Axial AX10 RTR Build

['84 Bronco II]

I decided I would throw up a quick build on my OG Axial AX10 RTR. Nothing too exciting, but hopefully it interests someone else.

Prior to stepping up to a proper hobby-grade crawler, I had cut my teeth for a few years on the OG 1/18, and later 1/6, Nylint crawlers. They were a lot of fun for what they were, but they were fragile, lacked power, and repair/upgrade parts were not available. The 1/6 just took up too much space and it was hard to find fun terrain around the house, and I ended up breaking the 1/18 beyond where it was worth repairing.

Here are some pictures of the AX10 RTR as it was straight out of the box

Even straight out of the box, the AX10 RTR (AX90002) could literally run circles around the modded Nylints. What it lacked in finesse it more than made up with brute power and could easy bash through lines that were extremely difficult with the Nylints. However, the center of gravity was too high as was the stock gearing, and the springs were way too stiff.

The first round of upgrades I made were the Axial 55T motor (AX24007), a 10T 48P pinion gear, 2 green "medium" 2.25 Lb/in springs (AX30215), gray aluminum link and hardware kits (AXA1432 & AXA1411). These upgrades definitely helped the crawlability, but the 10T pinion with the 55T motor lacked the wheel speed necessary for some climbs so I would often run the 20T pinion with the 55T motor. The high-clearance rear link helped a bit, but other than that the aluminum links didn't make that big of a difference. I put one green spring on the front axle, and one on the rear axle to improve articulation and keep torque twist at bay. I also ditched the foams and swapped over to some Proline Moab tires that I felt gave a little better performance than the Axial Rock Lizards that came with it. Overall, it was still very rollover prone and I am not sure the tradeoff with the 55T motor was worth it and I occasionally swapped back over to the 27T motor.

I ended up trimming the body some later because the tires rubbed horribly with the additional articulation provided by the green springs.

Around this same time I got the idea that I wanted to build a scaler, so I got an SCX10 frame set (AX30525) and an HPI Bronco body. I also got a couple of sets of 7x70mm posts (AXA1431, mine were actually the red ones since gray was out of stock at the time) to use as upper links since the AX10 uppers were way too short for the SCX10 chassis. The AX10 shocks were way too long, and it sat up stupid high. The driveshaft angles were atrocious It looked kind of neat, but the loss of performance was unacceptable and I wasn't willing to commit to the scale thing, so I converted it back to an AX10 before long.

After wheeling it in that configuration for a while, the wishbone uppers were completely blown out on the axle end. I made a quickie fix for the rear, but there wasn't a simple way to fix the front since the servo is in the way.

This is where I really started going down the rabbit hole and pissing away money

 

['84 Bronco II]

I started by looking at 4-link conversion parts to remedy the shitty factory 3-link setup and I ran across this kit on eBay for stupid cheap, so I decided to take the gamble.

In hindsight I wish I went with one of the servo plate style 4-link mounts because these brackets fit like garbage, don't get the upper links mounted high enough IMO, and are unnecessarily heavy compared to the plate-style mounts. I am stubborn though and spent way to much time sanding to make them fit. Apparently I didn't get any pictures, but the bottom surface needed heavy sanding to get it to match the contour of the axle housings and seat properly so there wasn't a gap at the screw mounting interface.

I was looking at the SCX10 belly plate and realized that it is 78mm wide vs 80mm for the AX10 belly plate, but would bolt righ up to the AX10 chassis side plates. The advantage of the SCX10 belly plate is that it inboards the chassis-side lower link mounts and lowers them at the same time while also lowering the transmission and motor slightly. This helps get the lower links flat and give more clearance when turning the tires in addition to improving the flex steer and removing a major hang up point. It is also double shear

SCX10 belly plate top, AX10 belly plate bottom:

Next I started working on flipping the transmission. The idea here is to move the motor, which is relatively heavy, to the side of the chassis that tries to lift under torque to help combat torque twist. This also requires the belly plate to be installed in the opposite orientation of what's normal. Note the motor is on the left side when facing the spur gear as assembled from the factory.

You have to disassemble the entire tranny in order to flip the input around. The inside of the tranny looked great for never having been opened up before. I took this opportunity to add a little more grease.
Here you can also see the Axial spur gear cover (AX80078) I bought, but ended up not being able to use since I upgraded to a Kimbrough 93T 48P spur gear (141) which does not fit inside. You might be able to use a 90T spur, but even the stock 87T spur is a pretty tight fit.

You need to pop out the plug on the back side of the input gear so you can flip the input shaft around. Just pop the plug into the other case half now.

Ta-da! the motor is now on the right side when facing the spur gear.

 

['84 Bronco II]

I also splurged and bought the Axial HD 43T/13T gear sets (AX30402) for both axles in an effort to further improve my crawl ratio, reduce torque twist, and take some stress off the drive shafts. Stock ratios are 38T/13T for reference (3.31:1 vs 2.92:1). Some people recommend keeping a higher ratio in the front to help climb and steer better, but that just seems like a good way to put too much stress on the drivetrain to me. Assembly is pretty straight forward.

HD 43T/13T gears on the bottom and stock on top. Oddly, the HD gears do not have the shear pin/alignment dowels that engage the differential case.

Here's the axle re-assembled with the eBay-special 4-link truss installed. If you look closely, you can tell where it was sanded to fit. I also used some nylon nuts to bolt the axle back together since the wishbone upper link mount that the upper bolts previously treaded into no longer fits. You can see the angled RC4WD M3 Axial-width rod ends (RC4ZS0833) I replaced most of the stock Axial suspension link rod ends with now that the lowers and uppers are triangulated. These add a little bit to the overall length of the links compared to the stock Axial rod ends.

I had to take off ~1mm from each side of the upper chassis cross-members to to match the SCX10 belly plate.

I ordered a 1500 piece 304 stainless M3 SHCS assortment in lengths from 4 to 45 mm and an assortment of 7mm OD ABS spacers for M3 hardware in lengths from 3mm to 25mm which were awesome since I was reconfiguring a bunch of things on the chassis/suspension.

Here is how I set up the rear suspension. Stock, the tops of the shocks were sandwiched between the gray aluminum 55mm posts and the plastic crossmember I sanded down. I replaced the shocks with 8mm ABS spacers, and used 6mm aluminum spacers to space the tops of the shocks outboard of the chassis side plates. At the axle end, I moved the lower links to the inboard position on the axle brackets and used worn out rod ends as spacers to fill the axle brackets. I then used 3mm ABS spacers to push the lower end of the shocks even further outboard. The rear tires do not touch the springs at all despite how far everything has been pushed outboard. This spring position greatly improved stability while climbing, and along with the lower axle gears and motor relocation, has nearly eliminated any torque twist despite running the Axial red "super soft" 1.32 Lb/in springs (AX30213) at all four corners. With the red springs, I've got just a little static suspension sag so the shocks aren't completely topped out. I would like to have about the same ride height with the shocks at 50/50 or even lower so the suspension could droop out more when it gets bellied out. The inboarded position of the lower links has also helped keep them out of the rocks a lot better.

The 70mm upper links are too long using the stock mounting points with the 106mm 30º lower links and cause the pinion to roll up a lot under compression. I have the material to make some custom links, but I think I want to drill the chassis plates the move the chassis-side upper mounting points down and a little inward if I can. Due to the bend, the lower links get close to binding on the upper links. This is part of the reason I wish the axle-side upper mounts were higher.

Here's how the front ended up. Initially I had them mounted outboard similar to the rear, but there was just no way to clear the tires like that. I did lose some stability having to mount the springs inboard like this, but since the front is usually light while climbing, it wasn't a huge sacrifice. I had to move the lower links to the outside of the axle brackets to keep them from interfering with the shocks. There is still adequate clearance between the tires when turned due to the chassis side now being inboarded thanks to the SCX10 belly. I also upgraded the anemic stock servo with a cheapo Chinese "FeeTech 35Kg" servo. It is a little slow, but that's not a problem for a crawler application. I don't think it actually puts out the advertised torque, but it is definitely a huge upgrade over stock and not bad for under $30 I had to use a plastic servo horn instead of the aluminum one it came with due to clearance issues with the front diff. The plastic horn has held up fine so far.

I added 1.16 Lbs of water to the front tires (total). I think I might remove a little, but it has helped stability while climbing tremendously.

Rear tire without water

front tire with water

 

['84 Bronco II]

Of course, one run after getting it all put back together, the receiver crapped out I was pretty sure it was just the receiver, but I decided I may as well upgrade the ESC too in case that is what was bad. I went with a FlySky GT5 transmitter and BS6 receiver combo along with a Hobbywing 1080. The Hobbywing 1080 ESC did not come with connectors on the motor wires, so I decided to solder on an XT60, since that is what it had for the battery connector, and convert my motor connectors to an XT60 as well. I just used an XT60 to Tamiya adapter for my NiMH battery pack.

The AX10 might not look that different after all of these upgrades, but it is a night and day difference in performance It is so much more stable when climbing and more controllable. The lower gearing with the original 27T motor seems to be about the perfect balance of torque/control and wheel speed. It is really nice having enough steering power to be able to hold lines and not be slipping off because I couldn't turn.

I still need to figure out how to lower the battery in the chassis to further improve stability. I don't like the way axle-mounted batteries look, so I am not going to do that even though that is probably the best option performance-wise. I also need to fine tune the upper link geometry. The wheelbase is currently sitting at ~12 7/8" with a belly height of ~2". I think it needs a little bigger tires and more droop to avoid hanging up on the belly as much. The new servo also seems to be putting a hurt on the stock plastic knuckles and "C"s. I might need to look into doing the XR10 mod and upgrading the knuckles at the same time to get more strength and steering angle.

 

['84 Bronco II]

I just weighed it it and I am sitting at 6.2 Lbs right now.

Here's a current action picture even though it still looks the same as all the other pictures I had to butcher the RTR body a bit more. I would like to lower the body an inch or so, but I am not sure how that is going to look after I trim it again for more tire clearance.

 

[Bmxbry9]

Looks good. I want to outboard my rear shocks like that too, cool to see it done. I have a red cat e10. I've never heard of someone putting water in the rc tires before either

 

['84 Bronco II]

Looks good. I want to outboard my rear shocks like that too, cool to see it done. I have a red cat e10. I've never heard of someone putting water in the rc tires before either

The water helps a ton and actually gets the weight lower than wheel or knuckle weights will. I grew up around tractors and crawlers, so water in the tires for the RC too just made sense, and it is free

I am not sure how good of an idea water would be if you are running foams since you wouldn't be able to have a vent hole, but water actually helps if you are going pneumatic like me since it creates a much smaller volume of air to expand and contract with temperature and ambient pressure changes. The smaller volume of air makes the stiffness of the tire much more progressive as well which helps keep the tires from folding over as much.

 

[carslut]

nice build, i also have a first release ax10 that is getting freshened up. just put a set of ar60's on it and am looking to setup the suspension a bit better than stock. keep up the good work!

 

['84 Bronco II]

nice build, i also have a first release ax10 that is getting freshened up. just put a set of ar60's on it and am looking to setup the suspension a bit better than stock. keep up the good work!

Just curious, why the AR60s over the AX10 axles? I am debating whether on not it is worth doing the XR10 mods to the AX10 axles or just starting with something more up to date.



I attended an informal comp the local club (NMRCC) put on today. I didn't actually compete on the 2.2 "Trail Class" course since no one was able to get past gate 4 (there were 10 gates) and it was apparent I would "point out" from reverse penalties alone trying to get through the first three gates that people actually made it through even if I were able to run them clean. I played around on the 1.9 and 2.2 Trail Class courses after everyone finished, and I think I could be competitive with a steering angle upgrade and doing something to get my battery down lower in my chassis.

I got shit for pictures, and none of my rig, but here they are:

Gate 4 on the 2.2 Trail Class course

Some of the 2.2 Trail Class rigs

The AX10 parked next to the 2.2 course after screwing around on some side lines

Some of the "Sportys"

Group picture

 

['84 Bronco II]

I am debating whether on not it is worth doing the XR10 mods to the AX10 axles or just starting with something more up to date.

Too late, I just pissed away money buying all the parts to do the XR10 mod to my AX10 axles tonight

 

[YotaAtieToo]

Can't say I've heard of water in rc tires before.

I'd think running air instead of foams would make them more likely to bounce on climbs, but I guess you'll see.

I've actually wondered about the opposite, running foam in a fullsize buggy tire

 

['84 Bronco II]

Can't say I've heard of water in rc tires before.

I'd think running air instead of foams would make them more likely to bounce on climbs, but I guess you'll see.

I've actually wondered about the opposite, running foam in a fullsize buggy tire

From what I saw yesterday, I think air/water works better than foams, and you can get weight a lot closer to the ground. Honestly, I think mine handled pure vertical climbs about as well as the other trail class rigs there despite having a nearly 1Lb battery strapped to the highest point in the chassis.

My biggest reservation not running foams is that this club likes to run courses right through cacti

 

['84 Bronco II]

A picture one of the other guys got of my pile at the meet last weekend. He was appalled I was beating the shit out of my AX10 since they are apparently collectors items now

 

['84 Bronco II]

Still waiting on the Vanquish Wraith Stage 1 kit I ordered through RC Mart to get on with the XR10 mod on my axles.

I am debating building my AX10 to the WRCCA Performance Scale class rules or just the local "Trail Class" rules for 1.9 or 2.2 that NMRCC has which are much more lenient.

Here are a couple of pictures of the AX10 out in the Doña Ana mountains.

 

[carslut]

i chose to toss ar60 axles into my ax10 because the ar60 ended up the same width as the ax10 axles with spacers so now i don't need spacers and the diffs line up directly with the t-case output so i get way better drive-line angles. i kept it all setup as a bolt-on swap so all the oe stuff can go back to a stock setup easily. i also test fit the spiral cut gears from the ar60 in the stock ax10 housng, looks like the gears fit fine making for a easy upgrade.

 

['84 Bronco II]

Time for an update.

It took way too long to get the XR10 mod finished and the truck converted back to the SCX10 chassis to make it compliant with the NMRCC trail class rules, but I finally got it back together and competed in my first comp at the San Ysidro Trials area this weekend. Unfortunately, I started out documenting things well, but slacked off later in the build, so I'll have to take some pictures after the build has been completed. It took so long, I have also forgotten some of the details for the challenges I overcame that might help someone else wanting to do the same thing, but you should still get the idea.

First, the parts I ordered for the XR10 mod that snowballed the whole thing. I ordered Axial XR10 front shafts (AX30563), RC Bros 7075 "Burly tubes" to convert to Wraith/XR10 outers, the Vanquish Wraith Stage one aluminum outers (VPS06509), and Vanquish "Currie" XR10-length rear axle shafts (VPS07570). Apparently the Axial XR10 rear shafts aren't available anymore, so I took a gamble on the Vanquish "Currie" XR10 width axles and they ended up working out. Of course, you could be cheap and just run spacers in the rear to match the width of the front as well, but this setup should be a lot stronger.

I went with the RC Bros "Burly" tubes since they don't require you to hack up the stock axle housings like the other "Burly/Beef" tube options on the market do, and they cost pretty much the same amount. I did end up having to do some minor trimming on the stock plastic housings, but I do not blame RC Bros since the outer bearing support pass through for the axle shafts where the outers mount to was pretty out of round.

I slipped the collars that came with the Burly tubes over the housing ends and ran a 21/64" drill bit (IIRC) through by hand so that the plastic housings would seat correctly on the Burly tubes.

Here you can see this leaves the molded features inside the housing mostly intact (Most Burly/Beef tube kits require you to trim this completely out).

Now the Burly tubes seat in the housing correctly.

The next snag I ran into was that the Vanquish rear axle shafts would not fit through the Burly tubes, and neither would the stock ones for that matter. I thought about drilling out the ID of the Burly tubes, but that would make the wall thickness uncomfortably thin where the groove was machined in the OD to avoid having to trim the plastic housing. Instead, I chose to sand down the flange where the shaft engages the carrier with some 180 grit I had lying around.

 

['84 Bronco II]

A comparison of the diameter of the stock AX10 rear shafts and the Vanquish rear shafts.

The next issue was now that I had turned down the diameter of the flange on the carrier side of the axle shafts, the axle shafts would slide too far into the carrier and the drive pin on the threaded end of the shaft would rub on the outer straight axle adapter. To fix this I used a washer (#10 or 4mm I think?) to seat the axle against the carrier.

This caused the axles to stick out slightly too far and bind on the outer bearings in the straight axle adapters. I gave the axles a calibrated tap with a hammer to "cone" the washers which worked out perfectly to seat the axles at the proper depth.

The spline engagement between the RC Bros Burly tubes and Vanquish Wraith outers was extremely tight and basically a press fit. I did some light sanding primarily to the OD of the splines on the Burly Tubes to get them to the point I could barely press them together by hand. I didn't see a need to run the bolt to clamp the Vanquish outers to the splined ends of the Burly tubes, and the hardware supplied by Vanquish didn't really work anyway. The XR10 conversion added 57g to the rear axle and over a full inch to the WMS width.

 

['84 Bronco II]

The Axial XR10 shafts weren't quite as beefy as the Vanquish shafts I used in the rear, but still a decent upgrade over the .134" stock AX10 shaft diameter. However, the Axial XR10 shafts did not require any modification to fit through the Burly tubes.

Unfortunately at this point, I hit another snag. When I went on to the front axle, I realized that RC Bros had mixed a mod-required version of their Burly tubes in with my order. They eventually sent me the correct part, but it took them over a month to get it to me

Once I had the right parts, the front went together pretty smoothly after the experience I had gained from doing the rear axle. The front picked up a total of 70g over stock.

 

['84 Bronco II]

Now to mount the axles in a class-legal SCX10 chassis, I removed all of the stock cross-members, and shock hoops to be able to get the ride height as low as I wanted without any interference between suspension components. I 3D-printed new shock hoops, a battery tray, boat-sides for electronics mounting, upper link/servo mounts, upper links, and lower coil seats for the shocks. I would have liked to get the body mounted lower so that the molded bumpers would be at the correct height in relation to the frame rails and trim the sides of the body up, but I would have had to butcher the body for tire clearance and to stick the rear shock towers through the body. I didn't think it was worth it, so I lowered the body until it was sitting on the rear shock towers and called it good.

Completed chassis:

Rear shock towers:

Front Shock Towers with integrated body mount post receivers:

Battery tray:

Boat side for electronics mounting:

I ordered some 6061 aluminum and 302 Stainless 3/16" rod off Amazon to make links out of along with some Traxxas 5347 M4 and DKKY M4 offset rod ends. I had a hell of a time trying to run a die over the rods which I don't understand since the max OD for #10 thread is .190" and both of these rods were slightly under 3/16" I actually ruined a #10-32 Gear Wrench die trying to cut threads on the 302 stainless with plenty of lube and ended up using the 6061 I was planning to use for upper links for the steering linkage (I ended up keeping the 3D printed upper links that I was planning on replacing with metal). I had to cut the threads in the aluminum with a #10-24 die, but it was still not happy and looked more like it was cutting 50% threads on the aluminum rod despite obviously being too tight on the rod. Is there something I am missing, or are Gear Wrench dies just junk?

The steering angle I have after the XR10 mod It has more to give, but I am hitting my springs and any more and the U-joint hop gets pretty bad.

I spent way too much time calculating the rates and lengths of springs I needed and ordered them from TheSpringStore.com, but the springs I ordered were not going to arrive before the comp. I printed up some lower spring seats that dropped the springs down and eliminated the preload on the springs with the shocks at full extension. This helped get the ride height closer to where I want it with the current Axial "Red" 14mmx90mm springs I had previously installed.The spring comes loose on the shock at full droop now, but I don't think that is really much of an issue on a crawler. Currently my belly height is about 2.5". The stock AX10 shocks have roughly 35mm of travel and are 115mm eye-eye. I am about 50% up/50% down on the front shocks and 57% up/43% down on the rear shocks.

 

['84 Bronco II]

I also decided to upgrade to 3S LiPO from the 6S NiMH packs I was previously running, and WOW, what a difference. I have plenty of wheel speed now despite my 57:1 overall gear reduction with the stock brushed 27T motor. I went a bit overboard and got a 5200 mAh pack since it was only $1 more than the 3200 mAh pack from the same company I think the battery size definitely hurt me in the comp and I should probably buy a couple of 600-1000 mAh packs for comps. My weight distribution is currently around 65% front and 35% rear (~6.4 Lbs total), which makes it hard to pop the front up obstacles and not push when I have poor traction.

I used this stuff from Walmart to mount the electronics. It is easier to mess with than Velcro, but I am not sure if it is as secure. My receiver came unattached after a hard roll, so I might change it later.

 

['84 Bronco II]

This was my first comp actually competing with NMRCC and it was at the San Ysidro Trials area as I mentioned in one of the previous posts. It was pretty cold and wet, but it was a super cool area I had not been to yet. I showed up to the comp with absolutely zero run time on the car and zero comp experience. There were 5 guys in the 2.2 trail class, and 3 courses.

I ran last on all three courses, which was nice since it let me watch the other guys and see what worked or didn't for them. It kind of sucked too though since some of the obstacles were dug out or wet and muddy by the time I ran.

The first course was the easiest aside from the last obstacle that everyone struggled on. I ran the first couple of gates and first bonus clean. I skipped the second bonus which was a U-turn on a very off-camber slab since I didn't feel like I could do it without rolling. In hindsight, I probably could have done it, but I had basically no run time with the car at that point. I tagged the cones on the next couple of gates I could have probably cleared if I had taken my time and repositioned to see the cones from a better vantage point. I screwed up the third bonus since I was flustered from hitting the last two gates and it had gotten pretty dug out from the previous run and covered in mud. I did alright through the rest of the course until I got to the last gate, and I just couldn't get up it. Everyone else struggled pretty badly on it too, but I think my relatively small tires killed me. I made many attempts, but ended up timing out.

The second course was brutal. I honestly didn't think it was doable when I walked it, but a couple of guys completed it. I just could not make the third gate (honestly I was surprised I made it through the first gate ). Here again, my small tires killed me. I struggled to even get two tires through the gate to get progression and head to the next gate, but the XR10 width with my small tires was getting me hung up on my axles hard. I forget if I ran out of time or ran out of points here, but it was ugly.

The third course was pretty cool (although gates 9 and 10 were bullshit). I did alright until I got to gate 7 which gave everyone else trouble too. I got my tires packed full of mud and could not get traction to save my life. It was nasty and I ended up pointing out after multiple roll overs.

I had a weird issue with my servo throughout the comp where I would lose most of my steering in one direction and the neutral position was biased way over to the opposite side. I do not remember if it was consistently right steering I lost or not. At first I thought my servo horn was slipping on the the servo splines, but then after trying to tighten it, I realized it was still in the correct position when the wheels were pointed straight If I power cycled the truck and transmitter, it would usually be fixed momentarily then happen again pretty quickly. I am not sure if the servo is pulling too much power and I need a dedicated BEC, but it never did this before when I was running my 7.2V NiMH packs.

I am sure you can figure by now, I didn't do well. I ended up getting last place, but I had a blast. I think if get some bigger tires, drop down to a 600-1000 mAh battery pack, and figure out what is going on with my steering I could be competitive. Also, the SCX10 chassis is very limiting. Currently, the chassis rails bottom out on the rear axle housing and tie rod before the shocks fully bottom out, and my ride height is still higher than I would like. I think I might look into designing my own chassis next.

Here are the results of the competition:
1st: -99
2nd: -68
3rd: -42
4th: +20
Me: +82

I am super happy with the new steering angle, and it is definitely a game changer, especially for comps. I am also pleasantly surprised all the 3D-printed parts held up, especially the links. I had some fairly hard rolls, and had to get more abusive than I would have like several times. After the courses, I ended up loosing an upper knuckle screw and the knuckle started trying to fall off. I guess I need to put some thread locker on those screws or figure something else out.

 

['84 Bronco II]

I think the servo issues during the comp I mentioned were just my FeeTech servo dying. After running the rig a bit more during the week it quit altogether. I took it apart for shits and grins to see if I could fix it, but no cigar.

I am thinking I killed it with heat. I was working the truck pretty hard and the servo was too hot to touch at the end of the run. The next time I went to run it, the servo barely moved at all and had no torque. I also found out that this servo was specified at 3.9A stall current at 7.4V and my Hobbywing 1080 only puts out 3.0A at 7.4V. That explains why the servo always seemed a bit underpowered for its rating. The new 1080 G2 can do 4.0A at 8.4V, but I feel like that money would be better spent on a direct power servo or brushless-capable ESC at this point.

I wanted the new NSDRC RS700 V2, but it is not quite available yet and it is pretty expensive. I had made plans to meet up with some co-workers this last weekend to do some crawling, so I needed a replacement quickly. I ended up ordering another Amazon special which showed up 34 hours after ordering it
It was listed on Amazon as an "Injora" servo, but came in a box that was branded "SPT." It is brushless, 8.4v capable, and a little lower profile. It is definitely a lot faster than the old servo, but on 7.4V, the torque seems about the same which is a bit lacking with the really short Vanquish steering arms on my truck.

The springs from Acxess Spring showed up. I installed PN PC032-625-10.000-SST-3.407-CG-N-IN all around and my ride height ended up just about where I wanted it. I might need to add small preload spacers to the front to keep the frame rails off the tie rod better, but I am really happy with the balance of the suspension now. The Axial red springs were way too stiff with my current setup.
Comparison with the Axial red spring:

Some action shots from Sunday:

 

['84 Bronco II]

A couple more updates:

The screws holding my knuckles on were constantly backing out and falling out which was no bueno. I picked up the correct Vanquish brass knuckle bushings with the flange this time so I could properly torque the screws. The stock plastic bushings would just crush and bind up the knuckle if you tried to give them a proper torque. I also used 12mm screws with washers and put some red thread locker this time. Even torqued as tight as I felt comfortable with, the knuckles still turn easily with no perceptible bind. So far, no more backing out issues

The last time I was running it I lost the driveshaft pin on the front driveshaft. I was just going to buy more driveshaft pins, but this Injora driveshaft was only a couple of bucks more than a pack of pins themselves, and I figured it was worth a couple of extra bucks to have a spare driveshaft. Not bad and all steel for only about $10.

I also upgraded to an 11T Team Brood 5 slot motor. It is smooth and has more wheelspeed than I need, but the throttle input is really jumpy now. I might swap over to a 10T pinion from the 12T I have been running lately.

I bought a 1400mAh 3S LiHV to cut some weight. I moved the receiver over to the passenger side boatside and mounted the battery on the driver side boatside since that got the battery a little lower than mounting on the battery plate I printed and helped balance the rig a little better. The front end is noticeably lighter now though when I am nearly vertical, so I might add a little more water to the front tires. It definitely seems to steer better now with the weight off the front.

I bought some J-Concepts Landmines since their tires are supposed to be the shit, and the Landmines are the shortest (5.79") of their 2.2 offerings. I think they are way too big and soft though, so I think I am going to sell them off and try something else. I would really like a good tire in the 5.25-5.5" tall and 1.75-2" wide range that is stiff enough to run without foams. Maybe the Proline SXs or low profile Hyraxes will be the ticket in the G8 compound.

 

[carslut]

rad build! keep the updates flowing.

 

['84 Bronco II]

rad build! keep the updates flowing.

Thanks!

 

['84 Bronco II]

I did a bit of prep to get the car ready for the comp today. I hadn't run the car in weeks, but on my last recreational run, I noticed my servo/upper link mount broke. This is the first of my 3D printed parts to fail (PLA). It lasted well enough that I added a tiny bit of thickness to the servo mounting posts; it is a tight fit between the frame rails when articulating. I also noticed it had become distorted from the heat of the servo (look at the leading edge near the screw holes. I really need to get my printer set up to run the 5Lb roll of carbon fiber impregnated Nylon I have for better strength, stiffness, and heat resistance.

I also found that the M3 stud between one of my rear aluminum lower links and the rod end had bent. Must have been from some of the back flips I was doing off some slab climbs. Surprisingly the RC4WD bent rod end was still useable.

The stock Axial plastic ball offset rod ends I was using on my upper rear links were pretty slopped out, so I finally replaced them with some of my RC4WD offset rod ends with metal balls. This required shortening the upper links 15mm which was pretty easy with my hollow printed upper links. I am actually pretty impressed with how the printed upper links have been working on the truck, especially considering the bent stud above I have no intention of replacing them with metal at this point.

The Injora/SPT servo was working okayish considering how much I paid for it, but it would over heat and start doing funny stuff. The splined output for the horn also had an unnerving amount of slop in it which I believe caused/contributed to the servo shake I would get when there was little to no load on the tires. I got tired of dealing with servo issues, so I finally ponied up for a direct power servo which I should have done from the beginning My advice for anyone wanting to get into competing is to avoid the frustration of Chinese cheapos off Amazon, and just get a good direct power servo from the get go. I had been eyeballing the NSDRC RS700V2 for a while, but it still isn't available, so I just picked up a Holmes Hobbies SHV500LP which had pretty similar specs. I went ahead and got another Protek 1400mah 3S LiHV as well so I can swap battery packs between courses if I need to and not run the 5200mah monster pack. I had a brain fart and ordered a 12T pinion gear instead of a 10T which seems really hard to find in 48P these days

I also picked up a set of 1.9 JConcepts Ruptures and some China-special aluminum beadlocks off Amazon ($11 shipped to my door for the wheels ) so I could run in both the 1.9 and 2.2 classes my local club does. The Ruptures are supposed to be the shit and are the same diameter as my OG Moabs so I figured it should perform pretty similarly. The Ruptures are like baloney skins and don't have any support at all without foams. I tried running foams in the back and water up front, but that was a terrible idea. I immediately drained the front tires and stuffed foams back in after the first course. Of course that completely ruined the weight balance of my rig and moved my CG way up. Even with the foams, the Ruptures really wanted to fold over laterally even worse than my Moabs without foams I guess I need to look into brass knuckles or something to get low slung weight on the front axle and figure out some better performing foams.

I ran 3 courses for each class, and this area was pretty hard on the rig. It was on an a highway berm erosion control area made of concrete and volcanic rock from the area and the courses generally worked their way up hill. Roll overs were common, and it was a long way to the bottom. I ended up bending my aluminum drag link and perhaps my tie rod too. I need to look at things to assess the full extent of the damage, but the rig is still drivable after all 6 courses.

The 1.9 courses were a disaster for me. On the first course, I had water in the front Ruptures, and I punctured one after jumping the truck through the first gate monster truck style The 11T Team Brood motor was way jumpier than I remembered. The tires were folding over all over the place and I was barely able to control the truck. I ended up pointing out at the 4th gate. I broke down the front tires, dumped the water out, and reinstalled foams before the start of the second course. I didn't have time to swap the motor out, so I struggled with control issues, a nearly 50/50 weight distribution, and higher COG. I remembered the 11T motor being kind of touchy, but today it felt almost undrivable. I timed out at the 7th gate. I got the motor swapped out to the original Axial 27T and things were much better, but the stability was still really lacking. I don't remember where I ended on the last course, but it was my best run.

1.9 Results:
1st: -114
2nd: -69
3rd: -20
4th: +28
5th: +61
6th: +62
Me: +92

The 2.2 course were pretty brutal. Everyone was struggling a bit on these courses. Maneuverability was killing me on these courses, and with the stock AX10 wheels and my XR10 width axles I was one of the widest rigs if not the widest. I didn't finish any of the courses, but things weren't nearly as ugly as the 1.9 courses for me. I ran out of points on the 4th gate of the first course which gave everyone grief. I had my battery pop out on the second course early on and ran with it dangling to avoid the 10 point penalty. I ended up getting to the 5th gate which I just could not get up. My battery popped out again on the final course, but I chose to take the 10 point penalty and fix it. This caused me to point out on the third gate when I killed a cone.

2.2 Results:
1st: -53
2nd: -12
3rd: +84
4th: +98
Me: +102

I really need to work on my competition nerves. I get all worked up and make a bunch of stupid mistakes that I know are dumb at the time. I really need to improve my maneuverability and the tire roll situation. I am thinking maybe an Element transmission for some front overdrive while keeping the low axle gears and a bit more caster to improve the negative camber gain while steering. The OG SCX10 chassis is really limiting me as well and needs to go. I can't get it any lower because the frame rails hit the axles and tie rod, and the upper link geometry is limited and the chassis lifts under traction rather than sucking down.


Here are a few shitty pictures, of course, none of my rig.

 

['84 Bronco II]

So after the last comp, I ordered some eBay Chinese knock offs of the brass Dlux knuckles to try and get some front weight bias with the 1.9" wheel setup. They weigh the same but are ˜$25 vs $84 and looked nearly identical. They were also cheaper than the brass add-on weights for my Vanquish knuckles as well and got me longer steering arms in addition to weighing slightly more. 102g per knuckle for the Chilux vs 13g for the Vanquish.

I went ahead and put some red thread locker on the screws holding the upper and lower pivot plates in place (you can see some of the rough machine work in this picture).

Unfortunately, the saying that you get what you pay for is true, and they were machined incorrectly. They pulled the axle shaft out too far so that the U-joint was not in the axis of the knuckle pivot and caused some serious binding. The hardware that came with them was also pretty shitty. I rectified this by getting some "narrow" 8mm washers from my local hardware store and drilling out the wall between the inner and outer bearings. The outer bearing has a 13mm OD, so I used a 1/2"step drill to drill it out and used a Dremel with a 1/4"sanding drum to take the lip off. Unfortunately I didn't take a picture after I drilled and Dremeled.

A picture of the thin separating wall you need to drill out with a 1/2" drill

With this mod, the axle sits pretty close to where it should for bind-free turning. I should have listened to DWT though and not have installed the outer axle tube bearings when I did the XR10 mod since they cause some binding at high steering angles I had to make some new steering links and chose to install the drag link in the shorter hole on the servo horn since that still gives me all of the steering throw I can use and helps increase steering force. Steering power is the best it has ever been now, but I still feel like I could use more. Maybe I just need to lose more weight since I have 528 oz-in with reasonable length steering arms now.

I also reinstalled the 11T 5-slot Team Brood motor and figured out that I had the Exponential function on the GT5 transmitter adjusted 100% in the wrong way (negative instead of positive) After adjusting the "Start Punch"setting on the HW 1080 to the lowest setting and adjusting the throttle exponential setting on the GT5 to +50%, the 11T motor is extremely controllable. I might add some "Start Punch" back in or lower the throttle exponential setting some more since it is a little slow to get on the power if you need a good size bump, but it can low speed crawl super technical lines just fine now.

Went to another comp today, but most people bailed, so it was just the club president, me, a guy with a new 1.9" build, and his young son with a completely uncompetitive rig (SORRCA Class 2? It had a winch ). Due to the low turnout, we set up a few courses mostly for fun, but the president still cleaned house like he did at the AZ state comp . I finally feel like I am getting close to having a legit comp car. I still don't have enough forward weight bias with my 1.9" wheel setup and need to figure something out as well as some better foams since the ones that came with the J-Concepts Ruptures are way too soft and they fold over worse than my old-school 2.2" Proline Moabs with no foams With the brass knuckles I now have too much weight on the front with the water-filled Moabs since my rear falls off the line when I work the steering. It's easy to dump some water out though. I feel like I did alright, but there weren't many people to compare to. I need to get some overdrive badly, I am still too wide, my tires are too small, and my chassis is still preventing me from getting the COG as low as I would like. Here are a couple of pictures:

 

[DWT]

You're in NM, you ever run into Scot McKee? If you do tell him White-Trash said to fuck off. He'll know exactly who and laugh about it. Good dude even if he is involved with ottsix.


Those knockoff knuckles are hit and miss. I have a set that fits fine but the hardware is all tapped at an angle.

I can give you a cheaper recipe for a kick ass rig if you want it, I found a cheap chassis on Amazon and I've been drinking with it for a year or so. Solid performer for cheap.

 

['84 Bronco II]

You're in NM, you ever run into Scot McKee? If you do tell him White-Trash said to fuck off. He'll know exactly who and laugh about it. Good dude even if he is involved with ottsix.


Those knockoff knuckles are hit and miss. I have a set that fits fine but the hardware is all tapped at an angle.

I can give you a cheaper recipe for a kick ass rig if you want it, I found a cheap chassis on Amazon and I've been drinking with it for a year or so. Solid performer for cheap.

Scot has been at most of the competitions I have been attending, I'll have to pass along your message the next time I see him

I am open to hearing what you came up with because I am all about value

 

['84 Bronco II]

So I decided I needed a new chassis, links, and rear axle before the State Championship competition and tore it completely down. I decided to weigh a few parts while I was at it, but I ended up scrambling to get it finished in time, so I didn't get a weight on the new chassis when I finished it, or some of the details.

The old SCX10 chassis with my PLA parts:

Axial 3-gear transmission with a 93T 48P spur gear sans motor, 86g:

I had really been wanting to upgrade to a chassis I could set lower than the SCX10 chassis and get some overdrive in the front. I was looking into several transmission options, but DWT pointed out a Capra axle would get me the front overdrive in addition to more rear ground clearance between the portals and high pinion while being cheaper than most transmissions. I had assumed that the Capra axle would rotate the wrong way due to the 2-gear portals, but it works perfectly with the XR-mod AX10 front axle. Regardless, you can flip the 3rd to rotate backwards without any modification if you needed to.

I used a stock Axial Capra housing (AXI232005), Axial hardware (AXI235016, AXI235014, & AXIC3165), Axial stub shafts (AXI232008), SSD 27T/8T overdrive diff gears (SSD00349), SSD Locker (SSD00196), Treal 19T/16T Overdrive portal gears (X0034LUD9B), Vanquish axle shafts (VPS08083), and a TRB bearing set (140041).

With the overdrive diff gears and overdrive portal gears, my rear axle ratio works out to 4.01 vs 3.31 for my front axle which is about a 21% overdrive on the front.

The new parts:

Link to the cheap Carbon Fiber Amazon Chassis

The Capra/AR44 axles have a 1.063" ring gear vs 1.482" for the AX10 axles. Hopefully between the hypoid design and ˜19% reduction provided by the portals the strength is similar. The extra ground clearance is certainly welcome though.

I am not sure why this was the case, but the SSD pinion had some clearance issues with the SSD locker. I just chucked the locker up in my cordless drill and sanded that side of the locker down a bit.

The other big issue I ran into is that the Treal 16T/19T overdrive portal gears do not fit in the stock Capra housing. I used my Dremel with a 1/4" sanding drum to remove the bulk of the material, then I wrapped some sandpaper around a 1/2" drill bit to finish it up. I was a bit uncomfortable with the amount of material I had to remove, but it's holding up so far; you have to really cut into two of the screw bosses for mounting the portal cover.