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A brutally honest suspension comparison...

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
As most of you know and are familiar with the Duck, I tried to spare no expense wherever I could and what was not priority. Those of you who know me personally also know I have worked hard to develop a great relationship with most of our vendors so this is a comparison, not a bash and a good line on what to expect with the various vendors that I have personally tried. I tried to do a comparison as quasi scientific as I could and here are the results with pics.

Starting off we are comparing Wild Horses 2.5" Premium lift to Duffs 2.5". We switched from stock radius arms to TRex. On the stock system with WH 2.5" I ran 7° C Bushings and had a final caster of 6° D side and 5.4° P side. We had a total droop measured from the bottom of the frame at the spring bucket to the top of the axle of 13" with or without the shocks attached. This is caused by the limiting bind of the factory arms and bushings. We did a flex test with our fork lift to see what else would change if anything and we lifted the vehicle on the rear pass tire till the front tire just was starting to lift off the ground and we had a measurement of 29".

Now we worked most of the week to swap suspensions, we remained with the Bilstien 5100 series shocks and everything else was changed. We also added a Torque Tamer on the rear diff to better control axle wrap. With the new suspension installed we repeated the same tests and measurements. With the front shocks both connected and disconnected we had a droop of 16" so we gained 3" of downward movement simply by switching the radius arms which help reduce the bind at the pivot point. When we flexed it we also repeated the test and gained an additional 3" of flex. The only tradeoff I lost with this conversion is about 1.5° of caster after the fact. With the TRex, they come with a built in 4° offset and I went with the 4° C bushings. Due to the added droop I also had to lightly clearance the edges of the front double cordon on the drive shaft as I was getting to its limits. If you want to run this suspension with 7° c bushings and get about 7° total caster you will def need to invest in a high angle drive shaft or look into having your C knuckles cut and rotated to maintain acceptable driveline angles.

Onto the drivability, first and foremost, if you have any axle wrap, low gears, high power motor, large tires, any and all of the above, you have wrap. Get a torque Tamer, it sops that in its tracks and does not interfere with ride quality or suspension movement. I noticed right away, no more rear end squat when I get on the skinny pedal as well as my once abrupt shifts from 1st to 2nd are smoothed out. The biggest benefit of all is I am no longer getting excessive nose dive on hard braking, the whole vehicle tends to squat even now because the axle is being controlled and I am almost certain it is helping to reduce the braking distance some. It is a great investment in my opinion and will be included on all of our future builds that are getting any of the above causes or enhancers added. With the overall ride comfort, Duff springs are a little longer when side by side to WH however there is good reason, WH are a 3 stage spring while Duff is a 4 stage. Duff also has a softer stage in there and it helps tremendously when hitting road bumps etc. The biggest difference I noticed right away was the vehicle seemed to soak up the bumps and pot holes rather than react to them abruptly. With the TRex arms removing the binding and allowing the suspension to move more freely I can feel a slight difference in added body roll. It is still not enough for me to want to add a sway bar yet but I could see where a good sway bar could make it handle like a modern vehicle if that is what you are after, for me, a slight body roll will help you subconsciously keep the speed down in sharp turns which is always a good thing I think.

Bottom line, my overall opinion is we have found our new go to suspension setup for our builds. When our customers want more street friendly we will add a sway bar for them but outside of that you cannot go wrong with either suspension system. I was very happy with both and would use WH again if a customer requests it with no issues but my personal seat of the pants feel and comfort, Duffs has truly knocked this one out of the park in this configuration.
 

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englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
The rest of the photos:
 

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Glass Pony

Contributor
Bronco Guru
Joined
Feb 13, 2012
Messages
1,817
Loc.
Sussex County Delaware
Great write up!
I was a couple months too early when I was replacing C bushings before the T-Rex arms came out or I would have purchased them then. I was wondering what the change in caster would be going from a stock arm 7 degree bushing to a T-Rex arm and 4 degree bushing and you spelled it out.
Next time I am into the front end I will probably get a set of the T-Rex arms.
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
Good job of being cordial.

Duff & WH are the industry leaders. They carry a lot of different stuff too.

Love me some Duffs too.
 

toddz69

Sponsor/Vendor
Bronco Guru
Joined
Nov 28, 2001
Messages
10,080
Nice writeup! A few questions:

How much higher is the lower mount on the T-Rex arms than the stock arms? Any concerns with coming close to bottoming the shocks out since it appears it's higher?

The next time you have it on the lift or flexed with the forklift, disconnect the front pivot point on the Torque Tamer and take a photo of how far away the pivot point is away from its mounting point - just curious.

The Duff springs are about 50 lb/in lower in initial spring rate than the WH springs - I like them better too.

Todd Z.
 

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Due to the added droop I also had to lightly clearance the edges of the front double cordon on the drive shaft as I was getting to its limits.

Mine is doing the same. I didn't think about giving some extra clearance, but I guess I'll do that before I get it all back together. Thanks.

Bottom line, my overall opinion is we have found our new go to suspension setup for our builds.

Not mention, it's not as from you to TN as it is to CA??? lol.

One question. When you welded the torque tamer brackets on the housing, did you check to see if there was any bending in the housing? We did my dad's a while back and ended up cutting the housing and rewilding the cut in order to straighten it. I guess we got way too much heat in the front side during the welding. Mine wasn't as bad, but I did have to straighten it.
 

BGBronco

Contributor
N A S H V I L L E
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Jun 23, 2017
Messages
1,543
Loc.
Tennessee
I just bought a '76 and shopping for a 2.5" suspension kit. What are you thoughts on the Duff vs WH kits for primarily street use? Thank you.
 

Slednut10

Contributor
Guru? That's funny!
Joined
Sep 26, 2013
Messages
2,394
Just curious about the caster-you mentioned that you lost caster with the t-rex arms and 4 degree bushings. Wouldn't you actually gain about 1.25 degrees with that combo over the 7 degree bushings on the original arms? If you lost caster I wouldn't think you would have to clearance the driveshaft. Please correct me if I missed something here.
 

hyghlndr

Contributor
Bronco Guru
Joined
Jan 19, 2009
Messages
5,020
Loc.
Hockessin, Delaware
I just bought a '76 and shopping for a 2.5" suspension kit. What are you thoughts on the Duff vs WH kits for primarily street use? Thank you.

Duffs without a doubt. I installed the 2 1/2 WH deluxe kit with Bilsteins on a good driving stock Bronco and was unhappy with the driving at highway speeds along with turns. I had to use front and rear sway bars to bring it back to a nice driving Bronco.

With the Duffs kit on another stock Bronco, drove dramatically better without any additional modification.

This is not a slam on WH, they have a ton of great products and have always been very helpful. My review is limited to their 2 1/2 kit and MY experience.
 
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73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
I see you discovered the dreaded front axle hard brake line interference issue:)

Wish we could get a longer "stainless braided" soft line and avoid all that by setting the hard line bracket closer to pumpkin.

I really like that torque tamer, I have an exact "version" of it on mine. Again, only drawback is frame mounted stuff needs to go on top because of the mount into the side of the inside of the frame, and again, the rear brake line hard line interference.
 

migs

Sponsor/Vendor
Bronco Guru
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Nov 12, 2011
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1,311
Nice write up and thanks for taking the time to do the comparison, but I'm a little confused on that caster thing as well... The caster would be measured at ride height which the 2-1/2" lift dictates, and which one droops more would be irrelevant.
Also, it's not super clear to me, were the WH's springs only tested on the stock arms and the duff springs only on the t-Rex arms? So no direct comparison of springs with all else being equal?
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
So when you were done did you get a pretty even 2.5" lift or more or less?
 

suckerpunched

Sr. Member
Joined
Aug 24, 2006
Messages
882
it's not super clear to me, were the WH's springs only tested on the stock arms and the duff springs only on the t-Rex arms? So no direct comparison of springs with all else being equal?

I had the same question in mind when reading about it.
 
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englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
Nice writeup! A few questions:

How much higher is the lower mount on the T-Rex arms than the stock arms? Any concerns with coming close to bottoming the shocks out since it appears it's higher?

They are very close to stock location, we compressed the shocks and we will go into coil bind before the shock is bottomed out and the droop out is about 1/2" less than the shocks lower limit. I feel there is no worry for the shocks at all and this system uses them to their min/max. Bilstien rates them fro a 2" to 4" lift and with this setup they are like a match made in shock heaven.

The next time you have it on the lift or flexed with the forklift, disconnect the front pivot point on the Torque Tamer and take a photo of how far away the pivot point is away from its mounting point - just curious.

I will try to do that but it will be a while, you may have to remind me again later on. Too many irons in the fire and getting this thing ready for Bronco Takeover in 2 weeks.


The Duff springs are about 50 lb/in lower in initial spring rate than the WH springs - I like them better too.

Todd Z.

One of the biggest advantages and benefits we feel I am sure. I love this suspension as is and am looking forward to my 12 hour road trip one way to Silver Lake in 2 weeks.
 
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englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
I just bought a '76 and shopping for a 2.5" suspension kit. What are you thoughts on the Duff vs WH kits for primarily street use? Thank you.

I like them both but my newer preference is for Duffs. It is a much smoother and more plush ride, in my opinion it is about as best you can get for a 92" wheel base. If you are going to be primarily street use then I would def look into adding a Hellwig Sway Bar with quick disconnects for the front. You can get them from Krawlers Edge but get your order in soon if you want one because they have been running behind on production and meeting demand. If you want to order this exact suspension from Duffs just ask them for the DuckTuff suspension package. They will know what parts you will need.
 
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englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
Just curious about the caster-you mentioned that you lost caster with the t-rex arms and 4 degree bushings. Wouldn't you actually gain about 1.25 degrees with that combo over the 7 degree bushings on the original arms? If you lost caster I wouldn't think you would have to clearance the driveshaft. Please correct me if I missed something here.

It all has to do with clearance and droop. The loss in caster is not noticeable on my vehicle but the fact that he front axle now droops down an additional 3" created a bind in the double cordon. If the suspension did not drop out as far then yes, there would be no need for additional clearancing but because it does, it did. Now if I want to add more caster I will have to go back to 7° bushings and then I will be dealing with needing a high angle drive shaft to make it work and not bind at full droop.
 
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