is this right on fork preload

[89kdx200rdr]

i have some .35 fork springs i want to use. they are 470mm. my stock springs are 495mm. preload is close to 30mm. if i use the shorter spring with the stock spacer will this give me 5mm preload? just wanted to see if i had this right before i tried it. thanks

 

[G. Gearloose]

Might ride a little <correction> low; If your unladen sag is less than 3/4", and/or your laden sag is less than 1.5", you may want to reduce the preload to meet these minimums, (you want the tire to stay on the dirt some when unloaded, vs always bouncing on the stops)

<correction>
Try it and measure.., might be too little preload, your estimate sounds right to me...

 

[G. Gearloose]

Similarly, if your laden sag is over 2", increase preload...

 

[canyncarvr]

What's the spring rate of the springs you're taking out?

Sorry...not germain to the question. I'm just curious.

Thanks.

 

[89kdx200rdr]

the stock ones (495mm) are .296kg

 

[twocycle]

I just did exactly what you are doing. I ended up with 12mm of preload.
I weigh 150 lb. This gave me 7/8 static sag and7/8 race sag.

 

[twocycle]

Sorry had a typo that should have been 1 7/8 race sag.

 

[89kdx200rdr]

twocycle, how did you do yor spacers? pvc plus the stock metal spacer or one spacer out of pvc to get the needed preload. i went ahead and put the springs in with stock spacer to see what i came up with and i need more preload. my static sag is a whopping 1.6". thanks

 

[twocycle]

I just used 1" PVC and left the original steel spacers out. The PVC was cut with a miter box to make sure the ends of the pipe were square.

 

[JasonWho]

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[89kdx200rdr]

thanks, twocycle.

jasonwho, i'll check when i take the forks back apart. if i remember right, with the springs and spacers in and forks all the way compressed i will be doing a balancing act. why do you ask "with forks fully compressed"? thanks

 

[JasonWho]

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[89kdx200rdr]

i thought you musta meant extended. my spacers were about 5mm inside top of tube. i'm going to add the difference in spring heights plus old spacer length and make a new spacer. i'll see where that puts me. thanks

 

[JasonWho]

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[89kdx200rdr]

i was taking the thickness of the fork cap into account. it sticks down into tube about 5mm. i need to lose about 25 and these springs might be fine. back when i rode her alot and hard i was 145. im 185 now. hopefully i can get everything i need and tear into it tomorrow before work. i might even take some pics if i remem to take the cam. thanks

 

[JasonWho]

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[canyncarvr]

Seems this would be eaiser measuring it the generally prescribed way.

You measure the 'space' between the top of the spring and the bottom of the cap, add the desired preload, subtract any washer thickness, cut your spacer, done.

Proper preload is a pretty big deal. It's what determines your sag (natch), and where your suspension rides in the stroke is ...well, a pretty big deal.

 

[89kdx200rdr]

well i was mistaken before. im not 5mm in on the tube im 16 on left and 19 on right . my fork caps are 18 mm thick so i basically had 0 preload. i added 10 mm and it only gave me .3" on the unladen sag. so best i can figure im going to end up with 30mm preload to get 3/4" unladen sag. i'll let ya know. after 2ft of pvc i should be good. i havent checked travel yet but im thinking i would be better off with some 495mm springs and 10mm preload. ill ride it awhile and see.

 

[89kdx200rdr]

i meant 2ft worth of pvc cutting spacers not 2ft in the tubes. hehe

 

[JasonWho]

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[89kdx200rdr]

see pic jasonwho.

 

[89kdx200rdr]

hows that look. it feels pretty good.

 

[JasonWho]

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