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The Fundamentals of Dirt Bike Handling

Paul Olesen

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Have you ever ridden a buddy’s bike and walked away wishing that you didn’t have to get off because everything just clicked as you were riding it? On their bike, you could rail every corner, absorb every bump effortlessly, and feel completely stable at high speeds. Once you got back on your bike it feels slow, riding over rough terrain wears you out, and taking corners is best described as unpredictable. To make matters worse, you and your buddy could have the exact same bike! What could possibly account for the huge gaps in handling between the two machines?

By design, numerous tweaks can be made to significantly influence how your dirt bike handles. Some of these alterations are as simple as turning a few adjusters, while others require more involved labor such as disassembling forks to swap out springs and dampers. Today’s focus will be on introducing all the different variables that can be adjusted, which ultimately impact how your bike handles. This is the start of an in-depth series on motorcycle handling where I’ll be going into extreme detail on how to make adjustments to individual areas on your dirt bike.

For the sake of clarity, I’ve broken out all the things that we can consider adjusting into two categories: geometry variables and suspension variables. What is challenging about tuning the handling of a dirt bike or motorcycle is that all the different options available to adjust are in one way or another interconnected. This means that geometry variables often influence suspension variables and vice versa.

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If we consider the bike as a whole we have:

  • Center of gravity - The center of gravity is simply a point in space where, if we consider the weight of all the bikes components, the distributed mass sums to zero. For visualization purposes, the center of gravity is a hypothetical point in space where the entire weight of the bike is concentrated. For our purposes, these definitions may not seem particularly tangible, however, what is important to consider is that the center of gravity’s position will have a significant influence on the bike’s stability and handling.
  • Wheelbase - The wheelbase defines the distance between the front and rear tires’ contact patch. Wheelbase adjustments will affect how stable the bike feels.
  • Weight Bias - The weight bias defines the distribution of the bike’s weight between the front and rear wheels.
  • Seat Heat - Seat height can influence handling by altering the combined center of gravity of bike and rider as well as be an ergonomic consideration.
  • Ergonomics - Ergonomics refers to all the small adjustments that can be made to make the rider feel comfortable on the machine. Examples include shift and brake lever position, seat height, handlebar position, and foot peg location.

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Front geometry variables include:

  • Ground Trail - Ground trail is a measured or calculated distance used to compare the distance of the steering stem axis (extended to the ground) to the center of the contact patch.
  • Rake Angle - Rake angle defines the angle between the steering stem axis and vertical plane.
  • Contact Patch - The contact patch is the portion of the tire that is in contact with the ground.
  • Triple Clamp Offset - Triple clamp offset defines the center point distance between the fork tube axis and steering stem axis.
  • Axle Offset - Axle offset defines the center point distance between the axle and fork tube axis.
  • Total Offset - Total offset accounts for both the axle and triple clamp offset.
  • Front Wheel Diameter - The measured diameter of the wheel.

Most of the parameters discussed here all influence ground trail, which is a key variable used to assess the bike’s stability.

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Rear geometry variables:

  • Swingarm Angle - The swingarms angle relative to the horizontal or ground plane.
  • Contact Patch - The contact patch is the portion of the tire that is in contact with the ground.
  • Front and Rear Sprocket Diameter - The sprocket’s pitch diameter.
  • Rear Wheel Diameter - The measured diameter of the wheel.

The rear end variables outlined here are not particularly important when considered on their own but have a significant influence on a critical handling concept called “Anti-Squat.” Anti-squat is used to characterize the effects the swingarm angle, and chain force has on the rear suspension. Anti-squat will be explored in further detail in a future post.

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When it comes to suspension, numerous adjustments can be made to influence the bike’s response. These include:

  • Fork and Shock Preload - Fork and shock preload quantifies how much the fork or shock springs have been compressed upon installation. Preload adjustments predominantly affect the ride height of the bike.
  • Fork and Shock Compression Damping Adjustments - Compression damping adjustments alter the suspension system’s response to events that compress the suspension.
  • Fork and Shock Rebound Damping Adjustments - Rebound damping adjustments alter the suspension system’s response to events that extend the suspension.
  • Fork and Shock Compression Damping Selection - Significant alterations to the way the forks and shock respond to compression events can be made by swapping out dampers or modifying existing dampers.
  • Fork and Shock Rebound Damping Selection - Significant alterations to the way the forks and shock respond to extension events can be made by swapping out dampers or modifying existing dampers.
  • Fork and Shock Spring Selection - Fork and shock springs are selected based on their spring rate. Different applications and riders require different spring rates to optimize the suspension system.
  • Fork Oil Level - The volume of air found within a fork acts as an air fork. The air volume can be increased or decreased by adjusting the amount of fork oil used.
  • Fork and Shock Oil Viscosity - Viscosity is a measure of an oil’s resistance to flow. Changes to oil viscosity in the suspension system will affect how the damping system responds.
  • Front and Rear Tire Pressure - Tire pressure settings influence traction and also the overall response of the suspension system since tires also act as air springs.
  • Shock Linkage Ratio - If the bike is equipped with a linkage that connects the shock and swingarm the geometry of the linkage can be manipulated to alter the shock's response.

I hope this overview of all the different variables that can be manipulated to improve the handling of your machine has you excited for what’s to come! Making a dirt bike or motorcycle handle well can mean the difference between a podium finish and a mid-pack finish when racing. It can also make or break the riding experience when out on the track and trail. The number of variables that can be altered can seem overwhelming, but in future posts, I’ll walk you through a systematic approach to make the job less daunting. If you want to stay up to date on the latest tips and info I have available regarding dirt bike handling and suspension I want to invite you to sign up for my email newsletter on the subject. Click here to sign up and I’ll keep you in the loop!

- Paul
DIY Moto Fix

 

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This is the nicest summary I've seen put together ANYWHERE. Nicely done!

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36 minutes ago, Keebler750 said:

This is the nicest summary I've seen put together ANYWHERE. Nicely done!

I would have to agree.  I like how every term is pointed out like a glossary.  It gives someone totally new to this the proper terminology so they are lost or feel over their heads in a suspension or handling related thread or forum. ?

 

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35 minutes ago, Donny18 said:

I would have to agree.  I like how every term is pointed out like a glossary.  It gives someone totally new to this the proper terminology so they are lost or feel over their heads in a suspension or handling related thread or forum. ?

 

Well the thing is we're constantly battling misinformation and improper use of terminology, so this kind of stuff is always great for the community at large!

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48 minutes ago, Keebler750 said:

Well the thing is we're constantly battling misinformation and improper use of terminology, so this kind of stuff is always great for the community at large!

Couldn't agree more.  Misinformation (or lack thereof) is the worst.  Especially so for someone trying to learn.  I'd love to see more articles like this on different topics.  Not too deep into the subject matter, just a brief summary with proper terminology.  Again, great job @Paul Olesen!

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Pretty complete,  but tire selection and air pressure weren't even mentioned.

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100% accurate! Bravo! The only thing is when the dude gets off a friends bike, is just the opposite, my hillbilly buddies set everything back wards, oh well, my bike is nice enough!?

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Sometimes when a guy owns a car and drives it for a few years and nobody else drives it, he gets use to the patterns of his own. Then when he lets someone else drive it for a few weeks and he gets his car back, you might hear him say "I could definitely tell someone else has been driving my car."

I had an instructor say that is because everyone drives a car differently and the guy might step on the brakes nice and slow 40 feet from the stop sign and the person he let borrow the car might step on the brakes harder and closer to the stop sign and start turning and speeding up differently than the owner, making a small difference in wear patterns that can be noticeable to the owner. These wear patterns are more noticeable in somewhat older cars. Cuz today's cars are being made with much higher quality precision machined materials that don't have as much friction and wear as the older cars.

This can somewhat apply to dirt bikes and quads if you let lots of people use your ride, I have one friend that let lots of people drive his quad and it wasn't functioning as well later on. I told him to not let anyone drive his quad and he knew that it had been thrashed on and he listened to me when he got a different quad and it has lasted much longer functioning better with only him driving it.

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That was a really helpful overview/summary. I'm hoping you follow up with some detailed explanations, in particular, a nagging question I have about compression and rebound damping. It's concept I can't fully grasp until someone explains it precisely. Here's how I understand it (and I think I'm wrong!!!) right now:

1) "damping" suggests softening, right? 2) Therefore, if you increase damping, you soften the reaction of the suspension, right? 3) Therefore, if you increase damping of compression, that means you reduce the amount compression, effectively making you fork or shock stiffer (i.e. less compressable)? 4) And, in following that logic, if you increase damping of rebound, that means you reduce the amount of rebound, effectively making your fork or shock more sluggish to extend?

If I have this concept right, it is the reason I find it confusing: because to increase a tuning dial actually gives the opposite effect, because you're adjusting the damping on the action, not the action itself.

I'm probably overthinking this, and look forward to being corrected, or at least having my complicated perspective simplified!

Thanks Paul!

- Mike

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14 hours ago, Fruitfarmer231 said:

Pretty complete,  but tire selection and air pressure weren't even mentioned.

Yes "Tire Pressure" is clearly displayed. therefore it was mentioned. 
I too love this article so much, and anticipate learning how to use the information in the future so that I too will enjoy future rides:)

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I believe you might be overthinking it Mike.  Of course, I am no expert and I could be wrong here, but the way I always thought of it was + meant stiffer and - meant softer.  An over simplification, yes, but it's worked for me ?.

Of course, none of that means a hill of beans if you don't have the proper springs for your weight and your sag set.  However, that's an entirely different thread.

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Found a very good thread about suspension setup a while ago in a UK forum.

Explains pretty fine what to do to dial your suspension in, proper springs ( in my opinion the most important thing) and proper valving must be done first.

 

All taken from Ride Concepts INC setup giudes. This is the best setup guide I have seen to date.

Spring Rates and Tyres

Motorcycle suspension uses springs to hold the bike and rider at the proper height and position.
The spring rate, or "stiffness" of these springs needs to be correct for the bike, 
rider weight, rider height, ability, and application. 
These springs are designed to have a certain amount of sag, with the rider on the bike. This is absolutely crucial!

Most dirtbikes role off the showroom floor with an un-ballanced combination of suspension springs. Some brand new dirtbikes come equipped with very poor performing springs as well.
Example: If you are a 200 pound vet rider on a brand new RM125, you will absolutely need to install stiffer springs, front and rear. 
This bike was designed to be riden by a 150 pound rider.

Having too soft of a spring rate makes a bike sag more than it is designed to. If this happens, the suspension will feel stiff, and soft, AT THE SAME TIME. The small bumps won't be absorbed properly, due to the increased spring preload. The large bumps will cause the bike to bottom easily, due to the lack of overall bottoming resistance and available travel.
Having the incorrect spring rates will always make the bike handle poorly, 
and DANGEROUSLY!
You could have the best motorcycle on earth, but if it has the wrong springs installed, 
it will never handle the way it was originally designed to.

The majority of off-road motorcycles have poor overall chassis set-up. This is whether they are new or used, regardless of displacement/plastic colour, or how cool and flashy the stickers are! 
One of the major differences between a beginners's bike and a factory rider's bike is the knowledge of the person who wrenches on it.

There are a lot of handling problems associated with incorrect chassis set-up. The most common problem is incorrect race sag/free sag. The proper amount of race sag for a full sized japanese motocross bike is 95-100mm. The proper amount of free sag is 15-25mm. KTM's can run as low as 110mm race 35/40mm free sag. Contrary to popular belief, 2mm difference in race sag makes a dramatic difference in overall handling! 

Step 1: Put bike on a stand with both wheels off the ground.
Step 2: Take a tape measure and measure the FULLY EXTENDED length of the rear suspension. This is done easiest by measuring from the rear axle to a spot on the rear fender, THAT IS DIRECTLY ABOVE THE AXLE. I usually put a small piece of tape on the fender and leave it there as a consistent reference point. DO NOT MEASURE FROM THE REAR AXLE TO THE SEAT BOLT, AS THIS USUALLY ISN'T EXACTLY VERTICAL. Like I said earlier, 2mm is a very big deal. WRITE DOWN THIS MEASURMENT!
Step 3: Put on all of your riding gear that you would normally race with. Take the bike off the stand. Have someone stand in front of the bike, holding it upright. Sit on the bike in the attack position, with your feet on the pegs. 
Step 4: Have a friend pull down slightly on the rear of the bike, then SLOWLY let it come back up on its own. Measure the exact distance between the same reference points. WRITE DOWN THIS MEASUREMENT!
Step 5: Now have a friend lift up slightly on the rear of the bike, SLOWLY letting it settle. Measure between the reference points again. WRITE THIS MEASUREMENT DOWN!
The average of these two measurements is the TRUE RACE SAG. If the two measurements are more than 5mm different, the rear suspension linkage assembly is sticking and must be serviced. 
If the race sag isn't between the 95-100mm range, it can be adjusted by tightening or loosening the shock spring preload with the spring's retainers.
Step 6: Stand beside the bike and hold the the bike straight up by the end of the handlebar. Have a friend slightly compress the rear suspension, then SLOWLY let it extend on its own. Measure between your reference points. WRITE DOWN THIS MEASUREMENT!
Step 7: Now slightly pull up on the rear of the bike, then SLOWLY let the rear end settle under its own weight. Once again, WRITE DOWN THIS MEASUREMENT! The average of these two numbers is the TRUE FREE SAG. As with the race sag, if the two numbers are any more than 5mm different, your linkage is sticky.
If the free sag isn't between 15-25mm, WITH THE CORRECT RACE SAG, you will need a different rear spring rate. If there isn't enough free sag, your spring is too soft. If there is too much free sag, your spring is too stiff.
IF YOU DO NOT CHECK YOUR SAG USING THIS METHOD, YOUR SAG WILL BE INCORRECT. THIS IS ABSOLUTELY THE BEST, MOST ACCURATE WAY TO DO IT, HANDS DOWN!
www.racetech.com is an EXTREMELY GOOD website, and it has a spring rate search. This is the only website that I have found with this. Every spring rate that RaceTech recommended that I install, had the EXACTLY perfect amout of free sag vs. race sag. TRULY GOOD STUFF!


90% of riders do not set their tire pressures properly! The majority of riders just set their pressures somewhere between 12-15 psi, and never really give it much thought. The majority of riders have absolutely no idea what tire pressure they should run, so they usually ask their buddy, who probably has even less of a clue as to the reasons why he runs what pressure! Especially if he's stubborn and says he's run 38psi for 50 years, and it always worked good...
There is only ONE METHOD to deciding the proper tire pressure. Its called RIM CLEAN... There must be up to, a max of 4mm of a clean strip to the outside of the rim where it contacts the tire. The tire rolls over the rim somewhat, keeping this part of the rim clean! ALL off-road motorcycle tires are DESIGNED to work this way! Front and rear. "D" shaped rims will require less rim clean for obvious reasons.
The tire pressure is adjusted so that the proper amount of rim clean is visable. The tire pressure will differ DRAMATICALLY from tire to tire, tube to tube, bike to bike, track to track!

A soft carcass tire with a stock tube may require 16 psi in order to have the proper rim clean. A hard carcass tire with a heavy duty tube, may only require 6psi! So if you have a stiff tire, with a stiff tube, and you have say, 15psi in it, it is almost the equivalent to running 25psi!
It is very easy to run the wrong pressure, but most people don't know how to calibrate it. If you have the proper amout of rim clean, and your buddy has the exact same bike/tires/tubes but he has no rim clean, you theoretically have say 10% MORE TRACTION! Now thats a big deal!

Tire pressure (psi) is only a number, and that number is used to calibrate the rim clean...
Steering head bearing tension is also another thing that is often overlooked. 
Place the bike on the stand, with BOTH wheels the same distance off the ground. Slowly turn the bars from side to side. There must NOT be any "crunchy" feeling spots throughout the sweep. If there is, the head bearings are roasted, and must be replaced.

With the proper amount of bearing tension (and a well serviced bearing set), the wheel will stay 1"-2" OFF OF CENTER BEFORE IT FALLS TO THE STOP. If the wheel won't stay centered on its own, the bearings are too loose. If the wheel stays more than 2" off of center, without falling to the stop, the head bearings are too tight.
This is a general guideline. Most riders prefer it this way. There is absolutely no bad handling traits associated with the head bearing tension, if they are set using this procedure.
Slightly loose bearings tend to make the bike want to headshake more while braking hard, and it makes the bike feel sloppy. Slightly tight bearings tend to make the steering darty, especially on the face of a jump. Both increase arm-pump!

Bleeding the air out of your forks. 90% of riders aren't aware of the fact that your forks need to have the excess air blead from them. 1/2 the guys that are aware of it don't do it properly!
Put your bike on the stand, so that at least the front wheel is off the ground. Take a small screwdriver, and crack the bleeder screw loose from the top of each fork leg. DO NOT try and turn the damping adjuster, the bleeder screw is located to the side of the fork cap, NOT in the center. Leave this screw loose for a few seconds, until you can't hear any air hissing out, then re-install it. DO NOT DO THIS WITHOUT THE BIKE BEING ON THE STAND!!! (front wheel off the ground).

It is best to do this before and after EVERY RIDE, as it will make the suspensions' performance alot more consistant, and it will lessen the chance of a blown fork seal!
If your bike is going to be tied-down in the back of a truck or trailer, for an extended period of time, It is also a great idea to bleed the forks when they are compressed. This will take the pressure off of the fork seals. Just remember to re-bleed them as soon as you un-tie the bike!!
So as far as chasis set-up goes, having proper spring rates, race sag, head bearing tension, rim clean, and freshly blead forks, is the absolutely the FIRST STEP in getting your bike to handle better. ALL of these MUST be done prior to any suspension adjustments!

NOTE: A lot of riders just ride thier bike, and never adjust anything. In a lot of ways, that is perfectly fine. Most riders only do the bare minimum required maintanence on thier bikes. Everything listed here is just a good recommendation. Having a properly set-up bike won't necessarily decrease the bike's laptimes, on it's own. But, having as many mechanical advantages as possible, will lessen the chances of INCREASING your laptimes unknowingly.

 

Hardpack Setup:


Step 1: FORK LOW SPEED REBOUND. 
The forks rebound is adjusted FIRST because there is no point in adjusting the compression if the rebound is way out of whack. This is first adjusted with the compression in the middle of the range. Therefore later compression adjustments will be WAY more accurate! 
This is also the first step because the front tire usually hits an obsticle PRIOR to the rear wheel. If the forks rebound adjuster is way out of whack, it will transfer the wrong loads into the chasis at the wrong times. ALL THE OTHER ADJUSTERS ON THE BIKE WILL BE VERY HARD TO SET-UP!!!
Find a fairly flat, somewhat smooth hardpack corner, preferably one that is slightly off-camber, with no berm.
Ride through this corner several times to get used to the way the forks react coming OUT of the corner, paying attention to HOW FAST the forks go back out to the extended position, when coming OUT of the corner, ROLLING ON THE GAS. 
Turn the forks rebound adjusters IN (2 click intervals) until the front of the bike wants to KEEP TURNING to the INSIDE of the corner, after the apex, when you are on the gas, trying to accellerate straight out. Having a very light grip on the bars helps to feel this.
Once you notice the front end wanting to turn MORE and LONGER than you want it to, STOP! Turn the rebound adjusters OUT (1 click intervals) until the front end comes out at a rate that you feel safe at.
WRITE DOWN THIS SETTING!!!

On the exact same corner, do the exact same thing with the fork rebound adjusters, but test how FAST you can safely stand the rebound being set at. 
Turn the adjuster OUT until the forks want to drift to the OUTSIDE of the corner, while exiting, ROLLING ON THE GAS. Test different settings to come to a conclusion about how FAST and how SLOW the rebound adjuster can be.
Find a bunch of closely spaced square edged bumps, usually braking bumps. The forks must rebound fast enough to absorb every bump, otherwise the forks will stick down in their travel, and pack. Set the rebound adjuster fast enough to work in this condition, but not so fast as to effect cornering!!!
WRITE DOWN THESE SETTINGS!! This is the range of rebound clicker adjustment which you will be using. Running a rebound setting out of this range will be DANGEROUS! Both forks must have the same setting.

Step 2: FORK LOW SPEED COMPRESSION. 
Ride the track and find a spot where there is some good sized, square edged bumps, braking bumps or whoops are ideal. Turn the compression adjusters IN until the forks get harsh, then go out a click. WRITE DOWN THIS SETTING.
Find the part of the track which will require the most bottoming resistance. Turn the compression adjusters OUT until slight bottoming is felt. WRITE DOWN THIS SETTING. You want your forks to bottom slightly on the worst bump, this means that you are using the maximum amount of travel, without being harsh.
WRITE DOWN THESE SETTINGS!! This is the usable range of compression clicker adjustment for your bike, for that track. Going out of this range, will result in poor/dangerous handling on that track. Both forks MUST be set at the same setting.

OIL LEVEL: Most forks have an certain amount of "compressable air space" in the top of the forks. This air space acts like an "extra spring". This is usually measured in millimeters, with the forks compressed, and the springs removed.
This "oil level" is adjustable. The more oil in the fork, the stiffer it will be in the last third of its travel, and the opposite with less oil. (More oil means less air space, the less air, the stiffer the "air spring" is). 
Most forks have an adjustable range around 80mm-140mm. CHECK YOUR MANUAL FOR YOUR SPECIFIC BIKE!!! and DO NOT ADD TO MUCH OIL!!
As a rule of thumb, 5mm in oil hight is the same as 5cc's, or 5 ml's.
Increase the oil level in 5mm increments untill the forks start to get harsh in the last third of their travel, then suck 5mm back out (with a syringe).
This effects the compression adjusters usable range. Test and adjust as required, as I said earlier.
WRITE DOWN YOUR OIL HIEGHT!!

STEP 3: SHOCK LOW SPEED REBOUND. 
This adjustment on most shocks is the REBOUND/COMPRESSION adjustment. Not just rebound. Therefore the rebound is set prior to the compression.
Ride through a good set of evenly spaced whoops. Turn the rebound adjuster IN until the shock "packs", then go out a click. WRITE DOWN THIS SETTING!
Packing is when the shock hasn't rebounded back to its fully extended length before hitting the next bump. This will feel like the shock is very stiff, and the rear ride height will squat on consecutive bumps. It will be more noticable at the END of a whoop section. 
Hit the same whoops, but test how FAST you can have the rebound. When the rebound is too fast it will be extremely obvious because the rear of the bike will start to swap from side to side. 
Once swapping occurs, go IN one click. WRITE DOWN THIS SETTING. 
This will be the usable range of shock rebound.

STEP 4: SHOCK LOW SPEED COMPRESSION: (for single adjuster shocks).
Find the same big square edged braking bumps you rode on to set up the fork's compression, and/or a good set of whoops. Turn the shock's compression clicker IN until a harsh feel is felt, then go out one click. WRITE DOWN THIS SETTING.
Find the same big bumps that required the most bottoming resistance when setting up the forks, and/or a good set of whoops. Turn the shocks compression clicker OUT until slight bottoming is felt, then go in one click. WRITE DOWN THIS SETTING.
This is the usable range of compression clicker adjustment for that bike, on that track. Test and find a happy compromise between both extremes, on all the suspenions adjusters. 
Note: The shocks rebound/compression adjuster setting will effect the bikes attitude in the air. If the shock is rebounding too slow, the bike will jump nose high. If the rebound is set too fast, the bike will jump nose low. Test and adjust as nessesary, without going out of the "safe" range. Perfectly shaped table tops or boubles (without kickers) are the ideal place to dial this in.

STEP 5: SHOCK HIGH SPEED COMPRESSION (for dual compression adjuster shocks only).
Adjust the low speed compression the exact same way as you would with a "single compression adjuster" shock. This is done with the high speed compression adjuster in the middle of it's range.
The high speed compression adjuster is a big aluminum nut, located AROUND the outside of the low speed compression adjuster. It can usually be turned easily with a 14mm or 17mm box end. It is adjusted in the same basic manor as your low speed compression. In is firm, out is soft. There is usually about 3-4 turns of an adjustment range. When this adjuster is at "full stiff", or "full soft", it only needs to be LIGHTLY SEATED!

Once your low speed compression is set correctly, you can then adjust the high speeed.
The high speed compression adjuster only works on a high speed impact. A high speed impact happens any time the rear shock gets a firm spike applied to it. Example: under or overshooting a jump, big hard whoops, nasty braking bumps, etc.
Note: the high speed adjuster has NOTHING to do with how many MPH the bike is moving!
Stupid Example: If you accidently dropped your bike out of the back your truck while you were loading it, and the rear wheel hit the ground hard, this would be considered a "high speed impact". A high speed impact can occur even without the rider on the bike. The MPH of the bike has NOTHING to do with how this adjuster is set.
This adjuster helps the rider balance the shock's high speed impact absorbing characteristics to the forks. Turn this adjuster in until the shock is obviously stiffer than the forks, in large whoops or anywhere the suspension's bottoming resistance could be tested. Turn the adjuster out in 1/4 turn increments until a nice balanced feel is achieved between the front and rear wheel.

Sand Setup

Always refer to "hardpack motocross" for basic set-up procedures, as that basic procedure will apply to every type of riding.
Go to www.racetech.com and check if you have the proper spring rates, if not, install the correct springs. Always refer to "SET-UP TIPS" before adjusting anything!

Step 1: FORK REBOUND
Start by setting the fork's rebound adjuster at the "slowest safe setting" that you came up with for your hardpack set-up. For sand riding, you are never going to be setting this adjuster FASTER than this setting! 
Set the adjuster using the same method you used for hardpack. Just make sure that your forks rebound fast enough to absorb the braking bumps on the track, and so the forks won't stay compressed after hitting the face of a jump, causing a "nose low" sensation in the air.

Step 2: FORK COMPRESSION
Start by setting your fork's compression adjuster to the "starting to get harsh" setting you have for hardpack. For sand riding, you are never going to be setting this adjuster SOFTER than this setting! Sand is very soft and springy. Sometimes it will require a surprisingly stiff compression clicker setting, depending on the type of sand you are racing in. 
Set the adjuster using the same method you used for hardpack. 
If you race in sand most of the time, it would be a great idea to get your suspension revalved for it, as stock supension valving is usually to soft. If not, your compression clickers will need to be so stiff to prevent bottoming, that harshness will become a major issue. You will have to test and see what works for you, and/or how much harshness you can stand...
You need to keep in mind that the compression adjuster adjusts the LOW SPEED DAMPING more than the HIGH SPEED DAMPING! If your adjuster is too stiff, your bike won't weight transfer properly during braking, and your bike won't squat enough on jump faces, both making the handling somewhat quirky and dangerous.

Step 3: SHOCK REBOUND
Start by setting the shock's rebound adjuster at the "slowest safe setting" that you came up with for your hardpack setup. For sand riding, you will never need to set this adjuster any FASTER than this setting.
Set this adjuster using the same method you used for hardpack. You will be surprized to see how slow the rebound needs to be to combat swapping in the whoops. Make sure the rebound isn't so slow that it makes the shock pack in the whoops, and make the bike jump "nose high".

Step 4: SHOCK COMPRESSION (single compression adjuster shock)
Start by setting the shock's compression adjuster at the "stiffest safe setting" that you came up with for your hardpack setup. For sand riding, you will never need to set this adjuster any SOFTER than this setting.
Keep in mind that this adjuster sets the LOW SPEED COMPRESSION. Set this adjuster using the same method you used for hardpack. Like setting the fork compression adjuster with stock valving, you will have to test and see how much harshness you can stand. A revalve is the only good option.

Step 5: SHOCK COMPRESSION (HIGH SPEED) IF APPL.
Adjust the low speed compression the same way as you would with a "single compression adjuster" shock. This is done with the high speed compression adjuster in the middle of it's range.
Like the hardpack procedure, turn this adjuster in until the shock is obviously stiffer than the forks. Large whoops or any place on the track that requires a fair bit of bottoming resistance is ideal. Turn the adjuster out in 1/4 turn increments until a nice balanced feel is achieved between the front and rear wheel.

Hope this helps ya to understand what the adjustments do.....

Cheers, Michael

 

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Does anyone have tips or tricks for a gentleman with air spring forks?

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On 6/4/2019 at 11:56 AM, Keebler750 said:

This is the nicest summary I've seen put together ANYWHERE. Nicely done!

I appreciate the feedback and am glad you enjoyed the article.

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On 6/4/2019 at 2:05 PM, Donny18 said:

Couldn't agree more.  Misinformation (or lack thereof) is the worst.  Especially so for someone trying to learn.  I'd love to see more articles like this on different topics.  Not too deep into the subject matter, just a brief summary with proper terminology.  Again, great job @Paul Olesen!

Thanks for the kind words. We'll definitely dive more into all of this in future posts. Stay tuned and subscribe to my blog if you haven't already done so!

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On 6/5/2019 at 6:55 AM, Gabes1 said:

Very informative. Thanks.

You're welcome, happy to help.

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