大気開放 Damper

07/07/2015 at 12:32 am

So I’m not a huge fan of damper maintenance, and the way I currently build my dampers shortens the maintenance cycle a little. I wanted to keep a similar damper feel to what I have now, where there’s minimal pressure build up on the top of the diaphragm. This way the dampers are linear and won’t rebound due to diaphragm pressure.

I’m not sure what the english term would be but drilling a hole on the shock cap is fairly common shock build method in Japan. The new GRK Globals come stock with the hole drilled out as well. Depending on the hole’s diameter you can change the feel as well but I went ahead and started off with a 2mm drill bit.

2mm

This time around I went ahead and shimmed the pistons for no play. I kept a little bit of play previously but to build the dampers as smooth as possible I added another shim.

Piston Shim

φ3

No play, but will still spin by hand

No play, but will still spin by hand

As usual, I let the TRF x rings sit in oil then use VG damper grease to coat them.

VG Damper GreaseDual O Ring

I do a dual o ring build but I do plan to go back to a single o ring soon. Shimmed properly, a single o ring setup shouldn’t leak but do prevent any leaks I went ahead with a dual for now. Also, make sure you don’t tighten the bottom cap at this step! Insert the piston + rod, then while moving the rod up and down slowly tighten the bottom cap. If you don’t do this the o rings wont center properly leading to increased friction and leakage. I had to do this step multiple times to get the bottom capped off and the rod moving smoothly.

HRC Springs

Combined with the HRC springs and Yokomo 1000 shock oil these dampers do seem to move in and out a lot more linearly. The hard TRF diaphragm do add some pressure probably but I don’t like how soft diaphragm expand so I don’t plan to swap those out. In addition, because the dampers are very linear I don’t have to worry about piston location as well. I would usually try to place the piston in the middle of the cylinder  but I would imagine that doesn’t matter as much anymore.

I only did this with my rear dampers but the increase in traction on polish concrete was immediately noticeable. My GRK RWD would hold more angle before spinning, and straight line speed increased probably due to increased pitching. I want to say both roll and pitch is more noticeable now but that could just be in my head…