Setup & Suspension Design

Setup Tips

Below you will find setup tips for ride height settings, camber settings, and toe settings:

Ride Height:

Always set Ride Height first!

You will need two people to do this.

The following is a suggested starting point for setting your ride height.

1. Try to find a level concrete floor.

2. Make sure you have the correct tire size and tire pressure on all four tires that you will be riding/racing with.

3. Put on all your protective/riding gear on and sit on the quad in normal riding position.

4. Have someone push and hold down on the front bumper while you turn the bars left and right a few times (This lets the front-end settle down where it should be)

5. Stand up and bounce up and down a few times to work the suspension in and then sit back in normal riding position.

6. Have someone measure at the bottom of the frame by the foot pegs to the ground and write that number down.

7. Go forward 20 inches from the pegs and measure again from the bottom of the frame to the ground and write that number down.

8. Take the two numbers and refer to our chart below to see if you are within our guidelines.  Please take in consideration that the higher the front is than the rear the more rear wheel traction you will get but if you get the front too high you will notice that the front will start pushing towards the outside of a turn.

Below is also an example:

Say at the foot pegs your measurement is 7″
Then your front measurment is 7 1/4″
So your front is 1/4″ higher than the rear so you have a 1/4″ of rake. (You never want the rear higher than the front!)

Below is a good starting point on your ride height for each quad:

TRX450R

XC – 7″ at pegs and 7 1/8″ at front measurement + or – 1/4″ (Standard Travel setups may run a little higher)

MX – 6 1/4″ at pegs and 6 3/8″ at front measurment + or – 1/2″ (Standard Travel setups may run a little higher)

TT – 5 1/2″ at pegs and 5 5/8″ at front measurement + or – 1/2″

Desert – 7 1/2″ at pegs and 7 5/8″ at front measurment + or – 1/2″

KFX450R

XC – 7″ at pegs and 7 1/8″ at front measurement + or – 1/4″ (Standard Travel setups may run a little higher)

MX – 6 1/4″ at pegs and 6 3/8″ at front measurment + or – 1/4″ (Standard Travel setups may run a little higher)

TT – 5 1/2″ at pegs and 5 5/8″ at front measurement + or – 1/2″

Desert – 7 1/2″ at pegs and 7 5/8″ at front measurment + or – 1/2″

LTR450R

XC – 7″ at pegs and 7 1/8″ at front measurement + or – 1/4″ (Standard Travel setups may run a little higher)

MX – 6 1/4″ at pegs and 6 3/8″ at front measurment + or – 1/4″ (Standard Travel setups may run a little higher)

TT – 5 1/2″ at pegs and 5 5/8″ at front measurement + or – 1/2″

Desert – 7 1/2″ at pegs and 7 5/8″ at front measurment + or – 1/2″

KTM450/525

XC – 7″ at pegs and 7 1/8″ at front measurement + or – 1/4″ (Standard Travel setups may run a little higher)

MX – 6 1/4″ at pegs and 6 3/8″ at front measurment + or – 1/4″ (Standard Travel setups may run a little higher)

TT – 5 1/2″ at pegs and 5 5/8″ at front measurement + or – 1/2″

Desert – 7 1/2″ at pegs and 7 5/8″ at front measurment + or – 1/2″

YFZ450, YFZ450R/X

XC – 7″ at pegs and 7 3/8″ at front measurement + or – 1/4″ (Standard Travel setups may run a little higher)

MX – 6 1/4″ at pegs and 6 5/8″ at front measurment + or – 1/4″ (Standard Travel setups may run a little higher)

TT – 5 1/2″ at pegs and 5 5/8″ at front measurement + or – 1/2″

Desert – 7 1/2″ at pegs and 7 7/8″ at front measurment + or – 1/2″

Tips on different track conditions:

Muddy races with tacky mud that sticks to the quad run a higher ride height and a little more compression damping.
Sandy whooped out tracks run higher ride height with more compression damping so you will not bottom as much and that will also help with swapping and kicking.

These measurements are just starting points everybody has their preferences some make like it higher or lower and some might like more or less rake so you will have to find out what works for you!

Camber Settings:

Camber is not adjustable with most stock a-arms but it is on most aftermarket a-arms.

Note: Always set camber first because this WILL change toe, if at some point camber is adjusted, you must go back and re-adjust toe!

The following is a suggested starting point for setting your camber:

Set Camber with no rider aboard

1. First take two tie-downs and hook from the handlebar grips to the grab bar or foot pegs and tie the bars down to where they feel straight to you.  Once this is complete, you don’t have to worry keeping the bars straight.

2. Take a L square and butt it up against the sidewall of the front tire in the center of the axle.

3. Measure the gap at the top from the sidewall of the tire to the edge of the square (pay attention to the raised lettering on the sidewalls, this can mess you up on your measurements).

4. You want the top of the tire leaning in towards the chassis between 1/8″ to up to 1/2″.  If this measurement is off then you will need to adjust the upper ball joint in or out until you reach 1/8″ to 1/2″ and make sure both sides are equal.

Again these settings are rider preference and vary for different front-ends and type of riding.

Below are our suggested starting points for different types of riding/racing:

XC/Desert – 1/8 to 1/4″ all models
MX/TT – 1/8″ to 1/2″ all models

Toe In Settings:

The following is a suggested starting point for setting your Toe In:

Set Toe In with no rider aboard.

You will need two people to do this.

1. First take two tie-downs and hook from the handlebar grips to the grab bar or foot pegs and tie the bars down to where they feel straight to you.  Once this is complete, you don’t have to worry keeping the bars straight.

2. Find a straight edge that is long enough to go from the rear sidewall of the rear tire to the front sidewall of the front tire.

3. One person holding the straight edge at the rear of the quad, butt it up against both the front and rear sidewalls of the rear tire at the center of the front and rear axles (The other person is holding the other end of the straight edge at the front tire).  The straight edge should not be touching the sidewalls of the front tire (Rear should be wider than the front, if not use a two by four and put it against the sidewalls of the rear tire and put the straight edge on top of the two by four using it as a spacer).

4. Measure the gap from the rear sidewall of the front tire to the straight edge, and measure the gap from the front sidewall of the front tire to the straight edge and subtract the two measurements and that is how much toe in you have.

Note: Again when doing this pay attention to the raised lettering on the sidewalls, this can mess you up on your measurements.

For example:

If the rear sidewall measurement on the front tire is 1″ and the front measurement is 1 1/4″ then you have a 1/4″ of toe in, if the rear sidewall measures 1″ and the front measurement is 3/4″ then you have 1/4″ toe out.

5. You want to always have toe in not toe out!  You will always want to have between 1/8″ and 1/4″ of toe in.  If this measurement is off then you will need to adjust the tie rods in or out until you reach 1/8″ to 1/4″ of toe in, and make sure both sides are equal.

Again these settings are rider preference and vary for different front-ends and type of riding.

I know some of this is going to be hard to understand, we will be adding some pictures soon that will help you understand all of our measuring points and how we do things so check back often!  Also if you have any questions about setups please feel free to contact us.

Coming soon – Tips on adjusting air pressures for air shocks, compression adjusters, rebound adjusters, and so much more! 

 

Suspension Design

Having the right spring(s) and motion ratio is a very critical part of any suspension system. The spring(s) resist the forces of input from the ground to the chassis, the suspensions motion ratio determines how the spring(s) will operate, and the shock controls the spring’s reaction to those inputs. Obtaining a desired leverage curve and spring combination is the starting point of building a suspension system in relationship to the shock. To understand how a shock works in relationship with how a suspension system works, you need to know a little bit about motion ratios, spring rates, and shock damping.

Springs

Most of the springs you will see are straight rate or linear compression springs. Linear means that there is a constant progression of force in relationship to compression movement. For example: a linear spring with a rate of 300 lbs. means that it takes 300 lbs of force to compress that spring one inch.

(1 inch = 300, 2 inches = 600, 3 inches = 900, etc…)

With a dual rate spring combination you have two springs stacked on top of each other and they are compressed simultaneously. Because both are moving at the same time, it takes less force to compress both springs one inch. For example: when you compress two linear 200 lb springs stacked on top of each other for one inch, both springs are going to yield a linear rate of 100 lbs. Both of the 200 lb springs will have compressed ½” or .50”. By multiplying the spring movement .50 by the spring rate 200 lbs., it will give you the working spring rate (200 X .50 = 100).

The main purpose for using a dual rate spring combination is to enhance the progression of the chassis’ motion ratio. A dual rate spring stack consists of two springs, a shorter tender spring on top and a longer main spring on the bottom. This progressive rate system is used to produce a lighter initial spring rate for a desirable lower ride height as well as providing a smooth, supple ride over small surface irregularities. Then, at a determined point in the shaft travel, via the tender crossover height, the tender spring stops working and the initial rate then crosses over to the stiffer rate of the main spring. This progression to the stiffer rate is used to prevent harsh bottoming during high speed input, such as jumps or whoops, and also to prevent excessive chassis roll.

The important thing to remember is that springs are resistance poundage. It takes a given amount of preload poundage to establish a desired ride height, a given amount of spring poundage to prevent chassis roll and a given amount of spring poundage to prevent extreme bottoming.

Tender Spring Crossover

Tender spring crossover height is directly related to chassis roll and bottom out forces. Changing the tender spring crossover height is the most significant handling change that you can make, using the shock’s external adjustments. The crossover height moves the dual spring rate’s point of progression in relationship to the shaft travel and motion ratio. Increasing the crossover height decreases the tender spring travel, making the main spring crossover sooner in the wheel travel, providing stiffer spring poundage for more spring resistance during chassis roll and bottoming. Decreasing crossover height increases tender spring travel, making the main spring crossover later in the wheel travel, resulting in less spring poundage for softer spring resistance during chassis roll and bottoming.

Static Preload

Static preload is the amount of spring poundage your shock has in fully extended condition. Basically it’s how much the spring or springs are compressed when installed on the shock. Example, you put a 300 lb spring on your rear shock and the spring has a free length of 10 inches before installation. After installation, you measure the spring again with the shock fully extended, and the compressed length is now 9.75 inches (10” – 9.75 = .25” of spring preload). Then multiply the spring preload by the spring rate and that will give you static preload (300 lbs X .25 = 75 lbs of static preload)

The main purpose of static preload is to raise or lower the vehicles ride height by means of adding or subtracting spring preload poundage. Never add preload to prevent excessive chassis roll and bottoming.

Damping

The function of shock damping is to control the spring’s reaction to input. This is done with the compression piston. It is attached to the end of the shock shaft inside the shock body. The piston has passages that allow the shock fluid to flow from one side of the piston to the other. On either sides of the piston there are tuning shims or Valving shims stacked to control the fluid flow. When the shock is compressed it is forcing the fluid through the passages and has to push open the compression shims. When the shock extends back the fluid is forced through the rebound shims. You can tune the shock’s compression and rebound with the Valving shims using different shim thicknesses and diameters. Too much compression damping will give you a harsh ride, and too little compression damping will allow the shock to blow through the Valving and bottom too easy. Too much rebound Valving will make the shock recover too slow and cause a packing problem. (Shock will not recover quickly enough for the next bump) Too little rebound Valving will cause the shock to recover too fast and kick up or dance around.

There are a few different Valving stacks that you will see in different shocks. You have a single stage tapered stack, two stage tapered stack, and a three stage tapered stack. With the two and three stage stacks you have more control over the oil flow. On a single stack the shims are considered high speed Valving, on two stage Valving you have a low speed shim stack and a high speed shim stack, and on a three stage stack you have a low speed stack, a mid speed stack, and a high speed stack. The low speed stack will control low shaft speeds. Example hitting the takeoff face of a jump makes the shock compress slow and progressively that is controlled with the low speed Valving. The mid speed stack will control little larger forces to the suspension making it a little more progressive. The High speed stack will control the harder hits like flat landing a jump or roots and rocks, basically anything that makes the shock shaft move at high speeds. With the different stages of Valving the damping is progressive just like the multiple spring setups. The single stage Valving is similar to a single spring, the two stage Valving is similar to a dual rate spring, and the three stage Valving is similar to a triple rate spring setup.

Below are diagrams of each stage of valving.

 

 

 

 

Motion Ratios

The motion ratio or “Leverage Ratio” is the path the shock goes through its travel in relationship to wheel travel. This is determined by the type of suspension hardware arrangement and geometry that the chassis manufacture decides to use. The most commonly used suspension hardware is either a linkage type or a no-link type. Linkage systems generally use less space to operate where no-links have to have more space to operate. I.e. (Airbox clearance)

Obtain Leverage Ratio:

1. Set your bike on a stand and level the bottom of the chassis with a level.

2. Using the front as an example, you will need to take off your shock a tire.

3. Measure the shocks free length eye to eye. Write it down.

4. Block up the spindle to where the distance between the center of the upper shock mount and the center of the lower shock mount equals that of your shock’s free length.

5. Measure from the center of the spindle to the ground. Write it down.

6. Block up the spindle to where the distance between the center of the upper shock mount and the center of the lower shock mount equals that of your shock’s compressed length. (Compressed length = free length minus shaft travel.) DO NOT subtract for the bottom out bumper. Measure the full length of the shaft.

7. Measure from the center of the spindle to the ground. Write it down. The difference between the two shock mount measurements and the difference between the two spindle measurements is your “leverage ratio”. For example if your shock has 4.75 inches of shaft travel and you measured 9 inches of spindle movement, your leverage ratio would equal 1.89.

To Find Preload Poundage:

1. Put the shock in the vise and remove the lower spring retainer.

2. Measure the “relaxed combined” spring assembly. (The springs and dividers only. Do not measure the spring retainer or preload ring.)

3. Put the lower spring retainer back on and measure again. The difference is your spring preload.

4. Multiply your preload by your combined spring rate and that is your beginning poundage. Write it down. (Example: .25 in X 80 lb. Spring rate = 20 lbs. of preload)

Spring Rate Formula

To rate an unknown spring:

11,500,000 x (wire diameter) to the 4th power

8 x (ID and wire diameter) cubed X active coils

Example: wire diameter = .362; ID = 2.575; active coils = 9.2

Your rate is 105.9

Stacked Spring Rate Formula

To figure the combined rate using multiple springs:

The formula for two springs is: 1/K + 1/K2 = 1/K3

The formula for three springs is: 1/K + 1/K2 + 1/K3 = 1/K4

K=Spring Rate

Example: You have a 80 lb tender and a 370 lb Main spring combination

1 divided by 80 + 1 divided by 370 = 1 divided by K3

Kt = 65.8 lbs

We hope that this information will be helpful to everyone. If you have any questions on any of this material please feel free to contact me at anytime.

Thanks,

Santo DeRisi


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