Suspension set-up theory

[Hillclimb#42]

Hi guys. Another easy one that should be interesting to pick your brains on. I have my own preferences, but in the pusuit of the best Kx500 in two states (at least) I would like a worldly education on your preferences and technique to the overall set-up for different conditions that we ride.
  I will go first, since i am basically already saying that I don't have it all figured out. I like my bikes set-up the same way. Stiff going down and slower coming up than going down. I really only got to that point by checking other bikes and it seemed everyone was set-up stiff and slow rebounds. Last year I raced a guy that races many harescrambles, and only hillclimbs occasionally. He beat evryone in my class by two seconds on a 600ft hill. He was set up as soft as his bike would go. Needless to say, I began wondering about my own set-up. That paticular hill was very rocky with turns and jumps. Most of the hills are straight 200ft or less hills with 1-2 "breakers" (big humps in the hill) and all dirt if not mud.
  So first real question is how do you like the bike to be set-up, and then the second is at what point would you change to the other end of the spectrum? Any do's and don'ts would be appreciated. I would like to develop a strategy from the collection of experts here. Thanks alot for the input ahead of time.

[kaw rider]

softer, tire stays on ground longer,plus doesn't pull frontend up as fast.

[dsrtrider]

what i have heard in general is that most bikes come with weak springs that are overpreloaded and stiff valving.  suspension companies reverse this and use heavier springs, lighter valving and reduced fork spring length to lessen preload.  this is what they did to mine years ago on my old 1990 kx500.  that was supposes to help with deflection, etc.  it seemed to work.  it wouldn't bottom on face of jumps anymore and gave me confidence over fast stuff.  it was alittle harsh over stutter bumps however.

when you go stiffer in springs the rebound moves faster so you need to slow it down a few clicks

[Hillclimb#42]

I don't mean heavier or lighter springs or anything real deep like that. I mean let's say you're riding  harescrambles and normally are set-up soft, and maybe start stiffening up 5-6 clicks or 2-3 for a track that has jumps or creek crossings. Or maybe for a motocrosser stiffer on a smooth track vs. softer on a rocky rutted one. Whatever conditions that make you alter your original set-up and why. I am constantly set the same way, and am curious about what I might be overlooking.
  So then kaw ridr, wher would you be or what would you be doing that would make you change it stiffer about 5-6 clicks? and would you change them equally?

[dsrtrider]

this is from an older MXA magazine article on suspension:

1) set your sag correctly (typically 100mm rider and 10 to 20mm free sag).  this can affect feel over stutter bumps.
2) go out on your test track/trail and ignore rebound for now and just concentrate on comrpession.  they say go in until it "lightly bottoms over big jumps and/or largest G-out then go in a few clicks.  or you can go harder until they feel harsh and then back out a few clicks.  They say its better to be on the slightly harsher side.
3) once compression is set then concentrate on rebound.  if you are pogoing through the woops or kicking out then go in a few clicks.  if you feel like rear is "hanging down" or packing through acceleration bumps then go out (softer on rebound).  optimum is the loosest you can get away with.

i don't think you can get the perfect setup for all situations.  if to soft you get great feel over soft stuff but harsh bottoming.  if stiff to not bottom then harsh over small stuff.  have to balance it.

i can make a coy and mail it to you.  ts a god guide to how to set you clickers for everything

[jazg]

this might be a dumb question but how should a well set up bike behave through long whoop sections? what would you be feeling for? the trails i ride are just endless whoops and i've got used to the way they feel but some of the guys are still riding away from me there so maybe i could do something with suspension

[TheGDog]

Yo jazg... don't forget to adjust your tire pressure too.  Makes a WORLD of difference everywhere!

When that rear tire has too much air in it... it can feel pogo-y in a scary way.  Then... once you drop it down to the right pressure where things seem to hook-up the best as far as traction goes... you'll notice FAR less business in the rear.

on my IRC M5B 140/80 18" rear. 11 Lbs. is the sweet spot.  I run 14/13 Lbs in the front Maxxis Desert IT.

Get your tires pressures sorted out first even BEFORE you start messing with the clickers.

And when it comes to messing with the clickers.  Only change one thing at a time.   And only change it 1 click at a time.  And keep repeating your testing runs until that part of "the problem" feels better.

If you try to adjust both the compression AND rebound clickers at the same time you'll end-up over-adjusting in one direction... the re-over-adjusting back in the other direction. (Hope that last part makes sense to you)

[Hillclimb#42]

alright, yeah thats the kind of info I'm lookin for. I kinda already get that you want to use the travel of the suspension for softest ride without bottoming out, and rebound has to be at least as fast as the obstacles are spaced.
  I believe that your bike should eat woops for a small snack,Jazg. My 500 loves em. I would think that you would want to be set-up pretty soft with a fairly fast rebound, as woops are usually very closely spaced. Going for stability and straight tracking.
  Along these lines, how do you balance front forks to rear shock? How do you make sure that front forks are set exactly the same to each other?
  We use tire pressure frequently. Loose and dry = reduce air to below 10psi in rear, wet and serious traction might have people putting in over 20psi. This is mostly a traction deal. Probably don't want anything less than 12psi on normal riding unless its all sand or snow.
  What happens when you have mixed conditions? Say rocky, woops and jumps with hard landings. Keep in mind, I don't get practice rides to tweek things into perfection. I need generalizations, if thats even a word.
   

[dsrtrider]

if your bike is "stinkbugging" where the rear feels higher you can lower your forks to raise front up or increase rear sag to lower rear.  If you feel its like a chopper than decrease sag to raise rear and move forks down tubes to lower front. adjustting sag is important for proper ride geometry.  i am more familiar with proper settings on ktm's becasue they talk about it to death on ktmtalk.com but for KX's i will just say in general i read adjust yuour rear sag to get the position you like for stability and/or turning.  if you get proper rear sag with gear on (100mm or so) and you don't have much free sag(10 to 25mm??) or to much free sag that points to a different spring rate.  Forks can also be adjusted for rider and free sag with springs but i am not sure on correct numbers for KX's.  i have some articles that talk to it and there is likely some suspension guys on this site that knows more on this.  Once you get correct sags via springs and you adjust to the geomtry front and rear that feels good then start working with clickers.  if you don't have correct springs you can make mistakes with clickers.  proper springs hold you up in the correct place on suspension.  to weak of springs drops you further down in the stroke where its harsher.  adjusting clickers at this point maybe misleading.  get your sag and springs set first.

assuming your springs are good you shouldn't have to deviate to much from the manufacturs clicker settings.  maybe 8clicks either way (??).  if you are maxed out on your clickers that is also a sign of spring or valving is needed.

Clickers work low speed circuit (rolling woops, g-outs,). valving is more for high speed circuit (square edge bumps, major bottoming, etc).  That circuit is afected by valving and some spring and fork oil height adjustments.  Fork oil hieght can help resist bottoming but to high makes mid-stroke harshness if to high.

If you go over major jumps think stiffer settings, more oil, heavier springs. if you ride fast over smaller obsticles try softer clickers, lower oil heights, softer springs.  go to extremes on clickers till you learn how your bike behaves.