All 4 arms are bent. I didn't even notice it until I replaced the arms and compared them. They aren't straight. The bend occurs right where the shock mounts to the arm. It pushes down and pivots the arm downwards in that exact location. It has been months since I've had the old arms removed and they've self straightened a bit, but they are still noticeably bent. I won't run those HD springs for that reason. Whether they bend the arms or not, nobody can deny that there shouldn't be that much static preload when there isn't even weight applied. You have to compress the HD springs hard just to mount them on the shock. That doesn't make any sense. I've never seen any RC shock/spring designed like this. Even with the preload collar all the way out, the weight doesn't compress the springs at all in the rear.
There's a German company out there (can't remember the name) which makes several proper sets of "shortened" springs in different stiffnesses for the DBXL. Those are designed properly and IMO the DDM springs were a very lazy design. I doubt they were tested in any way. I was already skeptical of the DDM design from the get go. That german company also makes the wing for the DBXL. I'll post the link when I find it.
Here's the link...
https://rc-car-online.de/en/product...uning-springs-dirt-spring-dbxl-xl-e-mtxl.html
The description they provided actually sums up exactly what I've been saying.
From their website...
"The Desert Buggy XL stock springs use a high preload, which is even bigger than the shock’s travel. This means that the stock spring action increases not that much going through the available suspension travel. To handle hard impacts high viscosity oil is used in the shocks; however, this oil is too heavy for these springs for a proper rebound. A sensible suspension tuning becomes much pretty difficult.
For this reason, the tuning springs Dirt-Spring Desert Buggy XL are shorter than the stock springs, but also use heavier gauge wire in return. Therefore the change in spring action during the suspension travel is noticeably higher than the preload; the suspension settings can be influenced more effectively."
What I've been saying all along is that the DDM springs are designed to take hard impacts from jumps, but handling wise they're just terrible. There's no suspension travel unless all you do is land hard jumps! I've discussed this in another thread a while ago. I'm not expert in suspension, but I did work in sales and technical support for H&R and Bilstein Canada for 5 years.
I guess the DDM HD springs were designed as a band aid solution for the bashers who bottom out their rigs too often from landing hard jumps. The racer and Losi fan in me says the springs aren't designed properly.
