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Just wondering what the max pre-load should be on the rear shock? Trying to get my new YZ setup and having issues with shock setup, ordered spring for my weight but it still feel wonky back there. Running 12mm of pre-load to get the sag settings where they are supposed to be but back end is still very bouncy and unsettled. I've even got the rebound set to 5 clicks out which is almost max for these and 11 click on compression. To me that seems very high for both, if I run the rebound closer to middle (15) then it's really springy and just feels terrible. So I'm wondering if my spring is to soft and if I'm running to much pre-load to get my sag numbers which is making whole setup just off??

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Does not feel ok, RaceTech tech guy was telling me 10 is max but he sounded like an idiot too so I'm not sure I can trust him.

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Why are you measuring preload?

What is the race sag set at and what is your free sag at that setting?

Race Sag should set in 100-110mm range. Free Sag should be between 30-40mm. If you have more than 40mm of free sag, your shock spring is too stiff. Less than 30mm and your spring is too soft.

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Sounds like you don't trust him or me

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20 minutes ago, indy rider said:

Why are you measuring preload?

What is the race sag set at and what is your free sag at that setting?

Race Sag should set in 100-110mm range. Free Sag should be between 30-40mm. If you have more than 40mm of free sag, your shock spring is too stiff. Less than 30mm and your spring is too soft.

+1

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38 minutes ago, mog said:

Sounds like you don't trust him or me

Don't know who to trust but he sounded like a stoner.........so I came here

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54 minutes ago, indy rider said:

Why are you measuring preload?

What is the race sag set at and what is your free sag at that setting?

Race Sag should set in 100-110mm range. Free Sag should be between 30-40mm. If you have more than 40mm of free sag, your shock spring is too stiff. Less than 30mm and your spring is too soft.

Are you saying then that it does not matter how much pre-load it takes to get to those numbers? Or is it just that once you get those numbers then your pre-load will just end up in the right place? 

All I know is the shock feels really unstable and I've about maxed out my rebound (slowed it down) and the bike also feels ass high.

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There are plenty of knowledgeable & helpful folks on the forum but more infos are needed to help you:

-what make/model/year of bike

-what application: MX, woods etc.

-what is your height/weight, 

-what are the current spring rates (stock?)

-when was the last time the suspension was serviced (fluid, bushings etc.)

 

Too fast shock rebound is often a complaint of late model YZ 125/250 owners (like me)

If you close off the rebound adjustment to much to compensate, that messes up low speed compression as well.

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What are the sag numbers? How are you measuring free sag? After compressing the shock, or after lifting up the rear and setting it down, or taking the avg?  If sag numbers are good you'll need it revalved, stiffer rebound shim stack, could add 1 or 2 low speed rebound shims. Or if there are 3 crossover shims, try using just the smaller one. 

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11 minutes ago, mlatour said:

There are plenty of knowledgeable & helpful folks on the forum but more infos are needed to help you:

-what make/model/year of bike

-what application: MX, woods etc.

-what is your height/weight, 

-what are the current spring rates (stock?)

-when was the last time the suspension was serviced (fluid, bushings etc.)

 

Too fast shock rebound is often a complaint of late model YZ 125/250 owners (like me)

If you close off the rebound adjustment to much to compensate, that messes up low speed compression as well.

2017 YZ250X, ridden trails, Dez, and some track "planned"

5' 11" - 230

Fork - .48 / Shock 5.4kg per MX-Tech chart

don't know the numbers right off hand as I measured about a month ago. I need to do it again this weekend. 

Forks feel awesome it's just the shock that is wonky............

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Try going in 2 or 3 more clicks on rebound, it will slow it down alot more, see how that feels. You'll feel it just pushing down on the seat. 

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3 hours ago, indy rider said:

Why are you measuring preload?

What is the race sag set at and what is your free sag at that setting?

Race Sag should set in 100-110mm range. Free Sag should be between 30-40mm. If you have more than 40mm of free sag, your shock spring is too stiff. Less than 30mm and your spring is too soft.

Preload plays a big role in shock or fork performance as well as ride height of bike which effect handling.  End results is stored energy which is different between the two examples. Personally I like 10-15mm preload on the rear. Front is different between brands but usually 5+/- some.

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1 hour ago, weantright said:

Preload plays a big role in shock or fork performance as well as ride height of bike which effect handling.  End results is stored energy which is different between the two examples. Personally I like 10-15mm preload on the rear. Front is different between brands but usually 5+/- some.

According to RaceTech anything over 8mm is too much as their is already so much rise in the linkage...

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Racetech recommends 6mm preload on my crf250r but I end up with more preload than that to get my sag right, I think it's more like 8-10mm, with their recommended rear spring, seems like the preload is always more than they recommend on the bikes I've worked on. 

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If you have 12mm preload, 35mm free sag and about 105mm sags , then there is no real problem

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The yz is the softest linkage and the cr the stiffest, therfore you will need to run more preload on a yz than a cr

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12mm way to much. go up 2 springrates and land on 3-7mm

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For offroad, here is a good starting point:

FORKS
Rebound Damping, bottom adjuster 12
Compression Damping, top adjuster 12

SHOCK
Rebound, lower adjuster 9-10 (slower = softer)
COMPRESSION, Upper adjuster
   Low Compression = screw, 14
   High Compression = nut, 1.5 - 2.0

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7 hours ago, Wrfrk said:

Are you saying then that it does not matter how much pre-load it takes to get to those numbers? Or is it just that once you get those numbers then your pre-load will just end up in the right place? 

All I know is the shock feels really unstable and I've about maxed out my rebound (slowed it down) and the bike also feels ass high.

Since the bike feels ass high and the rebound feels too fast reduce your preload to 6-8 mm and try it. This will only take a few minutes.

I'm about 240 pounds, I've never had good luck getting sag set perfect and always ended up adjusting the spring to where the bike rides good which ends up with close to 5 inches of sag on most bikes that I've had. I figure at my weight the front is sagging down a little more too so having a little extra rear sag doesn't hurt.

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