Setting Sag

[Wannabe_4x4]

For those of you who have done it, what did you set your sag to front and rear?

 

[canyonman]

Just did mine a while back. cranked in a shit load of preload to get about 1 3/8 in the front.

Nothing you can do with the rear if you run a stock shock.

Lots of posts on this already.

 

[ahchiu]

To do it right you need new parts, I went the cheaper route and got the HyperPro combo spring kit, it replaced the rear spring using the OEM shock and new front springs, it made a big difference. they are having a 15% off sale on all there stuff till the end of the year. I got my combo kit for $225.00 6 mo ago.

EPM 732-786-9777

www.hyperpro.com

 

[happyPuppy]

I would watch this , it depends on your gear and body weight

 

[road runner]

Nice flick HappyPuppy. Those are the same sag #'s Ohlins recomends.

 

[3dogs]

I would watch this , it depends on your gear and body weight

The procedure used in the video is incorrect because it does not take into account friction present in the suspension. This is less of a problem on the rear, however the front end on many bikes can have a great deal of friction due to the fork seals. Using the technique in the video will not produce any type of consistant measurements. This can result in an incorrect sag measurement as well as ordering the wrong springs etc...

Here is a link to the Race Tech webstie where measuring static sag (race sag) is more better explained. Look for the questions regarding "What is Race Sag (Static Sag)"

Measuring Race Sag

 

[Patriot]

Google search is your friend.

google "setting sag site:fjrforum.com" or just "sag"

your welcome,

Mike in Nawlins'

 

[Wannabe_4x4]

The procedure used in the video is incorrect because it does not take into account friction present in the suspension.

I had a friend help me, and we followed the same technique in the video.

I mildly dissagree with you. Yes, there is some "stiction" in the forks and spring when the bike is cold. I think that's why Dave Moss in the video says to make sure the bike is hot, almost like you just came back from riding 50 miles through the canyons and freeway.

I measured my sag after a 50 mile trip matter of fact, jumped on the suspension, put the bike on the center stand, back off of it on the side stand a few times to see if the #'s were the same. Came out to 35 mm front and rear sag every time when the bike was hot. After a few hours of it sitting in my garage, and got cold, I then noticed that I was off by a few mm + or -.

That's the key to setting your sag and suspension... have to do it when the bike is hot.

 

[3dogs]

You are correct in that there is very little stiction in the rear suspension because the seal used on the rear shock piston rod is less than ½ inch in diameter.

The front suspension will have considerably more stiction because the oil seals are 52mm (a little over 2 inches) on an FRJ. There is just no way that the front will not have some stiction.

Getting the bike hot (I assume that you mean riding it so that the suspension moves) will have some affect on the rear because of the rear suspension linkage ratio which makes the rear shock operate rapidly even on a relatively smooth road.

The front suspension on street ridden motorcycles operates at close to ambient temperature so riding the bike will not affect how much friction the seals/bushings will have.

Teaching Total Control classes for 10 years (a section on suspension is included in the class) I have measured sag on well over 1000 motorcycles and all of them had enough stiction in the front to cause sag measurement variations. Most bikes will have about 10 to 25mm of stiction in the front suspension. What this means is that front suspension sag number can vary by the same amounts unless it is accounted for.

By taking 3 measurements the stiction can be mathematically averaged out of the sag measurements. Here is the procedure:

(always use the same two points to measure from for all three measurements)

1. Measure the suspension fully extended (wheel off the ground)—this is length 1 or L1

2. With the rider on board push the suspension down (about ½ inch) and SLOWLY let it up and come to a stop (this is one of the things the guy in the video does wrong—he bounces the suspension) Take another measurement—length 2 or L2

3. With the rider on board lift the suspension up (about ½ inch) and let it down SLOWLY until it stops (no bouncing as it causes the measurement to be inconsistent). Take the last measurement—length 3 or L3

Here’s the math that removes the affects of stiction.

Find the average of L2 and L3

Subtract that number from L1—now you have an accurate/repeatable sag measurement.

You can use the difference between L2 and L3 as a way to determine if there are any problems with the movement of the suspension. If the difference between L2 and L3 is more than 40mm on the front there is too much friction indicating a problem. The difference in the rear should not be more than 3mm. This is especially useful when buying a used bike as you can determine if it’s been crashed.

 

[happyPuppy]

I am confused. The video shows the same way Keith Code showed it and sets sag to 30 -35 front and back , I went to his school a long time ago, so perhaps it has changed? He had you measure , get on the bike with gear, bounce, adjust front and back. I went in the early 90's when I lived in CA and he had only been teaching for several years

 

[getagrp1k]

What preload do you have? What c/r settings are you running for what kind of riding? How much do you weigh, which is the MOST iimportant?

The procedure used in the video is incorrect because it does not take into account friction present in the suspension.

I had a friend help me, and we followed the same technique in the video.

I mildly dissagree with you. Yes, there is some "stiction" in the forks and spring when the bike is cold. I think that's why Dave Moss in the video says to make sure the bike is hot, almost like you just came back from riding 50 miles through the canyons and freeway.

I measured my sag after a 50 mile trip matter of fact, jumped on the suspension, put the bike on the center stand, back off of it on the side stand a few times to see if the #'s were the same. Came out to 35 mm front and rear sag every time when the bike was hot. After a few hours of it sitting in my garage, and got cold, I then noticed that I was off by a few mm + or -.

That's the key to setting your sag and suspension... have to do it when the bike is hot.