Wildcat Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
3,231 Posts
Discussion Starter · #1 ·
Here is a little something I typed up to help the numerous questions on suspension

HOW SHOCKS WORK/TUNING SHOCKS

First is the Spring. The spring is categorized as spring rate. Spring rate in most cases is measured in lbs/in. So how much force it takes to compress that spring in 1”. So if you have 100 lb/in spring, that means it takes 100lbs to compress it 1”.So what does it take to compress a 100 lb/in spring 2”? 200 lbs. 3”? 300lbs. This is called “spring rate.” However, progressive and dual/triple-rate springs differ vastly.

If you were to put 2 100 lb/in springs on top of the other one then this would cause a softer initial rate. In this case since its 100 lb springs we are using, then ur rate is actually 50lbs/in until one fully compresses and acts like a solid (or if you have a crossover to lock it out, ill explain later.) Once one spring is either locked out or fully compressed, then the secondary will retain its true rate of 100 lbs/in. Manufacturers can get a softer initial ride from progressive or multi-rate springs while retaining bottoming resistance further down in the stroke.

The second is damping. Damping is does not vary according to stroke position like the springs do as mentioned earlier. Unlike springs, damping is usually unrelated to the shock’s stroke position. The deeper the spring is compressed in the stroke, the more force is created. Damping of the shock only comes into play with velocity of the shock shaft via shim stacks, and piston.when a wheel hits a bump, the compression of the shock through its stroke forces shock fluid through the piston and around the shim stack and controls compression and rebound. Think of the force of water exiting a synringe. When you push a large syringe quickly and hard it has resistance based on the exit of the syringe causing damping effect. If there were holes in the syringe pusher then the syringe would move easier, less resistance, less compression. Anytime the holes in the shock piston are made smaller, the fluid is moving at a slower rate causing the shock to become stiffer. Now back with the syringe, bigger the holes, faster the fluid, lesser the compression. Think of it this way: the spring controls the ride height and stiffness, but the damping controls how quickly the suspension can move through its range of motion. This is where we get the adjustments from.

WHAT THE CLICKERS DO

COMPRESSION
In the shock, between the reservoir and the body, there are ports that the oil must flow through when the shock is compressed. The term “valving” is based off internal valving using shim stacks in conjunction with a shock piston. This valving can be tuned using large steel washer that very in strength and vary in diameter, all giving different effect to the shock.One of the most import shims within that stack, and definitely the smallest of the shims is called the “crimp” shim. The crimp shim is the shim that the other shims “BEND” around when the shock is being compressed. The smallest valve shim is called the “crimp,” and it is the shim which all the other shims bend around when the shock is compressed. Valving is complicated; we could talk for days. Just think of it as, bigger the shims, less room for oil to flow. Increasing compression and exact opposite for smaller shims.
Compression adjusters can only adjust 20-30% away from the internal base valving as mentioned earlier.You have 3 different clickers on top tier shocks. On most OEM offered shocks you have 1 clicker. In the premium shocks with 3 clickers, you have Hi speed compression, lo speed compression and rebound. Don’t be confused with the names and base it off vehicle speed. It is shock shaft speed. On single adjustable shocks, the compression adjuster is pretty much low speed compression while hi speed is internally fixed via piston design and shim stacks. Hi speed adjuster is used for quick hits, like jump landings, G-outs and big holes/whoops. The high-speed compression adjuster is a large port with a preloaded spring inside and is attached to a beveled stop at the end of the port. So another words, the shock compresses extremely fast forcing lots of oil quickly. This force will push the stop out of the way which allows the small internal spring to compress which allows the oil to be pushed into the reservoir. The tighter you make the high-speed adjuster by turning it inward, the more spring tension is placed on the stop, requiring more force to move it out of the way to bypass the oil. The slow speed adjust port is a lot smaller. The oil flow is also controlled in a different manner. Flow is controlled by a tapered needle that is inside a port. When the adjuster is turned in the softer direction, the needle is backee away from the port more fluid can then pass into the reservoir at low shaft speeds potentially bypassing the valve stack.
Low-speed controls body roll and slow elevation changes, like shallow, rolling G-outs. Tightening up low-speed compression will reduce the machine’s tendency to dive and squat under acceleration and braking by slowing shock-shaft movement.

REBOUND
Rebound is compression, except in reverse pretty much. Rebound limits shock speeds just like like compression does except it limits the shocks return after being compressed. If you have no rebound dampening, the shock will extend itself extremely quick which can cause a bucking motion because the springs energy is not being controlled. Rebound clickers (if fully adjustable shocks) are located on the bottom of the shock near the bottom of the shaft. Rebound oil flows through a port on the shaft itself and circulates back into the body above the stack and piston.Rebound works very much like compression, but it limits the shock’s speed when it extends after being compressed.
Rebound adjusters use a needle-port design,however they allow back flow unless a check valve is used. On most shocks, when you stiffen your rebound or known as slow ur rebound down, it will also slightly stiffen ur lo speed. I know JRI uses completely different circuits.

SPRING
Your spring’s stiffness and preload affect the ride and ride height. There are many options available for springs. You can use a single-rate spring that is preloaded, a zero-preload setup that uses a small “top-out” spring just to keep the springs in place when the shock is fully extended, a progressive-wound single spring that changes rate depending on its position, dual-rate springs that offer different stages of stiffness during the stroke, or even triple- or quad-rated springs. Multi-rate spring setups are used to control stiffness during different parts of the stroke using crossovers, which are solid pieces of material that change when the springs come into effect in the shock’s stroke. Again, for simplicity, we will use single-rate springs for our examples.
Preload is the measure of how much tension is placed on the spring when the shock is fully extended.

Bottoming out?
– Increase spring rate
– Increase preload on same spring
– Increase compression dampening
Too much body roll?
– Increase preload on spring
– Increase spring rate
– Install aftermarket swaybar(s)
Rear end kicking up higher than the front over bumps or jumps?
– Increase rear shock’s rebound dampening
– Reduce rear shock preload
– Decrease rear spring rate
– Decrease front shock’s rebound dampening
– Increase front shock’s compression dampening
– Increase preload on front shocks
– Increase spring rate on front shocks
Front end pushing through corners?
– Reduce front shock’s preload
– Reduce front shock’s compression dampening
– Reduce front shock’s spring rate
– Raise air pressure in rear tires
– Stiffen rear
– Make sure your swaybars are in working order


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
2,296 Posts
I just hauled the shocks off my Trail beater, Ugly Betty and revalved them. Had a bit to much kick in the rear and it bottomed a touch to easy. I added shim to the middle of the stack on the rebound side and a shim at the start of the compression stack, made a huge difference and while it isn't snow cross valving it certainly tightened the rear up a lot. Fronts are getting it next week when I get the nitrogen bottle refilled. Great post by the way, good guide for set up issues!
 

·
Registered
Joined
·
1,929 Posts
Great write up and info!
 

·
Premium Member
Joined
·
3,783 Posts
Great post!! You wrote it so that I could even understand what you meant. I like how you put everything in layman's terms, so the average person can use this to adjust their shocks. Thanks!!
 

·
Administrator
Joined
·
28,031 Posts
Great write up. Made it a sticky.
 
  • Like
Reactions: 16foxracing16

·
Registered
Joined
·
1,125 Posts
Great job!
How does Nitrogen PSI come into play? FOX has said the RC2 spec is just 75psi for the Cat while I believe it's twice that for the RZR.
 

·
Registered
Joined
·
3,231 Posts
Discussion Starter · #8 ·
Most of the time nitrogen isn't used for tuning. It's set to spec and tuned with other methods. Every shock and every application will have their own spec on nitrogen, shock oil type, and shock oil amount. Etc


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
166 Posts
Nice writeup! I know that your summary was intended to be "shock 101", but let me add that some companies who build shocks for off road motorcycles use "position sensitive damping" for resistance to bottoming and control under extreme conditions (Fox and WP-KTM have patents). I'm courious if other shock manufacturers incorporate something similar, especially in the world of 4-wheel off road racing?
 

·
Premium Member
Joined
·
1,243 Posts
That was an excellent write up......will need to read it about 3 more times lol for it to sink in. Helped me out a lot. Thanks for
sharing.
 

·
Registered
Joined
·
3,231 Posts
Discussion Starter · #11 ·
Nice writeup! I know that your summary was intended to be "shock 101", but let me add that some companies who build shocks for off road motorcycles use "position sensitive damping" for resistance to bottoming and control under extreme conditions (Fox and WP-KTM have patents). I'm courious if other shock manufacturers incorporate something similar, especially in the world of 4-wheel off road racing?
Yes I believe the new yxz SS SE shocks may have it. And that technology is so super simple but so dang complex and smart lol. I still have more I need to add. Just need he time.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
5,210 Posts
Here is a little something I typed up to help the numerous questions on suspension

HOW SHOCKS WORK/TUNING SHOCKS

First is the Spring. The spring is categorized as spring rate. Spring rate in most cases is measured in lbs/in. So how much force it takes to compress that spring in 1”. So if you have 100 lb/in spring, that means it takes 100lbs to compress it 1”.So what does it take to compress a 100 lb/in spring 2”? 200 lbs. 3”? 300lbs. This is called “spring rate.” However, progressive and dual/triple-rate springs differ vastly.

If you were to put 2 100 lb/in springs on top of the other one then this would cause a softer initial rate. In this case since its 100 lb springs we are using, then ur rate is actually 50lbs/in until one fully compresses and acts like a solid (or if you have a crossover to lock it out, ill explain later.) Once one spring is either locked out or fully compressed, then the secondary will retain its true rate of 100 lbs/in. Manufacturers can get a softer initial ride from progressive or multi-rate springs while retaining bottoming resistance further down in the stroke.

The second is damping. Damping is does not vary according to stroke position like the springs do as mentioned earlier. Unlike springs, damping is usually unrelated to the shock’s stroke position. The deeper the spring is compressed in the stroke, the more force is created. Damping of the shock only comes into play with velocity of the shock shaft via shim stacks, and piston.when a wheel hits a bump, the compression of the shock through its stroke forces shock fluid through the piston and around the shim stack and controls compression and rebound. Think of the force of water exiting a synringe. When you push a large syringe quickly and hard it has resistance based on the exit of the syringe causing damping effect. If there were holes in the syringe pusher then the syringe would move easier, less resistance, less compression. Anytime the holes in the shock piston are made smaller, the fluid is moving at a slower rate causing the shock to become stiffer. Now back with the syringe, bigger the holes, faster the fluid, lesser the compression. Think of it this way: the spring controls the ride height and stiffness, but the damping controls how quickly the suspension can move through its range of motion. This is where we get the adjustments from.

WHAT THE CLICKERS DO

COMPRESSION
In the shock, between the reservoir and the body, there are ports that the oil must flow through when the shock is compressed. The term “valving” is based off internal valving using shim stacks in conjunction with a shock piston. This valving can be tuned using large steel washer that very in strength and vary in diameter, all giving different effect to the shock.One of the most import shims within that stack, and definitely the smallest of the shims is called the “crimp” shim. The crimp shim is the shim that the other shims “BEND” around when the shock is being compressed. The smallest valve shim is called the “crimp,” and it is the shim which all the other shims bend around when the shock is compressed. Valving is complicated; we could talk for days. Just think of it as, bigger the shims, less room for oil to flow. Increasing compression and exact opposite for smaller shims.
Compression adjusters can only adjust 20-30% away from the internal base valving as mentioned earlier.You have 3 different clickers on top tier shocks. On most OEM offered shocks you have 1 clicker. In the premium shocks with 3 clickers, you have Hi speed compression, lo speed compression and rebound. Don’t be confused with the names and base it off vehicle speed. It is shock shaft speed. On single adjustable shocks, the compression adjuster is pretty much low speed compression while hi speed is internally fixed via piston design and shim stacks. Hi speed adjuster is used for quick hits, like jump landings, G-outs and big holes/whoops. The high-speed compression adjuster is a large port with a preloaded spring inside and is attached to a beveled stop at the end of the port. So another words, the shock compresses extremely fast forcing lots of oil quickly. This force will push the stop out of the way which allows the small internal spring to compress which allows the oil to be pushed into the reservoir. The tighter you make the high-speed adjuster by turning it inward, the more spring tension is placed on the stop, requiring more force to move it out of the way to bypass the oil. The slow speed adjust port is a lot smaller. The oil flow is also controlled in a different manner. Flow is controlled by a tapered needle that is inside a port. When the adjuster is turned in the softer direction, the needle is backee away from the port more fluid can then pass into the reservoir at low shaft speeds potentially bypassing the valve stack.
Low-speed controls body roll and slow elevation changes, like shallow, rolling G-outs. Tightening up low-speed compression will reduce the machine’s tendency to dive and squat under acceleration and braking by slowing shock-shaft movement.

REBOUND
Rebound is compression, except in reverse pretty much. Rebound limits shock speeds just like like compression does except it limits the shocks return after being compressed. If you have no rebound dampening, the shock will extend itself extremely quick which can cause a bucking motion because the springs energy is not being controlled. Rebound clickers (if fully adjustable shocks) are located on the bottom of the shock near the bottom of the shaft. Rebound oil flows through a port on the shaft itself and circulates back into the body above the stack and piston.Rebound works very much like compression, but it limits the shock’s speed when it extends after being compressed.
Rebound adjusters use a needle-port design,however they allow back flow unless a check valve is used. On most shocks, when you stiffen your rebound or known as slow ur rebound down, it will also slightly stiffen ur lo speed. I know JRI uses completely different circuits.

SPRING
Your spring’s stiffness and preload affect the ride and ride height. There are many options available for springs. You can use a single-rate spring that is preloaded, a zero-preload setup that uses a small “top-out” spring just to keep the springs in place when the shock is fully extended, a progressive-wound single spring that changes rate depending on its position, dual-rate springs that offer different stages of stiffness during the stroke, or even triple- or quad-rated springs. Multi-rate spring setups are used to control stiffness during different parts of the stroke using crossovers, which are solid pieces of material that change when the springs come into effect in the shock’s stroke. Again, for simplicity, we will use single-rate springs for our examples.
Preload is the measure of how much tension is placed on the spring when the shock is fully extended.

Bottoming out?
– Increase spring rate
– Increase preload on same spring
– Increase compression dampening
Too much body roll?
– Increase preload on spring
– Increase spring rate
– Install aftermarket swaybar(s)
Rear end kicking up higher than the front over bumps or jumps?
– Increase rear shock’s rebound dampening
– Reduce rear shock preload
– Decrease rear spring rate
– Decrease front shock’s rebound dampening
– Increase front shock’s compression dampening
– Increase preload on front shocks
– Increase spring rate on front shocks
Front end pushing through corners?
– Reduce front shock’s preload
– Reduce front shock’s compression dampening
– Reduce front shock’s spring rate
– Raise air pressure in rear tires
– Stiffen rear
– Make sure your swaybars are in working order


Sent from my iPhone using Tapatalk

nice write up Tim
 

·
Premium Member
Joined
·
393 Posts
I have a 2014 Wildcat X with the Fox podiums. I recently increased the spring preload to gain back original ground clearance after installing a winch and mount up front and a tool box strapped into the rear bed. How much 'free play' , if any, should the plastic slider between the upper and lower spring have before it contacts the adjuster rings. Right now the upper spring has 'zero' movement during normal driving. Thanks in advance. Outstanding writeup BTW.
 

·
Premium Member
Joined
·
2,661 Posts
There is no hard and fast rule for where the crossover rings should be set. If you feel like your machine leans too much when cornering, you can move the crossover ring closer to the slider. If you think your machine rides too hard and has very little travel between the slider and the crossover ring, move the crossover ring up so you get more suspension travel before the higher spring rate kicks in.

I scanned the thread looking for a definition of low speed and high speed compression adjustments. When I bought my X Ltd (used), the guy selling it thought the speed reference was MPH. I didn't bother to correct him, I just loaded it up and took it home.

Low speed compression refers to the speed that the shock shaft is moving into the body of the shock. As you turn into a corner and the 'cat leans, that is low speed no matter how fast or slow you are driving. When you hit a rock or a pothole, the shock shaft is driven much more quickly into the shock body. That's high speed compression.

Going back to the car leaning in a corner, adding low speed compression would tighten up the response. If the corner is long enough, the 'cat will eventually lean to the same degree as before, but the compression damping will delay it. If the corner is short, the shock might hold it more level all the way through the corner (which is more typical - I don't think there are too many long sweeping turns in offroading). Setting the crossover so that you get into the stiffer spring rate will limit the amount of lean.

I usually say "roll" in these discussions. Road racers that are suspension nerds talk about roll-rate quite a bit, but if I wrote "if you think your 'cat rolls too easily in a corner" an off-roader could interpret that as getting upside down!
 

·
Premium Member
Joined
·
393 Posts
There is no hard and fast rule for where the crossover rings should be set. If you feel like your machine leans too much when cornering, you can move the crossover ring closer to the slider. If you think your machine rides too hard and has very little travel between the slider and the crossover ring, move the crossover ring up so you get more suspension travel before the higher spring rate kicks in.

I scanned the thread looking for a definition of low speed and high speed compression adjustments. When I bought my X Ltd (used), the guy selling it thought the speed reference was MPH. I didn't bother to correct him, I just loaded it up and took it home.

Low speed compression refers to the speed that the shock shaft is moving into the body of the shock. As you turn into a corner and the 'cat leans, that is low speed no matter how fast or slow you are driving. When you hit a rock or a pothole, the shock shaft is driven much more quickly into the shock body. That's high speed compression.

Going back to the car leaning in a corner, adding low speed compression would tighten up the response. If the corner is long enough, the 'cat will eventually lean to the same degree as before, but the compression damping will delay it. If the corner is short, the shock might hold it more level all the way through the corner (which is more typical - I don't think there are too many long sweeping turns in offroading). Setting the crossover so that you get into the stiffer spring rate will limit the amount of lean.

I usually say "roll" in these discussions. Road racers that are suspension nerds talk about roll-rate quite a bit, but if I wrote "if you think your 'cat rolls too easily in a corner" an off-roader could interpret that as getting upside down!
I will give the rings a little space and see how it works out. The wife and I are going to Mesquite NV/AZ on Sunday for a few days of riding. Hopefully the 'roll rate' stays under control and we keep the rubber side down.:p Thanks for the info/clarification.
 
1 - 16 of 16 Posts
Top