progressive rate
3" Front Progressive Coils are 200/320 lbs rate

This can usually be seen because the rear springs look slightly larger. I don't know what the rate is of the stock springs. But I know one of the Cheap bastard lifts was to put stock rear springs in the front which would yield roughly a 2" lift in the front. I've also heard about people running FJ80 spring in the rear.

 

This makes sense and was the point of my question. Good info. My rear measures 16mm and front 14mm. I thought this was the case until i called a rovers north and they told me the opposite.

Never listen to a salesman I guess. I have 2" square tube at .20 thick and 3" @ .25 just in case for mounting atop the perches for lift was thinking about welding on. then go with the swivel cup offset to address positive caster.

 

Here's a link that shows the different factory spring rates, which I found useful:
land rover spring specifications


Putting the rear springs in the front is what I've done for now to support the weight of my winch bumper and it seems like it did the trick. From what I understand, Its commonly done as a "budget" lift so you just need to buy rear springs.
I have not got my truck on the road yet though, so I can't comment on handling, though I expect the ride to be somewhat rougher.

I think the rear springs should bear the weight of your diesel, but for lift beyond that, you might need some spacers or ideally new springs.

 

I have fj80 Springs in the rear and moved my stock rear Springs to the front. If you have any questions let me know.

 

Whilst in the process of fabricating my lift blocks, it seamed I could not get my axle low enough to fit the blocks and springs in with out the aid of a spring compressor. Tool I have yet to use enough to warrant the purchase...I had to just throw them on without the blocks.

Long story short, I stole the rears from my 95 and fitted them in front of my 98. What an incredible difference! It rides a bit firm but handles well. I also gained 4" from my saggy **** of springs that came off. It is also level. Now I have no more clearance issues with my oil pan reference the diff.!!!! Whooooo! I don't need the blocks... go figure.

One thing does baffle me is one spring is certainly taller than the other after removing them I saw this side by side comparison. Who does this?

 

Many theories on the different hight springs, but that's just how they come.

You should not need a spring compressor, just unhook the sway bar and put a bottle jack between the axle and bump stop. Just make sure you don't break the brake or abs lines.

 

and tweak the control / track arm bushings? I thought so but didnt want to hurt them. would you suggest loosing them or just jack for space? that makes total sense now. I inspected the bushings on the betwixt the body and the track arm and they are supple and not dry or cracked