Twinshock Shocks - damping rates

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Rob W
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Twinshock Shocks - damping rates

Postby Rob W » Thu Sep 07, 2006 8:17 am

I've just pulled apart the shocks on my SWM Jumbo (no idea what brand the shocks are?) and found what I consider a very MX style setup to the valving. (some compression damping and lots of rebound damping). Those of you who tried to ride the old tractor will not be surprised by this.

I have just altered the shim stacks to give it slightly less compression damping and much less rebound damping.

I test rode it yesterday afternoon. Amazing difference, it feels like the bike is 10kg lighter! But I think I can do better.

Trouble is, the shocks piston design will stop me ever getting the rebound anywhere near the compression damping. So I am considering flipping the piston over (so I can get the rebound damping close to or even slightly less than the compresion damping).

So my question is:

Is having low rebound damping a good idea on trials bikes. Any thoughts? Sir Feetupfun?

Thanks


Rob

Ca plane pour moi

David Lahey
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Postby David Lahey » Thu Sep 07, 2006 7:15 pm

Good to hear you are doing something about those shockies Rob.

Yes lightish damping both ways is a good thing for riding obstacles. The balance of the damping is important too. I don't know why but from my playing around with Konis and Marzocchis, the compression damping seems to need to end up equal to or a bit lighter than the rebound to feel right.

I've found that there is a bit of a practical limit to reducing the damping due to how the bike rides at higher speeds between sections.

In case this is of use, Falcon classic shocks only have a single large shim for the compression damping and holes for the rebound. They feel to have pretty close to equal damping both ways at hand speed (with no gas pressure).



Rob W
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Postby Rob W » Fri Sep 08, 2006 8:21 am

Thanks David,

I'll flip the piston when I get a chance. The shocks on the SWM have shim stacks either side of the piston, and holes/recesses through the piston to guide the oil. With six shims in the original stacks I still have a bunch of adjustment available, so I should be able to get it close with a bit of persistance. I'll let you know how I get on.

See you


Rob

Ca plane pour moi

Stanm
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Postby Stanm » Fri Sep 22, 2006 3:54 pm

Rob
I have been mucking around wit some Koni shocks and adjusting shims and drilling holes in pistons etc. I have examined a friends pair of new Ikon shocks with the spring off and damping is very slight. If you can examine some good shock for the damping rate this will give you a guide.

The shims and the porting are designed for both fast and slow damping rate and I am no expert. My Koni's are OK but I am close to buying a pair of Falcons.

A good site I found is the Gas Gas website --go to suspension tuning.
http://www.gasgas.com/Pages/Technical/t ... -tips.html
Good Luck

Stan




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