[ST] Re: ST rear suspension sag

[Darren_Mason@xxxxxxxxxx]

>>Freddie  recommends between 3/4ths and one inch of sag at the rear,
>>while RaceTech recommends 30 to 35 mm (1.17" to 1.365").

Blake,
     I respect the experience of RaceTech & Freddie Spencer, they have
probably forgotten more about suspension than I will ever know. However,
some books I have read recommend the static sag should be a percentage of
wheel travel. This makes a lot more sense to me as travel can vary from 3
to 12 inches depending on the bike.
     I think Freddies recomendation would be biased towards & suitable only
for a racetrack (ie: very smooth surface combined with hard riding). It is
probably too hard for the street. The racetech figure would probably be a
better starting point.
     I have seen 25% travel for static sag recommended. This may also be
for racetrack use & too hard for the road, as it was in an engineering book
about motorcycle design for road-racing. The ST has 120 mm travel on the
rear. My bike at 12 turns out had about 36 mm sag ( 30% travel). I
increased preload to try to raise the ride height & found the same as you,
the actual sag does not reduce much as you increase the preload. I went to
about 8 turns & went for a ride. I found the ride too harsh around town
over sharp square edge bumps, so I put it back where it was. 8 turns may be
ok for me for solo sports riding, but for around town I prefer the softer
ride so leave it at 12 turns. I should add that I dont have the panniers or
load that you mention.
     Anyway, after that I came to the conclusion that 25% travel is for the
track & 30% ok for a soft setting for comfort. Freddies recommended 3/4 to
1 inch is only 15 to 21% static sag on an ST. This means the bike is nearly
topped out & has too little extension travel, plus small bumps are
transmitted straight to the rider as they are not large enough to overcome
the preload on the spring.
     Let us know your findings & what settings you end up using.


Darren Mason.
2000 ST.
Melbourne, AuSTralia.



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