monkeyracer
I wanna be Dave
The RULR V3's have started to ship out, so I wanted to make a thread to show everyone how to install them, and the different variations that are possible with the re-design. This thread will also servo to document the increased capability and the reason these help the SCX10 improve performance with some technical details about the benefits of the RULRs.
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What is a RULR?
Pronounced like the measuring device, 'ruler', It is an acronym that stands for Rear Upper Link Riser.
What does it do?
The riser moves the chassis side upper link mounting point vertically up about 15 mm and back about 5 mm. This allows the links to have better vertical separation at the chassis to in turn provide better anti-squat.
What is anti-squat?
There are many threads about Anti-squat, but sometimes the information can be hard to weed through, so here's a quick run-down.
Anti-squat or sometimes abbreviated to AS is the tendency of the rear of the chassis to raise up when forward power is applied. This fights the natural gravity/momentum induced squat where the rear of the chassis wants to 'squat' down on the suspension.
[Very technical engineering related explanation]
How this happens is that when power is applied through the transmission, it rotates the drive-shaft, which rotates the axle gears, and eventually the wheels. All this rotation experiences friction and that friction causes a reaction force (Newton's 3rd law - every action has an equal and opposite reaction...) in the axle housing (as well as reaction forces from the traction of the tires, the couple moment reaction from the normal force reaction of the left and right tires on the ground, and a reaction moment couple from the left and right shocks... all of these contribute to torque twist, squat/anti-squat, etc. regardless of what is causing the moment of inertia, it is there and affects the way these vehicles drive...)
This reaction creates a couple moment with the upper links and lower links. This rotational moment is transferred to the chassis, and depending on the geometry of the links will determine the direction of rotation of the chassis.
A squat geometry will rotate the chassis downward toward the axle, anti-squat geometry will go the other way.
Why is improving anti-squat important for the SCX10?
It's important to all vehicles, but especially for the SCX10. When climbing a steep ascent, the higher COG (due to more scale realistic features, heavy bodies, scale accessories, larger batteries, battery placement, etc) tends to allow the front end to lift, reducing traction to the front tires, causing the vehicle to eventually flip over backward.
Anti-squat helps to combat this tendency to reduce traction on the front tires by rotating the rear of the chassis up moving the weight of the vehicle more towards the front allowing better traction.
Anything else cool that these do for the SCX10?
With stock length links, the RULRs also rotate (or clock) the rear axle to improve the pinion angle, getting the driveshaft in better line and above the bottom of the lower links. This reduces the stress on the driveshaft as well as gets the UV joint of the driveshaft up out of the rocks to help them last longer. If you are using links that already clock the axle, you will need to modify them to account for this extra clocking.
So, how do I install these?
The next post has a pictorial guide on how to install them. They are very easy to install, but there are some options depending on the set-up you use. It will be up to you to decide which mounting option works the best for your set-up.
What if I have more questions about these?
Any questions about installation, or anything not relating to price or where to get them (link to the vendor thread is at the end of post 2) please post a reply here. Also, if you have installed a set of these, and have some good information about how they improved your performance, please share your experience here as well.
<hr>
What is a RULR?
Pronounced like the measuring device, 'ruler', It is an acronym that stands for Rear Upper Link Riser.
What does it do?
The riser moves the chassis side upper link mounting point vertically up about 15 mm and back about 5 mm. This allows the links to have better vertical separation at the chassis to in turn provide better anti-squat.
What is anti-squat?
There are many threads about Anti-squat, but sometimes the information can be hard to weed through, so here's a quick run-down.
Anti-squat or sometimes abbreviated to AS is the tendency of the rear of the chassis to raise up when forward power is applied. This fights the natural gravity/momentum induced squat where the rear of the chassis wants to 'squat' down on the suspension.
[Very technical engineering related explanation]
How this happens is that when power is applied through the transmission, it rotates the drive-shaft, which rotates the axle gears, and eventually the wheels. All this rotation experiences friction and that friction causes a reaction force (Newton's 3rd law - every action has an equal and opposite reaction...) in the axle housing (as well as reaction forces from the traction of the tires, the couple moment reaction from the normal force reaction of the left and right tires on the ground, and a reaction moment couple from the left and right shocks... all of these contribute to torque twist, squat/anti-squat, etc. regardless of what is causing the moment of inertia, it is there and affects the way these vehicles drive...)
This reaction creates a couple moment with the upper links and lower links. This rotational moment is transferred to the chassis, and depending on the geometry of the links will determine the direction of rotation of the chassis.
A squat geometry will rotate the chassis downward toward the axle, anti-squat geometry will go the other way.
Why is improving anti-squat important for the SCX10?
It's important to all vehicles, but especially for the SCX10. When climbing a steep ascent, the higher COG (due to more scale realistic features, heavy bodies, scale accessories, larger batteries, battery placement, etc) tends to allow the front end to lift, reducing traction to the front tires, causing the vehicle to eventually flip over backward.
Anti-squat helps to combat this tendency to reduce traction on the front tires by rotating the rear of the chassis up moving the weight of the vehicle more towards the front allowing better traction.
Anything else cool that these do for the SCX10?
With stock length links, the RULRs also rotate (or clock) the rear axle to improve the pinion angle, getting the driveshaft in better line and above the bottom of the lower links. This reduces the stress on the driveshaft as well as gets the UV joint of the driveshaft up out of the rocks to help them last longer. If you are using links that already clock the axle, you will need to modify them to account for this extra clocking.
So, how do I install these?
The next post has a pictorial guide on how to install them. They are very easy to install, but there are some options depending on the set-up you use. It will be up to you to decide which mounting option works the best for your set-up.
What if I have more questions about these?
Any questions about installation, or anything not relating to price or where to get them (link to the vendor thread is at the end of post 2) please post a reply here. Also, if you have installed a set of these, and have some good information about how they improved your performance, please share your experience here as well.
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