This is an introductory explanation of the Raptor's steering knuckles and a preface to my installation write-up. I decided to keep the two separate for ease of searching and further referencing.
First of all, let's start with the basics of what a steering knuckle on a Raptor does and why it can be potentially catastrophic if one (or both) of them bend or break. But before we go any further, the term "splindle" that's commonly used in reference to the Raptor's steering knuckles is descriptive yet inaccurate in describing what's on the Raptor. I don't mind if you call them spindles, just don't let pirate air catch you saying it. When you hear someone say "splindle" they are talking about the Raptor's steering knuckles.
QUIZ:
Q: What do all of the following well known parts have in common?
Upper Control Arm
Lower Conrol Arm
Wheel Hub
Integrated Wheel End
Brake Caliper
Tie Rod
A: They all attach/bolt to the...steering knuckle!
So what is this mysterious, ugly piece of cast steel and how does it bend or break? The steering knuckles on the Raptor are the main terminal where the front suspension, drive line and braking components meet and move together. Let's keep it simple. When your suspension moves up or down, generally speaking all of the above mentioned components will need to move, right? And they need to move in unison. The steering knuckle, amongst its other duties, makes all that happen by being the workhorse of the suspension's operation. Also, when you turn your steering wheel, your tie rods pull or push on your steering knuckles, which rotate on the upper and lower control arm ball joints, turning your wheels.
Pretty boring, right? Let's get to the interesting stuff.
We all love shiny 3.0 shocks (GRRRRR DUAL SHOCKS BRO) and massive control arms; but sadly, our steering knuckles are the unsung heroes in all of this. They bear the brunt of the force that is generated by the movement of the suspension when things go wrong. If the suspension is overloaded or unable to do its job, guess what, the lowly knuckle will take a beating. It might not bend at first, it might bend a little, it might bend a lot...or it might break. If a steering knuckle breaks, you're screwed. Plain and simple.
Now I'm not trying to start "Frame-a-geddon 2.0" here, but this is something that has recently become very important to me. At FRF's Havoc in the Hills I managed to badly bend my passenger's side knuckle and slightly bent the driver's side. The result was me being stranded in a dirt lot near the start line of the Day 2 runs for 8 hours with my truck on a jack stand. Unpleasant, annoying, but my truck and I were otherwise OK. If it weren't for the guys at Krazy House Customs I might have been stranded for days.
So...what the hell happened? How does a steering knuckle bend (or break)? As I said above, when the suspension (front shocks, control arms, etc.) can't help or reach their limits, the knuckles have to hold it all together. Don't get me wrong, they hold everything together even while you truck sits in your garage, but they can handle that. Things start getting ugly when:
- You brake hard (panic brake) over an obstacle (rock, rut, whoops, etc.)
- Pile drive your front suspension in hard compression over an obstacle larger than available wheel travel.
- Turn your wheels over an obstacle
- Any combination of the 3.
Your suspension starts with your wheels and tires. Your tires are the only part of your vehicle to contact the ground while off-road. Well, unless you're rasco or Motumute then basically the entire underside of your truck contacts the ground at some point, but I digress.
When your front wheels are free to rotate and pass over obstacles within usable suspension travel, your suspension will move up and down according to the terrain that you're driving over. In essence, that's all your suspension is meant to do, move up and down. It can't move front to back and it can't move left to right. As long as your suspension is allowed to smoothly and freely move up and down over bumps, all is well in steering knuckle world (for the most part).
Panic Braking
When you brake hard (panic brake) over an obstacle, you are stopping your front wheels from rotating. This immediately places torque on your steering knuckles which would rotate if it weren't for the upper and lower control arms keeping them from doing so. When you impact an obstacle or land from a jump with your brakes locked the torque placed on the knuckle can become overwhelming. Now all of the force from your suspension compressing in conjunction with your brakes being locked will add up and rely on the steering knuckle to withstand the forces working against it. When it can't, it bends. In this scenario the top neck of the steering knuckle below the upper control arm will either bend back or outwards (or both).
Pile driving your suspension
By this I mean staying off the brakes and just stuffing your front suspension under compression. This can occur over a jump, through a rut or over a whoops that blows through the front suspension travel. While at rest, your steering knuckles are being acted on by the weight of the truck. To put it visually, if you removed your upper control arm and put your truck back on the ground, the tires would fall in toward the truck at the top. This would occur because the lower control arm is longer than the upper control arm. The lower ball joint sits further away from the truck than the upper ball joint, so your steering knuckles are resisting that in/out rotation (torque). The upper control arm pushes out against the top of the steering knuckles at all times to stop your wheels from collapsing inward. When you compress your suspension, all of those forces become greater depending on how "hard" you land (introduce a moment about the axis
). When it becomes too much, the upper neck of the knuckle will bend outward (toward the tire).
Impacts while steering
When you impact an obstacle with your wheels turned many things can happen. Depending on which way your wheels are turned and how you impact the obstacle, your tie rods can buckle, or the knuckle can take a beating again. When you combine any number of forces discussed above with having your wheels turned that's just icing on the cake. We already know the knuckle is keeping your wheels from collapsing inward at the top so running up on an obstacle with the sidewall of a tire is only going to make things worse. Again, combine any of the 3 scenarios above and you're only upping your chances of something going wrong.
How Raptor owners unknowingly make this problem worse with many popular modifications.
Wheels: Low or negative offset wheels are incredibly popular with Raptor owners. Let's face it, Method 0mm offset wheels are by far the most popular aftermarket wheel in the Raptor community, and for good reason. However, when you install wheels with a lower offset than what comes on the Raptor from the factory (+34mm), you are only upping your chances for bending or breaking a steering knuckle. Simply put, you are moving the wheel and tire further away from the axis between your upper and lower ball joints. Just like using a longer wrench to gain leverage on a stuck bolt, you are increasing the leverage and torque which is being introduced to the steering knuckle by moving the center of the wheel further away from the ball joints.
Also, the 0mm offset wheel introduces another problem. If and when you bend your steering knuckle due to hard compression, the top of the neck will be pushed outward, toward your tire. With factory offset wheels there is less distance between the top of the steering knuckle and the tire. If you bend your steering knuckle it will be immediately obvious that something is wrong because your upper control arm will likely come in contact your tire. If you have lower offset wheels, the distance between the top of the steering knuckle and the inside of your tire becomes greater. Since the distance is greater, it's unlikely the bending will push your upper control arm into your tire. If you're not diligent in inspecting your suspension after a run, you may never notice that your steering knuckle has bent. You might even be able to get your truck aligned to counteract the bent knuckle and never know that something bad has happened. The next time you go out for a run, cast steel doesn't like to bend more than once or twice. Next time, you may break your knuckle and now you're in big trouble. What was a $200 fix just became a $10,000 fix and that's if you make it out alive.
Shocks: All things being equal, a larger 3.0 (or dual) shock(s) will soak up more force than a factory shock. This is good for the steering knuckles. But nobody buys upgraded shocks so they can go the same speed as what's possible with factory shocks. We want to go faster off-road. When speeds increase, all other forces acting on the suspension will increase as well. In the event that something goes wrong like I outlined above, now you're traveling at a much faster speed which obviously combines and increases the forces placed on the steering knuckle. Like I said at the beginning, we all love shiny 3.0 shocks, but the shocks are only a small piece of the puzzle if you want to off-road safely and without breaking other suspension or steering components.
Weight: Bumpers, air tanks, larger tires, chase racks, lights, recovery gear, multiple girlfriends, etc. It doesn't take a rocket scientist to realize that throwing more weight around can't possibly reduce the forces placed upon suspension components.
So what's the solution? Right now, there are only 2 solutions.
1. Slow down
2. Purchase upgraded steering knuckles with supportive gussets welded to them.
Ok, so there's really only one solution. I recently purchased new steering knuckles from SDHQ with mild steel gussets TIG welded to the cast steel knuckles. As an additional upgrade, I opted for the SDHQ tie rods with a double shear outer connection. My next post will be an installation write up for the new steering knuckles and tie rods from SDHQ. Assuming your knuckles aren't already bent, you can purchase the fabricated gussets themselves and have a competent welder attach them for you or you can purchase the new steering knuckles which come ready to install with the gussets welded on already by the experts at SDHQ.
Stay tuned for the installation write-up and thanks for reading.
First of all, let's start with the basics of what a steering knuckle on a Raptor does and why it can be potentially catastrophic if one (or both) of them bend or break. But before we go any further, the term "splindle" that's commonly used in reference to the Raptor's steering knuckles is descriptive yet inaccurate in describing what's on the Raptor. I don't mind if you call them spindles, just don't let pirate air catch you saying it. When you hear someone say "splindle" they are talking about the Raptor's steering knuckles.
QUIZ:
Q: What do all of the following well known parts have in common?
Upper Control Arm
Lower Conrol Arm
Wheel Hub
Integrated Wheel End
Brake Caliper
Tie Rod
A: They all attach/bolt to the...steering knuckle!
So what is this mysterious, ugly piece of cast steel and how does it bend or break? The steering knuckles on the Raptor are the main terminal where the front suspension, drive line and braking components meet and move together. Let's keep it simple. When your suspension moves up or down, generally speaking all of the above mentioned components will need to move, right? And they need to move in unison. The steering knuckle, amongst its other duties, makes all that happen by being the workhorse of the suspension's operation. Also, when you turn your steering wheel, your tie rods pull or push on your steering knuckles, which rotate on the upper and lower control arm ball joints, turning your wheels.
Pretty boring, right? Let's get to the interesting stuff.
We all love shiny 3.0 shocks (GRRRRR DUAL SHOCKS BRO) and massive control arms; but sadly, our steering knuckles are the unsung heroes in all of this. They bear the brunt of the force that is generated by the movement of the suspension when things go wrong. If the suspension is overloaded or unable to do its job, guess what, the lowly knuckle will take a beating. It might not bend at first, it might bend a little, it might bend a lot...or it might break. If a steering knuckle breaks, you're screwed. Plain and simple.
Now I'm not trying to start "Frame-a-geddon 2.0" here, but this is something that has recently become very important to me. At FRF's Havoc in the Hills I managed to badly bend my passenger's side knuckle and slightly bent the driver's side. The result was me being stranded in a dirt lot near the start line of the Day 2 runs for 8 hours with my truck on a jack stand. Unpleasant, annoying, but my truck and I were otherwise OK. If it weren't for the guys at Krazy House Customs I might have been stranded for days.
So...what the hell happened? How does a steering knuckle bend (or break)? As I said above, when the suspension (front shocks, control arms, etc.) can't help or reach their limits, the knuckles have to hold it all together. Don't get me wrong, they hold everything together even while you truck sits in your garage, but they can handle that. Things start getting ugly when:
- You brake hard (panic brake) over an obstacle (rock, rut, whoops, etc.)
- Pile drive your front suspension in hard compression over an obstacle larger than available wheel travel.
- Turn your wheels over an obstacle
- Any combination of the 3.
Your suspension starts with your wheels and tires. Your tires are the only part of your vehicle to contact the ground while off-road. Well, unless you're rasco or Motumute then basically the entire underside of your truck contacts the ground at some point, but I digress.
When your front wheels are free to rotate and pass over obstacles within usable suspension travel, your suspension will move up and down according to the terrain that you're driving over. In essence, that's all your suspension is meant to do, move up and down. It can't move front to back and it can't move left to right. As long as your suspension is allowed to smoothly and freely move up and down over bumps, all is well in steering knuckle world (for the most part).
Panic Braking
When you brake hard (panic brake) over an obstacle, you are stopping your front wheels from rotating. This immediately places torque on your steering knuckles which would rotate if it weren't for the upper and lower control arms keeping them from doing so. When you impact an obstacle or land from a jump with your brakes locked the torque placed on the knuckle can become overwhelming. Now all of the force from your suspension compressing in conjunction with your brakes being locked will add up and rely on the steering knuckle to withstand the forces working against it. When it can't, it bends. In this scenario the top neck of the steering knuckle below the upper control arm will either bend back or outwards (or both).
Pile driving your suspension
By this I mean staying off the brakes and just stuffing your front suspension under compression. This can occur over a jump, through a rut or over a whoops that blows through the front suspension travel. While at rest, your steering knuckles are being acted on by the weight of the truck. To put it visually, if you removed your upper control arm and put your truck back on the ground, the tires would fall in toward the truck at the top. This would occur because the lower control arm is longer than the upper control arm. The lower ball joint sits further away from the truck than the upper ball joint, so your steering knuckles are resisting that in/out rotation (torque). The upper control arm pushes out against the top of the steering knuckles at all times to stop your wheels from collapsing inward. When you compress your suspension, all of those forces become greater depending on how "hard" you land (introduce a moment about the axis
). When it becomes too much, the upper neck of the knuckle will bend outward (toward the tire).Impacts while steering
When you impact an obstacle with your wheels turned many things can happen. Depending on which way your wheels are turned and how you impact the obstacle, your tie rods can buckle, or the knuckle can take a beating again. When you combine any number of forces discussed above with having your wheels turned that's just icing on the cake. We already know the knuckle is keeping your wheels from collapsing inward at the top so running up on an obstacle with the sidewall of a tire is only going to make things worse. Again, combine any of the 3 scenarios above and you're only upping your chances of something going wrong.
How Raptor owners unknowingly make this problem worse with many popular modifications.
Wheels: Low or negative offset wheels are incredibly popular with Raptor owners. Let's face it, Method 0mm offset wheels are by far the most popular aftermarket wheel in the Raptor community, and for good reason. However, when you install wheels with a lower offset than what comes on the Raptor from the factory (+34mm), you are only upping your chances for bending or breaking a steering knuckle. Simply put, you are moving the wheel and tire further away from the axis between your upper and lower ball joints. Just like using a longer wrench to gain leverage on a stuck bolt, you are increasing the leverage and torque which is being introduced to the steering knuckle by moving the center of the wheel further away from the ball joints.
Also, the 0mm offset wheel introduces another problem. If and when you bend your steering knuckle due to hard compression, the top of the neck will be pushed outward, toward your tire. With factory offset wheels there is less distance between the top of the steering knuckle and the tire. If you bend your steering knuckle it will be immediately obvious that something is wrong because your upper control arm will likely come in contact your tire. If you have lower offset wheels, the distance between the top of the steering knuckle and the inside of your tire becomes greater. Since the distance is greater, it's unlikely the bending will push your upper control arm into your tire. If you're not diligent in inspecting your suspension after a run, you may never notice that your steering knuckle has bent. You might even be able to get your truck aligned to counteract the bent knuckle and never know that something bad has happened. The next time you go out for a run, cast steel doesn't like to bend more than once or twice. Next time, you may break your knuckle and now you're in big trouble. What was a $200 fix just became a $10,000 fix and that's if you make it out alive.
Shocks: All things being equal, a larger 3.0 (or dual) shock(s) will soak up more force than a factory shock. This is good for the steering knuckles. But nobody buys upgraded shocks so they can go the same speed as what's possible with factory shocks. We want to go faster off-road. When speeds increase, all other forces acting on the suspension will increase as well. In the event that something goes wrong like I outlined above, now you're traveling at a much faster speed which obviously combines and increases the forces placed on the steering knuckle. Like I said at the beginning, we all love shiny 3.0 shocks, but the shocks are only a small piece of the puzzle if you want to off-road safely and without breaking other suspension or steering components.
Weight: Bumpers, air tanks, larger tires, chase racks, lights, recovery gear, multiple girlfriends, etc. It doesn't take a rocket scientist to realize that throwing more weight around can't possibly reduce the forces placed upon suspension components.
So what's the solution? Right now, there are only 2 solutions.
1. Slow down
2. Purchase upgraded steering knuckles with supportive gussets welded to them.
Ok, so there's really only one solution. I recently purchased new steering knuckles from SDHQ with mild steel gussets TIG welded to the cast steel knuckles. As an additional upgrade, I opted for the SDHQ tie rods with a double shear outer connection. My next post will be an installation write up for the new steering knuckles and tie rods from SDHQ. Assuming your knuckles aren't already bent, you can purchase the fabricated gussets themselves and have a competent welder attach them for you or you can purchase the new steering knuckles which come ready to install with the gussets welded on already by the experts at SDHQ.
Stay tuned for the installation write-up and thanks for reading.
