Rear Suspension - Shackles vs. Springs - Dakota Durango Forum
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post #1 of 10 Old 06-02-2019, 07:45 PM Thread Starter
Agar426
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Rear Suspension - Shackles vs. Springs

I realize that extended shackles are cheap, and really the only option these days. The deal with shackles is that you need twice the length for 1/2 the lift....2" of lift requires 4" longer shackles, for example. Well, what about a new leaf pack that will provide the lift? Those longer shackles seem to be in harms way on departure angle. Are there any options for rear leafs? Is custom the only option?
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post #2 of 10 Old 06-02-2019, 09:51 PM
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There are about 5 general options to lift a factory type leaf spring suspension.

1) Extended shackles; this is a cheap option if the shackles are of the compression type.



^ This is an example of a compression type shackle




^ This is an example of a shackle in tension, in which case, extending the shackles lowers your truck. This type of shackle would first require a shackle-flip, which by itself would add a few inches of suspension lift.

There is a limit to how much you can safely lift a truck using longer shackles. Personally I wouldn't go more than 2 inch longer shackles due to stability issues. As you also mentioned, you gain only half the amount of lift from shackles. However you could gain some lift with shackles if you also drop the front spring hanger

2) Lift springs; Many suspension lift kits typically include new leaf springs which increase ride height by incorporating a greater amount of spring arch. However, depending on the manufacturer of the springs, they are not all the same. Some springs may tend to be stiffer while some are called soft ride springs. When buying springs I would tend towards the soft ride springs for greater articulation.

3) When new lift springs aren't available, an older set of springs can be re-arched. This can be performed by spring shops which specialize in leaf springs. The downside is, there are not that many spring shops.

4) Lift blocks. This is an old school method of lifting and it can be relatively cheap, but this can also be dangerous if pushed to the extremes and could cause damage to the suspension, in the form of axle wrap. First thing however is never use blocks on a front leaf spring suspension. Besides being illegal in many states, their use on front suspensions is very dangerous because the leverage they can create can cause the axle to twist, changing your critical caster angle and making it impossible to steer when panic or hard braking. Also blocks in front are known to pop out. This isn't exactly a problem for your average Dakota or Durango since they all use an IFS suspension system, but if you have plans for a solid axle swap and plan to use leaf springs, heed this warning. For the rear suspension, blocks are fine, so long as they aren't too tall. But keep in mind that axle wrap will increase with taller blocks which may require adding some kind of traction device to control wrap.

5) Add-a-Leafs; Basically an add-a-leaf is a single highly arched leaf spring which you place into an existing leaf spring pack. When tightened, it forces the rest of the springs in the pack to conform to the arch which lifts the truck. The main problem with add-a-leafs is they greatly increase ride harshness. However, as I understand it, there are soft ride AALs on the market, but I can't say for certain if they ride as well as advertised.

Each method of lift comes with pros and cons, but you can also combine some of these methods to minimize the cons. However if none of these options will work for your needs, the next option is to go custom suspension and that can involve 4 link w/ coils (or coil-overs) or older school quarter elliptic rear suspension, etc.

Ed

6BT, 3200GSK, M&H#3, W/A IC, 5X.012, AirDog100, HE351.
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post #3 of 10 Old 06-05-2019, 06:48 PM Thread Starter
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Quote:
Originally Posted by RXT View Post
There are about 5 general options to lift a factory type leaf spring suspension.

1) Extended shackles; this is a cheap option if the shackles are of the compression type.



^ This is an example of a compression type shackle




^ This is an example of a shackle in tension, in which case, extending the shackles lowers your truck. This type of shackle would first require a shackle-flip, which by itself would add a few inches of suspension lift.

There is a limit to how much you can safely lift a truck using longer shackles. Personally I wouldn't go more than 2 inch longer shackles due to stability issues. As you also mentioned, you gain only half the amount of lift from shackles. However you could gain some lift with shackles if you also drop the front spring hanger

2) Lift springs; Many suspension lift kits typically include new leaf springs which increase ride height by incorporating a greater amount of spring arch. However, depending on the manufacturer of the springs, they are not all the same. Some springs may tend to be stiffer while some are called soft ride springs. When buying springs I would tend towards the soft ride springs for greater articulation.

3) When new lift springs aren't available, an older set of springs can be re-arched. This can be performed by spring shops which specialize in leaf springs. The downside is, there are not that many spring shops.

4) Lift blocks. This is an old school method of lifting and it can be relatively cheap, but this can also be dangerous if pushed to the extremes and could cause damage to the suspension, in the form of axle wrap. First thing however is never use blocks on a front leaf spring suspension. Besides being illegal in many states, their use on front suspensions is very dangerous because the leverage they can create can cause the axle to twist, changing your critical caster angle and making it impossible to steer when panic or hard braking. Also blocks in front are known to pop out. This isn't exactly a problem for your average Dakota or Durango since they all use an IFS suspension system, but if you have plans for a solid axle swap and plan to use leaf springs, heed this warning. For the rear suspension, blocks are fine, so long as they aren't too tall. But keep in mind that axle wrap will increase with taller blocks which may require adding some kind of traction device to control wrap.

5) Add-a-Leafs; Basically an add-a-leaf is a single highly arched leaf spring which you place into an existing leaf spring pack. When tightened, it forces the rest of the springs in the pack to conform to the arch which lifts the truck. The main problem with add-a-leafs is they greatly increase ride harshness. However, as I understand it, there are soft ride AALs on the market, but I can't say for certain if they ride as well as advertised.

Each method of lift comes with pros and cons, but you can also combine some of these methods to minimize the cons. However if none of these options will work for your needs, the next option is to go custom suspension and that can involve 4 link w/ coils (or coil-overs) or older school quarter elliptic rear suspension, etc.

Ed
Great response! Thank you for your time. I can't find any aftermarket springs for the Durango that aren't stock replacement. Are custom springs or re-arching my only options?
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post #4 of 10 Old 06-10-2019, 03:13 PM
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Best shot I have of my 2 longer shackles:

https://www.instagram.com/p/Bv-OqyJh...d=patbwy2f6apv

Ill still plow the receiver hitch into things before they take a hit in most cases.

(Thats 3 body and 1 torsion bar / drop shackle lift on 33x12.50s)
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post #5 of 10 Old 06-10-2019, 04:38 PM Thread Starter
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Quote:
Originally Posted by tntoy View Post
Best shot I have of my 2 longer shackles:

https://www.instagram.com/p/Bv-OqyJh...d=patbwy2f6apv

Ill still plow the receiver hitch into things before they take a hit in most cases.

(Thats 3 body and 1 torsion bar / drop shackle lift on 33x12.50s)
Great shot.....well illustrated! Any comments on the wheel offset? As it is my son's daily driver, I am thinking 32x11.50 will be the size, just to lay it safe. Of course, he wants snazzy wheels....so I want to make sure I don't cause a problem with too much or too little offset.
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post #6 of 10 Old 06-10-2019, 04:48 PM
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Best shot of the wheel / tire / stance is here, swipe right for the second photo:

https://www.instagram.com/p/BwAwqxxh...d=eg4efrpp1k42

What I did was to measure the backspacing on the factory wheels which were 15x7s. I then found myself a black 15x8 steel wheel ($45ish each) through 4wheelparts which had almost the same backspacing. This means that the wheel is wider, but all of that additional width is outboard of centerline.

I dont recall the numbers at all - so youd have to repeat the exact same procedure. Good luck, pickings are slim amongst 6 on 4.5 bolt pattern wheels.

It looks perfect. Not tucked in and goofy, and not sticking out crazy wide like a jacked-up lowrider.

A 32 x 11.50 would still look really good with this setup, and you might be able to fit them without the body lift. Just crank the torsion bars up 4 turns and install drop shackles. Trim the snot out of the back corner of the front bumper and it might be good to go.
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post #7 of 10 Old 06-10-2019, 05:40 PM Thread Starter
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Quote:
Originally Posted by tntoy View Post
Best shot of the wheel / tire / stance is here, swipe right for the second photo:

https://www.instagram.com/p/BwAwqxxh...d=eg4efrpp1k42

What I did was to measure the backspacing on the factory wheels which were 15x7s. I then found myself a black 15x8 steel wheel ($45ish each) through 4wheelparts which had almost the same backspacing. This means that the wheel is wider, but all of that additional width is outboard of centerline.

I dont recall the numbers at all - so youd have to repeat the exact same procedure. Good luck, pickings are slim amongst 6 on 4.5 bolt pattern wheels.

It looks perfect. Not tucked in and goofy, and not sticking out crazy wide like a jacked-up lowrider.

A 32 x 11.50 would still look really good with this setup, and you might be able to fit them without the body lift. Just crank the torsion bars up 4 turns and install drop shackles. Trim the snot out of the back corner of the front bumper and it might be good to go.
Excellent info, thank you! Interesting comment on the bolt pattern, I hadn't even considered that. Go figure, the wheels my son likes aren't available in that pattern. That may explain why so many use the factory wheels and just paint them black.
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post #8 of 10 Old 06-10-2019, 06:01 PM
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Quote:
Originally Posted by Agar426 View Post
I hadn't even considered that. Go figure, the wheels my son likes aren't available in that pattern. That may explain why so many use the factory wheels and just paint them black.
What wheels *HE* likes? He’s a kid. He’s gonna scrub, scrape, and bend those things just like we did when we were young idiots.

Tell him he gets black steel wheels and he’s gotta like it. It’s a POS old Dodge truck. No sense putting $600+ worth of fancy wheeled lipstick on a pig. 😁
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post #9 of 10 Old 06-10-2019, 06:17 PM Thread Starter
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Quote:
Originally Posted by tntoy View Post
What wheels *HE* likes? Hes a kid. Hes gonna scrub, scrape, and bend those things just like we did when we were young idiots.

Tell him he gets black steel wheels and hes gotta like it. Its a POS old Dodge truck. No sense putting $600+ worth of fancy wheeled lipstick on a pig. 😁
Lol! Good point.....my suggestion is the factory wheels until he can buy his own wheels!
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post #10 of 10 Old 06-12-2019, 09:19 AM
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While I haven't personally done it, supposedly you can use full sized 1500 springs that give about 2" over the stock 4x4 Dakota springs. Food for thought.
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