RC10Talk - The Net's Largest Vintage R/C Community

I have to say the CAT 2000 style shocks are growing on me a bit - I like the adjustable pistons. I wonder why those haven't been adapted to modern shocks?

One thing that does bug me is the black foam piece that goes into the shock seal assembly. As it gets old, it hardens and breaks up, and then oil leaks around it and through the shock. Apparently, fresh O-rings aren't enough on their own to keep the oil in the shock body. Both of my rear shocks completely leaked out as a result of this. Replacement black foam bits are understandably old, so I'm wondering what people have tried here as a fix...

What I did yesterday was to cut a length of foam and wrap it around the plastic insert piece (where the original black piece goes) as a substitute to fill the space in there. It is softer/less dense than the stock unit, but since it's soft, you can wrap it around multiple times and end up with something that's nice and snug. So far, it seems to be holding, but time will tell for sure.

I wonder how close the associated macro shock foam would be. It's used for the same purpose, volume compensation, but it's length may differ

I think the pistons were a good idea, but any reduction of weight to a true race design will trump the ease of adjustment

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Checked the shocks this morning after a couple of days with fresh oil, and there does not appear to be any leakage. So it looks like the foam trick worked. Good, because I have plenty of that stuff

I really can't say that I buy the weight argument, especially in a modern R/C world where we have bigger, heavier, "big bore" shocks on our racing chassis. The heaviest 1:10 pistons are made of delrin, and the weight of the oil far outweighs that of the piston. The adjustable piston on the Schumi shocks probably weighs the same as a standard piston anyway, since each half is thinner than a conventional piston for a combined volume that is quite similar. These shocks have four piston settings which are easy to see, so there should be no confusion about which damping setting you are using here.

So I really don't get why we don't see any big bore adjustable pistons on the market. Any manufacturer could make a killing on them (provided they have bottom loaded shock bodies such as Kyosho), because I am certainly not the only one who hates wasting shock oil every time I want to try a new piston setting. That's just stupid, and I am genuinely surprised there is not a larger effort to address this. Maybe I should do it myself and corner the IP on it. Buy a 3D printer...sell a ton of them...make some dough...