All You Need to Know in Order to Maintain An Ideal Suspension For Your Motocross Dirt Bike
Motocross is a bike that performs for speed and for air. It’s a racer, it’s a dirt devil, it’s the ride you want to show off, and it’s a ride that encourages you to hone in on your skills. These skills are for you to pull off some amazing feats of talent, bravery, and sick tricks!
What many don’t realize is that a lot of the control over the bike relies upon the suspension of a bike. The wrong suspension on your bike could make or break your motocross experience. The goal is to create that perfect balance of suspension that combines the rider and the individual bike itself.
We’ve put together a quick and easy guide filled all sorts of life hacks for motocross riders and racers to make your suspension setup far more easy to understand and ultimately give you that perfect ride you’ve been itching to have.
So What Makes up a Motocross Suspension?
While there are many different factors involved, the essential parts of a suspension are the spring and the damper. Each of these is vastly different in function but useless without one another.
The springs hold the weight of the machine and absorb impacts from the ground while riding. The damping is used to slow down the compression of the spring. There’s one more critical piece…
Of course, the start of any good suspension lies not only in the springs and damper but in the “sag” as well.
Setting Your Sag
This is perhaps the simplest and most often overlooked adjustment you can make to improve the overall handling of your bike. Sag, in a general sense, is the distance between the rear end of the motocross bike and the ground. There are two types that you should take into account when setting up your sag for an upcoming ride.
However, before setting the sag, make sure that the chain is adjusted properly. Check to see if the linkage and swingarm bearings are in good condition. Even if you find the ideal setting of sag, if they aren’t in good working order, even a top shape suspension won’t do you much good.
This is the distance that the rear end of the bike settles in when on the ground and under the load of the rider’s weight.
Quick Tip for Easy Rider Sag Setup:
- Measure with the rider sitting.
- Bounce a few times on the suspension before measuring
- Sit where you actually sit on the bike, not where you think the rider should be.
- Measure from the same spot on the bike every time after that. This guarantees consistency.
Also known as “free sag”; this is the distance that the rear end settles when on the ground under only its own weight
Quick Tip for Static Sag:
- The static sag on an average large bike should be about 30mm to 40mm.
You need to find the right balance of sag that works for you and your motocross bike. No two bikes will always have the exact same sag, and this is because it factors into the weight of the bike (whether it has heavier tires, added features, etc.) and the weight of the rider. Doing it correctly will position the bike so that the front and the rear of the bike will be loaded successfully.
Quick Tip for Setting Up Your Static Sag:
- Before you start your measurements, top off the bike fuel and have the rider in full gear. This creates the maximum weight your bike could potentially carry.
- Check out this blog by Rider expeditions, which will break down the finer details of how to accurately measure out the static and rider sag.
Measurement is Key in Motocross – it all Connects to the Springs
If you aren’t careful in these measurements, you could create a sag that is either too soft or too stiff. Neither of these is what you’re looking for when trying to achieve the optimal motocross ride. This ends up tying into the springs of the bike. Another factor in the proper set-up for suspension.
Too Soft: This is when the measurement is 20mm or less. If it’s too soft, it forces you excess preload to get the desired sag; a chain reaction of unloading too much in the air and top out. This creates a harsh feel when riding. If this happens, you want to create a stiff spring rate.
Too Stiff: Usually 35mm or more. If the spring is too stiff, you won’t be able to gather maximum traction when accelerating the bike. This will cause you to feel every bump and divet in the road. Not a pleasant ride.
The Second Motocross Suspension Factor is the Damper
As we said earlier, damping is used to slow down the compression of the spring in order to bring it back to the original dimensions. It refers to the controlling of the spring action; the oil flow through various orifices and valve plates from one side of a moving piston to the other. This means that it splits into low speed and high speeding damping.
There are Two Types of Damping in Motocross – Rebound and Compression
- Compression is when the damping squeezes down on the springs. Low-Speed Compression means damping adjustment usually occurs by turning the adjuster at the top of the shock absorber reservoir.
- High Speed is adjusted using a spanner on the outer nut at the top of the shock reservoir.
Quick Tip for Compression Damping:
- Too much: Far too much resistance to movement and you can’t use the full suspension on your motocross bike.
- Too little: The bike becomes unstable and you have an uncontrollable suspension. This ends up causing the back to lose traction continuously.
Quick Tip for Rebound Damping:
- Too much: The bike ends up sitting low and take a long to correct its height. This creates poor traction and drive. All are equaling an unenjoyable ride.
- Too little: The bike is unsettled as the suspension jumps over every hill, uneven road, and bump.
For a more in-depth breakdown of the damping please check out this blog here, a great source of information if you need just a bit more detail in setting up the damper just right.
A motocross bike is a fine-tuned machine, and while these are key factors, there are many other components you should consider. For starters, this includes elements such as the tires’ air pressure to the oil height. This blog has a helpful checklist you should review to ensure you keep your bike running as smoothly as possible.
A Proper Motocross Suspension is More than Two Parts
Taking care of the suspension of your motocross bike is more than taking care of two parts. It requires an attention to all parts. This includes changing the oil in the forks when needed. Just like engine oil, the oil in the suspension (the fork oil) degrades over time. You want to monitor how much you use your bike.
The hours you spend riding can dictate when you have to change the oil next. Ideally, you want to change the fork and shock oil every 20 hrs of use and replace the seals and brushing every 40 hrs of use. If you don’t monitor the hours you put into your machine, it’ll be harder to realize when the oil needs to be changed.
If you need to adjust your clickers to compensate for the change in compression, that’s a sure sign the oil should be changed. If you wait too long the seal starts to leak. Sometimes the seal can be saved by a simple cleaning, but often times that isn’t always the case; it really should just be replaced.
If you notice a seal leak before changing the oil in the forks? Check out this guided DIY video on cleaning and properly reinstalling that seal back onto your fork. If the seal on your bike is still in good condition, you can save it.
There are two parts that need to be separated: the upper and lower forks. As far as taking the two pieces apart and actually replacing the oil, it’s a rather straightforward procedure.
- Remove the bleeder screws; this is to bleed off any pressure
Tip:All forks build up air pressure when you ride them. To do the best by your machine, bleed your forks after every ride. When bleeding out make sure they are completely cooled down. This way the air expansion from heated forks can return to normal levels before you bleed.
- Loosen the fork cap. Don’t remove it though
Tip:The wheel should be removed and, depending on the bike, the handlebars. The type of bike will also determine if you need to remove the fork guard clamps. Then loosen the pinch bolts on the triple clamps.
- Remove the fork; once the fork cap is loose you can easily slide id down the lower fork.
- Tip the upper fork upside down to drain the oil into the pan. Usually, this takes about 5-10 minutes. It drains very slowly so you might want to find a place to lean the fork against.
- Now that it’s drained use the correct fork oil weight using a fork oil level gauge.
Tip:The weight and the volume affect how the forks work. Follow the manufacturer’s guidelines to get the right amount.
- Reattach the fork leg
Maintaining Your Motocross Bike is the Priority
Learning how to set up and install the different components of your bike is one thing because it does give you a clean slate on the upkeep of the vehicle. However, it is the maintenance of the machine that allows it to have the longevity and ability to stand the test of time. This saves you money in the long run and gives the ideal control for an amazing ride.
Keep your bike running at its best by consistently observing and maintaining the following:
- Grease: Sticky linkage will ruin a suspension. Grease the steering head, the shock linkage, and the swingarm pivot periodically to keep everything running smoothly.
- Tire Pressure: Tire pressure, if it isn’t monitored or checked, can cause severe damage and suspension problems. Too much air makes the suspension stiff as too much air will cause the bike to wallow and push. Check out this blog from Motocross Action, explaining the proper way to inflate your tires.
- Oil Height: Adjusting the height of the oil determines the amount of airspace there will be in the forks and changes the damping when in the second suspension travel. Adding oil to the forks stiffens them. Increasing the bottoming resistance of the bike while removing oil softens them.
Tip: To add oil to the forks, use a good syringe to squirt oil through the fork bleeders. When adding the oil, do so in small 10cc gradients so as to have better and more concise control.
- Chain Tension and Length: Running a longer wheelbase will offer a more straight line stability. A shorter wheelbase creates instability on the improved turning capability of the bike. However, this particular type of maintenance more or less depends on the type of riding you do.
- Troubleshooting: Learning this can help you better maintain and get the most out of your suspension. This is a practice that takes time to learn because you need to have an individual, unique understanding of how your bike works from other bikes.
Learn how your bike sounds in all of its conditions, learn the ideal sag that works in tandem with yourself. Find out the particular ticks of your bike. The sooner that you are able to understand how your bike works, the easier it will be to foresee when it’s under duress. Going forward, you’ll be able to have an easier time finding the problem and resolving it.
This blog has a handy-dandy checklist you should check out to ensure you keep your bike running as smoothly as possible!
Now You’re On Your Way to an Amazing Motocross Ride
We want you to have the best ride you can possibly have, and that means keeping your motocross bike in excellent running order. Doing so will determine your ability to have a great riding experience and also to have a machine that stands the test of time.
Well, you know what to do now. Get your behind in your garage, make the tweaks and adjustments necessary, and get ready to rev that engine and rip out of your garage with a motocross suspension you can rely on!
If you’re looking for tools, equipment, or gear check out TMS Parts to help give you the ideal adrenaline coursing riding experience.