Setting rear sag

[triman11427]

Has anyone figured out how to set the sag of the rear shock without a second set of hands?

 

[Firefight911]

Let's see. How heavy are you? Over than 180lbs? The answer is yes. Max it out and you're closer than you were.
Anything over that, no. Get the right rate spring first, then the answer is no. Not properly.

 

[tomatocity]

Let's see. How heavy are you? Over than 180lbs? The answer is yes. Max it out and you're closer than you were.
Anything over that, no. Get the right rate spring first, then the answer is no. Not properly.

Agree with Phil.

 

[78YZ]

What is the significance of 180 pounds? I ask because that is my weight.

Let's see. How heavy are you? Over than 180lbs? The answer is yes. Max it out and you're closer than you were.
Anything over that, no. Get the right rate spring first, then the answer is no. Not properly.

 

[tomatocity]

What is the significance of 180 pounds? I ask because that is my weight.

Now add riding gear and luggage and you are over the 180 pounds. The stock shock maximum is good for about 180 pounds.

 

[Firefight911]

Everything about suspension set up starts with having the correct pieces in place, FIRST. There are no shortcuts. Your spring on your bike has a "rate" to it. That rate applies to a given amount of load applied to your bike. The stock spring rate is only good up to about 180 pounds. As Tim said, you add gear, luggage, etc. and you are over your weight and in need of the correct rate spring, FIRST.

There are several very good, in depth, but easy to understand threads on here about suspension. Search my profile and search AVC8130s profile for some very good threads.

 

[tubebender]

Has anyone figured out how to set the sag of the rear shock without a second set of hands?

As Phil has said, you need to establish the correct rate for the given load, but you can't begin to do that without a measuring first.
And the first thing about measurement is not accuracy, but repeatability.

So, to answer the question - yes. It depends on how much do you want to spend and / or how handy you are.

You could do it with a yard stick and a video camera. But it would not be very repeatable unless you could position the camera in the exact same place every time.
It's do-able (hence my handy comment)

There is the Noleen Sag tool on Ebay. It's just a glorified yard stick. Still need a way to record the numbers.
http://www.ebay.com/itm/Noleen-J6-Suspension-Technologies-Sag-Scale-Ride-Height-Tool-/111179249912

Racetech makes the Shock Clock but it's $$$
http://www.racetech.com/page.aspx?id=37&menuid=96

If you fool around with Arduino's, you could make something with a rotary potentiometer.
There are plenty of YouTube videos describing similar scenarios.

Speaking of rotary potentiometers, and because my job is data acquisition, I built my own. Yes, it's over the top, but I did it as an engineering exercise.
I 'borrowed' some left over string pots and an 8 channel DAQ device from work, wrote some code, built some mounts, and produce some nice graphs.
I wish I could afford some LVDTs (Linear Variable Differential Transformer) which is what all the major racers use, but they are $$$$

 

[cetan]

Its overcomplicated and overhardwared but I like your arduino way.. good job...

 

[mrpete64]

In the past two issues of Motorcycle Consumer News there has been very good articles on this topic in very good detail.

Mr. Pete------>
aging hippie

 

[Checkswrecks]

If you fool around with Arduino's, you could make something with a rotary potentiometer.
There are plenty of YouTube videos describing similar scenarios.

Speaking of rotary potentiometers, and because my job is data acquisition, I built my own. Yes, it's over the top, but I did it as an engineering exercise.
I 'borrowed' some left over string pots and an 8 channel DAQ device from work, wrote some code, built some mounts, and produce some nice graphs.

Nice job Tubebender!


This is the first real data I've seen for our bikes and as another engineer, naturally it creates questions.



First is what the units are? 50mm is roughly 2" so I'm guessing mm on the Y-axis and seconds on the X?


Assuming the big spikes before each plateau are where you rocked the bike, there are three front plateaus and two for the rear. Are these the result of compression or spring adjustments?


Are we looking at maybe 1-3mm in the front of stiction and a bit more in the rear?


Inquiring minds and all that!

 

[rem]

I don't think there's much to be done about my rear sag ..... ::012:: R

 

[booner223]

Nice rem. Lol

 

[snakebitten]

I love this forum. You guys are crazy.
And so dang smart.
(and witty, a couple)

 

[klunsford]

Rear Sag is directly proportional to age and the amount of furniture disease that you might have accumulated over your vast years of experience. ::025::

 

[tubebender]

I'm actually more worried about my front sag ???



Anyways, to answer Checks questions:

Y is millimeters, X is seconds

Only the first 2 'plateaus' tell the story - static and race sag.
I make an adjustment, drop it off the center stand, then climb aboard.
I can make and measure quite a few adjustments in a short period of time.

The small offset when on the center stand is weight on the front, and it looks like I didn't zero out the rear correctly, but +/- 2 mm is acceptable to me.

The graph is what I see on the laptop screen, after I do data reduction I also produce consolidated tables.

 

[Bikedude987]

http://www.motool.co/product-p/slacker.htm

best. tool. ever.

 

[snakebitten]

That is too cool!

 

[triman11427]

That's what I'm talkin about. Looks like a great tool.

 

[theroamr]

So sag is 1/3 of total suspension ? So about 2.25 inches?

Sent from my Nexus 5 using Tapatalk

 

[snakebitten]

I think I have it memorized as millimeters. 55-60mm if I'm not senile.

But yes, on the ~1\3, many would agree.