heres what nate of porterbuilt posted on the 67-72chevytrucks.com site:
---Originally Posted by porterbuilt
Well, I think there has been enough information released by Thorbeck Bros., on their version of the Dropmember, to where I feel like I can start making comparisons and pointing out what makes the Porterbuilt Dropmember a better choice.
Let's first discuss the differences in the two kits stated by Thorbeck Bros.:
Thorbeck Bros. has stated in his thread that his version maintains factory C-10 geometry. Thorbeck Bros. wrote, "basically the kit keeps the factory geometry but everything is raised and brought in so you can lay frame on a 29.3." (
http://www.67-72chevytrucks.com/vboa...91#" target="_blank" rel="nofollow">
http://www.67-72chevytrucks.com/vboa...91#post2910991)
The Porterbuilt Dropmember DOES NOT maintain factory suspension/steering geometry, due to the fact that the factory C-10 geometry is UNDESIREABLE. The arcs and lengths of the control arms in their factory geometric settings cause the camber to go positive under compression first, and then as the suspension compresses more, the camber turns negative. Positive camber is not a desireable characteristic. The Dropmember puts this undesireable result in check, and also changes the camber curve, eliminating the excessive negative camber gain under extreme compression inherent in the FACTORY C-10 geometry.
The second main difference stated by Thorbeck Bros. is in the manufacturing techniques:
Thorbeck Bros. stated, "our crossmember kit is built alot different than porters. although seeing his inspired us to manufacture one of our own. we build ours out 1/4" thick laser cut sheet vs his 3/16" material. we also use far less pieces to assemble the unit. just for example, if you look at the top plate on both units, you will see that ours is one piece that was press brake formed, and his is welded out of several pieces like a puzzle." (
http://www.67-72chevytrucks.com/vboa...91#" target="_blank" rel="nofollow">
http://www.67-72chevytrucks.com/vboa...91#post2910991)
It is very true that the Dropmember is put together differently than the SD unit. The reason that the Dropmember's top section is put together "like a puzzle" is that it in order to give it the optimim structural integrity and strength it needs to have some bracing or trussing inside the unit. If I were to design and build the Dropmember to have a one-piece top section, it would then be hollow and not be able to reach its optimum potential for strength and rigidity. In order to add this trussing, and have it welded to all sides of the interior, it cannot be one piece. I agree that a one piece top would look a bit sleeker, but I design/build my parts with function as the dominating factor.
In reference to the thickness of steel used (1/4 vs. 3/16), it plays no role in this comaprison. I could build this unit out of 10ga. steel and have it be plenty strong enough to handle the abuse any C10 owner could throw at it. One might ask "then why don't you". It's an easy question to answer, the general public has a lesser understaning of engineering and design, and would automatically assume that thicker is stronger. I decided to blend the two and go with a 3/16 pickeled plate.
The last main difference bewteen the two is the amount of time, and miles invested. The Dropmember has been making waves in the industry for two years and has had hundreds of units sold, and thousands of miles logged. Before it became public, it was designed and developed for over a year. It was road tested before it was made public or released to be sold. Proven by hundreds of satisfied customer, and thousands of miles on the road!
One more thing, the Dropmember comes with shock mounts at no extra charge!