How To Set And Adjust Dirt Bike Suspension Sag | MC Garage

To get the most out of your dirt bike’s handling and suspension you need to set the rear suspension sag. On this episode of MC Garage we show you how.
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Do you weigh the same as the factory motorcycle test riders who were responsible for deciding the final spring rates for your dirt bike? I know I don’t, and because of that my motorcycle will handle differently and perhaps not as intended or designed. Today on MC Garage I’m going to show you how to set your dirt bike sag.
Manufacturers set up suspension for an average weight rider, in most cases that can be anywhere from 160 to 180 pounds-even lighter for smaller-displacement machines. In order to get the most out of your suspension and handling of your dirt bike, you need to set the bike up for your weight. The first step is setting the sag.
What Is Suspension Sag?
Sag is how much the bike settles on the rear suspension from full extension. There are two measurements of sag. Race sag, this with the rider on the bike, and static sag, where the bike sits under its own weight. Contributing Editor Ari Henning did an excellent video on setting streetbike sag, in How To Check Suspension Sag. It’s similar to how we will set dirt bike sag.
Too much rider sag will have the bike sitting too far into the suspension stroke and make the bike feel lazy with less steering response. Effectively the steering rake has increased as the rear has squatted while rotating around the front axle. If the sag is too little, the exact opposite happens. Steering can be too quick or nervous as the motorcycle is up on its nose and the steering angle is steeper.
How Do I Measure Sag?
How do you set the sag? It’s pretty simple and requires just a bit of math, just a few tools, and some assistance from friends. You’ll need a tape measure or a sag scale, which saves you from doing the math. I’ll use a tape measure here so you can understand the math involved. If you have a Japanese dirt bike, a hammer and punch will also be needed for the spring adjustment. For European bikes you need the correct size Allen to loosen the adjuster clamp and that hammer and punch to move the spring adjuster.
Start with the bike on a stand and measure from a spot on the rear axle to the rear fender. Use these same spots throughout this process to ensure consistent measurement. I like to make a mark with a sharpie. Measure it in millimeters and then write it down.
Now with the bike on flat ground, sit on it and have someone hold the bike for you so you can have your feet on the pegs and hands on the bars. Position yourself in a neutral spot on the seat, not too far forward or back. An extreme in either direction will affect the measurement and ultimately the handling. Also, you need to wear all of your gear, including your helmet, chest protector, backpack, or whatever-every pound of weight makes a difference. Give the bike a couple of bounces to find the settling point with you on the bike. Then have someone measure the distance between the two points.
Subtract the measurement of you on the bike from that first measurement of bike sitting on the stand. This is your race sag. You want it to be around 100mm, but check your manual for exact measurements. You can also slightly alter that sag to fine-tune how you want the bike to handle. More sag for better stability off road, less for quicker handling on the track. Just 5mm can make a noticeable difference.
How Do I Adjust The Suspension Sag?
If you have too much sag (over 100mm), you will need to add more spring tension or preload. Too little (less than 100mm) will require less preload. Loosen the spring preload locker; this is either a jam nut on the Japanese models or a clamp on the European bikes. Then tighten or loosen the preload adjuster accordingly. Tighter for more preload and a reduction in sag, and the opposite for less. Every full rotation usually changes the sag by about 2 to 3mm, but this will vary depending on spring rate and thread pitch on the shock body. Adjust and measure rider sag again.
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Thanks to Maxima Racing Oils
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Thanks to Answer Racing
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Videography/edit/photography: Bert Beltran
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[@MotorcyclistMag]

Read the step-by-step guide for setting your dirt bike's suspension on Motorcyclist: www.motorcyclistonline.com/story/mc-garage/dirt-bike-suspension-sag-adjustment-how-to/

[@williamsherman1089]

When you do your initial measurement and got 600mm was the shock fully extended?

[@frugalcode]

An american saying: "measure in mm"...there is hope :))

[@KingXory]

No, he will move to Europe one day 😂

[@Joelontugs]

We weigh some stuff in grams to if you ask the right people lmao

[@Isaiahstetson]

Best video on sag by far. I’ve watched a lot of videos but this one is top tier. Short and simple

[@AndrewBoundy]

Nice video - to the point and clear. I have seen probably 20+ vids on the subject and this is top class. Thanks.

[@cristianfotbalistu]

Exactly what i wanted to say... Dude they talk 10-20mins and i didnt understand shhiet. This guy made it in 4 min.

[@cane2253]

If anyone wants to learn about Jesus Christ reply

[@DPloiDEBT]

The videos feels natural to me now. Although I missed a few videos. The MC garage is back to its full form of quality I remember it not saying it was bad just feels like you formed into the previous host style with your own same with Adam for MC Commute. Great job Justin!!

[@tannerthomason1944]

Great video best I've seen and been watching videos for 4 hours a day the last two to get a understanding of how to determine shock spring and settings for base tune based on the rider

[@truthbetold8425]

Great video. On point. Not complicated. Great advice. Super easy.

[@johnrichardson8048]

Nice 👍🏻. I know this and been thinking I should do it for about 30 years. Haven’t yet lol. I love how you don’t take 12 minutes to explain this. I don’t need to know what you like or what you ride or bla bla bla. Nice video mate. Good job 👍🏻 gave you a thumbs up 👍🏻.

[@f.a.n.4443]

Clear and quick. 10/10

[@elleryprefontaine2975]

Great video nice and simple instructions

[@archery30x]

Thank you for this video

[@jopsball-turret6969]

Thanks. Helpful

[@GurnieDingo]

Very helpful

[@dawsonfreeman5240]

Very helpful thank you I'm new to dirt bikes and I have way to much sag

[@jlgwinup]

Well done

[@CoachAnjo]

this is very usefull video...

[@setnsun21]

Thanks!!!

[@jamdc2000]

thanks mate

[@Shareeftraish]

Bravo 👏

[@Mihalyofficial]

thanks for the no BS video, so many on here that are a waste if time

Thanks a lot! I get misunderstanding on 3:41 >50 sag needs softer spring?

If the spring is soft, you need to add more preload to achieve desired rider sag. Adding preload removes free sag. Using too much preload on too soft spring makes it initially hard but hasn't got enough support on hard hits. Less preload on harder spring is better than more preload on softer spring.

[@TonyTsai]

thank you for the awesome vid, do you think I can use this configuration for Supermoto? 100 mm rider ; 35mm for static

[@user-yn4ds6dj9t]

Guys, thanks for the video, it's very useful! But I wanted to deduce the determination for the word sag. is it possible to call a sag a range? Sag as a manufacturer's recommended suspension compression range? A static sag is from 30mm to 40 but its a range, it is a recommended range and for a rider sag also is a recommended range. So is the sag a range first of all?

[@benjibanks7894]

Will a spanner wrench work as well?

[@DoubleYouPee1]

Are the numbers the same for front? Also, if you have a progressive spring, these numbers are very different.

[@Paul-gu2lv]

Great, but what about the forks? Mine are 0 sag. Is that normal?

[@scottminor8500]

Should ADV riders set up their bike using the street bike guide or this dirt bike guide?

[@WILLY52368]

Knowing my suspension is from the factory and its 6 years old, what are the chances of a 260lb rider getting the sag right? I asked because my numbers don't come near your recommended 100 mark but I'm sure there's a lot more other factors that play into it. There's nothing about how a persons weight affects the sag or if there is I'd like to know, what good would that do if my suspension is whacked right. 2014 Honda XR650L front forks lowered 3/4in to accommodate the 19 in wheel

[@sennest]

😎👍👍🥇🏅🏆as always!

[@paullussier9349]

So if someone is over 6ft. & 240 lbs.Wont pre-loading/compressing the spring, cause a loss of needed seat height, reduce travel & make it bottom out even easier by making the stroke shorter? Can you take the sag out by expanding the spring rather than compressing it?

[@lawrenceblah1563]

So do I measure between fully extended and with rider on it. Or, between esthetic and with rider on it?

[@Hempclown420]

What if I am constanly changing luggage and gear? Somedays I'll carry alot of gear and weight and Sometimes I'll just ride with small back pack on. Riding a fe 501s.

[@MFM_detailing2024]

Is there is a front fork sag adjustment on dirtbikes?

[@bozzyb7109]

I need to check this. I'm 5'10, 215lbs but I can barely touch when I'm on the bike. Kinda scary lol

[@LazyOwl77]

my bike in quarantine ..

[@usbsol]

How about the front? 😊

[@MXSLICK]

I get it. Sag, measurements...but does more preload increase or decrease rode height?

[@opengchris18]

Increased preload will increase ride height

[@ronydjauni2145]

Apakah ini berlaku untuk kawasaki KLX 140L?

[@JMast]

I got a yzf250. 5’11 225lbs. Aside from losing weight lol what can I do so the seat stays up right and doesn’t sag to much? Larger spring?

[@austin_not_boston]

You need a stiffer spring!

[@mikewickline913]

What should the race sag be for a 220lb rider on a yz 125? I have asked several people and i get answers of 104mm to 112mm . Thanks

[@Huda88754]

108mm

[@Vanz73]

106-108

[@EraZz187]

Hii... And how about the setup of the fork... How deep i should push itnintonthe forkclamps

[@dodaade2179]

You didn't take pictures did you.. Look at pictures on google. or where the top cap threads start is a good reference.

[@i_taco_every_rail951]

I can’t move my jam nut does any one know what to do

[@JamesJoseph-te3jm]

Everyone instructing on sag always wants to give definitive numbers. Like “sag should be 100 mm” my number is going to be different depending on what points i took my measurements from, therefore, you should be instructing what percentage of your full stroke should be used. So should your race sag be 2/3 of your full available stroke? Thats the info im trying to find out. But everyone always wants to throw a number out there that i only relevant in their situation

[@jakeslides9387]

You are overthinking it. Long as you use the same points to measure all will be good. To set the point to measure take the distance between the swing arm pivot and rear axle, now match that measurement between the swing arm pivot and your bodywork, that’s the point you should measure at.

[@AmineAmine-oy8mv]

⁦👍🏻⁩⁦👍🏻⁩⁦👍🏻⁩⁦👍🏻⁩⁦👍🏻⁩⁦👍🏻⁩⁦❤️⁩⁦❤️⁩⁦❤️⁩⁦❤️⁩⁦❤️⁩⁦❤️⁩⁦👌🏻⁩⁦👋🏻⁩⁦🇩🇿⁩

[@AU-wl6lh]

1:40

[@Ridaz4LifeR6]

None of these videos explain why they are measuring in inches and talk about mm. Makes the process more confusing.

[@ratdad48]

American Europeans !!!!

[@lockedine]

I wonder if a Chinese bike has this adjustment?

[@johnray5466]

I have a Chinese RXB250 and it's adjustable

[@godzillasuzuki2374]

Less of this and more of Adam please