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Thread: JCAD RULR V3 Install Instructions and tech info

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Old 01-18-2014, 08:42 PM   #1
I wanna be Dave
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Default JCAD RULR V3 Install Instructions and tech info

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.

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.

Last edited by monkeyracer; 01-23-2014 at 09:21 AM.
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Old 01-18-2014, 08:42 PM   #2
I wanna be Dave
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Default Re: JCAD RULR V3 Install Instructions and tech info

1. Remove the screw holding the rear lower link on the chassis.
[Note] Also remove any sliders or other items that would get in the way of the RULR installation.

2. Temporarily mount the RULR to the outside of the chassis.
[Note] Make sure the bottom of the ruler is flush with the bottom of the chassis, and make sure the ruler is pointed in the right direction as shown in the above picture.

3. Mark the hole location for the extra hole that is needed to mount the RULR, and drill the hole.
[Note] Use either a 3 mm or 1/8" drill bit for this step.

4. Remove the RULR and begin to decide how you would like to mount them. There are some examples below that should help depending on the set-up you use.

4A. Option 1 - Mount to the inside of the chassis. With or without spacers.
[Note] With this option, the RULR is inside the chassis rails, and will not interfere with any sliders you may have. However, there is also a possibility of clearance issues with the driveshaft as well as the chassis rails depending on your links and rod ends. If your set-up involves a transfer case, this option is a simple method to install the RULRs. With spacers you can mount the links on the outside of the RULR to prevent clearance issues with the driveshaft.

Here is a closeup to show how close this is to the driveshaft. In this position, I would need bent rod ends for the links to clear the chassis rails. (These can be found on Axial Parts Tree AX80005. They are the ends in the left hand portion of the picture in this link.)

4B. Option 2 - Mount the RULR on the outside of the frame rails. You will need spacers to mount the links. This method allows you to more easily access the screws and bolts, but will not work with sliders unless the other mounting bolts are spaced out 1/8" as well.

4C. Option 3 - Mount the RULR on the inside of the chassis, without spacers, similar to option 1, however the RULR is bent about 30 degrees to clear the driveshaft.

The 30 degree bend is simply a recommendation. The RULR can be bent by putting the bottom portion into a bench vise, then using strong pliers or a hammer, bent into position.
[Note] Remember that you have a left and a right side, so mirror your bend from one RULR to the other.

**This is the method I am planning on using on my own vehicle for simplicity.

4D. Option 4 - Weld the RULR to the chassis. Using one of the previous options, you have the ability to weld these directly to the chassis. I would recommend option 3 so that the RULR boxes in the frame rails. This option is obviously more advanced and requires welding equipment and experience. It's a simple weld, and some one that has the equipment and experience would probably only charge a couple bucks (or a couple beers) to lay down some quick weld beads.

5. Repeat for the other side of the chassis.

6. Finally install the upper links and get back on the trails!

Other notes and info:

- There may be some slight surface rust from the waterjet process. I highly recommend painting these to prevent rust from forming on the RULRs. Any basic spray can paint will work fine, but I recommend cleaning up the surface and applying a primer coat before the final coat. These can also be powder coated if you access to that process.
- I recommend getting a variety of length M3 screws. This is useful for more than just installing these risers. Harley (another vendor on this forum) offers a very nice and inexpensive kit with a variety of lengths of screws.
- The instructions above are guidelines to help figure out what might work for your set-up. Each truck is built and customized a little different than the next, but the majority of builds will be able to use one of the above options for mounting the RULRs.

The vendor thread is located here for more information about these and how to purchase them.

Last edited by monkeyracer; 01-18-2014 at 10:08 PM.
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