Fork Me.

Ok someone clever like Tack, Mum Goose, A DozenR Yoda. Dave, Rossi or any of you other clever buggers. Mind telling me about forks, oils, levels etc & their effect on settings ?.
I would like some advice specifically about lowering the oil level to compensate for too heavy fork springs. Is this a cheap way to get a softer preload so that i can then increase rebound & lessen compression dampning. Will this firm back up the front end of a bike designed for someone heavier then myself ?. It's pretty rideable (after 2 years of tweakage) but doesnt search for the ground as much as i would like.
Tiggr needs a fork service anyway & i was considering going to 2.5wt n lowering the levels by 5%.
Thanks Guys,
Cheers Brett

Brett reducing oil height wont change spring weight same as adding preload doesnt change spring rate the spring remains constant and for example a .85 spring with preload is still a .85 spring.

Have a look at this and you can sort of work out if you are inside the range thats recomended.

http://www.traxxion.com/technical.springrate.shtml

Use silkolene pro rsf fluid its slipery stuff and a bit dearer but thats what all the suspension dudes use.

Fork oil height stops bottoming out on soft springs because air compresses and oil doesnt so less airgap means less air to compress so the forks will stop compressing before the bottom of their stroke dont know if the oppisite is true not many people have the springs are to hard problem its the other way around.

Set it to a lower height and try and if that doesnt work get a big syrnge and top it up 5mm at a time its easy enough once the fork caps have been off.

Any 9rs i have a look at seemed very soft in the damping dept with bugger all happening from full in to full out havnt had a push at yours though.

Also seen elswhere on a forum where polishing the forkleg lots with metal polish reduces seal drag by heaps also making the front wheel reach more.

When mick sticks that front whell on does he just chuck it on or does he stick it on the ground and give it a few pumps up and down to make sure its sitting right before tightening the pinch bolts etc.

Better leave the rest to the southerners i supose.

Ok someone clever like Tack, Mum Goose, A DozenR Yoda. Dave, Rossi or any of you other clever buggers. Mind telling me about forks, oils, levels etc & their effect on settings ?.
I would like some advice specifically about lowering the oil level to compensate for too heavy fork springs. Is this a cheap way to get a softer preload so that i can then increase rebound & lessen compression dampning. Will this firm back up the front end of a bike designed for someone heavier then myself ..snip...

Brett

the springs affect compression..and to a small extent rebound
the oil weight affects rebound and compression a little bit
Barrabob is spot on when he sez....Fork oil height stops bottoming out on soft springs because air compresses and oil doesnt
but I should add-normal springs are there to stop bottoming out too
You should note that soft springs will also allow an increase in 'dive' when braking

imho
if you want to firm up the front end I would leave the standard springs
(assuming they are the correct length and ok) and use a HEAVIER weight oil (not lighter) . If you use 5w, go to 7.5w...at the recommended height.
I am aware of ppl adding another 20mm of oil to stop bottoming out
but that really is the job of the springs and if it happening, the springs need to be looked at.

You say you want to firm up the front end but also you want to increase rebound but reduce compression settings.
That confuses me a little...
coz as far as I know, if you want to firm up the front, an increase in both compression and rebound settings is the way to go.
..otherwise the front end will act like a pogo stick



hth

cheers

[MadKaw]

Bob is about right.
Lowering the oil level won't achieve what you want, if you can't get the preload right and its currently too stiff, the only option is to get lighter springs.
If you then want to increase rebound and or compression, more than the adjustments available, you should use a heavier oil.
If you are having bottoming out issues or want more compression than the adjustments, you should add extra oil, only about 5 to 10mm though.

Wait until after the supers though. With that huge pack of yours, I bet the weight on the bike would be up enough to compensate..

Last edited by MadKaw on Thu Feb 09, 2006 8:45 am, edited 1 time in total.

... With that huge pack of yours, I bet the weight on the bike would be up enough to compensate..

if in doubt.....get more weight
Brett...GROW

Thanks for the quick replies Bob & Ian. I think i may have mis represented "my Drama".
The stock fork springs are TOO HARD for my HUGE bodywt. @60kw after a baked dinner.
So to get them to work i have set them at the long end of the range 35mm Rider sag. But this is actually too soft So I had to wind in the Rebound to stop it hitting the stops under brakes & then had to Increase Comp dampning to take out all the little bumps out of the handlebars.
I may be going bum up about it but it's by far & away the best compromise i could find with everything OEM.
But since i will do changing the fork oil i thought i may be able to take advantage of that to Steal some adjkustment so that i can get it back closer to the middle settings. IE softer on Preload so i can get more range from rebound & comp dampning.
cheers Brett

Thanks for the quick replies Bob & Ian. I think i may have mis represented "my Drama".
The stock fork springs are TOO HARD for my HUGE bodywt. @60kw after a baked dinner. ...snip

aaaaah
all is clear !

mate
sounds to me like you have so far managed to make a silk purse
out of the sows' ear
I guess your 'nine' is like most of Kwakas...standard
setup is x clicks out..based on a 69kg rider (manual tells you this)

reducing the oil level or the oil weight will help in the direction
you want to go to set 'er up
but really,
the best result would be a softer set of springs
with the right oil at the right level..and then you set preload
compression and rebound for your weight

there any susp specialists in Bris you can talk to?

Brett I think your better option is going to be to change to lighter springs.
I know on my young blokes MX bikes we always had this prob as they are designed for about 80kg's when he was about 60kg's.

More expensive but the results were exceptional. When they're apart you can get 'em revalved too.

Cheers

Thanks guys, I just rang alex at LAE. New springs are @ $170 a pair He agreed With Dave & said that going up a grade on the fork oil will move the compression dampning back towards the middle settings which will give me more room to play with it.
So i'll try that first before I run out to Rob a Bank to buy new springs.
As Dave said The 30kg in the 2 Venturer bags does the job for the oversprung rear end.
cheers Brett

Compare the price to the dynamic traxxion springs, I dont know how the dollers convert because i ahvent had any for a while(dollars) but they come with precut spacers and a tube they run in that stops them bouncing all over the place while they are inside the forktubes.

If you get a new set of racetechs springs they are a diferent length spring to the one that comes out and you will need new spacers.

The new springs will change the velocity at which your front end moves (quicker action) which hopefully you will be able to slow down with a bit of dampening just have to make sure that theres some going on.

Hmmm I found something I'd like to get.......... from hardracing.com
if only i had the spare $$$.......
---------------------------------------------------

OHLINS "R&T" Complete Fork Cartridge Kit

This kit is The equivalant of a Set of Ohlins Forks,
Less the Sliders, and Bottoms.
Everything INSIDE a Set of Ohlins RT Forks, comes in this Kit.

• Includes Complete Internal Cartridge
NEW Compression Pistons,
NEW Rebound Pistons
NEW Piston Rings
NEW Shims
Complete Set of One-Way Valves,
NEW Washers
NEW 25mm Fork Springs
Recommended Track Settings
External rebound Damping
External compression Damping
External Spring preload adjusters
Same 25mm Fork Springs that are on the R&T Forks
Works with STOCK Fork sliders and bottoms, so it's SuperSport Legal
In nearly all regions.

RETAIL - $1937
Sale Price.... Only - $1559

Well Ponti, all bases are pretty well covered. Lighter springs, and heavier weight fork oil will do the job.

As long as you keep the fork oil brand the same, you can mix'n'match different weight oils to obtain the *exact* viscosity you are looking for.

I used Progressive Springs in a couple of my old zeds, the difference is phenomonal. If you can get Gold Valve cartridge emulators for the 9, get'em. These are the ducks guts.

See you on the Road girlfriend !! We'll see you, just like we saw the NIGHTRIDER !!!

So to get them to work i have set them at the long end of the range 35mm Rider sag. But this is actually too soft So I had to wind in the Rebound to stop it hitting the stops under brakes & then had to Increase Comp dampning to take out all the little bumps out of the handlebars.
I may be going bum up about it cheers Brett

Yeah a little mate. Compression damping is what helps stop the forks collapsing under brakes, and rebound controls/slows it as it is returning!

If you find the front sort of pulling out of your hands or falling away from you when going over undulations, you prob have too much rebound. If it is harsh over little imperfections like seams/joins/potholes/bumps/cats eyes, then it is most likely too much compression damping, or spring pre-load or both.

I reckon if you have it at 35mm front rider sag, then it should be pretty much right regardless of your weight. If it is still too harsh try reducing compression damping a little. If you are bottoming under brakes, add half a turn of pre-load even to the detriment of a little rider sag and just work yr way between the two till you feel comfy on it. HTH

Thanks guys just to clarify a point or two, to get 35mm rider sag with my HUGE frame on it with comp & dampning in midrange of adjustment. It bottomed out regulary & dived like a "Daygo soccer player" under brakes.
I've been tinkering over the past 2years 45 thou ks & i believe i have the best compromise i can get with the OEM gear. BUT ..............
Information is Confidence & confidence is Pace.
Besides oil is $15 a bottle thats a damn cheap way to STEAL any improvements, if it's actually obtainable.
Cheers Brett