fasterz
01-04-2005, 09:57 AM
i had to write this paper for school and thought it was pretty informative so i figured id post it here and if you think its good mabey it can get moved to the FAQ section since there are always so many questions on the topic. feel free to add any thing missed.
There are many parts on vehicles. One of the most important is the front end and how it is set up. Stock front ends are very limiting but an aftermarket front end has unlimited adjustment possibilities. There are four mains parts that need to be adjusted. The adjustments are camber, caster, toe in/out, and suspension adjustments. Geometry is so crucial with any front end that any slight adjustment will dramatically change the handling characteristics. Different set ups are used for different terrains and also vary for rider preference.
Stock suspension adjustment is very limited but with top of the line aftermarket shocks, adjustment possibilities are almost endless. There are three adjustments: compression, rebound, and ride height. The compression adjustment will differ from track to track. The adjustment is made on a knob either on the top of the shock or on the reservoir. First, set the compression half way out. Next, go out on the track and ride hard. If the shock bottoms out with a slam then turn the compression knob clockwise to slow it down or vice versa if they are too stiff. You will want the shocks to bottom out lightly once on the track to ensure you are using all possible shock travel. The rebound adjustment controls how fast the shock “rebounds” or returns to its original position from a compressed position. This can be slowed down or sped up via either a knob on the bottom of the shock or a flat head screw. Too slow of a rebound will cause the shock to “pack up,” which means eventually the shock will be riding totally bottomed out. Too fast of a rebound will cause a pogo stick like condition where the vehicle will bounce after coming in contact with a bump. Ride height is an important but often overlooked adjustment; it will vary in different terrains. Lower ride height will increase the handling because of a lower center of gravity but will also bottom out more due to the chassis being closer to the ground. A higher ride height will give the advantage of more ground clearance but will also affect handling negatively since it raises the center of gravity. Ride height adjustment is made by a locking ring located above the top spring. Shocks are one of the most important and technical parts of the front end and should not be overlooked.
Camber is an adjustment made on the control arm, also known as the a-arm. Camber is the amount of degrees that the tire and wheel are tilted in or out at the top
in relation to the bottom of the tire. A wheel that is tilted in at the top and out at the bottom is said to have negative camber. The farther it angles out at the bottom the greater the amount of negative camber. For positive camber the top of the tire is farther out than the bottom. The reason for having camber in your front end is because the suspension is forced over in a corner and the tire flexes. With everything in motion, all this force wants to flex the tire more upright which reduces the amount of negative camber. As the corner is entered, the forces tend to bend everything over, adding positive camber. When the tire is set at negative camber, it hits the turn and bends towards positive so it will be perfectly straight while in the corner. Rest a straight edge against the outside of your front tire. Make sure both wheels are pointing straight and you are touching the same part of the tire, top and bottom to set the camber. The top of the straight edge should lean inward for negative camber. Now, put an angle finder against the straight edge and note the reading. If you need more or less camber, you are going to have to take off one of the ball joints to adjust it. Removing or adjusting the ball joints or heim joints can be done by, first removing the castle nut, and cotter pin then take off the joint. Then hit the side of the spindle right where the ball joint goes through the spindle to make the ball joint loose. It will take some pressure to remove it, and it helps if you lift up the arm itself as your hitting the spindle. On arms with spherical bearing joints it is not necessary to remove the joint from the spindle since there is a bolt on the bottom of the king pin that only needs to be removed to spin the joint for adjustment. For more negative camber, turn the upper ball joint into the a-arm. The recommended camber for different situations are: 4.5° for motocross, 4.5° for cross country, 2-4° for sand dunes, and 1-3° for recreational. Camber is usually set to extreme and people end up taking away their potential handling abilities.
The toe of an ATV measures the relation of the leading edge of the front tires to the back of the front tires. “Toe out” is when the front of the tires point out. “Toe in” is when the front of the tires point in. It is recommended to set the toe-in to 1/8th of an inch. So you will need is a tape measure. Make sure the handlebars are straight, then make sure both tires are pointing straight forward. To do this, measure from the inside of one tire to a point on the chassis. Write down the distance as you will need it in a later step. Then on the other side, measure from the exact same points as you did on the previous side. These measurements need to be exactly the same so that you know your tires are pointed the same. Adjust the tie rods so that this measurement is the same. Now that you're sure the tires are the same distance apart, you need to measure for the toe in. On the front of the tire about half way up, place one end of the tape measure on the inside of the tire and take a measurement from the same point on the other tire. Write down this measurement also. Then repeat this for the rear of the front tire, the same height from the ground as you did on the front, and make a note of this measurement. The front measurement needs to be a 1/8 of an inch less than the rear measurement. Adjust the tie rods so that you achieve this measurement. Remember to count how many times you rotate the tie rod. Then rotate the other side the same distance, so you can keep the tires going straight ahead, then take your measurements. One full turn on both tie rods will change the toe about 1/8th of an inch. Make sure to completely tighten all nuts and bolts on the tie rods and tie rod ends, install the cotter pins and grease the joints. Most people chose to leave camber alone and keep it set at the manufacturer’s setting since they initially set it for your riding style.
Caster is the amount of angle that the spindle has in relation to the vertical middle of the wheel. If the upper ball joint is farther forward than the lower ball joint, it has negative caster. If the upper ball joint is farther to the back than the lower ball joint, it has positive caster. The greater the amount of positive caster, the more stable the ATV will be at high speed. The less positive caster it has, the easier it will steer and the quicker it will turn. As the spindle is laid back, the tire has to lay over more when the front tires are turned. This adds stability. If there is not much angle, the wheel will turn more, making it quicker and easier to turn. Rest a straight edge against the side edge of the upper and lower ball joint threads. Make sure the straight edge is touching the same section of the ball joint threads. If the top of the straight edge leans towards the rear of your quad, you have positive caster. This is what you want. Rest the angle finder on the edge of the straight edge. This will tell you the exact caster setting. You may need to adjust the rod ends by turning one in or out more than the other to get the appropriate setting. The recommended caster for different situations are: 4° for motocross, 3° for cross country, 1-3° for sand dunes, and 1-3° for recreational.
Setting up a front end is time consuming and very frustrating. Many people opt to just throw it on. They figure if it works, then it’s fine. They will find after adjusting it that there is a huge difference and get their money’s worth out of it. Costs for a front end vary greatly all depending on how many options you want and how high of a quality the products are. The cost is also affected by the name. A front end made by a small company out of a garage is going to cost less then one that is precisely machined in a high tech machine shop. Its also best to get the best first instead of skimping out and having to get the good one later down the road. The adjustments are not hard to be made the hardest part is finding the setting that is right for your riding style and your wants for handling characteristics.
There are many parts on vehicles. One of the most important is the front end and how it is set up. Stock front ends are very limiting but an aftermarket front end has unlimited adjustment possibilities. There are four mains parts that need to be adjusted. The adjustments are camber, caster, toe in/out, and suspension adjustments. Geometry is so crucial with any front end that any slight adjustment will dramatically change the handling characteristics. Different set ups are used for different terrains and also vary for rider preference.
Stock suspension adjustment is very limited but with top of the line aftermarket shocks, adjustment possibilities are almost endless. There are three adjustments: compression, rebound, and ride height. The compression adjustment will differ from track to track. The adjustment is made on a knob either on the top of the shock or on the reservoir. First, set the compression half way out. Next, go out on the track and ride hard. If the shock bottoms out with a slam then turn the compression knob clockwise to slow it down or vice versa if they are too stiff. You will want the shocks to bottom out lightly once on the track to ensure you are using all possible shock travel. The rebound adjustment controls how fast the shock “rebounds” or returns to its original position from a compressed position. This can be slowed down or sped up via either a knob on the bottom of the shock or a flat head screw. Too slow of a rebound will cause the shock to “pack up,” which means eventually the shock will be riding totally bottomed out. Too fast of a rebound will cause a pogo stick like condition where the vehicle will bounce after coming in contact with a bump. Ride height is an important but often overlooked adjustment; it will vary in different terrains. Lower ride height will increase the handling because of a lower center of gravity but will also bottom out more due to the chassis being closer to the ground. A higher ride height will give the advantage of more ground clearance but will also affect handling negatively since it raises the center of gravity. Ride height adjustment is made by a locking ring located above the top spring. Shocks are one of the most important and technical parts of the front end and should not be overlooked.
Camber is an adjustment made on the control arm, also known as the a-arm. Camber is the amount of degrees that the tire and wheel are tilted in or out at the top
in relation to the bottom of the tire. A wheel that is tilted in at the top and out at the bottom is said to have negative camber. The farther it angles out at the bottom the greater the amount of negative camber. For positive camber the top of the tire is farther out than the bottom. The reason for having camber in your front end is because the suspension is forced over in a corner and the tire flexes. With everything in motion, all this force wants to flex the tire more upright which reduces the amount of negative camber. As the corner is entered, the forces tend to bend everything over, adding positive camber. When the tire is set at negative camber, it hits the turn and bends towards positive so it will be perfectly straight while in the corner. Rest a straight edge against the outside of your front tire. Make sure both wheels are pointing straight and you are touching the same part of the tire, top and bottom to set the camber. The top of the straight edge should lean inward for negative camber. Now, put an angle finder against the straight edge and note the reading. If you need more or less camber, you are going to have to take off one of the ball joints to adjust it. Removing or adjusting the ball joints or heim joints can be done by, first removing the castle nut, and cotter pin then take off the joint. Then hit the side of the spindle right where the ball joint goes through the spindle to make the ball joint loose. It will take some pressure to remove it, and it helps if you lift up the arm itself as your hitting the spindle. On arms with spherical bearing joints it is not necessary to remove the joint from the spindle since there is a bolt on the bottom of the king pin that only needs to be removed to spin the joint for adjustment. For more negative camber, turn the upper ball joint into the a-arm. The recommended camber for different situations are: 4.5° for motocross, 4.5° for cross country, 2-4° for sand dunes, and 1-3° for recreational. Camber is usually set to extreme and people end up taking away their potential handling abilities.
The toe of an ATV measures the relation of the leading edge of the front tires to the back of the front tires. “Toe out” is when the front of the tires point out. “Toe in” is when the front of the tires point in. It is recommended to set the toe-in to 1/8th of an inch. So you will need is a tape measure. Make sure the handlebars are straight, then make sure both tires are pointing straight forward. To do this, measure from the inside of one tire to a point on the chassis. Write down the distance as you will need it in a later step. Then on the other side, measure from the exact same points as you did on the previous side. These measurements need to be exactly the same so that you know your tires are pointed the same. Adjust the tie rods so that this measurement is the same. Now that you're sure the tires are the same distance apart, you need to measure for the toe in. On the front of the tire about half way up, place one end of the tape measure on the inside of the tire and take a measurement from the same point on the other tire. Write down this measurement also. Then repeat this for the rear of the front tire, the same height from the ground as you did on the front, and make a note of this measurement. The front measurement needs to be a 1/8 of an inch less than the rear measurement. Adjust the tie rods so that you achieve this measurement. Remember to count how many times you rotate the tie rod. Then rotate the other side the same distance, so you can keep the tires going straight ahead, then take your measurements. One full turn on both tie rods will change the toe about 1/8th of an inch. Make sure to completely tighten all nuts and bolts on the tie rods and tie rod ends, install the cotter pins and grease the joints. Most people chose to leave camber alone and keep it set at the manufacturer’s setting since they initially set it for your riding style.
Caster is the amount of angle that the spindle has in relation to the vertical middle of the wheel. If the upper ball joint is farther forward than the lower ball joint, it has negative caster. If the upper ball joint is farther to the back than the lower ball joint, it has positive caster. The greater the amount of positive caster, the more stable the ATV will be at high speed. The less positive caster it has, the easier it will steer and the quicker it will turn. As the spindle is laid back, the tire has to lay over more when the front tires are turned. This adds stability. If there is not much angle, the wheel will turn more, making it quicker and easier to turn. Rest a straight edge against the side edge of the upper and lower ball joint threads. Make sure the straight edge is touching the same section of the ball joint threads. If the top of the straight edge leans towards the rear of your quad, you have positive caster. This is what you want. Rest the angle finder on the edge of the straight edge. This will tell you the exact caster setting. You may need to adjust the rod ends by turning one in or out more than the other to get the appropriate setting. The recommended caster for different situations are: 4° for motocross, 3° for cross country, 1-3° for sand dunes, and 1-3° for recreational.
Setting up a front end is time consuming and very frustrating. Many people opt to just throw it on. They figure if it works, then it’s fine. They will find after adjusting it that there is a huge difference and get their money’s worth out of it. Costs for a front end vary greatly all depending on how many options you want and how high of a quality the products are. The cost is also affected by the name. A front end made by a small company out of a garage is going to cost less then one that is precisely machined in a high tech machine shop. Its also best to get the best first instead of skimping out and having to get the good one later down the road. The adjustments are not hard to be made the hardest part is finding the setting that is right for your riding style and your wants for handling characteristics.