- Article/photo's courtesy of
- Scott, AKA mrk5
Custom DoetschTech Shock Installation
Now I'm not expert on shocks, but I am a thinking man. So everything that follows is based on my own research and the conclusions I've drawn from that research. I did a lot of searching on several Internet forums and talked with several people I feel "know their stuff."
I think the first thing to look at is twin-tube versus mono-tube. Most of us are familiar with twin-tube shocks like the Explorer Pro-Comp shocks I was running in the past. Twin-tube shocks are less expensive to manufacture hence their pricing and popularity. The difference between the two types of shocks is evident in their design as illustrated in this picture.
Mono-Tube VS Twin-Tube
I decided on monotube shocks for a couple of reasons. Primarily I found through research and interviews that monotube shocks will give me the best results for what I desired in handling characteristics. I was also willing to pay the additional costs involved with monotube shocks.
I narrowed my decision to 3 choices in my $100-110 price range:
- Bilstein 5150
- Polyperformance's BBCS-15
- Doetsch Tech's Monotube 2.0 smoothbody
- Owner rebuildable
- Therefore owner revalveable
- Custom built to owner specifications
- Optional remote reservoir that can be added at any point.
Below is the chart of shocks available as of March 2007. There is also some sales information at the bottom:
Shocks available as of March 2007
The valving they set me up with was what they considered medium for my truck.
Front
Compression: 8 8 8 8
Rebound: 10 10 10 10
Rear
Compression: 6 6 8 8
Rebound: 10 10 10 10
I'll bet you're thinking the same thing I was when I received the information, "What the hell does that mean?" Well I sent a reply asking that very question, albeit a little bit less vulgar. This is the explanation I received:
2.0 monotube valving stacks are made up of 4 discs that control the compression and rebound based on the thickness of each disc stacked on top of each other. These discs flex upon the entry of oil through the piston port. The ports in the pistons have 3 rebound ports and 6 compression ports.
Below you will find the basic valve stacks and the dampening forces produced using the stacks listed for both compression and rebound. The valving that is installed in your new shock is the base line or "medium" valving for that type of vehicle. Valving or dampening forces are determined by personal preferences, i.e. soft, medium, firm
Doetsch Tech Shock Valving
Medium valving: #2/#5, or 2 over 5, or 2/5 This means you use discs from row #2 for compression and discs from row #5 rebound. Using these you would have a valving of 180 lbs. of compression and 350 lbs. of rebound.
The other options I chose were rod end mounting and 15" travel.
In hindsight I would not choose rod ends again. They ended up being almost as much of an adventure in research as the shocks themselves. They are just like little heim joints on the ends of the shocks.
The first obstacle was the necessity for some sort of spacers in conjunction with the rod ends. You can't just bolt them in because they need to be able to pivot with the suspension travel. I found some spacers through McMaster-Carr.com and they weren't cheap. You can also pay a little more for some fancy ones from Polyperformance. Below is how they look assembled with spacers:
Assembled with spacers
My final issue with the rod ends is noise. The rear shocks enter the cargo area of the K5 and at the time this is being written I don't have them enclosed yet. Because they are basically rigid with no urethane isolation, there is a constant "chatter" when going over rough terrain.
I don't know why I went with the rod ends. I guess it was a "cool factor" decision gone horribly wrong. Buy poly bushings!
Back to my order options, let's address the choice of 15" travel. Once I had the suspension installed, I built an RTI ramp so I could take some measurements. I clamped a flat piece of metal to the top of the frame rail and measured the total suspension travel at the factory shock mount. It came out to 10". I thought pretty hard about the 13" travel shock, but I ultimately decided on the 15" travel. It didn't cost any more and I hope to use these shocks for a long time and I may need more travel in the future.
I'm glad I went with the 15" travel now that I've finished the installation. The reason is I had 5" to play with. Meaning I didn't have to get the mounts to come out to an exact distance. This made the bracket fabrication much easier.
Below are some pictures to illustrate the length of 15" travel shocks:
Shock length
Shock length compared to young Off-Roader
- Mount shocks as vertical as possible
- Keep the shocks as close to the wheels as possible.
This is what I ended up with:
Front 1
Front 2
Front 3
Rear 1
Rear 2
Rear 3
Because I'd chosen the 15" travel shocks and had the extra 5", I set the brackets so that there was 5" of up travel and the rest remained for down travel. Plus I installed the bump stops at a height to prevent the springs from excessively over-arching in the wrong direction so I have plenty of room for up travel.
The other factor or measurement to consider was how far out to lean the top of the shocks. The front driver side was the determining element on the front brackets because of the steering shaft. I didn't think about this when I started and the first bracket I made didn't clear the steering shaft. In the rear I just leaned them out enough to keep the shock inside the fender wells.
To make the brackets I used a piece of 4" square tube with 3/16" wall. I cut the tube in half to make a C. Next, I notched the brackets and bent them for the outward lean and then welded up the seam. I drew a straight line from top to bottom through the seam and cut the excess off. This made a nice smooth bracket. The final step was to add tabs for the shocks to bolt in. Hopefully the drawing below helps explain what I did:
Custom shock bracket
Next I made the tabs for the axle mounting. The rears were pretty straight forward but the fronts were a little goofy. The axle tabs landed right next to the inner C on the axle end. I cut a piece of cardboard and used that to trace and cut all of the tabs.
Cardboard template
Front axle shock tabs
Installing the shocks with spacers is a HUGE pain and another reason to avoid rod ends.
Doetsch Tech recommends waxing the shafts periodically with good car wax. This creates a protective barrier on them and helps prevent dirt and debris from sticking to the shafts and creating future problems. To remove mud and debris from the shafts they recommend using WD40 (or similar product) to wipe it down and rinse with water.
So, how do I like them? They work awesome! I feel no difference with street performance compared to my old standard lift spring suspension with no swaybar. I actually feel less body lean on the curves now with 52" springs in front and 56" springs in the rear.
On the trail is where they really shine. The slow crawling stuff is not much different, but now I can fly down the "smooth" sections of the trail. Rough bumpy access roads are not nearly so horrible anymore. The best way I can explain it is that the softer springs take the force out of the initial impact and the shocks eliminate the rebound lurch in the opposite direction. I'm no longer getting jarred back and forth over the trail.
A buddy rode with me and immediately noticed the difference. My wife confided that she initially thought the shocks were a bit extravagent but after riding in and driving the General she feels they were worth the money! Now there's an endorsement you can't beat!
Testing on RTI ramp