KDXRIDER.NET

http://www.motocross.com/garage/thegarage.html

Look to the right column for the procedures.

Sure. It's great.

***edit***

Well, of course...unless I'm backwards...in which case I look forward to enlightenment!

**Which I got! Thanks for keeping after me about this. I was 180º out..wrong and otherwise incorrect.

Sorry, folks. It's a sad thing! It's times like these I wonder about other basic errors of mine. Maybe I'd ride better if I wasn't sitting on my bike backwards? ;)

***edit**** (to remove all the wrong stuff. I was still wrong!...but don't wany anyone else reading it to be 1/2 as far off as I was!

here's another good one for the curious---http://www.motocross.com/motoprof/moto/ ... cycle.html

Same guy cicone.

CC... I don't see it as difficult to understand, Regardless if you tighten or loosen the spring... the original height doesn't change. Why you ask? because the shock is always the same length no matter how tight or lose you have the spring. That is a constant.

Ain't got no control over their addy!

Here we go again!!!!

Cranking down on the spring will increase it's tension. Yes, the spring is now shorter due to the preload tension but the total length of the shock remains the same. Again, in big letters, THE SHOCK IS NOT BEING SHORTENED, only the spring preload is different (increased). Increasing the preload on the spring will affect how much the shock will resist a fixed load. More preload on the spring, the less the spring will compress to a fixed or given load.

Less compress on the shock for a fixed weight due to added preload on the spring means less sagging, because now to compress the spring, the ring at the top isn't being used, but instead, the shock piston is being used. Hence, increasing spring tension via the tightening of the nut will result in less sag for a fixed weight.
So, If 50 more pounds of preload is added to the spring tension, then it will take an extra 50 pounds to get the bike to sag down to the point first measured. From that point on, the sag will react to weight at the same rate if the spring is a singe rate spring. If it is a progressive weight spring, things work a bit different from this point on.

I don't think I can say it any more ways than that.
(I sure hope I'm right, if not, then the world no longer makes sense to me. Hand me that ginsu!)

**edit**...The following is all wrong. Left in place so the other posts make sense. Read it for no reason other than to scratch yur head and say, 'What on earth was he thinking?' Don't ask me...I probably don't know! ;)

**edit**

Here we go again, indeed.

The shock is not being shortened. I got that. If, sitting on the bike, the measurement is 125mm...how is making the spring shorter, squeezing it tighter going to make that measurement 100mm? It's not! While the distance the spring compresses will be less with more preload..you also added to the sag when you increased the tension on the spring.

Yes. The more preload on the spring, the less the spring will compress to a fixed or given load when applied. But...when adding that preload you are also adding to the sag measurement.

Take a bike just sitting there...don't care what the sag is. Add preload..shorten the spring..tighten the spring to 1mm from coil bind. What is going to happen to the back end of the bike? It's going to drop...a LOT. That amount will be added to the sag measurement. The sag is NOT the amount the bike drops when you sit on it...it's the amount the bike drops from being topped out to the point it sits at when you sit on it. In the above example, your free sag would be over 11". Free sag is part of race sag.

I don't know why you guys are arguing about this...I don't know what I'm missing to make you see it my way!!

I don't think I can say it any more ways than that.

HERE'S YER GINSU!!

I will bet you CC that it doesn't drop. It will stay the same height or raise slightly due to the free sag being altered. If you can't get the desired free sag and race sag to come out correctly...then you need to change your spring. Maybe the procedure is making assumptions that you know what free sag is... but the method is solid.

Sag is not measured at the spring!

Time to simplify. If one is going for the initial 4" of sag, and it is sagging more than 4", does one loosen or tighten? If one is going for the initial 4" of sag, and it is sagging less than 4", does one loosen or tighten?

Thank you.

P.S. If the stock spring on an '87 is 4.4 and I currently have a 6.0 on there, how many buses can I jump without it bottoming out too harshly? Also, if I am 220 pounds now, how many more Double Quarter Pounders with Cheese do I need to eat to make the free sag the correct amount? Thanks.

Less than 4 inchs... loosen... more than 4 inches ...tighten!
As you tighten the spring tension, the sag decreases.
As you loosen the spring tension, the sag increases.

OK, that was easy enough. Now what about my other questions.

Sounds like you need to do some testing Jason!

Hell, I been testing for the last two years, and I still ain't close. I'll give it a few more months and if the sag is still wrong, I will just switch back to the stock 4.4.

When you tighten the preload (squeeze the spring harder) it will push UPWARD on the seat harder and therefore the seat height will RISE.......Thus making the sag less.

Sorry, no way around it.

Think about the front forks, if you put a spacer on top of the spring (adding preload, exactly like the rear) the front end sag will lessen (raising the handlebars)................ not lower them.

Another way to think about it......loosen (unscrew) the preload nuts on the rear shock until the spring is totally loose (nuts off the threads, ie, same as removing the spring, not the shock, from the bike) what happens when you set on the seat?

It will sag quite a bit , in fact, 11.8 inches of race sag!

HB

Hellbender wrote:When you tighten the preload (squeeze the spring harder) it will push UPWARD on the seat harder and therefore the seat height will RISE.......Thus making the sag less.

ONLY the free sag! And it can only rise to the limit of that the weight of the bike exerts on the spring. I guess what I am trying to say is there is a maximum affect that it can have on free sag. The main thing you should be looking at is the affect on the race sag. That difference will be much much greater.

*****I'll reply in your quotes*****

canyncarvr wrote:Here we go again, indeed.

Take a bike just sitting there...don't care what the sag is. Add preload..shorten the spring..tighten the spring to 1mm from coil bind. What is going to happen to the back end of the bike?

*****It will feel solid when you sit on the seat, the shock will be totally extended (ie. NO SAG) if you (and a coupla buddies) bounce really hard on the seat it will compress approx. 3mm before it coil binds (estimating a 3:1 ratio on the suspension linkage and 1mm to coil bind on the spring)******

It's going to drop...a LOT. That amount will be added to the sag measurement. The sag is NOT the amount the bike drops when you sit on it...it's the amount the bike drops from being topped out to the point it sits at when you sit on it. In the above example, your free sag would be over 11". Free sag is part of race sag.

***** your free sag would be 0" *****

I don't know why you guys are arguing about this...I don't know what I'm missing to make you see it my way!!

I don't think I can say it any more ways than that.

HERE'S YER GINSU!!

Can I have a GINSU, too?

HB

GINSU'S ALL AROUND!

Hell... they are only $9.99 for 200 or so!

Indawoods wrote:

Hellbender wrote:When you tighten the preload (squeeze the spring harder) it will push UPWARD on the seat harder and therefore the seat height will RISE.......Thus making the sag less.

ONLY the free sag! And it can only rise to the limit of that the weight of the bike exerts on the spring. I guess what I am trying to say is there is a maximum affect that it can have on free sag. The main thing you should be looking at is the affect on the race sag. That difference will be much much greater.

If you increase the preload (tighter on the adjustment nuts) it will also DECREASE (ie, raise the seat) the race sag, NOT only the free sag...........I think we are saying the same thing, and I agree that adjustments may affect the race sag MORE than the free sag, because of the mechanical advantage of the suspension linkage.

The spring will affect the suspension slightly differently as the angles of the linkages change. The linkage could be (& probably is) designed so that it takes more (or less) linear force at one extreme of the suspension movement.

HB

Yes... we are saying the same thing. Just different ways of saying it. The question is... does everyone else understand it?

i set the race sag on my friends bike the other day. i did indeed turn the nut clockwise to get from 120 to 100mm. i thought i was compressing the spring. uh i'm sure i was.

Don't let quotes from CC confuse the issue. Take into account the **edits** in his posts that pointedly point out that he's incorrect. Just plain wrong, too!

The 'free knife' line forms around the corner to the left, please. Please be advised..You must have your thread printouts to receive your FREE GINSU!!

I could say how I arrived at my backwards point of view...but ya'll wouldn't believe it.

Cheers!

BTW...the sig says, 'Consider the source' for a REASON!! ..the latin actually means something, too!

I am properly and rightfully abashed.