Those running Evo 4.5 or 6.5" coil springs: HD or Plush. Your experience?

[Dickster]

First work day with the 4.5" Evo HD aka Diesel rear coil springs.

Off the bat they feel MUCH lighter than the 2.5" Skyjacker springs they replaced, which... When it came to trail riding I always felt the rear Skyjacker springs were too firm always- preventing a good range of travel for the rear axle. But for work they were great. Never could overload the bed.

This may work out well once I get the loose ends of this lift tied up. (Proper bump stop lengths, shock travel, steering reinforcement, brake lines, sorted.)

How much weight do you have in your bed when testing ride? My RSI Adventure canopy comes sometime next week.

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[Pescatoral Pursuit]

I'd say around 350.

It's very bouncy compared to the Skyjacker springs. For what I like to do unloaded it'll be fine. Were I to hit the trail loaded with gear I would not want these springs in the back.

(EDIT: AFTER SOME USE, I THINK THESE SPRINGS WOULD DO JUST FINE LOADED WITH GEAR ON THE TRAIL)

I would trust longer Skyjacker springs though. Loaded down during the work week they kept the rear pretty solid.

 

[Dickster]

I'd say around 350.

It's very bouncy compared to the Skyjacker springs. For what I like to do unloaded it'll be fine. Were I to hit the trail loaded with gear I would not want these springs in the back.

I would trust longer Skyjacker springs though. Loaded down during the work week they kept the rear pretty solid.

What shocks do you have? With my decked system and gear and canopy I'll be over 450lbs. Maybe you need more weight as they are triple rate springs?

 

[jjmstang]

If it's "bouncy" you need better/ stiffer shocks.

 

[Pescatoral Pursuit]

What shocks do you have? With my decked system and gear and canopy I'll be over 450lbs. Maybe you need more weight as they are triple rate springs?

Rough Countrys.
Yes so as it turns out, an extra 80lb hanging off the tailgate really tamed the ass end nicely and without sagging.

 

[Dickster]

Rough Countrys.
Yes so as it turns out, an extra 80lb hanging off the tailgate really tamed the ass end nicely and without sagging.

Awesome sounds like I'll be happy with them. Once my top comes in and I get a good run with them I'll report back as well. Fox 2.5s going on today.

 

[slowstang305]

I have the 4.5 plush springs. Half Rack/Tent and to be honest the truck is pretty leveled out. I do have a 12k winch on the front end.

 

[Pescatoral Pursuit]

I have the 4.5 plush springs. Half Rack/Tent and to be honest the truck is pretty leveled out. I do have a 12k winch on the front end.

What part of the 305 are you in?

 

[slowstang305]

What part of the 305 are you in?

I'm out of Fort Lauderdale, FL. You out of Orlando?

 

[Pescatoral Pursuit]

I'm out of Fort Lauderdale, FL. You out of Orlando?

Technically that would make you a 954, right? Jk.
Now yes. But originally SoFl.

 

[Lynn_F]

I ran the 4.5" plush springs and Bilstein B8 5160 2" piggyback shocks on my gas rig and have the 6.5" hd springs and King 2.5" rr/piggybacks on my ecodiesel. It's hard to compare just the springs due to the different shocks but the hd springs/King shocks combo is defintely a better ride than what I had on the gasser. The King's are far superior to the Bilsteins. Hydro Blue = Ecodiesel / Billet Silver = 3.6

 

[Pescatoral Pursuit]

It's hard to compare just the springs due to the different shocks but the hd springs/King shocks combo is defintely a better ride than what I had on the gasser.

Could you be specific when you say "better ride?" I've had a variety of shocks and they all have their ride characteristics. I think primarily coils are responsible for length of travel under a certain load. What I want from my springs is the longest possible travel on short arms, while managing the ride characteristics with the shocks. I would think a single rate spring would best facilitate that but difficult to find a brand which markets such.

 

[piroman683]

Could you be specific when you say "better ride?" I've had a variety of shocks and they all have their ride characteristics. I think primarily coils are responsible for length of travel under a certain load. What I want from my springs is the longest possible travel on short arms, while managing the ride characteristics with the shocks. I would think a single rate spring would best facilitate that but difficult to find a brand which markets such.

I've been working with a spring supplier specifically for rear springs because all the aftermarket springs end up being too soft for going fast in the desert because of the multi rate approach they take. Because the average softer they do well for flexing and crawling, but multi rates also run into the issue of having a very tall "compressed" spring height. The springs I'm testing in the rear in 2-3 weeks are single rate, 7.5in compressed height, 25.5in free length. (160 and 150 lbs rate) This allows me to fully use the shock travel of my 2.5dsc. however, in order to gain the benefits of the last 3-4 inches of up travel you have to remove factory bumps stops and install the fox or king ones so you can tuck it way up into the frame. This yields between 17-18 of wheel travel (I say 17 because you get limited by the Rock Jock sway bar unless you order different arms for it, assuming you also already extended brake and abs lines)

I've tested Rock Krawler 4.5, Synergy 4, and Synergy 3in lift springs and my favorite was Synergy 4. That allowed the most travel with good stiffness. The Rock Krawler 4.5 were about 1 in longer in free length, but less travel because of it being a quad rate spring. The quad rate was notable softer. My rig is only about 5300lbs, so for yours I'd expect to want a single rate around the 180-200 range.

 

[Pescatoral Pursuit]

I've been working with a spring supplier specifically for rear springs because all the aftermarket springs end up being too soft for going fast in the desert because of the multi rate approach they take. Because the average softer they do well for flexing and crawling, but multi rates also run into the issue of having a very tall "compressed" spring height. The springs I'm testing in the rear in 2-3 weeks are single rate, 7.5in compressed height, 25.5in free length. (160 and 150 lbs rate) This allows me to fully use the shock travel of my 2.5dsc. however, in order to gain the benefits of the last 3-4 inches of up travel you have to remove factory bumps stops and install the fox or king ones so you can tuck it way up into the frame. This yields between 17-18 of wheel travel (I say 17 because you get limited by the Rock Jock sway bar unless you order different arms for it, assuming you also already extended brake and abs lines)

I've tested Rock Krawler 4.5, Synergy 4, and Synergy 3in lift springs and my favorite was Synergy 4. That allowed the most travel with good stiffness. The Rock Krawler 4.5 were about 1 in longer in free length, but less travel because of it being a quad rate spring. The quad rate was notable softer. My rig is only about 5300lbs, so for yours I'd expect to want a single rate around the 180-200 range.

Geeze, finally.
How do you come up with 17" of travel?

I wheel with minimal weight in the bed (<200lbs) which I think balances out the diesel up front and keeps the back end from flying around.

Please post pics. Thanks.

 

[piroman683]

Geeze, finally.
How do you come up with 17" of travel?

I wheel with minimal weight in the bed (<200lbs) which I think balances out the diesel up front and keeps the back end from flying around.

Please post pics. Thanks.

The longest rear fox shocks you can get has a piston travel length of 13in. This translates to a wheel travel of about 18.5+

Right now with the spring I have the max travel I can actually use is 18in since the springs are compressed in a linear way. It is possible to make them a little longer, but that will also impact ride height and reduce fatigue margin so 18 was basically the limit of good tradeoffs. I'm stuck at 17 at the moment because at full bump my sway bar arms smash into the wheel well of the truck bed. By swapping those out to a different style arm I can achieve more travel. I also do not use bump stop spaces/pads on my rear axle, and still have 2in of uptravel clearance for my 37's

I'm in Spain at the moment, but will be doing work on my truck in about 2 weeks. I'll grab photos then.

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