silverfox.xx
quocunque jeceris stabit
I have just acquired some new front fork springs.
WP pro line linear, which are 0.95Nmm, against OE which I believe are 0.82Nmm. The new WP springs are 18mm longer than standard at 250mm, OE are approx 232mm, will I need to shorten the fork tube spacers by 18mm?
Initially I was advise to go for 0.90Nmm, but according to a 1200pete post above 12stone, 0.95Nmm is better. So taking into account I'm nearly 13 stone, allowing 14 stone with bike gear on, ride 2 up sometimes, tankbag/luggage... etc.
I shall refill the forks with 10w fork oil and according to previous posts set the air gap to 125mm (quote: 1200 pete post) Up the air gap (gap between the top of the oil to the top of the fork, checked with no spring in the fork and the fork and damper rod fully compressed) to 125mm. I'm assuming that this'll be about the same as a Jaws post of 142mm with spring in?
http://www.bikersoracle.com/blackbird/forum/showthread.php?t=48822&highlight=fork+air+gap
http://www.bikersoracle.com/blackbird/forum/showthread.php?t=28056&highlight=fork+springs+rate
I have contacted the supplier, but am awaiting a reply..
EDIT 16/10/2010.. from end result:
WP 250mm long 0.95Nmm linear fork springs fitted, I left the extra 17mm as potential preload prior to cutting 17mm off the spring spacers if I felt it necessary. Absolutely fine, static sag is 34mm (Road sports bikes I believe should be between 30/35mm, about 1/3rd of full suspension travel). Handling has been much improved, greatly reduced nose dive, rear now does not come up off the ground during heavy braking, powering out of corners it doesn't drift out but holds line, bumps are considerably smoothed out, Braking hard coming into corners once the brake is released the bike immediately settles as the forks are not still returning to ride position, thereby allowing a smooth transition. Power on mid corner does not unsettle the bike. NB: 6mm rear shock spacer is also fitted.
As the forks were left in place, I sucked out the old fork oil using a piece of tube with wire wrapped around it to keep it stiff, and used a 25ml syringe heatshrink/cable tie attaching it to tube for suction, according to the amount removed most of it came out. Refilled with 10w shock oil.
It was a but awkward holding the spring spacer down (flat blade screwdriver) to allow initial fitment of the fork top nut to the damper rod, due to the 17mm preload being left on, however once started a 14mm spanner held the lock nut/fork tube spacer in place. Assembly was made a little bit more awkward as I have bar raisers fitted, but not frustratingly difficult.
Good news is that the suspension drag (fork seal/linkage) has been reduced from 15mm (OE) to 3mm (new springs) on the front. The back OE is excellent at 0mm drag.
The removed OE springs were on top length of service limit spec, with a static sag (or should I say sog) of 49mm
. Currently rear OE has 55mm static sag , so that'll be the next thing to do, now the new front has made the back feel very slightly under sprung, as you would expect.
WP pro line linear, which are 0.95Nmm, against OE which I believe are 0.82Nmm. The new WP springs are 18mm longer than standard at 250mm, OE are approx 232mm, will I need to shorten the fork tube spacers by 18mm?
Initially I was advise to go for 0.90Nmm, but according to a 1200pete post above 12stone, 0.95Nmm is better. So taking into account I'm nearly 13 stone, allowing 14 stone with bike gear on, ride 2 up sometimes, tankbag/luggage... etc.
I shall refill the forks with 10w fork oil and according to previous posts set the air gap to 125mm (quote: 1200 pete post) Up the air gap (gap between the top of the oil to the top of the fork, checked with no spring in the fork and the fork and damper rod fully compressed) to 125mm. I'm assuming that this'll be about the same as a Jaws post of 142mm with spring in?
http://www.bikersoracle.com/blackbird/forum/showthread.php?t=48822&highlight=fork+air+gap
http://www.bikersoracle.com/blackbird/forum/showthread.php?t=28056&highlight=fork+springs+rate
I have contacted the supplier, but am awaiting a reply..
EDIT 16/10/2010.. from end result:
WP 250mm long 0.95Nmm linear fork springs fitted, I left the extra 17mm as potential preload prior to cutting 17mm off the spring spacers if I felt it necessary. Absolutely fine, static sag is 34mm (Road sports bikes I believe should be between 30/35mm, about 1/3rd of full suspension travel). Handling has been much improved, greatly reduced nose dive, rear now does not come up off the ground during heavy braking, powering out of corners it doesn't drift out but holds line, bumps are considerably smoothed out, Braking hard coming into corners once the brake is released the bike immediately settles as the forks are not still returning to ride position, thereby allowing a smooth transition. Power on mid corner does not unsettle the bike. NB: 6mm rear shock spacer is also fitted.
As the forks were left in place, I sucked out the old fork oil using a piece of tube with wire wrapped around it to keep it stiff, and used a 25ml syringe heatshrink/cable tie attaching it to tube for suction, according to the amount removed most of it came out. Refilled with 10w shock oil.
It was a but awkward holding the spring spacer down (flat blade screwdriver) to allow initial fitment of the fork top nut to the damper rod, due to the 17mm preload being left on, however once started a 14mm spanner held the lock nut/fork tube spacer in place. Assembly was made a little bit more awkward as I have bar raisers fitted, but not frustratingly difficult.
Good news is that the suspension drag (fork seal/linkage) has been reduced from 15mm (OE) to 3mm (new springs) on the front. The back OE is excellent at 0mm drag.
The removed OE springs were on top length of service limit spec, with a static sag (or should I say sog) of 49mm
. Currently rear OE has 55mm static sag , so that'll be the next thing to do, now the new front has made the back feel very slightly under sprung, as you would expect.
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