fork tuning for enduros

Taffy, I still think you are way off the hydraulic sweet-spot, not many compression damping shims, clickers nearly wide open. Maybe I was lucky to fail in the right direction, and ended up on the right slope of the valley of bad damping, had I ended up on the other slope the improvements may have gone in the direction of the plateau of damper goodness (softness) instead of the mountain of damper goodness (plushness). Much of My Fork Struggle is actually condensed in this single post linked. It was added to as the development went on.
Using the compression clickers the sweet-spot seems narrow, one click off and I'm off the peak of plushness. On the peak of plushness the fork is like having ascended to heaven. Not launched.
If it was me I'd throw in more shims on the compression side, both on MV and BV, to dissipate the hits as they occur leaving little energy in the springs for the rebound to deal with, and ride a lot experimenting with clickers finding the narrow sweet-spot of plushness. If only I could give any concrete advice, the good tuners could probably, but I can't because of the lack of experience. Still I hope that this somehow can be of help.

Regards.

ok

but i really need to do something about all this and at present i'm too busy. my rear shock settings are very extreme which represents service time me thinks.

i'll re-look at your post and take from it a few lessons.

regards

Taffy

The method of fishing out the cartridge for the adjustment of MV speeded up the progress and lowered the threshold of getting in there a lot.
Regards

Deltas in the fork BV a good idea?

Deltas in the fork BV a good idea? Like this for instance:
24d
24d
16
24d
24d
20
18
14
12
9.5x0.3
15x0.25
No it is not a rebound stack, it's intended for the Base Valve. The idea being that deltas wouldn't be in the way for the cartridge refill. The 16 is a large diameter split shim and the idea is that it should give the 1st stage more support so that a 3 shim 1st stage can be avoided. Any thoughts, you suspension gurus?
Regards

RE: Deltas in the fork BV a good idea?

smorgy

when steve came over from australia he left me two packets of drill bits as a present! so it only seemed right to put them to good use.

i drilled the two compression pistons in three places. once on each trianglular section from underneath. dangeroo0 had assured me i need many bits but it was real easy. i did 3 x 1.1mm in each one.

the suspension over the first 2-3" was lovely, definately an improvement! you could feel the forks moving quicker in order to follow the land.

i have yet to tackle the rest. one probelm though is that i can't find my shims anywhere! moved house and i have a doiuble garage of gear that i can't walk amongst. chocka! so quite how i'm going to sort this i don't know!

regards

Taffy

RE: Deltas in the fork BV a good idea?

i have found the shims smorgy!

tora! tora! tora!

if you would even like to hazard at what you'd shove in the BV and MV and where i'm all ears. my set up is as a few posts above but now i have these three drilled holes in each BV. although the seals went south and i started to leak fluid i immediately noticed that irt was only the oil level that had stopped the biike from bottoming out regularly.

PM me or here. doing it in 21 hours so be quick! i only have 13, 23 and all the even numbers for my MV.

i'm thinking of an extra 22mm on the MV. also 24, 16 24, 24 with a 16 back between the 18 and 15. i believe that my LS damping is nice and would like to just beef up the HS for now. keep the 120mm air gap to see how the full travel goes.

anyway. viking, where are you nowadays?

BTW, Per, i know you didn't like the MxTch needle i showed you but it's getting VERY good reviews over at k-talk.....

cheers

Taffy

Taffy
what works for KTM does not necessarily work for a Husaberg when comes to shocks
problem that I see is that that bulk of the needle comes into play too late to be
a real benefit or improvement over stock that said I have not tryed that set up

cheers Per

whato!

i did my first tests today for 10 months at the local swaffham track where oddly enough i met arkley 123. had a chat and showed him a few tips on how to get up to speed!

swaffham, as said before is a wooded circuit in a kinda 'new england' type setting. the track was damp souffle and the whoops and rollers were really really deep and big. no matter how hard you tried the bike would be airborne 50% of the time and the rider only partially in control. it's also a slow circuit with just 3 x 50 yard straights - otherwise it's second gear and berms like the wall of death!

on the rear i took the HSCD from 2.25 turns in to 3 in and the difference was fantastic and added 3-5mph to my speed along the straights. i did it again to the full 3.5 turns in but the last part made little difference.

while staying on this theme i knew that my sag was 104mm which is outside the 85-100mm recommended on the later frame. so i gave it a full turn of the preload nut and the bike was better again along the roller straights although it felt like the forks were impacting too deep and needed - like the rear just to skip the tops more. took a little LSCD off the rear and addeda little rebound.

the 1.05mm float on the MV seemed lovely! the front end was back to as was a year ago before i started 'tweaking'.

tried raising the forks through the clamps 8mm but need more time to check it out!

as for the forks, i added a 24 before and after the splitter. the splitter itself went to a 13mm which is within 2mm of the pivot shim and as recommended by some.

so: BV is now 24, 24, 13, 24, 24, 22, 20, 18, 15, 11, [email protected]

with the MV i added a shim and this in itself closed the float slightly.
23, 23, 22, 20, 18, 16, 14

so 1.1mm became 1.05mm float.

i had a hankering before i started that i needed to leave the LS shims and go for the mid and high. i know i modified the LS but i jst want to test the parameters -- it's how i am!

the LS was good, still excellent despite adding three shims in this area (2 in the BV and 1 in the MV) i could feel what those bumps were though rather than a remote feel. it may be spot-on at LS or i can even removeone sometime.

i would like to try it on a faster circuit as well because i used all bar 1" on this slow circuit. i think that adding some shims in the mid area between 14-20 and see where it goes, THEN remove a LS 23 or 24 maybe.

the drilled holes in the BV piston worked a treat. i don't know smorgy, whether it's the BV or MV or both pistons i should have done this too? but so far - excellent!

i'd like to try these rollers again and have a slightly harder setting on the front to match the rear. i think i'll really flly over them then.

the trouble at the moment is that as the front sinks deep on contacting the bump just before the crest: it sinks a long way and fires back, this actually steers the bike rather than letting me do the job! i'm pinged off to the side when i'm not absolutely stood vertically upright.

but with .48s fitted it has to be the compression damping going too deep and the rebound can't help but 'fire' me off again as i crest the hump....

regards

Taffy

I read this subject with facination. I can not feel such small differences in any bike set up. I have ridden same make bikes but with different set ups. I have altered my riding style to overcome handling on the different set ups. I rode 3 bikes from same team during Enduro training. I could recognise that each was set up differently, but could not have specified where the differences where! I adapted to suit each bike, so could not be so precise about various set up alternatives!
I look forward to trying the above variations and then feeling each difference as I alter/adjust my settings.
I tend to train in deep sticky mud! so I should have a reference to work from as I have a stable variant of terrain and lap speed!

Taffy
raise the oil level thats the way to get progression with 48 springs you should be styling
and you dont pac the girth you should not even need 48 springs, with 48 springs fork
tends to too gt heavy handed at the first part of the travel where as raising the oil
level stronger feel at the end of travel so get on with it raise the bloody oil level and
feel the difference and change the rebound as need be when you get a fork that dont use to much travel the stock rebound is not to far off, oil level 125-120mm

cheers Per

but per!

i'm on 120mm now!

am i getting close to the fabled 110mm that the manuals say i should be running but nobody ever seems too?

i'll try 15mm and maybe even ride next weekend!

regards

Taffy

Now, if the 48s are heavy handed in the first bit of travel and you think the sag is over the top you would not like the fork to pack since it would make your issues much worse. Maybe the opposite, unpacking it slightly would make it much better. You could try to make it unpack by dialling in more LS damping on the clickers, you'd probably need less rebound damping if you do since you'd get less launching. Unless the BV is too weak to bear the front.

If it was me I'd not remove any of the 24's in the base valve, I'd put back the 16 splitter OR add a LS 24, or even both, BEFORE altering the MV. And only then add to the MV if the HS was not overly harsh and too sharp to the hands. But that's me. And then increase speed to spend less time on the bumps.

You are probably on the right track, generally, having drawn some conclusions riding with 50% of the time on terra firma and 50% in space. Half the time means you have to have twice the force to keep the front up since it is effective only half of the time. Think of it this way: would you fit a twice as strong spring to do the additional job or would you let the hydraulics take care of the extra force needed?
Most people are not all muscle and hard as nails, sag numbers are not everything.
The air spring is a spring too and more oil would rise the spring factor even more, stick to your present level or even remove oil to 130 or 140 to get the thing more linear and add more BV shims instead. If you have added as many to the BV as you can stand when hitting stuff hard and still want to ride with a higher front then decrease the MV float another notch, but I think the 1 mm float is good and adding a 23 while removing the 14 would be an alternative.
This is only an opinion.
Regards.

Smorgasbord said:

Now, if the 48s are heavy handed in the first bit of travel and you think the sag is over the top you would not like the fork to pack since it would make your issues much worse. Maybe the opposite, unpacking it slightly would make it much better. You could try to make it unpack by dialling in more LS damping on the clickers, you'd probably need less rebound damping if you do since you'd get less launching. Unless the BV is too weak to bear the front.

Click to expand...

i agree with all that except i thought "mmmm, more HS will also affect LS" so it's the HS i've adjusted knowing it'll knock off some LS. so i removed one 24 in anticipation of this.

If it was me I'd not remove any of the 24's in the base valve, I'd put back the 16 splitter OR add a LS 24, or even both, BEFORE altering the MV. And only then add to the MV if the HS was not overly harsh and too sharp to the hands. But that's me. And then increase speed to spend less time on the bumps.

Click to expand...

OK, it goes in ma noggin but the LS fluffy stuff is lovely now that i drilled those three holes per BV piston. haven't touched the MV this time as i did it all through the BV with the bike feet up. 20 minutesd from walking into the garage to walking in the house - LOVELY!!

The air spring is a spring too and more oil would rise the spring factor even more, stick to your present level or even remove oil to 130 or 140 to get the thing more linear and add more BV shims instead. If you have added as many to the BV as you can stand when hitting stuff hard and still want to ride with a higher front then decrease the MV float another notch, but I think the 1 mm float is good and adding a 23 while removing the 14 would be an alternative. This is only an opinion.

Click to expand...

interesting slant on oil level - it's another spring! no way am i going back from 120 at the moment. i have oil flowing over the MV, i have no rebound problems for the first time in a long, long while! what i'll say is: "if i can keep that LS plushness, strengthen the HS and get the feel right, i'll THEN THEN see how the bottoming out is fairing. if it all feels good and i'm bottoming- i'll have look at the oil level.

these .48s aren't harsh, they're fast! i don't think i can explain how choppy this track is! on the rear i'm flying over them. but it's the front i now need to control better.

i'm sure we've talked about 'balance' before: the bike lands from a jump evenly but when you push both ends by hand you feel like it's hard on the rear and really light on the front! weird!

this is what i've done today:

was: 24, 24, 13, 24, 24, 22, 20, 18, 15, [email protected]
is: 24, 14, 24, 24, 22, 20, 18, 17, 16, 15, [email protected]

ride height feels great, dip/nod is spot on.

preload is 2mm at present so i may look at another 3mm max (as the 48s are strong nough).

regards

Taffy

Try this:

24, 24, 13, 24, 24, 24, 22, 20, 18, 15, 13, [email protected]

oh dear!

looks like both lew and smorgy think i went the wrong way!

Lew, i know your a man of few words due to idea stealing but am i right in guessing that a completely new 13 is picked to toughen up the whole stack?
no need for the 16 and 17 i put in?
you feel i should have added even more 24s???? wow? so i guess you wouldn't agree with ZP3's stacks then!

i'll take my shims with me sunday and do a swap if i can.

honest!

regards

Taffy

zp3 ran .39s, single stack BV and is fairly skinny and on a 200 cc 2-stroke, a lighter bike, a lighter guy. And a .8 mm float on a 4 shim MV too, which bore on a 30 deg tap shoulder.
You could try that float too but I bet you will be better off with more shims in the MV than was used in the zp3's skinny 2-stroke. I like 1 mm.
By all means try the lew-stack above, but keep your 14 splitter. Bring a 16 splitter to try if your smoothbleeding of the BV is smooth enough to allow it. Again just an opinion, the pudding will provide the proof regardless if I'm right or wrong and should be the guide rather than some free advice on an internet forum. But as you previously stated, talk is cheap.

Regards.

the drilled holes in the BV piston worked a treat. i don't know smorgy, whether it's the BV or MV or both pistons i should have done this too? but so far - excellent!

Click to expand...

can you hear me!PM me if you want. i have simply drilledd 3 holes, one in every other side on the underside of the BV pistons where it's easier to drill.

the trouble at the moment is that as the front sinks deep on contacting the bump just before the crest: it sinks a long way and fires back, this actually steers the bike rather than letting me do the job! i'm pinged off to the side when i'm not absolutely stood vertically upright.

but with .48s fitted it has to be the compression damping going too deep and the rebound can't help but 'fire' me off again as i crest the hump....

Click to expand...

the rebound in itself is fine, more a case of the pitching at the front i suppose.

lots to try this week. Per's oil level, lews settings, and a tweak from you smorgy!

as far as freebies go i have now done the following:
preload corrected
bottoming cups have two drill holes each
later 34mm top out springs
the 18cm drill mod
ZP3 mod
early float springs (softer)

i haven't diamond papered the legs, daisy plate - worth it? should try kabooms seals sometime!

regarding the rear: with a heavy spring, with mucho preload and the HSCD now on full: it's clear that i need to work on the rear shock as well. i bought what i thought was a 2002 shock but came as a 2001 and without the split HSCD / LSCD. what will that take to make right?

regards

Taffy

Pitching front, yes I agree and think that the rebound is ok too, even though it's hard to tell remotely. Still think the BV too weak.

i don't know smorgy, whether it's the BV or MV or both pistons i should have done this too?

Click to expand...

Sorry, didn't understand that sentence at first..., but it should be better to drill the BV smoothbleeds only, I guess. Can't tell really, haven't done it myself.

i haven't diamond papered the legs, daisy plate - worth it? should try kabooms seals sometime!

Click to expand...

Get some really heavy dielectric silicone grease instead and pack it full inside the scrapers.
regards.

Well Taffy, I've been thinking about the pitching fork...

Maybe it should have been PMed to save me from the embarrassment of being totally wrong, but it may take more than one person to put me right.

Anyway, I think that if the compression stacks are firm enough then you don't need to run a very small air gap to prevent bottoming since the increased damping would allow less travel. You will still have your bottoming cone dealing with the very brutal bottoming that occasionally will happen. The air gap is another spring, only much more progressive.




Here is my kind of way of thinking of rebound, lacking any real knowledge. Do correct me if I'm wrong. Read this several times and try to understand how I meant it.


I think of the rebound as doing two very distinctive opposite rebound damping jobs (and
then everything in between):

* Let's call the "first" job Free Air Rebound Damping.
(Edit: I now call this Drop Rebound damping. End of Edit.)
Rebound damping when the wheel is not in contact with the ground. Like when the wheel is kicked up by a root, the rebound of the wheel will then be in free air until it hits the ground or the fork tops out. This rebound movement should be fast so that the front wheel gets back to work as fast as possible. Too slow rebound will not get the fork ready for the next bump and it would mean hitting next root a lot harder, possibly launching you by bouncing hard on the tyre or, if the hit is not square, deflect badly.
The full force of the spring is on your side to do this fast rebound and you would like
the rebound stack to be weak enough open wide from the pressure created by the spring (and air spring pressure). By the end of travel the spring force will have diminished and (ideally) the rebound stack can catch the rebound movement smoothly.

* Let's call the "second" job Ground Contact Rebound Damping.
(Edit: I now call this Launch Rebound damping. End of Edit.)
Rebound damping from firm ground contact. Like when landing after a jump. The springs are now compressed and will launch you unless the rebound is slow enough to prevent it. On your side is the fact that the full force of the spring is not available to shoot out the fork.
The part of the spring force bearing the weight of the bike and rider will bear the weight of the bike and rider and is now not available to extend the fork. The rest of it will.
How great that "rest" spring force is depends on how far beyond race sag the fork has compressed on landing (with a given spring constant). You'd like the rebound stack to
be firm enough to hold back rebound enough so it won't pitch and launch.




A conclusion regarding pitching:

If you can make the fork resist compression more hydraulically then resistance will be
better higher up in stroke and the less "rest" spring force you will get to launch you
once the fork starts to rebound. If you rely more on the progressivity of the spring and
air spring to resist compression, the resistance will be found deeper in stroke leaving
more "rest" spring force to launch you.




Some conclusions regarding rebound stacks:

If you can make the rebound stack to resist the "rest" spring force on Ground Contact
Rebound well, the fork will not launch.

I try to do this in four ways,
*The springs are not too firm, this reduces the "rest" spring force.
*The rebound valve face is ground concave, preloading the rebound stack which rises the opening threshold to where the "rest" spring force has difficulties opening it.
*Keeping the air gap to where the progressivity is just enough to be comfy, letting the
bottoming cone soak up hard bottoming, which is rare anyway since
*Compression stacks are made as firm as possible while still remaining within the comfy
zone. This prevents the fork from compressing more than necessary and that reduces
excessive "rest" spring force for the rebound damping to deal with afterwards.

If you can make the Free Air Rebound to be fast, the fork will recover and be ready for
the next hit fast and the next hit will not be harsh or deflective. I try to get this by
maintaining a weak rebound stack which the full force of the fork springs easily can open
wide to extend the fork fast. I think I get away with it because of the concave rebound
valve face.
Too much fork spring preload would leave too much spring force near full fork extension
making it difficult for the weak rebound stack to dampen the fast movement and the fork
would top out hard. Same thing if a too weak BV would let out more oil than what
corresponds to the piston rod displacement, harsh topping out would result.

(A voice in the back of my head says "get a life Smorgy, you're at over 200 posts".)
Enough for now.

Regards

well i think that you're saying that i need to stop the fork using too much travel because it'll launch if it's too deep and i have a soft rebound?

i agree. i am strengthening the compression equally at both MV and BV. if you watch carmichael et al, they actually have weak rebounds which gives them the chance to control the bike in mid flight on bumps and keeps the front up. i think we're agreed again.

as i have PM'd you and also i shout it aloud? someone has put me right on getting more oil over the MV/rebound stack, reduced aeration and as a result oil levels have gone 140, 130, 120. what next?

i'm on shims first and a touch of oil second to see which has the desired effect!

i'll also put another scenario to you. ready!

people often criticize steering dampers because they say 'that i can't turn the steering quick enough'. yet the deflection of a bump v someone wanting quick steering in a switchback is incomparable!

the difference between controlled return to ride height from a G-out v pinging off the back of a roller is incomparable.

a sloth 'on the draw' v billy the kid.

i therefore conclude that you need your rebound to work hardest in a HS or landing enviroment and be soft and quick when going from race sag to fully open? free bleed HAS to come into this through the ports versus shim deflection.

add in air pressure over the first third, reduce as you say preload for full extension softness.

you're right WE need to get a life!!! (LOL)!

regards

Taffy