What Is Motorcycle Sag And Why It Matters
Do you want to be faster, better and safer permanently in just a few minutes?
If yes, motorcycle sag will do this for you. As a part of motorcycle suspension set ups, it is often overlooked and with the right set up, it helps contribute to “invisible” speed.
So let’s find out what motorcycle sag is, why it is important and how to measure it, and find the right motorcycle sag for you in this article!
Contents
Why Motorcycle Sag Is Important
What Is Motorcycle Sag
Motorcycle sag is the amount your motorcycle’s suspension compresses under its weight relative to its fully extended position.
There are two types of sag:
- Static sag: is the amount the suspension compresses under the bike’s own weight,
- Rider sag (also known as race sag): includes the weight of the rider and the gear he’s wearing.
Why Motorcycle Sag Is Important
Trust me, that setting the right motorcycle sag even though it may sound like a small deal is as important as getting that coveted knee down picture for your Instagram!
In fact, despite riding on the regular road for years I never paid much attention to the technical aspects and I was introduced to motorcycle sag for the very first time on my first track day.
Carrying over my bad habit of neglecting the technicals, I thought that pushing hard and fighting with the motorcycle in the corners was normal until the track mechanic told me that my sag was way off! Here’s why motorcycle sag is important:
Impact on Handling and Stability
When your sag settings are off, your bike can feel unstable, especially in corners. Proper sag ensures that your bike’s suspension is working as it should, keeping your tires in contact with the road and giving you better control.
It may also feel like fighting to control the motorcycle which is how it felt for me when my sag was off.
Rider Comfort and Fatigue
Since it is related to suspension and geometry adjustments, If your sag is off you’re going to feel discomfort in places such as your arms or back.
I’d been knocked out after the 20 minute track sessions but this changed after setting the right sag, which allowed more smooth riding on the track; the motorcycle and I were in sync, inevitably leading to better performance and I no longer looked like I returned from a war in the pits!
Proper sag settings help distribute your weight more evenly, reducing the strain on your body and making for a much more comfortable ride.
Suspension Performance and Safety
Your bike’s suspension is designed to absorb bumps and keep your ride smooth. But if your sag settings are off, your suspension can’t do its job properly. Proper sag settings ensure that your suspension has the right amount of travel to absorb bumps and keep you safe. Too soft or too stiff is a sign of incorrect motorcycle sag.
Whether you’re a track rider or regular road rider, all motorcycle owners must adjust their sag correctly. Together, motorcycle sag makes you faster, better and safer and the best part is that unlike a skill that needs practice such as body positioning, or trail braking this only takes a few minutes to adjust!
How to Measure Motorcycle Sag
Calculating motorcycle sag can be a bit tricky which is why this free, easy to use motorcycle sag calculator is perfect for measuring motorcycle sag correctly.
This calculator can recommend the best sag for you based on not just whether the use is for the racetrack, road, off-road but it also tells you if your seals are worn, the linkage system needs lubrication and if your spring rates are correct!
But before you start measuring sag, here’s what you need:
- Your motorcycle
- Yourself! (In full riding gear)
- A friend or someone who can measure for you
- A measuring tape
- A notepad (or your phone’s notes app)
- Preload adjustment tools (Any tools needed to adjust front and rear’s preload)
- A Paddock stand
Let’s go over the step-by-step guide on obtaining the data to input in the calculator finding the perfect sag for you!
Front wheel
First you need to get the wheel in the air away from contact with the ground. This can be easily done if your motorcycle has a center stand. If not, carefully lean the bike on its side stand while your friend measures L1 which is the exposed portion of the fork.
Now with both wheels on the ground, with you sitting on it, ask your friend to push down on the suspension and then let it go to its rest position. Measure the exposed part. This is your L2.
Do the same thing except this time ask your friend to pull up or lift on the suspension and then let it go to its rest position. Measure the exposed part. This is your L3.
This accounts for friction within the suspension making it more accurate.
Rear Wheel
Remove your motorcycle from the paddock stand and ask your friend to measure L1 which is the distance from the axle to a fixed point on the tail while you lean it carefully on its side stand.
Put the motorcycle back in the ground and repeat how you calculated your L2 and L3 for the front wheel.
Now that you’ve collected this data, just add it to the motorcycle sag calculator and that’s it! You have the best sag recommendation!
After the calculator provides the right sag value for you, use your preload adjustment tools which can be a wrench or another tool specific to your motorcycle (See your motorcycle’s owner’s manual to see how to adjust it) to either increase preload if your sag it too large or decrease preload if too little which the calculator also displays so you’ll know exactly what to do.
It’s also important to check your sag settings regularly. I make it a habit to check mine periodically, before track days and especially after any major changes to my motorcycle setup, like getting new tires or adjusting the suspension for a different type of riding.
It is possible that you might encounter the fact that your sag settings are still off even after adjusting the preload. This could be due to worn-out suspension components which the calculator informs you of too!
A common issue you may face is that your bike might feel different after adjusting the sag, and not always in a good way. This is where patience comes in. It might take a few rides to get used to the new settings.
After the mechanic adjusted my sag it did feel weird for a few laps to not have to force the motorcycle harder like before, but soon I got used to this and my lap times were faster too!
Conclusion
It might seem like a small detail, but it’s a key when it comes to your bike’s performance and your riding experience whether you are heading out to the track or for everyday road use, setting the right sag is a must.
Motorcycle sag is only one part of the larger topic of suspension adjustment and a reason why many riders avoid delving into the technicals is because it “seems” difficult and complex leaving opportunities to become better whether on track or on the road on the table.
However, with the Motorcycle Suspension Adjustment course you leave no stone unturned in getting the most from your motorcycle. Just ask Alberto Servera, one of the many who loved the course, on what he says about it:
“Lots of information and well explained step by step. The trainer also did very well, with good explanations so that everyone could understand. Everything was perfect!”
So what are you waiting for? Check out the course now!
Guest Author Biography
Grshaan Mahesh is a professionally trained track rider and MotoGP and WSBK addict for over a decade having had a chance to interview many racers from his favourite series, and writes about various aspects of motorcycle road racing such as racing techniques, track day tips, reviews, guides and more at Motoracers.
Motocourses GA Academy can help you get what you want. Contact them at info@motoiservices.com
