How and why do I set sag on my suspension?
- Thread starter Holeshot
- Start date
shouldnthave
Taze away, Yana...
What is "Sag"?
Aware
Well-known member
Somehow this seems rhetorical.
Why? Foundationally it is a reasonable benchmark (well, starting point) for making the suspension firm enough so that the combination of the bike's weight and your weight are well-enough supported for a safe, controlled riding experience.
How? Twiddle the preload adjusters until the recommended sag is reached ... sag being the difference between how much the suspension compresses with the weight of the bike alone, and how much it compresses with you sitting on the bike.
Full setup can only be reached by also setting compression and rebound adjustors (if available) to suit your riding style and preferences, alongside fine tuning preload.
So science plus guesswork plus personal taste plus riding style plus the roads you ride.
Why? Foundationally it is a reasonable benchmark (well, starting point) for making the suspension firm enough so that the combination of the bike's weight and your weight are well-enough supported for a safe, controlled riding experience.
How? Twiddle the preload adjusters until the recommended sag is reached ... sag being the difference between how much the suspension compresses with the weight of the bike alone, and how much it compresses with you sitting on the bike.
Full setup can only be reached by also setting compression and rebound adjustors (if available) to suit your riding style and preferences, alongside fine tuning preload.
So science plus guesswork plus personal taste plus riding style plus the roads you ride.
shouldnthave
Taze away, Yana...
Sounds super complicated. Is there anyone that would be willing to twiddle my knobs for a small fee?? Is it really worth it thought?
Aware
Well-known member
Yes totally worth it if you are in any way a "spirited" rider.
Probably not worth a can of beans if you are a low energy cruiser type.
EastBayDave
- Kawasaki Fanatic -
We always started at one (1") inch, & progressed to fine tune f/there.
You know this...? (Surprised you asked.)
You know this...? (Surprised you asked.)
David919
Ride Again!
None of my previous bikes had any really useful preload or any dampening adjustment. When I bought this bike I road for a few weeks with out making changes as I sorted through a few things. Once I adjusted the sag and dampening it was like riding a different bike. The handling improvement was unbelievable.
day004
Major PITA
I would mildly disagree. Odds are that even the cruiser suspension is not optimized for the individual. Getting it right makes a difference.
I bounced lots of newbie bike and found a many wrong and a few dangerously so.
Thanks Ernie...at 42, I was getting worried it would get better. Missed you at Buttonwillow.
Aware
Well-known member
No doubt. My thinking, though, is that a relaxed rider won't notice the difference because a relaxed rider doesn't focus on performance. The handling could be better or worse, but when you are the type of rider for whom a perfect ride is purring along and just enjoying your day, unless your undercarriage is scraping, there's probably little to notice.
motomania2007
TC/MSF/CMSP/ Instructor
While there may be little to notice by some riders, there are significant improvements in safety with a properly set up suspension v. a not properly set up suspension.
Even if the rider doesn't think they need or will notice the difference the suspension set up, they do benefit from it.
Aware
Well-known member
I did not say there was not significant improvement possible. :wtf
Once you ride a properly valved and sprung motorcycle over an improperly (read: OEM) one, it's really hard to go back to stock. Proper suspension has the most noticeable effect of consistent control of the bike. As Motomania explained, control = safety.
the 2015 Indian Scout has a weight weight of 560 lbs. It's front spring is a .51 progressive rate with nearly ineffective valving. The thing handled horribly, transferring far too much weight to the rear on acceleration, thereby losing almost all steering and when shutting the throttle, experiencing a noticeable "clunk" when the weight transitioned onto the front forks and bottomed out simply shutting the throttle off. It's a great little motorcycle, but the stock suspension is awful!
We put name brand twin shocks on the rear and a 25MM cartridge with weight correct springs in the front and the bike now handles with excellent confidence. Three of us rode the bike stock and then, with the upgraded suspension. No one wanted to go back to stock and all agreed, the cost was well worth the resulting product.
ontherearwheel
Well-known member
Sag is the amount bike and therefore a spring compresses when a force is applied. Since it's impossible to apply a force at the wheel
like in actual road going, it is done by pressing down on the bike.
To set the sag, a preload adjuster is used to apply a static force to the spring by compressing it.
Preloading a spring controls how much force is needed before the spring moves and also how much the spring moves. Also adding preload extends the shock or fork adding ride height.
Preload does not effect spring rate. This meaning once the spring starts moving, it will move at its spring rate.
Dampening controls the force being put into and coming out of the spring.
What wasn't asked was......setting sag for what type of riding.......street, touring, dual sport, dirt, racing and a few others.
And static setting on a bike are just ball park. What the bike does under motion is where the real magic happens. In use, the static settings may need to be changed to further improve the handling.
And remember.....in this valley.......there is no one perfect street setup. Impossible to do.
That's one question I ask when someone when I hear complaints. What road. The perfect, fast, setup for 84 will not be the perfect, fast setup for page mill.
like in actual road going, it is done by pressing down on the bike.
To set the sag, a preload adjuster is used to apply a static force to the spring by compressing it.
Preloading a spring controls how much force is needed before the spring moves and also how much the spring moves. Also adding preload extends the shock or fork adding ride height.
Preload does not effect spring rate. This meaning once the spring starts moving, it will move at its spring rate.
Dampening controls the force being put into and coming out of the spring.
What wasn't asked was......setting sag for what type of riding.......street, touring, dual sport, dirt, racing and a few others.
And static setting on a bike are just ball park. What the bike does under motion is where the real magic happens. In use, the static settings may need to be changed to further improve the handling.
And remember.....in this valley.......there is no one perfect street setup. Impossible to do.
That's one question I ask when someone when I hear complaints. What road. The perfect, fast, setup for 84 will not be the perfect, fast setup for page mill.
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dtrides
Well-known member
My simplistic understanding of setting the sag on your bike is two fold:
(1) keeping the tires on the road
(2) working the suspension in the best part of the damping stroke.
Ideally you want the suspension to be working some where in the mid stroke of it's travel, neither bottoming or topping out.
Without getting into "are the springs on your bike correct for your weight?":
No sag or too little sag and your wheels are less likely to remain on the road surface as you go over undulations. Too much sag and and you may bottom out also causing lose of grip (and maybe a bent rim
) as that energy is now sent into the wheels and frame.
Too much sag can also result in pitching of the bike as you brake or accelerate.
Then there is damping, if your suspension is either topped or near bottomed out you will have only a small amount of oil to force through the damping circuit in one direction or the other.
The damping circuit absorbs the energy of the spring as it compresses or as it decompresses (rebound).
In a ideal world , a properly adjusted suspension keeps the bike stable and tires loaded and in contact with the road.
Also, I have had some great suspension tuners get it completly wrong for my needs. It is best to learn the basics of how things work before you work with a suspension shop, that way you understand what they are doing and can give proper feedback for your unique situation. By properly informing your suspension shop on the changes they make you they will be able to move you into a good compromise for your desired riding.
That said, basic sag setting is pretty easy and could/should be done before a new bike rolls out of the shop IMHO.
Because I like to ride my bikes back home (quite often 4-6 hrs from dealer) , I have brought my own tools and done a baseline right on the sales floor if everything is accesable (at near 200 lbs, I am heavier than most normal factory set-ups manufacturers use ).
Just my 2 cents DT
(1) keeping the tires on the road
(2) working the suspension in the best part of the damping stroke.
Ideally you want the suspension to be working some where in the mid stroke of it's travel, neither bottoming or topping out.
Without getting into "are the springs on your bike correct for your weight?":
No sag or too little sag and your wheels are less likely to remain on the road surface as you go over undulations. Too much sag and and you may bottom out also causing lose of grip (and maybe a bent rim
) as that energy is now sent into the wheels and frame.Too much sag can also result in pitching of the bike as you brake or accelerate.
Then there is damping, if your suspension is either topped or near bottomed out you will have only a small amount of oil to force through the damping circuit in one direction or the other.
The damping circuit absorbs the energy of the spring as it compresses or as it decompresses (rebound).
In a ideal world , a properly adjusted suspension keeps the bike stable and tires loaded and in contact with the road.
Also, I have had some great suspension tuners get it completly wrong for my needs. It is best to learn the basics of how things work before you work with a suspension shop, that way you understand what they are doing and can give proper feedback for your unique situation. By properly informing your suspension shop on the changes they make you they will be able to move you into a good compromise for your desired riding.
That said, basic sag setting is pretty easy and could/should be done before a new bike rolls out of the shop IMHO.
Because I like to ride my bikes back home (quite often 4-6 hrs from dealer) , I have brought my own tools and done a baseline right on the sales floor if everything is accesable (at near 200 lbs, I am heavier than most normal factory set-ups manufacturers use ).
Just my 2 cents
DT
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