Jerold's Rlaarlo Build

[Jerold]

The Build List
Rlaarlo 1/10 Carbon Fiber On-Road Cars 200km/h Roller
TP POWER 3640
CONTACT J13773 26mm
Castle Creations Mamba Monster 8S
4S Battery & QS8 Connectors

Why are You Building This?
Some say I'm smart, others say I'm stupid or it maybe it's just poor life choices? In reality this build started from a video I saw from Tomely RC, called "Rlaarlo's NEW 100mph RC Car is So Cheap on Pre sale!"

I had never took Rlaarlo seriously, but it looked interesting and fairly inexpensive too. Spoiler - I didn't do all the math. Eventually, I saw a few more videos then my speed running buddies on Arrama Forums got into the game, so I purchased the Rlaarlo AK-917 CF roller. I was second on that thread to buy one and I was the first to get it.

This is a bit of adventure to do something brand new. As a side note, even though this started in the Arrma Forums, @WoodiE runs both forums and is very cool to let us play in the Arrma sandbox with other brands; I thought it would be appropriate to do the Rlaarlo build here.

What Will You Do To It?
Being brand new and from a small company is a bit of a challenge to get a plan. No one has built one before and none of the specs for the motor size, gear pitch, wheel hex, etc were published and it was an adventure to find the information. The good news is if you have questions and email them, the do get back to you the next day. Which is better than most US manufacturers.

Through several other videos and hours of research, I managed to figure out the max diameter of the motor was 36mm, thanks to Francis at RC Review. He had a good angle that I could see the 36mm can was flat on the chassis. Bars&Tones RC swapped the wheels for foam and I was able to see the hex size. The gear pitch appeared somewhere in the website at some point. Also Rlaarlo started to give a few more details on their website.

The Mock Up
To get some ideas I took the pic from the Rlaarlo website and scaled it in Visio to full size. Then started placing scale blocks of different components.

I went through a few iterations. Other's are stuffing the XLX2 in there which is an awesome ESC, but I did some back flips on the limitless to make everything fit gracefully and took the easy path on this one. It gets the MMX 8S ESC with a 4S battery and TP 36xx series motor. The basic layout I decided on is below.

When the shipping notice arrived, I made an order to Island Hobby, Amain and Amazon. THIS is the math I didn't do. So my $200 roller is now about $1K. Don't tell my wife, or she will get another Louis Vuitton.

Out of the box
It looks like good quality. The CF is smooth and fairly ridged. The pit fall is the HW. It looks like some of the hexes are buggered, but they just made that way. Maybe the manufacture has a crappy swage or they are the 2nds for batches. I don't know but I will eventually be replacing the HW with better stuff as I go through it. I use good tools but stuff happens and better quality HW makes a huge difference on the frustration scale and it's worth $20 and a it of effort.

When I pulled it apart there was thread lock on the metal-metal screws, which a bit of heat fixed. I used a soldering iron on the head which seems to work. You can use a torch, which is normally my preferred method, but you need to be careful of the carbon fiber.

The shocks feel decent but the springs are way too soft. The book that comes with it says they are 28mm x 65mm, so I'm hopping to find something that will fit. They will be getting some sort of limiter, otherwise it will just chassis slap on everything.

An added bonus is it comes with the lights and body fan. I don't care about the blinkers or exhaust, but just having head and tail lights make it easier to see at a distance.

The center spool shaft is 5mm and @LibertyMKiii and confirmed you can put a Mod 1 gear set in there. I'll be running the 48P gears for now, but will eventually move to Mod 1. If you are thinking about it, do the math to make sure they fit.

The Real Layout
This is the first pass at the fit and I've got plenty of room. Just pulled the battery tray. Unfortunately, the servo is right where I want to put the ESC. Since I don't want to drill holes and move the servo it's getting this layout for now.

I delayed putting it together because I thought I was missing a piece.

However, it turns out I wasn't paying attention and it's a different mount.... which is the one that is a total pain in the butt to get mounted with the correct mesh. I have the sliding mount ordered.

Mounting the Motor and Adjusting the Pinion
To get the gear mesh correct it's a bit tricky. This is how I did it. First thing is I pulled center brace. Then remove the back cage and wing support. Two screws on the shock tower and two in the back. The longer screws go in the back.

Leave the pinion off for now. With the back removed you can get a driver to the front of the motor mount between the control arms. It's not exactly aligned so be careful. Also the mount has recesses for the screw heads and they are M3x(shorter than I thought). Make sure your screws aren't too long and get into the motor. I snugged them up to keep it in place but could still move the motor a bit. Then slipped the pinion on the front and nudge the motor until the mesh was correct. Then re-tighten the screws. Then added thread lock, by removing them one at a time without moving the motor. The last step is to slide the pinion on from the front. Like I said it's a pain in the butt.

Another note on this is the shaft of the TP motors touches the gear cover, which you will probably want to keep, and I had to create some space on the plastic cover. The reason I decided to keep it is that it's next to the battery and would make a nice saw if there was a crash where the battery moved.

More to come. . .

 

[WoodiE]

Can't wait to see the speed runs @Jerold

 

[Dan B.]

The Build List
Rlaarlo 1/10 Carbon Fiber On-Road Cars 200km/h Roller
TP POWER 3640
CONTACT J13773 26mm
Castle Creations Mamba Monster 8S
4S Battery & QS8 Connectors

Why are You Building This?
Some say I'm smart, others say I'm stupid or it maybe it's just poor life choices? In reality this build started from a video I saw from Tomely RC, called "Rlaarlo's NEW 100mph RC Car is So Cheap on Pre sale!"

I had never took Rlaarlo seriously, but it looked interesting and fairly inexpensive too. Spoiler - I didn't do all the math. Eventually, I saw a few more videos then my speed running buddies on Arrama Forums got into the game, so I purchased the Rlaarlo AK-917 CF roller. I was second on that thread to buy one and I was the first to get it.
View attachment 164933
This is a bit of adventure to do something brand new. As a side note, even though this started in the Arrma Forums, @WoodiE runs both forums and is very cool to let us play in the Arrma sandbox with other brands; I thought it would be appropriate to do the Rlaarlo build here.

What Will You Do To It?
Being brand new and from a small company is a bit of a challenge to get a plan. No one has built one before and none of the specs for the motor size, gear pitch, wheel hex, etc were published and it was an adventure to find the information. The good news is if you have questions and email them, the do get back to you the next day. Which is better than most US manufacturers.

Through several other videos and hours of research, I managed to figure out the max diameter of the motor was 36mm, thanks to Francis at RC Review. He had a good angle that I could see the 36mm can was flat on the chassis. Bars&Tones RC swapped the wheels for foam and I was able to see the hex size. The gear pitch appeared somewhere in the website at some point. Also Rlaarlo started to give a few more details on their website.

The Mock Up
To get some ideas I took the pic from the Rlaarlo website and scaled it in Visio to full size. Then started placing scale blocks of different components.

I went through a few iterations. Other's are stuffing the XLX2 in there which is an awesome ESC, but I did some back flips on the limitless to make everything fit gracefully and took the easy path on this one. It gets the MMX 8S ESC with a 4S battery and TP 36xx series motor. The basic layout I decided on is below.
View attachment 164936
When the shipping notice arrived, I made an order to Island Hobby, Amain and Amazon. THIS is the math I didn't do. So my $200 roller is now about $1K. Don't tell my wife, or she will get another Louis Vuitton.
View attachment 164940View attachment 164941View attachment 164942

Out of the box
It looks like good quality. The CF is smooth and fairly ridged. The pit fall is the HW. It looks like some of the hexes are buggered, but they just made that way. Maybe the manufacture has a crappy swage or they are the 2nds for batches. I don't know but I will eventually be replacing the HW with better stuff as I go through it. I use good tools but stuff happens and better quality HW makes a huge difference on the frustration scale and it's worth $20 and a it of effort.
View attachment 164943

When I pulled it apart there was thread lock on the metal-metal screws, which a bit of heat fixed. I used a soldering iron on the head which seems to work. You can use a torch, which is normally my preferred method, but you need to be careful of the carbon fiber.

The shocks feel decent but the springs are way too soft. The book that comes with it says they are 28mm x 65mm, so I'm hopping to find something that will fit. They will be getting some sort of limiter, otherwise it will just chassis slap on everything.

An added bonus is it comes with the lights and body fan. I don't care about the blinkers or exhaust, but just having head and tail lights make it easier to see at a distance.

The center spool shaft is 5mm and @LibertyMKiii and confirmed you can put a Mod 1 gear set in there. I'll be running the 48P gears for now, but will eventually move to Mod 1. If you are thinking about it, do the math to make sure they fit.

The Real Layout
This is the first pass at the fit and I've got plenty of room. Just pulled the battery tray. Unfortunately, the servo is right where I want to put the ESC. Since I don't want to drill holes and move the servo it's getting this layout for now.
View attachment 164937

I delayed putting it together because I thought I was missing a piece.
View attachment 164938

However, it turns out I wasn't paying attention and it's a different mount.... which is the one that is a total pain in the butt to get mounted with the correct mesh. I have the sliding mount ordered.
View attachment 164939


Mounting the Motor and Adjusting the Pinion
To get the gear mesh correct it's a bit tricky. This is how I did it. First thing is I pulled center brace. Then remove the back cage and wing support. Two screws on the shock tower and two in the back. The longer screws go in the back.

Leave the pinion off for now. With the back removed you can get a driver to the front of the motor mount between the control arms. It's not exactly aligned so be careful. Also the mount has recesses for the screw heads and they are M3x(shorter than I thought). Make sure your screws aren't too long and get into the motor. I snugged them up to keep it in place but could still move the motor a bit. Then slipped the pinion on the front and nudge the motor until the mesh was correct. Then re-tighten the screws. Then added thread lock, by removing them one at a time without moving the motor. The last step is to slide the pinion on from the front. Like I said it's a pain in the butt.

Another note on this is the shaft of the TP motors touches the gear cover, which you will probably want to keep, and I had to create some space on the plastic cover. The reason I decided to keep it is that it's next to the battery and would make a nice saw if there was a crash where the battery moved.

More to come. . .

Great start on a cool build thread! After reading, I’m glad I ordered the sliding motor mount when I ordered the car. What a PITA to adjust mesh!
I think you nailed it on the electronics as well, with room to go up to a bigger KV 36xx motor if you want.
I“m going to try really hard to not give in to temptation and buy a MMX8S. You’re brave. And probably a better driver than me. This is one small, light car. I’ll probably go HobbyWing and keep it to 3 or 4S.
Can’t wait to see your runs, man!

 

[WickedFog]

I am amazed how nice that car looks for how much they are.

 

[Doom!]

Really is a great looking car, Looking forward to seeing it when it's ready to roll.

 

[Jerold]

Great start on a cool build thread! After reading, I’m glad I ordered the sliding motor mount when I ordered the car. What a PITA to adjust mesh!
I think you nailed it on the electronics as well, with room to go up to a bigger KV 36xx motor if you want.
I“m going to try really hard to not give in to temptation and buy a MMX8S. You’re brave. And probably a better driver than me. This is one small, light car. I’ll probably go HobbyWing and keep it to 3 or 4S.
Can’t wait to see your runs, man!

Hah, you over estimate my driving skills, but thank you just the same. I'm sure it a squirrelly little ballistic nightmare at speed.

I figured go with the the biggest I can get and I can always dial it back. That's what I did with the Limitless, started with 4S then dialed back the power in the ESC on 8S. It will be interesting to see what tweaks I need to do the the electronics, throttle curve, braking %, DR, etc..

 

[Jerold]

I stuck everything down, put some thread lock on the motor/pinion, and shaved the rear support. The receiver is on the center support. I'm not a fan of the placement but it's not under the motor wires.

Not a great picture but I shaved the lip on the outer edge of the rear wing support. It will easily get into the tires under load. So now it's flat-ish to avoid damage.

I also did the inital setup in the ESC.
Remove the cutoff voltage, update the firmware and modify they throttle curve.

Still to do

• Alignment - There is a fair amount of toe out that needs to be removed.
• Tune suspension - Ride height, shocks limiter. Stiffer springs if I can find them.
• Mount the antenna tubes. I have no idea what I'm going to do yet.
• Calibrate the ESC.
• Center the servo.
• Setup the radio.
• Setup the gyro.
• Clean up wires.
• Mount Switch.

 

[Jerold]

Still to do

• Alignment - There is a fair amount of toe out that needs to be removed.
• Tune suspension - Ride height, shocks limiter. Stiffer springs if I can find them.
• Mount the antenna tubes. I have no idea what I'm going to do yet.
• Calibrate the ESC. (I think?)
• Center the servo.
• Setup the radio.
• Setup the gyro.
• Clean up wires.
• Mount Switch.

Shock Limiting
I need to limit the travel of the shocks to prevent the rear from squatting too much and getting air under it, and doing a back flip. Also keep the pan from slapping the ground at high speed and max down force. Which means the front and rear need to be limited.

There are others that like to lock out the rear suspension with rod ends, and they are very good high speed runners, much better than myself. However, I don't like that because it creates and infinite spring rate and puts all the stress (flex) on the other components. My experience is with with full size race cars and when you put it on the bump stops it becomes bouncy, skips and is pretty much uncontrollable. But full size cars don't have flexible plastic bits for suspension either.

On my Limitless build I used some nitro tubing on the rear shocks shaft to reduce the travel. This was part of Raz Shifrin's speed secrets series and it works but it's messy and tedious. When I went to limit the front shocks as well I used some grommets. This is so much easier and more durable.

These are from Lowes, Hillman part number 884627. Unfortunately Lowes was out, so I went to Ace Hardware and they had some. They were a different brand but the dimensions are the same.

The dimensions are a bit complex, but what I need to know is the inside diameter, outside diameters and the thickness. The other dimension reference the groove, which I don't care about. The inside diameter is slightly larger than the shock shaft. The outside diameter has to fit inside the spring cup and the thickness limits the travel. If I go too thick it will be hard to get the bottom shock cup on there.

It doesn't have to be this exact grommet but it has worked in the past, so I'm running with it.

Stiffer Springs?
The stock springs are very soft, or at least the feel soft. I did a make shift measurement and found them to be about 12lb/in (assuming they are linear) and that's not bad but it still bottoms easily.

I tested the spring rate using my drill press and a food scale underneath (don't tell my wife). It's not super accurate but it gives me a benchmark. The springs don't quite have an inch of travel, so I had to use the 1/2" mark and doubled the reading. For comparison, the Limitless are 38 lbs/in in the rear and 32 lbs/in in the front. This is a much lighter car but down force is down force and I'm thinking something in the 15-20 lbs/in range would be a good place to start.

The spring dimensions are roughly 28mm tall and 17mm inside diameter. The actual measurements are below.

	inches	mm
tall	1.100​	27.94​
Inside	0.672​	17.07​
wire diameter	0.065​	1.65​
Outside	0.800​	20.32​

Looking for better springs, I made a trip to my hobby store to see if they had any springs. Alas they did not. However, the young man there suggested Traxxas 4-Tec shocks/springs might be good to look at, unfortunately they did not. So for now it's going to be the factory springs with my grommets.

Installation
This is pretty straight forwards. Unscrew the rod end, put the grommet on there and push the spring cup back in.

Yeah I used Vise-Grips with electrical tape, ya'll will have to get over it. I'm not that concerned and that part of the shock shaft should never reach the inside O-ring anyway.

The grommet fits perfectly inside the spring cup.

Then assembled shock with the bumper installed. You can see about 1/8" of shaft exposed, which is the max travel.

Of course the rubber will compress a little bit and that's OK.

Shock Angles
The factory setup has a bit of angle in the mounting shown by the red line. This is better for cornering but I don't really care about cornering and only want the most effective vertical dampening I can get. In this case I've opted for swapping it to the green line. This (in theory) allows more vertical motions to dampen more bumps than and angled shock.

At the same time the outer control arm holes have less leverage than the inner one and this may all be imaginary? Let me know if you think different of my shock angle theory.

Of course this get repeated on the rear shocks as well. Except for some reason the back is not as stiff as the front. I suspect it's because the shock towers are taller. So I used the lower inside setting on the shock tower.

More tuning coming up.

Alignment
Ok this was a bit weird. The driver left side had more camber than the other side. Everything looks straight. I adjusted the toe to and still it was wonky. The AK-917 has an odd camber adjustment. You have three holes in the inner control arm and 3 holes in the outer and the do not exactly align, i.e. the spacing is slightly off.

A close up of the right and left sides show the hole misalignment. If you pull the screw then align the wheel to the angle you want, you should see a hole combination that works. In this case I moved the screw to the outside hole on both and it aligns pretty good. You can see where I moved the screw on the driver's left and the gap that no appears.

I have no idea why it's off from the factory but it's straight-ish now.

Smoke Test
This part always makes me nervous; the first time you plug in the battery. I've seen enough videos and heard enough stories to know that it's not perfect every time.
It was successful with no smoke. I was able to center the servo. removing the front nose piece makes all of this stuff much easier!

I "think" I calibrated the ESC, but it's not giving me the feedback as the XLX2 does. I may have to mess with it a bit more.

First Drive and Oops!
For some reason the ESC fan is NOT working at all and the motor fan is intermittent? Just add it to the list. The oops (in the video) was the reverse is a bit agressive, I need to turn that way down.

 

[WickedFog]

Straight vertical shocks take more force to compress, and give the least amount of suspension travel. The farther out on the arms you are with the mounting location means more stability.

I've used regular pliers on shock shafts before. As long as the shaft is in between the grooves, they do fine. I have since bought shock pliers and will say I am glad I got them. They're really nice for installing pivot balls too.

 

[Bogda89]

It looks like it's going to be a sickening build. From videos that I have seen high speed stability is not that great. Hopefully with fine adjustments you can improve it.

What batteries do you plan to use? I don't think full size pack will fit

 

[Dan B.]

In regard to shock placement, the closer (more inboard) on the control arm it’s mounted, the less damping, as the effective spring rate is diminished. The farther outboard the shock is mounted on the lower control arm, the higher the effective spring rate/damping. It isn’t the angle of the dangle, so to speak, it’s the position of the shock in relation to the length of the a-arm. The closer it is (inboard) the less shock action because of the greater length to the outside, hence more ”lever” and the easier the shock is to compress. The farther out on the a-arm, the shorter the “lever” making it more difficult to compress the shocks. If you’re already dealing with soft springs, I’d recommend the outboard most hole for mounting, both on the a-arm and on the shock tower. (That will help to limit travel a bit and keep the shock loaded.)
So you might be achieving the opposite of your goal by moving them in to achieve a more vertical orientation.
@Jerold Thanks for doing such a detailed log. This is going to be very helpful when a lot of us finally get out cars. Nice job, man.
Also, was just looking at your pictures (well done!) and noticed pills on the rear suspension block. Can you alter their orientation, or does it come with other pills to reduce the rear toe-in?

 

[Jerold]

In regard to shock placement, the closer (more inboard) on the control arm it’s mounted, the less damping, as the effective spring rate is diminished. The farther outboard the shock is mounted on the lower control arm, the higher the effective spring rate/damping. It isn’t the angle of the dangle, so to speak, it’s the position of the shock in relation to the length of the a-arm. The closer it is (inboard) the less shock action because of the greater length to the outside, hence more ”lever” and the easier the shock is to compress. The farther out on the a-arm, the shorter the “lever” making it more difficult to compress the shocks. If you’re already dealing with soft springs, I’d recommend the outboard most hole for mounting, both on the a-arm and on the shock tower. (That will help to limit travel a bit and keep the shock loaded.)
So you might be achieving the opposite of your goal by moving them in to achieve a more vertical orientation.
@Jerold Thanks for doing such a detailed log. This is going to be very helpful when a lot of us finally get out cars. Nice job, man.
Also, was just looking at your pictures (well done!) and noticed pills on the rear suspension block. Can you alter their orientation, or does it come with other pills to reduce the rear toe-in?

@Dan B. & @WickedFog thanks for verifying my shock theory. I can't remember exactly where I got that from but I was thinking about angles and trigonometry and stuff. But I'm lazy these days and went with my gut.

Looking at this today, the rear shock really need to be longer. They are not nearly as stiff as the front and the front is much more compressed. Stiffer in the front is normal for cornering, you want the front stiffer than the rear to avoid oversteer. Which is how you would balance your car. I might try to make a small plate that would lower the shock mount.

Thanks for the kudos on the build. I will forget the details later and my build threads are essentially my notebook as I selfishly document what I did, good and bad. I know it's a bit (a lot wordy) and some people get lost in it, but it's worth it in the end. I've gone back to my Limitless log so many times.

The only thing I can see to adjust on the rear is the camber. There turn buckles on the upper control arms. The toe looks pretty neutral or maybe just a tick of toe in. A lot less then most cars.

It looks like it's going to be a sickening build. From videos that I have seen high speed stability is not that great. Hopefully with fine adjustments you can improve it.

What batteries do you plan to use? I don't think full size pack will fit

Sicking good or sickening bad? It could end up in a ball which always make good video.

After the test run around my court, I'm a bit concerned about the power. It's very light and I need to be slow and steady on the throttle and being a sensorless motor doesn't' help because you have to give it a bit of juice to get it moving. Realistically my street not the place to test it.

It's setup for 4S, but I might start with 2S or 3S until I learn to drive it. Maybe I will start with a smaller pinion too; although, I don't think I smaller have a 5mm 48p pinion in my tool box.

 

[Dan B.]

Looking forward to you sharing your journey, man!
Are you running internal limiters in the shocks for ride height, or just externally? This chassis must feel crazy small after a 1/7 Arrma. Steep learning curve for sure.
So you can’t really adjust the rear for toe? Maybe I’ll drill some of my old pills and see if I can fit them in there and try for 0° or close to it.

 

[mister_uk]

if you do speedrun with these , you must have foams like BSR, and sidewings carbon ones.
and gyro is a must they say.

Good luck man, this can be a beast
BSR foams and gyro makes huge difference.
Stock alloy wheels start slide easy in highspeeds many says

please watch this video

 

[Jerold]

Looking forward to you sharing your journey, man!
Are you running internal limiters in the shocks for ride height, or just externally? This chassis must feel crazy small after a 1/7 Arrma. Steep learning curve for sure.
So you can’t really adjust the rear for toe? Maybe I’ll drill some of my old pills and see if I can fit them in there and try for 0° or close to it.

It's just the external limiter, but I need more in the rear for sure.

Small? More like tiny. Just from the trip around the court it feels so squirelly.

I didn't see anyway to adjust the rear toe. I did find some more holes on the lower rear control arm for camber though.

A splitter up front might help, but I wont' know until I get to speed. Also a way to kick more caster would help it track straight. I maxed out the caster on the Limitless (about 20°) and it tracks pretty straight. The caster helps the wheels to recenter.

if you do speedrun with these , you must have foams like BSR, and sidewings carbon ones.
and gyro is a must they say.

Good luck man, this can be a beast
BSR foams and gyro makes huge difference.
Stock alloy wheels start slide easy in highspeeds many says

please watch this video

Thank you, I saw that video and a lot of others swapping ends too. It's a tail happy little guy. The foams are here but not on the car. I will use the rubber stuff for test and tune then switch to the foams when I start picking up the speed. BTW this whole thing is Tomely's fault. It started with him showcasing the pre-sale and for some reason I thought "Yeah, I need that". and here we are.

The side wings look like a good idea and I've definitely thought about it. I should have ordered them with the better motor mount. I may end up making some. Looks like the bolt on to the Lexan body.

 

[Dan B.]

if you do speedrun with these , you must have foams like BSR, and sidewings carbon ones.
and gyro is a must they say.

Good luck man, this can be a beast
BSR foams and gyro makes huge difference.
Stock alloy wheels start slide easy in highspeeds many says

please watch this video

Too bad GRP doesn’t make tires in this size, would be way better than foams. I can’t imagine trying to control a car this small, with that much power, with foams. Rlaarlo makes those carbon speed run wheels, I might have to check those out.
And yup, you’re right. If everything else is set to 0° and you can dial in a lot of front caster it helps straight line stability in a big way.
I did order tthe sliding motor mount and wish I would have done the winglets as well.

 

[Jerold]

I did some more testing today at a playground with some open space. The total time run is about 21 mins. The motor and ESC got to about 120F, which is pretty good. I limited my power to 50% hopping to keep out of trouble. Reducing the power combined with the wide open space kept it shiny side up this time.

It is a bit squirrelly at only 32 mph and it sort of tracks straight. It will take some time to learn to drive it.

Despite my efforts to limit the travel, it still dragged the chassis just a tiny bit and the surface was decent and reasonably flat too. It could have been some random rocks or something too. Turning the D/R down to like 30% helps but i really think the small wheels are a problem. Now I'm rethinking the suspension height and stiffness.

On the previous test run, ~1min, I had an over current situation. It pulled about 360A and the error will trigger on anything over 350A. That error did not occur; however, I did get some failure to starts and some stalls. It could be that the antennas are just laid flat on the brace and/or interference? I'm not sure but I will add it to the list. I also turned on the throttle delay to avoid current spikes like last time.

 

[Dan B.]

I did some more testing today at a playground with some open space. The total time run is about 21 mins. The motor and ESC got to about 120F, which is pretty good. I limited my power to 50% hopping to keep out of trouble. Reducing the power combined with the wide open space kept it shiny side up this time.

It is a bit squirrelly at only 32 mph and it sort of tracks straight. It will take some time to learn to drive it.

Despite my efforts to limit the travel, it still dragged the chassis just a tiny bit and the surface was decent and reasonably flat too. It could have been some random rocks or something too. Turning the D/R down to like 30% helps but i really think the small wheels are a problem. Now I'm rethinking the suspension height and stiffness.

On the previous test run, ~1min, I had an over current situation. It pulled about 360A and the error will trigger on anything over 350A. That error did not occur; however, I did get some failure to starts and some stalls. It could be that the antennas are just laid flat on the brace and/or interference? I'm not sure but I will add it to the list. I also turned on the throttle delay to avoid current spikes like last time.

Here’s my method…
Take the body off and put the chassis on a flat surface, wheels down. Push down the front of the chassis to get it where you want it for full compression with however many mm’s you want so your chassis doesn’t slap and measure the exposed shock shafts. I use metric Allen wrenches under each corner of the front splitter or chassis to get a baseline, but if you have one of those spiffy ride-height gauges then even better… (It helps to take the springs off and manually manipulate the ride height.) Pull it back up, measure the difference, and that’s the length of the spacers to put inside the shock body to set your ride height. Do the same for the rear. Again, this is for basic ride height, so the external shock shaft spacers/grommets/fuel tube will still be needed to limit compression, as the internal spacers only limit extension.
If you do both internal and external limiters on the shocks, then the droop screws aren’t all stressed out in the plastic arms and you can add much stiffer springs (or shims on the existing springs to increase the preload) and you don’t have to worry about suspension travel for compression or extension.
This has worked well for me, and allows for final suspension settings without totally loading up the suspension. After it’s done, I put the batteries in it for the running weight and set final ride height with the droop screws and corner balance it if you’re that OCD (I am) and you end up with a nicely set up chassis that has no ability to either bottom the chassis or let the rear sink lower than the front.
I know my explanations aren’t always the best, so let me know if you want clarification on anything. Or, just ignore all of this.

 

[Jerold]

Here’s my method…
Take the body off and put the chassis on a flat surface, wheels down. Push down the front of the chassis to get it where you want it for full compression with however many mm’s you want so your chassis doesn’t slap and measure the exposed shock shafts. I use metric Allen wrenches under each corner of the front splitter or chassis to get a baseline, but if you have one of those spiffy ride-height gauges then even better… (It helps to take the springs off and manually manipulate the ride height.) Pull it back up, measure the difference, and that’s the length of the spacers to put inside the shock body to set your ride height. Do the same for the rear. Again, this is for basic ride height, so the external shock shaft spacers/grommets/fuel tube will still be needed to limit compression, as the internal spacers only limit extension.
If you do both internal and external limiters on the shocks, then the droop screws aren’t all stressed out in the plastic arms and you can add much stiffer springs (or shims on the existing springs to increase the preload) and you don’t have to worry about suspension travel for compression or extension.
This has worked well for me, and allows for final suspension settings without totally loading up the suspension. After it’s done, I put the batteries in it for the running weight and set final ride height with the droop screws and corner balance it if you’re that OCD (I am) and you end up with a nicely set up chassis that has no ability to either bottom the chassis or let the rear sink lower than the front.
I know my explanations aren’t always the best, so let me know if you want clarification on anything. Or, just ignore all of this.

That's some good stuff, thank you.

The AK-917 has limited in height adjustments. It has shock collars and droop screws, but there isn't a large range of adjustment given the scale. The bump stops keep the chassis from slapping but they might be a bit too much. It's just going to take some tinkering.

 

[bozo]

Great write-up and good info!
My metal RTR will be here tomorrow...