Re: extra fork spring?
Posted: Thu Sep 03, 2015 12:48 am
This has been discussed before, but here's my 2 cents. The stock rubber bumpers inside the forks are absolute crap.
They dissolve in the fork oil, creating sludge and gumming up the internals. Springs leave your oil clean.
I recently did some radical mods to the front forks on my 1975 90/6 so that I could put on some large 310mm discs and 4 pot calipers . http://www.advrider.com/forums/showthread.php?t=1074183
I have Heavy duty Luftmeister springs in the front. From what was left of the lower bumpers, I could tell the bike had rarely, if ever, bottomed out. They were hard, bottoming would have smashed them. Believe me, I've had plenty of episodes that should have bottomed them out. The top bumpers, that prevent the "clunk" when the forks are fully extended were completely gone. I was worried the added braking might cause radical bottoming, so I opted to put some springs in the bottom of the forks (similar to the ones you described in the A area) to try and handle that, and I put some small springs in place of the upper bumpers to stop the "clunk". Everything works beautifully. I can fully engage my front brakes to the point where the rear end leaves the ground and, still, they don't bottom out. I run the main springs without preload to get the SAG rate right. I also use the updated factory amount of Spectra 5wt fork oil. Very happy with the whole setup. Not sure if the forks actually bottom out enough to activate the lower springs, but it's nice to know I don't have a hardened crumbly mess as my last resort.
The upper springs are actually the inner valve springs from a VW Vanagon. No more "clunk" at full extension when I'm hard on the throttle.
To each there own, but I don't want dissolving goo in my forks. Better to have something that will actually do the intended job if necessary.
They dissolve in the fork oil, creating sludge and gumming up the internals. Springs leave your oil clean.
I recently did some radical mods to the front forks on my 1975 90/6 so that I could put on some large 310mm discs and 4 pot calipers . http://www.advrider.com/forums/showthread.php?t=1074183
I have Heavy duty Luftmeister springs in the front. From what was left of the lower bumpers, I could tell the bike had rarely, if ever, bottomed out. They were hard, bottoming would have smashed them. Believe me, I've had plenty of episodes that should have bottomed them out. The top bumpers, that prevent the "clunk" when the forks are fully extended were completely gone. I was worried the added braking might cause radical bottoming, so I opted to put some springs in the bottom of the forks (similar to the ones you described in the A area) to try and handle that, and I put some small springs in place of the upper bumpers to stop the "clunk". Everything works beautifully. I can fully engage my front brakes to the point where the rear end leaves the ground and, still, they don't bottom out. I run the main springs without preload to get the SAG rate right. I also use the updated factory amount of Spectra 5wt fork oil. Very happy with the whole setup. Not sure if the forks actually bottom out enough to activate the lower springs, but it's nice to know I don't have a hardened crumbly mess as my last resort.
The upper springs are actually the inner valve springs from a VW Vanagon. No more "clunk" at full extension when I'm hard on the throttle.
To each there own, but I don't want dissolving goo in my forks. Better to have something that will actually do the intended job if necessary.