Definition of preload, rebound and compression - Yamaha R6 Forum: YZF-R6 Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old 07-01-2003, 02:14 PM Thread Starter
 
Join Date: Mar 2003
Posts: 831
Definition of preload, rebound and compression

PRELOAD
This adjustment is always found on the top of the forks. Clockwise increases preload, counter clockwise decreases it. The adjusters are usually integrated into the fork cap and are sometimes differentiated by color. The preload adjuster may have adjustment lines machined into it so that you can compare to check that they are even.

Preload is initially used when setting SAG. Preload can be added if the rider experiences the forks “diving” under hard braking. A more accurate way of assessing “dive” is to attach a thin zip tie on the slider tube (make sure that it slides easily but is not sloppy), or place an appropriately sized rubber “o” ring on the tube that slides into the fork leg (this will require one fork being removed). The zip tie/O-ring will allow you to see how much of the fork travel you are using. If the zip tie/O-ring is firmly against the dust scraper or axle casting, then the fork is bottoming out. In that case you need to add more preload, and then check the zip tie/O-ring again. If the zip tie/O-ring rests 5mm prior to the dust scraper or axle casting, this indicates that you are using almost all of the available travel.



REBOUND
The rebound adjuster is usually located in the center of the preload adjuster, and commonly requires a flat head screwdriver to be used for making adjustments (there are exceptions like Ohlins which require Allen wrenches). Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment.

Firstly turn the rebound adjusters all the way in on both forks and write down how many turns/clicks there were. Then take the rebound adjustment all the way out on both forks so that you know how much total adjustment there is. With the adjustment all the way out, hold the front brake on to lock the wheel and then push down vigorously on the forks. As the forks begin their upstroke, let them move naturally and observe the action of the fork. The stroke may come back and then return into the downward motion once more, and may even return again on the upstroke (do not let go of the front brake while doing this!!).

Then adjust the rebound all the way in on both forks, repeat the pumping action with the front brake fully engaged and observe the difference in the range of motion –the forks will rise back up slowly. What you are trying to achieve is the fork rising back almost to the top of the first rebound stroke and staying there. You will need to work the adjusters so that they are always the same on both legs until you have the rebound action set correctly.



COMPRESSION
These adjusters are usually found on the underside of the fork or close to the brake calipers at the bottom of the fork facing the rider. They commonly require a flat head screwdriver to be used for making adjustments (there are exceptions like Ohlins which require Allen wrenches). Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment.

Firstly turn the compression adjusters all the way in on both forks and write down how many turns/clicks there were. Then take the compression adjustment all the way out on both forks so that you know how much total adjustment there is. With the adjustment all the way out, hold the front brake on to lock the wheel and then push down vigorously on the forks. You will be able to feel the way in which the forks move through the downward/compression stroke, which will be fairly easily (do not let go of the front brake while doing this!!).

Then adjust the compression all the way in on both forks, repeat the pumping action with the front brake fully engaged and observe/feel the difference in the range of motion –the forks will compress more quickly and will not travel as far on the compression stroke up. What you are trying to achieve is the compression stroke allowing the fork to move without restricting the amount of travel in the fork, which causes the sensation of “packing”. You will need to work the adjusters so that they are always the same on both legs until you have the compression action set correctly.

NOTE: compression adjustment is very subjective compared to the rebound adjustment that is very easy to see. It takes a lot more feel when making adjustments, which will take time to acquire.

Also note that compression can be used in tandem with preload adjustment to help prevent the forks bottoming out. This is not the right solution to the bottoming issue, but one that helps in the interim.
dj1298 is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 07-01-2003, 02:18 PM Thread Starter
 
Join Date: Mar 2003
Posts: 831
THis is for your rear shock

Not all shocks share the same adjustment characteristics, so please take a look at the shock to see what adjustment you have. Also note the shock can come with no oil/nitrogen reservoir (eg: SV 650), with a piggy back oil/nitrogen reservoir built into the shock (eg: GSXR’s) or with a remote reservoir (eg: Penske, Fox, Ohlins)

PRELOAD
In the SV650 and R6, it is a simple ramp adjuster that can be moved using the OEM tool. Clockwise increases preload, anti clockwise decreases it.

Other shocks may have two rings, the upper serving as a lock ring. The lock ring can be moved using the OEM tool and the second ring can be moved clockwise or counter clockwise to adjust preload accordingly. Should the OEM tool be missing the trusty mallet and flat blade screwdriver will work to loosen the lock ring and adjust the second ring. Spray some lubricant onto the threads on the shock body to ease movement (eg: WD 40).

Some shocks require the use of a specific tool (eg: Penske) that must be present for any preload adjustments to take place.

Preload is initially used when setting SAG. Preload can be added if the rider experiences front forks becoming light or getting a “headshake” under hard acceleration. This causes the bike to squat on the rear wheel and alters the weight distribution on the front and rear wheels. Preload can be added to reduce this problem.



REBOUND
The rebound adjuster is usually located in the center of the hasp locating the shock to the rear suspension linkage, and commonly requires a flat head screwdriver to be used for making adjustments. Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment. Other rebound adjusters are rings at the bottom of the shock shaft that turn clockwise and anti-clockwise. Check to see what system you have!

Firstly turn the rebound adjusters all the way in and write down how many turns/clicks there were. Then take the rebound adjustment all the way out so that you know how much total adjustment there is. With the adjustment all the way out and the bike comfortably balanced between your legs, compress the shock vigorously by bouncing on the seat and applying all your weight to this motion. As the shock begins the upstroke, let it move naturally and observe the action. The rebound stroke may come back very quickly to cause the shock to top out (maintain the balance of the bike while doing this!!).

Adjust the rebound all the way in, repeat the same action with the bike comfortably balanced between your legs and observe the difference in the range of motion –the shock will rise back up slowly. What you are trying to achieve is the shock rising back to the top of the first rebound stroke naturally, not quickly or not too slow (or the rear end will “pack” in causing removal of weight from the front wheel) and staying there. You will need to work the adjuster until you have the rebound action set correctly.



COMPRESSION
This adjuster is usually found on the upper section of the shock and it commonly requires a flat head screwdriver to be used for making adjustments. Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment.

Firstly turn the compression adjuster all the way in and write down how many turns/clicks there were. Then take the compression adjustment all the way out so that you know how much total adjustment there is. With the adjustment all the way out sit on the bike and balance it between your legs, then push down vigorously compress the shock. You will be able to feel the way in which the shock moves through the downward/compression stroke, which will be fairly easily (keep the bike balanced while doing this!!).

Then adjust the compression all the way in, repeat the compressing action with the bike balanced between your legs and observe/feel the difference in the range of motion –the shock will compress more quickly and will not travel as far on the compression stroke. What you are trying to achieve is the compression stroke allowing the shock to move without restricting the amount of travel of the shock shaft, which causes the sensation of “packing”. You will need to work the adjusters until you have the rebound action set correctly.

NOTE: compression adjustment is very subjective compared to the rebound adjustment which is very easy to see. It takes a lot more feel when making adjustments, which will take time to acquire.

EXCEPTIONS
For shocks with remote reservoirs, there are differing ways to adjust compression. Some have high and low speed circuits separated by different controls, or one control mechanism. In instances such as these, you may want to refer to the manual provided by the manufacturer, or contact the manufacturer for guidance.
dj1298 is offline  
post #3 of 22 (permalink) Old 07-15-2009, 03:40 AM
my pipe's bigger than urs
 
Phatcow's Avatar
 
Join Date: Aug 2006
Location: in a house
Posts: 450
Bike: 2002 r6
Images: 4
Send a message via AIM to Phatcow
Re: Definition of preload, rebound and compression

THANKS! this was very helpful for getting my bike just right for the switch backs near home again after some crew chief adjusted my suspension for streets of willow.

i would rather live my life to the fullest on my bike and have those risks present, than never know the potential to which my life could be lived without one.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Phatcow is offline  
 
post #4 of 22 (permalink) Old 01-23-2010, 01:08 PM
I eat my R6
 
suggett48116's Avatar
 
Join Date: Dec 2009
Location: Brighton, MI
Posts: 434
Bike: 2006 R6
Re: Definition of preload, rebound and compression

just found this thanks.
suggett48116 is offline  
post #5 of 22 (permalink) Old 11-21-2010, 07:05 PM
Just made this great wheelie.. did you see it?!
 
JordanhaleR6's Avatar
 
Join Date: Nov 2010
Posts: 45
Re: Definition of preload, rebound and compression

Really helpful and while i knew a fair bit about it from my downhill mountain bike days, its great to get someone who knows the definitions to spell it out for the R6

Its what makes this forum so great!
JordanhaleR6 is offline  
post #6 of 22 (permalink) Old 11-21-2010, 07:13 PM
Old Fart
 
Join Date: Oct 2010
Posts: 81
Re: Definition of preload, rebound and compression

Great post, thanks for taking the time to post this.

Last edited by jethead; 11-21-2010 at 07:24 PM.
jethead is offline  
post #7 of 22 (permalink) Old 11-21-2010, 07:14 PM
AFM #327
 
Doc-Ram's Avatar
 
Join Date: Apr 2008
Location: East Bay
Posts: 15,209
Bike: 16 R3, 17R6
Re: Definition of preload, rebound and compression

how come this is not a sticky
To view links or images in this forum your post count must be 5 or greater. You currently have 0 posts.

AFM #327
2019 Sponsors:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Doc-Ram is offline  
post #8 of 22 (permalink) Old 11-21-2010, 08:57 PM
Yamaha Blue in any color
 
DanQ's Avatar
 
Join Date: Oct 2007
Location: Jacksonville, NC
Posts: 3,250
Bike: FZR-1K, R1, Vmax, R6
Re: Definition of preload, rebound and compression

Quote:
Originally Posted by r6rammy View Post
how come this is not a sticky
To view links or images in this forum your post count must be 5 or greater. You currently have 0 posts.
It's been a sticky for years. But I unstuck it and stickied it again for you.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



Dan

CCS #598
91 FZR 1000
04 YZF-R1
05 YZF-R6 (track bike)
05 V-Max 0098/2000 20th Anniversary
04 Roadstar Warrior

TEAM: SO FAST SO CLEAN
DanQ is offline  
post #9 of 22 (permalink) Old 01-29-2011, 09:20 AM
FastForward Performance
 
Tdub's Avatar
 
Join Date: Nov 2010
Location: OWB, Ky
Posts: 961
Bike: Honda Z50
Re: Definition of preload, rebound and compression

Quote:
Originally Posted by dj1298 View Post
Fork PRELOAD

Preload is initially used when setting SAG. Preload can be added if the rider experiences the forks “diving” under hard braking. A more accurate way of assessing “dive” is to attach a thin zip tie on the slider tube (make sure that it slides easily but is not sloppy), or place an appropriately sized rubber “o” ring on the tube that slides into the fork leg (this will require one fork being removed). The zip tie/O-ring will allow you to see how much of the fork travel you are using. If the zip tie/O-ring is firmly against the dust scraper or axle casting, then the fork is bottoming out. In that case you need to add more preload, and then check the zip tie/O-ring again. If the zip tie/O-ring rests 5mm prior to the dust scraper or axle casting, this indicates that you are using almost all of the available travel.
This description can be a bit misleading. Preload does not affect spring rate, so it does not directly affect bottoming resistance. Increasing preload will alter ride height which will allow more available travel. But if you are happy with your sag setting and the way the bike handles, why would you want to alter your handling because the front end is bottoming out?
There are several ways bottoming can be remedied, but just one that will not affect the way the bike handles elsewhere. By raising your fork oil level, the front end will resist bottoming but not affect the way the fork reacts for the majority of the rest of the stroke. This can be done in small increments, several ccs at a time.
A stiffer rate spring will resist bottoming, but it will change the entire travel so it is not a preferred option. The compression adjuster has the same drawbacks.
So, IMO the proper way to deal with bottoming is with oil level. Tdub

Say What??
Tdub is offline  
post #10 of 22 (permalink) Old 04-05-2012, 06:08 AM
make it a double
 
radiostar's Avatar
 
Join Date: Jan 2012
Location: Canada
Posts: 816
Bike: 2011 gsxr600
Re: Definition of preload, rebound and compression

Any chance we could have a picture beside each description so guys like me that have zero suspension knowledge can more easily identify what it is?

I realize theres many different types and bikes but even just an average or most common picture would help. Thanks!

"If God does not exist, then you are just a miscarriage of nature, thrust into a purposeless universe to live a purposeless life." - Dr. William Lane Craig

"Wrong is wrong even if everybody is doing it, and right is right even if nobody is doing it." -Augustine



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
radiostar is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Yamaha R6 Forum: YZF-R6 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Definition of a squid REPII General Discussions 4 05-11-2010 07:00 PM
What’s your Definition of a SQUID RIDER? dboyslade Off Topic Talk 66 03-08-2010 03:11 PM
preload or compression? saleman Suspension settings 3 09-21-2007 06:13 AM
What is the definition of mass confusion Alpine 318is Off Topic Talk 3 06-29-2007 02:35 PM
Racetech internals, new in box, compression/rebound gold valves, .90 springs bbirnie Bike Parts For Sale 4 04-30-2007 05:54 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome