Fork Spring Preload Spacers - what did you use?

[ragedigital]

I don't believe I have enough preload on the front and instead of adding washers, I'd like to have some different lengths for the "Track Day" and for street riding.

What materials are suggested and what are you using?

[modkingfzr600]

darrin, most people use thick PVC pipe, i think schedule 40 is fairly thick . anyway's it's cheap , bought by the foot , and strong enough to get the job done.

[ragedigital]

I've heard that, I just a little concerned about the PVC shattering under pressure.

[mpap]

D i use aluminum tubing, can buy at most hardware store, i have a few different lenths i try, I found what works for me, I am sure pvc works I just dont like the idea of pvc in my shocks

[ragedigital]

So, the next question is, thicker oil or more preload to stiffen the front AND what are the effects of either?

[mpap]

both...preload to set the sage ...thicker oil to slow down compression.. to much sage will make bike turn more slowly, to soft compression nose will dive hard on braking , there for as you turn front will colaspe, and you will have to compansate, to hard.. If you have too much front compression , do not get enough nose dive and the bike will be reluctant to turn and may drift wide on entry to the corner...

[yamaha_george]

So, the next question is, thicker oil or more preload to stiffen the front AND what are the effects of either?

Darrin ,
take a look at :-

http://www.saltmine.org.uk/kgb/faqindex.html

about halfway down is Jim Stewarts paper on suspension tuning with Jargon buster & how to.

I you can pin the link link it as it is a FAQ for sure let me know if you want to host it and I will call Jim and get a email permission for you

As for spacer material I use PVC pipe with a special " T washer" sets to pop into the bore so the plastic is not point loaded at any time but fully supported on all of its end circumference.

The top & bottom "washers" take the brunt of any wear as well so the chance of PVC dust getting in the re-bound oil holes or in your expensive emulators is greatly reduced Nerd
Geo

[haunter]

I wouldnt be too worried about PVC. The things I've put down my old spud gun and blasted w/o any shattering......

[ian]

alright guys, I'm starting to not like how short my spacers are because my bike dumped over today cause the front wasn't high enough for the stand to provide correct leverage. my question is: What diameter of schedule 40 pvc do I need?

[modkingfzr600]

well, the forks are 38mm, minus wall thickness... so say 4mm for that , minus an extra 2mm for freeplay = 32mm or 1.259 inch, so look for some 1-1/4" pipe .

[yamarossi46]

I think is better spacers in nylon.

[ragedigital]

I think is better spacers in nylon.

Aluminum is probably your best choice. That is also what they give you in the kit by RaceTech.

Darrin

[yamaha_george]

Hi,
It really depends on what you are doing to the forks? If you are setting up a bike for the first time with say new springs or emulators (PD Valves) or the bike is "new " to you.
Then can i suggest that you use any short length of tube ( as you see above bout 30mm or 1.25 Inches in diameter ) & a whole slew of thick flat steel washers .
The idea being that you set the bike up and add /subtract washers until you are happy with the ride !

my pre load is 18mm ie 18mm of the spacer sticks up above the fork tube top with NO load on the forks ie the wheel is NOT touching the ground !

The bike is stock (not fightered ) and I am190lb in gear
HTH

[pefrey]

PVC is fine. You will still need a washer between the PVC and the spring. You'll probably want on on the top as well but I don't think it is as critical.

[yamarossi46]

Hello. I´ve used nylon caps.