Well I had a long conversation on the phone with the Oz dealer for Hagon shocks, Darrell Groat, he's a pommy guy who has lived in Oz since 2001. You can read his brief here if interested
http://www.hagonshocksvictoria.websyte.com.au/site.cfm?/hagonshocksvictoria/1/He's a wonderful friendly knowledgeable guy and during our talk he passed on some of his knowledge that opened my eyes.
Firstly he said there will always be a degree of bottoming out when you hit big bumps or potholes etc, I wasn't impressed at first as this is not what I wanted to hear, but to cut a long story short it appears that in my attempts to rid the bottoming out syndrome I have in effect caused even more problems by having way too stiff spring settings. We must have spoke for an hour or more.
I must admit to some embarrassment over my lack of knowledge when it comes to suspension both front and rear. I have no excuses other than ignorance.
So due to very stiff settings on the springs the shocks were hardly working at all, I would go over the slightest bumps and feel the hardness, in my relentless pursuit to achieve no bottoming out I was going in the opposite direction to where I needed to go.
So at least I had done one thing right, I had long ago removed the #26 springs and put back on the softer #20 springs and had them adjusted to the middle position and had accepted that I would need to stand on the pegs when I could see trouble approaching but after our long talk I decided to soften the rear even more.
Darrell told me that contrary to common belief you don't have to set both shocks the same ( this was news to me, maybe not others?) for eg, I could put a #20 spring on one and a # 26 on the other which would give me the equivalent or #23 spring tension, or, you can adjust one differently to the other. To stress his point that you will not twist the swingarm or have any problems with mismatched sides he said you could even take one shock off completely as long as the one on the bike has a stiff enough spring and the bike would ride well with no twisting of the swingarm.
So now I'm thinking my 3 spring adjustment settings has now become 6 or 5 actually, so with this in mind I decided to set one on the lowest and the other on the middle thereby going softer by half a setting, I intend to try both on the lowest today but for now I can only comment on what is going on with the setting I tested yesterday ie one on the lowest and one on the middle.
Now that I have accepted that bottoming out is a part of life ( not withstanding those who say they have never bottomed out
) I am now able to soften up the spring tension thereby allowing the shocks to actually do some shock absorbing.
When I test rode the softer setting I was ,er, shocked to feel some smoothness "at long last" in the back end. Small bumps were no longer feeling like large bumps, it sounds obvious I know.
The proof is in one particular corner that we have in my town that you generally take at about 20 to 30 kph, it's like a tight sweeper and it is corrugated to buggery and back. With the harder settings the bike would bounce through the corner sidling towards the middle of the road due to the tyre/tire leaving the road, this again sounds obvious but when in " no bottoming out " mode I wasn't thinking straight, now with the softer spring tension you can feel the shocks absorbing "some" of the corrugations, I don't think the bike will ever like that corner but it does tell you about your suspension.
Another thing Darrell told me was in regards to pre loading springs, specifically in the front end, he said pre loading the springs does not make them any stiffer, it only makes them harder to start compressing, I think this is excellent info and should be helpful in determining how you look at your front end in the future. I don't think that works for rear shocks though, in my exp if you pre load the spring on the shock it definitely gets harder but I can see how this works in a long spring like in the forks.
I also determined that my swingarm bolt was done up too tight, if you disconnect the shocks at the swingarm then reach over both sides of the rear guard and pick up the wheel you can see if the swingarm is moving easily, in my case it was a little stiff.
He asked what oil I was using in the forks, I said ATF, he said, what does the manual say, I said I wasn't sure n that I'd been using ATF for ever, he then said to have a look in the manual and use what they recommend, "do what you're told" he said LOL. We laughed at that. He said ATF is rated at 10w which I didn't know.
So that's the end of the story, bottoming out is a part of life so it would seem? I have no idea if IKONs or even more expensive shocks will not bottom out while giving a smooth "softer" ride but for me, after going at it all wrong I have set the spring tension softer so the shocks actually do something and will accept bottoming out as part of the deal.
Darrell told me the first thing to look at with the rear is what he called "static sag" this is the amount the shocks go down with the weight of the bike, he said it should be around 10mm or 3/8" then when you sit on the bike it should go down another 20mm or so. If you get the static sag right you're well on the way to the correct spring tension.
He also asked what my air gap is, I hesitated and then he came back with, "your silence tells me you don't know what the air gap means" we laughed again, he explained that with the front forks you should take the fork out, take the spring out and empty the fluid out of it, fill it with new fluid, the amount you would use, in my case its 200cc, then let the slider fall as if fully compressed, the distance from the top of the fluid to the top of the slider is the "air gap" and said it should be 160mm. Something else to look at in the future.
The end, thanks.
