Axial AX-10 RTC to Comp Build

[mxracer33x]

Ill try to keep all my experience with my AX-10 RTC documented here. I've been out of the R/C loop for about 5 years, so am not a complete noob, but am considerably behind on the current products.

RTC UPGRADED COMPONENT LIST: (alot of the RTC parts are already upgraded from the RTR kit, so some things wont be an issue)
Driveline outputs are hardened steel units. I have not had a driveline problem yet. I read alot of posts about this and worried some till I realized they didnt have the steel units stock.
Stock AS-2 Steering Servo Torque = 132 oz/in @ 6.0v (per one of Benders Posts)
Stock Servo had Futaba Splines, if your going to go aluminum servo horn.

Purchased an AX-10 RTC from A Main hobbies (LHS).
Bought supplies to makea couple 1600 nimh sadddle packs.
Dusted off my Tekin 112C Charger

right out of the box it worked ok, it was obvious it was to light in the front, as it hopped on anythign you tried to climb, regardless of traction.

I read through Benders Budget RTC build Blogs on Axialracing.com (HERE & HERE and performed most of the mods listed there right away. (drilled wheels, chamfered foam, put 6oz/3oz in wheels, ran the antenna inside the body, used 5mm shims between the hexs and knuckles on the front axle to tighten up the steering)

I had severe issues with the ESC shutting off and not reacting when using the throttle and steering simutaneously. It was suggested I use a BEC. Ive been running a Castle BEC since. It made a tremendous difference, it actually works now. The BEC is an absolute must for any RTC owner.

I lowered the body and moved it forward about 3/4" each way. This required a bunch of trimming to the front. I thought I was pretty cool and had a nice looking trim job, then 2 days later I found one of benders threads and he had already done it, go figure.

Ive also read through and done some of the things on the AX-10 build from the tech section HERE at rccrawler.com. Starting with a new RTC alot of the things listed are already done. The biggest being the holes for using longer upper links are already in place. Others are better fasteners to help keep clearances at a maximum.

My next step was to go to aluminum links and revo rod ends. I picked up some aluminum stock from the local OSH hardware store. 1/4" OD and a slightly large 1/8" ID. This made it perfect cantidate for 8-32 threaded rod without drilling. I picked up 4-12" sections of the aluminum tube and 12" of 8-32 stainless threaded rod. The tap fit prefectly and I built all my lower links using the Traxxas Revo rode ends, also tapped to 8-32 without drilling. I made the front tie rod and drag link at the same time, but used the offset rod ends out of the hardware upgrade kit you would use for swapping in the Axial color packs. I will probably use the bent rod ends for my upper frame mounts if necessary as well. Kyosho has some Offset rod ends and balls that are said to be stronger than the Axial offset ends and the LOSI 17* rod ends are said to be stronger than the axial bent ends as well. I havent had a chance to get ahold of either one yet so I cant compare lengths to know if I will have to trim the links to fit them.

I ordered a set of the TCS Link plates to get my 4 link done. Hopefully they show up today or tomorrow so I can get the uppers completed. This thing crawled alot better than I could have imagined today on some natural terrain in our local park. I will definitly bring the camera next time.

A pic after lowering the body, before the lower links got done.

 

[mxracer33x]

When trying to decide what springs to try next I made a point of looking at what stock axial springs are included on the RTC. # reds and one Blue on the left rear to fight torque twist.

3 - Spring 14x90mm 1.32 lbs/in - Super Soft (Red)
1 - Spring 14x90mm 3.01 lbs/in- Super Firm (Blue)


Here is a pic of the newer chassis side plates. These plates have a set of holes drilled for longer a 3 link or 4 links to attach. Similar to the article mentioned above from rccrawlers Tech section.

Here are my 4 link materials and Tools used to build them.

Aluminum Tube .25" OD x .049" wall. Perfect for an 8-32 tap
Large Revo Rod ends with Hollow Balls
8-32 Threaded Rod

Calipers, for measuring lengths. You can set the length, then use the end opposite the tubing end to scribe your cut mark
8-32 tap and handle
Small Tubing cutter, a good RIGID brand cutter makes a super clean, accurate cut
A strong Tubing bender, for bending High Clearance Links
Sandpaper
Countersink Bit, for cleaning up the links after cutting and threading

I thread the links in 2 runs with the tap. This prevents galling the threads when removing the tap.

A pair of finished uppers

 

[mxracer33x]

I have been having a couple issues with the stock electronics. Knowing they are cheap Ive been trying to be patient. This was upposed to be a budget project for my daughter and I, but before Im done it will be over $700 Im sure.

BEC as mentioned took care of the Servos amperage draw. the more its used it seems to be loosing steering range. It turns alot further once direction than the other, with no load and nothing binding, and the servo centered properly. Time for a 5645 or Ace very soon.

ESC or radio Glitching. I am still trying to get a definitive answer for this problem. The car will "loose power" steering and motor current are killed. The steering will stop where it is and what little drag the motor has is gone and it will roll away if its climbing when it shuts off. The odd part is, on the radio, switching the steering switch to reverse steering, will "wake it up" and allow it to function. Sometimes you can switch it to refverse adn back and all is good. Sometimes only reversed steering will function, after a minute of use it can be returned to normal. Having the motor affected as well makes me think ESC, but I cant see why reversing the steering would make it function again.

I plan on either a Holmes Torquemaster ESC or a Tekin FXR, a new servo and most likely a Futaba PM-X radio to control a dig tranny but I dont want to do it all at once and not actually know what the problem is.

 

[mxracer33x]

I finished my 4 Link. Mounted on TCS Link Plates. No testing yet as it started raining on tuesday.
Wheelbase was at 12.5 with the rear lowers slightly longer than the fronts, about 1/10th of an inch. I made the uppers the same length and trimmed the rear lowers and its now 12.25" I wish I would have just made the rear uppers longer to get the pinion to point up a bit more. Ill prolly swap the bent lower to the front and make some more uppers and lowers for the rear.

2.25" - 2.5" Belly

Next will be spring rates. My LHS doesnt stock the Losi Springs, so Ill have to order some or run the Axial springs instead.

Still trying to hold off on replacing al the electronics at this point. I really dont want to spend the $$$, but decided on a Tekin FXR and 45T kit, Futaba PM-X 3 ch 2.4Ghz, and a Futaba S9156 Servo.

4 Link Setup

 

[mxracer33x]

Ordered some parts yesterday:
Tekin FXR
Futaba PM-X Tx/Rx
Futaba S9156 Servo

Everything should be here this afternoon. Time to clean up the wiring and move some stuff around.

Now if BWD would release his new Dig....

 

[NorCalScaleCrawlers]

so did you see that are crawling spots at that pit are under water i went to go work on it on saturday and it was under 6 feet of creek water

 

[NorCalScaleCrawlers]

btw i like the build so far nice job on the custom links

 

[mxracer33x]

Narrowed my glitching down to the Stock RTC Radio. Ill be sending it in for a replacement. Something is wrong internally, loose connection, you tilt it one way or another and it will work or not.

I picked up my Tekin FXR and Futaba S9156 servo:mrgreen:. Wired it all up, moving the ESC and reciever back to the rear axle. I got the ESC set pretty good, the drag brake set high seems to "induce" alot more torque twist since the motor doesnt get free when not on the throttle, so it takes some different driving technique.

Setup a Futaba 3PMX radio, very nice for the $$$. The whole car works so much better electronically now. EPAs and all the steerign/throttle speeds set, working great. I origiannly planned on getting an FXR and 45T motor to get some more wheel speed, Im glad I didnt get the 45T motor. The stock 55T really came to life wit hthe good quality ESC, a 45T would prolly be way to much motor for me.

Ill upload some pics of the setup tonite.

 

[mxracer33x]

I am unsure of my 4 link setup. Ill get some good pics of the mouting and some lengths to see if anyone can help me out. My at home "course" is small but has some very difficult features, and my problems may be simply expecting way to much out of the rig. Ill get some video for that.

While trying to test some setups I added more weight to the front tires to see the effect. It was dark so I dont really have a ggod base right now, but it didnt seem to help. I went from 6oz in the front tires to 11oz:shock:. My total wheel/tire weight is not 16.4 oz. Yikes, it was 11.7 oz. How much weight do you guys typically run? total car weight was 6lb 2oz. I was happier at the 5lb 8oz mark from before I think.

Some natural terrain testing this afternoon. Pics and video as well.

 

[mxracer33x]

Some videos from this afternoon. I need to get some time to test the fronts with the added weight and without on the same course to tell if it is better or worse. Ill get some pics ofthe 4 link setup tomorrow, I still need to get all my duck hunting gear ready and be up at 3 am tomorrow.

Short climb, undercut and hard to see much, but its there.
http://www.youtube.com/watch?v=isGFzAlZ8n8

Fun sidehill rock with drying moss on it, makes it a little unpredictable.
http://www.youtube.com/watch?v=6HPz8ydf5jU

small ledge taht matches the wheelbase, alot of wheelhop
http://www.youtube.com/watch?v=2E80raRmoq8

 

[n8big]

Very nice build thread!

Then no posts for a couple of months?

Come back so we know where you are at.

 

[mxracer33x]

I picked up and SSS roller and have been busy with that. I am in the process of trading for some parts so the AX-10 will be getting some more attention very soon. I pulled the FXR and 9156 off for the SSS and put the stock stuff back in it for my daughter. Next week Ill wire in a Rooster Crawler that should help get it up to speed. Ill pick up a set of tires and foams soon to get some more ground clearance back as well.

 

[perry3182]

If you're not getting a dig any time soon I would suggest mirroring the tranny, it will help you with some of the torque twist.

 

[TSK]

Your 4 link setup doesn't look right. As in it's not properly triangulated. The was you have it set up, both "triangles" are facing the same way. The way you have it knowm you probably have some funny axle movement.

So you need to move your loweres either out at the axle, in at the skid plate, or both.

Perhaps mount your lowers, just inside of where your shocks are currently 9based of the pic) and move your shocks to where your links are 9in the picsture)

 

[mxracer33x]

Your 4 link setup doesn't look right. As in it's not properly triangulated. The was you have it set up, both "triangles" are facing the same way. The way you have it knowm you probably have some funny axle movement.

So you need to move your loweres either out at the axle, in at the skid plate, or both.

Perhaps mount your lowers, just inside of where your shocks are currently 9based of the pic) and move your shocks to where your links are 9in the picsture)

I made a delrin skid and mirrored the tranny, and moved the links by the shocks. The old link position induced alot of axle steer. If i was planning on keeping this chassis forever I would prolly get a STRC skid with the links inboarded, or get some more delrin and mkae another. Im not sure if I can get the SSS to flex as much as id like, so I may be looking for a MSD or SWX and some shocks, then use whichever one I dont want for comps top this one.

 

[TSK]

I made a delrin skid and mirrored the tranny, and moved the links by the shocks. The old link position induced alot of axle steer. If i was planning on keeping this chassis forever I would prolly get a STRC skid with the links inboarded, or get some more delrin and mkae another. Im not sure if I can get the SSS to flex as much as id like, so I may be looking for a MSD or SWX and some shocks, then use whichever one I dont want for comps top this one.

Realistaclally, a SSS can get about 55-60 degrees of articulation (at least 5" under a tire), which IMO is more than enough to be a capable crawler. too much articulation will get you into more trouble than not, as the rig will tend to twist and get bound up.

How much articulation are you looking for?

 

[mxracer33x]

Realistaclally, a SSS can get about 55-60 degrees of articulation (at least 5" under a tire), which IMO is more than enough to be a capable crawler. too much articulation will get you into more trouble than not, as the rig will tend to twist and get bound up.

How much articulation are you looking for?

My problem has been getting it to flex at all, atleast without a bunch of wheel weight. I moved my links and torsion arms around again, but havent been able to test it since then. Basically it seems the "spring rate" of the arms is to high, but it is more likely due to incorrect link length/torsion arm length and binding.

I moved the arms back to the "stock" location and they seem alot more "free" or soft than they did when inboarded. Ill update my SSS thread when I get a chance to get it dirty again, damn 14+ hours of work a day and rain are killing me.

 

[TSK]

My problem has been getting it to flex at all, atleast without a bunch of wheel weight. I moved my links and torsion arms around again, but havent been able to test it since then. Basically it seems the "spring rate" of the arms is to high, but it is more likely due to incorrect link length/torsion arm length and binding.

I moved the arms back to the "stock" location and they seem alot more "free" or soft than they did when inboarded. Ill update my SSS thread when I get a chance to get it dirty again, damn 14+ hours of work a day and rain are killing me.

And you don't necessarily need wheel weight to get a good amount of articulation. i run no wheel weigts at all and i can get each wheel to get in the air about 5" with no problems.

Well i noticed the lowers are longer than the torsion rods if left as is. They either need to be triangulated more at the skid, or shortened up a bit to bit to match the eye to eye of the torsion rod. Both the lower link and torsion rod need to inboard of both axle tabs. Also make sure that the bolt isn't too tight as it'll cause binding.