Our Hot Bodies D817 / D815 / D812 Rear Carbon Arm Inserts offer your buggy another great tuning feature by reducing the flex and twist in the arm. After extensive testing, we found that the jump between the stock plastic insert and a 1.5mm carbon insert was too drastic of an adjustment. The solid carbon insert was best used in the rare high bite / smooth track conditions. We wanted to design an insert that had a noticeable change on the track feel from the plastic insert but wasn't so much that you could only pull them out every once in a while. Who wants to buy trick carbon arm inserts that sit in your box because the tracks you run on aren't maintained by Mr. Miyagi? So we made our insert out of 1.5mm thick carbon fiber and pocketed the underside making it 0.75mm thick. The only time you will pull out your plastic inserts is when your track is completely blown out.
We also had to tackle another issue with the carbon inserts. During development, we discovered that the front inserts would break after just a couple of runs. After much debate, we decided this wasn't good for our image. Even the solid 1.5mm carbons would break quickly. After tumbling across the track and killing several carbon inserts we figured out the issue. The inside screw near the droop screw was causing the breakage. Ultimately what happens is when you have a tumbling wreck, because you're not Ronnefalk, the front tire will take an impact that pushes the front arm down and the droop screw quickly stops the downward motion but the plastic arm wants to keep moving and this places a huge amount of focused stress on the carbon around the screw. We tested non-countersunk screws, an arced slot for the screw, and the ever popular method of super gluing the insert into the arm. All of them failed at some point. So we just removed the screw in that location and after countless hours of track time, not one insert has broken and we noticed no performance degradation from the screw removal. We removed the screw hole so you won't be tempted to break your inserts!