shock tuning for enduros

Re: suspension parts need 'em and have you tried them?

So why is he talking about a PDS 9? :?

I don't have a PDS 9 either, jumps directly to 10 (SS), progressive from 9.2 to 9.6.

9.0 kg/mm would be pretty stiff but that's just my own opinion, again, he does whatever he wants with his bike.

No need to use hard language or gather hard feelings, Taffy.

If you want to install the telescopic needle made by Terry himself, let us know how it works for you.

The more we try, the more we learn.

Re: suspension parts need 'em and have you tried them?

Hey Taffy. When you were in school, were you one of those bully kids that always picked on the nerdy kids?

Re: suspension parts need 'em and have you tried them?

LeFrog said:

So why is he talking about a PDS 9? :?

Click to expand...

Frog, I think he was referring to a 9.0 straight rate. It's tricky to keep up with, straight vs. progressive and they're all numbered.

As far as being too stiff, it's all about setting the sag. At 35mm of static sag, he wants to net the proper race sag.

For us big guys a stiffer spring nets a plusher ride as the shock is operating in the correct position in relation to travel.

Re: suspension parts need 'em and have you tried them?

Hey everyone leave Taffy alone you have to remember he is a POM !!!!


:twisted: :twisted: :twisted:


Long live the commonwealth.


AUSSIE AUSSIE AUISSIE
OI OI OI

:lol: :lol: :lol:

Damn Smart A55 Convicts

Re: suspension parts need 'em and have you tried them?

Taffy I tried bladders I could not feel any difference besides valves are
prone to damage from chain
I dont think needle design by it self makes much difference the needle
design concept is flawed since the rod diameter is larger than the bypass
between pistons under a high speed event oil has to pass through top
piston shim stack if it gets too much flow restriction you end up two
scenarios (1) if high speed adjuster is adjusted in from stock setting you are going to feel a harsh compression action (2) since flow restriction is
greater at piston shim stack than the compression adjuster which creates
seal head lift that leeds to uncontrolled rebound I think that the Ohlins
design is better since it has two different diameter pistons
I think that Husabergs needs progressive springs since it gives a rising
rate which a straight rate dont give the WP progressive springs
progresses to quickly for my taste keep mind that Husabergs shock
slowes down at the end of travel that makes it different from a KTM
So long
VIKING

Re: suspension parts need 'em and have you tried them?

fry has also warned me about a bladder extending the shock and of course katooms have left chain drive and we have the chain running right underneath the shock resevior. mmmmmm!

i don't think that's the route i'll be taking in that case. right now over at ktalk the secret to bleeding the shock and cherging it are slowly being revealed.

the needle is something i'll certainly chase because despite someones rare misfortune it would appear to really improve the shock.

mx tech for $20 sell a another primary piston to replace the secondary piston. it stops a mid/top stroke harshness.

you know viking but every time you write, i cut 'n paste to a sheet of paper. i add full stops, commas, hyphons, words, then i break it into sentences and paragraphs and do you know what-i still struggle :lol: :lol: :lol: :lol:

anyway, all good stuff! once again per; it's all jargon to me until i get in there and have a look around.

regards

Taffy

Re: suspension parts need 'em and have you tried them?

Taffy said:

replies to:



daleo
same as froggy i'm interested in your weight and any back to back stuff you might have done regards a straight rate and a progressive and how you felt they differed.

regards

Taffy

Click to expand...

At that time the bike was set up for a 195# ridier. As to how they differed, well with the new set up the bike would stay put better in the corners, IE did not want to stand up and spit me off. And the bike definitely tracked straight through the high speed chop.

Re: suspension parts need 'em and have you tried them?

Taffy I dont know your knowledge on the shock, If you dont understand
how the shock works just ask
VIKING

RE: Re: suspension parts need

great advice here from terry hay!

rear shock angle differences to ktm

here is a good description of a revalve by markfc550

here

shimstack advice from steve

as i work on the rear shock i shall put the info in this thread.

regards

taffy

RE: Re: suspension parts need

Per

in all the parts books the secondary piston (part number 55) is never mentioned. they forget it? the primary piston is marked as 1 off) so any idea what that second piston looks like? the only coding i have is

2003
secondary: 6+6 x 7/4.5
primary is 6+6x7/4.5 vb1.0

the primary then gets marked up every year after that?

did you know that in '06 they shortened everything?

the piston rod from 153 to 146mm
needle from 175 to 169mm
tube from 151.5 to 145.4mm
and the bottoming needle was lengthened twice from 33/47 to 52 to 6/57

the year of the straight rate?

i'm trying to gather as much info as i can on upgrading as i go.

joe?

how relevant are the shim stacks from '05 onwards when they becamse straight rate stacks. i like my progressive but could be persuaded....!

any advice gratefully received.

regards

Taffy

RE: Re: suspension parts need

shock bleed superb article. i've asked permission to reproduce it here in the doc.


regards previous post....
smorgy?

per?

lew?

where are you?

regards

Taffy

RE: Re: suspension parts need

anyone else working on their rear shock?

i'm in the process of having some tools made and the first steps to getting a vacuum pump built.

would be great if one or two others wanted to get involved in rear shock work?

regards

Taffy

Re: RE: Re: suspension parts need

Taffy said:

Per

in all the parts books the secondary piston (part number 55) is never mentioned. they forget it? the primary piston is marked as 1 off) so any idea what that second piston looks like? the only coding i have is

2003
secondary: 6+6 x 7/4.5
primary is 6+6x7/4.5 vb1.0

regards

Taffy

Click to expand...

Taff,
The secondary piston you mention above as the missing no.55 (designated no.58 instead) , well, thats not really the secondary piston is it.............. :wink:

The secondary and primary pistons look exactly the same, with the exception of a 1.0mm bleed hole through one of the compression ports of the primary.Hence the vb1.0 designation on the later shocks that have this primary piston mod ......

Re: RE: Re: suspension parts need

Taffy said:

did you know that in '06 they shortened everything?

the piston rod from 153 to 146mm
needle from 175 to 169mm
tube from 151.5 to 145.4mm
and the bottoming needle was lengthened twice from 33/47 to 52 to 6/57

the year of the straight rate?

i'm trying to gather as much info as i can on upgrading as i go.

Taffy

Click to expand...

Ok ausberg

by enlarging the screen i can now see that they marked the piston #58, as in 53, 54, 58, 56, 57. yeh i was ready for that one wasn't i!!!!

but what about this shortening? was the whole shock shortened?

and while i'm here i'll ask: where do you fit the 3mm spacer inside the shock? i want to try this but need to be sure? i guess i should have it all on the bench infront of me but i have looked at page 65 of the WPS5018 manual and it looks to go ontop of the quad ring assembly?

and while i'm here i'll repeat these words of wisedom from Terry Hay - an australian suspension revered on k-talk:

It is vital for all shock absorbers to have an element of compression. The linkage on conventional rear ends is designed to provide progression in both spring force and damping force. The PDS shocks lack significantly in this area. Straight rate springs are certainly an alternative to progressive ones as they will provide a different feel relative to the application. The simple problem with most progressive springs available for the PDS shocks, is that they are indeed, too progressive. An average linkage will provide appr. 30% progression. In other words...the starting ratio for shock shaft versus rear wheel movement may be 3.1mm - 10mm. Final ratio may be 4mm - 10mm. The .9mm change represents the leverage increase provided by the linkage. Just under 30%. Some are higher. Some are lower. A PDS shock experiences a relatively small change due to lean angle. This is approximately 11%. This is inadequate and some form of supplementation is required. The fixed needle due to deisgn constraints is limited to an effective range of appr. the final 30% of travel. When the needle finally comes into play the damping force is rapidly accelerated. Unfortunately there is little progression prior to this event occurring. Combine this with the fact that the bump stop will also come into play in the final travel and you experience a rapid rise in resistive force that can in some instances be quite brutal. I'm not in favour of the latest range of PDS progressive springs and much prefer the old PDS 0 - PDS 4 range. Although I would still prefer to see a spring with a rate increase of appr. 1 kg over the compressive range as opposed to the 2 kg rise we are currently offered. Considering this...A straight rate spring will also not be entirely suitable. The benefit of a straight rate spring will be that of compliance on small to medium bumps. Downside will be poor bottoming resistance. Progressive springs will offer greater bottoming resistance but the rising rate may be less comfortable for trail use.
Terry

regards

Taffy

Taffy,
If I were going to shorten a shock using a spacer I guess it would have to go between the rebound disc (57) and the top out bumper or spring depending on which variant of shock you have.

You suggest adding it to the top of the seal head (quad ring assy) but you cannot do this on top out spring equipped shocks as the top out spring has a groove it clips into machined in the seal head body

But I have never added a spacer- so you would want to confirm that with someone more qualified to comment than me.

Adding a spacer used to be one of Terrys fix's for the earlier Kato handling/steering woes- Is it really relevant to the Berg?

well as i say they shortened the shock so maybe it no longer is!

thanks for telling me "where to shove it!".

i'm in negotiations with someone to have a home made suspension bleed system made. many of you won't know but i got on the wrong side of someone on ktalk due to a completely different interpretation on what i was saying.

this guyy comes along and is real sweet to me. PMs me and then explains that he was on TT during the good years and respects the stuff that JD and i did. so the way he sees it he's going to be helping me as a thank you.

RESPECT

regards

Taffy

well i'm starting to build up the tools for doing my shock. firstly my engineer has made a big fat plate with two ayes to undo the cap off the rezzy, at the same time i got him to make a tool that would sit astride the DU bush/seal area so i could whack the bloody thing down and get the circlip out.

i then decided this last week that i wanted a tool to remove the needle at the bottom of the main body and do it without removing the body itself first. i collected this one today.

i have had several other things to consider and one of them was how to bleed the oil of air. a natural bleed by working the shock is very cheap and just requires a bleed bottle connected to the port. then there is the vacuum system whereby you connect a pipe to the shock at the top of which is a container of oil. that oil is 'sucked' from above removing the air from the container but also making any air in the oil twice it's normal size. like this it wants to rise and decant as soon as possible.

a third way is a pressure bleed through a circulation system. i'm not really sure what i'm looking at but i have asked drehwurm from austria to make me one. he is to be found on ktmtalk.

the next stage i'm looking forward too is the nitrogen charge. all i'm attempting to do is copy the one in the link

http://www.shocktreatment.com.au/ktmmods.html provided by ausberg.

the idea though is that we will put an 'O' ring inside the recess down in the bottom of the rezzy cap. the 'O' ring will go AROUND the outside of the protrusion which is a better system. a schraeder valve will be fitted higher on the side of the boy and a T-bar on the top.

WHAT I NEED TO SORT OUT is how to place that charge and where i'm going to get it from?

you'll get quotes of hundreds of pounds for just the gauges and then others of a few quid!

ideas please!

regards

Taffy

you'll get quotes of hundreds of pounds for just the gauges and then others of a few quid

Click to expand...

!

Not sure what the UK situation is Taff, but here in Australia N2 cylinder rental, gas costs and regulators arent cheap. It cost me a lot to get set up initially.

No point having a couple of hundred bucks worth of regulators,hired N2 cylinders etc laying around if you only use it occasionally

If you live in a reasonable large metro area, you will be miles in front to build your shock yourself and then simply take it to a bike shop/suspension tuner/hydraulic specialist and get them to charge it with N2 for you.

Leaving more money for other bike stuff and trips to the pub :wink:

now added the link after your reply aus but you knew the link i meant me guesses!

have you looked at the bottom phot? the replacement screw? the gas can escape between the thread and the inside diameter of the rubber washer.

i'm going into k-talk and suss out where to get this stuff. sometimes ebay or the USA seem to be the answer to so many things.

regards

Taffy

ok i have found out from BOC here in the Uk that i can rent a 3' nitrogen bottle for £46 + Vat per year. it'll cost £13.75 + vat to fill with a service charge to fill it of a further £10.75. need proof of identity, address, bank details etc as it'll have to be by DD.

i may end up going to someone local after all this hassle.

as far as fittings go well here are a couple:
this is a schraeder valve coupler and the idea is that you screw this on the schraeder valve and then fix the N2 to it. open top T and let in the 175PSI, close the T. turn off the N2 and remove. then unscrew the T and remove the coupler. you have 175PSI in your shock. [http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=556&ReturnPage=/shop/flyer.aspx?PageNo=1 here] from availl.

this is the Dill website (USA) and there are several items here. it's from august '06 so prices will have moved on. http://dillaircontrols.com/files/Catalog_Aug3.2006.pdf
ATS = Snap On aviation tools.

note items on page 21 # 8921 - the lock chuck as they call it and P22 #8874 which is a gauge and pipe for straight on the schraeder conversion.

i can get a nitrogen gauge off e-bay fairly cheaply for around £15.

regards

Taffy