not compliant suspension solved

[jerry]

My S4 has been a source of suspension confusion ,, the mods i made over the last few years sorted the handling issues but the bike has not been as compliant and comfy as i expected , in fact its been a bit crashy over bumps , yesterday counter intuitively i wound the front fork rebound from 8 clicks out of 18 to 1 leaving the compression setting at 8 out of 16 forks are 996showa with ktech internals and 7.5nm springs 7.5w oil

and reduced rear ohlins rebound to 10/48 and left the compression at 15/24

WOW what a difference bike floats over bumps no crashiness or wrist bashing yet the bike remains more stable and one can actually corner at steeper angles and carry more speed due to increased comfort and confidence ,, also high speed wobble under acceleration has gone bie hits 130mph with no fuss

i finished my ride today feeling fresh and not bruised about my bum , shoulders and wrists feel fine ,, cant wait to give it another thrash ASAP..

has given me some food for thought ..




oh one other thing when I replaced chain and sprockets i put a 42 on the back previously had a 43 ,,

i a suprised by how much 1 tooth has changed the bikes power delivery , its much tamer,, , top end maginally faster and maybe less fuel use but its lost a huge punch in the backside afterburner effect in low and midrange ,,

[utopia]

That does sound counter intuitive.
I would expect more compliance if compression damping was reduced, but not from reduced rebound damping.
I can only rationalise it on the basis that excessive rebound damping could have been causing the forks to fail to recover fast enough before the next bump in the road, effectively causing them to accumulate the compressive forces and "jack down" (there's probably a correct term for this but it escapes me). ...I have read about this condition.
Maybe this is exaggerated by the softer, 7.5N/mm springs which not only allow more deflection but, now that I think of it, would also perhaps affect the rebound damping since this would now be reacting against a lower rebound force .....?
I'm not entirely convinced by the above reasoning but its the best I can think of up to now.

[jerry]

well i have been out for anothe ride tonight and it all got a bit silly as my pal has a new 821 monny with full DP kit and he is 28 Russian from Vladivostok and nuts he wear a full face shoei and gloves but only t shirt shorts and trainers ,,

we ended up racing through the traffic for 20 miles ,, he could not get away from the old s4 i had him for acceleration and top speed every time and my bike was more stable on the bumpy roads ,,, he was a bit stunned that an old un could beat him we were hitting speeds of 220kph , i felt mega confident and brake dive is minimal even under really hard stopping the PR3 tyres are great too.
i think my suspension is now better set up than his bike ,, but the 821 is mechanically quieter and smoother than my bike, it sounds like a tank rattling away ..

Sometime when i take the forks off i might ry the 8.5nm springs again as the 7.5nm ones are only 2 lines off max preload ,, but for now im happy

next time i do a sprocket change i think that i will go back to 43 for more grunt over top end ..

[jerry]

been online today reading up all my favorite suspension sites and gurus and it seems that too much rebound is a very common issue ,, after setting sag and preload ,, most tuners reccomend turning it off completely and setting up 50% compression then add rebound to get desired effect.then fine tune compression for best results ,,