95PGTTech 1/10 2WD ECX Ruckus build

[95PGTTech]

“Fixed” my 45a Tazer ESC by internally bypassing it. Brother was right, somewhere in the board is an open (probably at whatever regulates the power from the lipo batt input down to 5a or whatever it should be at the diagnostic port). Next time we get together he can laugh at my soldering and we can see if we can find the original problem and address it but for now I have what I want back a test mule.



Addressed the camber arms popping off by flipping what side of the rear hub they bolt to. My other choice was to go m3 spacers on the inside mount and that made the angle even harsher. I can go through the whole suspension range of motion without it hitting anything or binding - since I made a change I did end up checking the rear camber and I did need to shorten them up 1/2 turn or so to get back to -2 so that tells me the geometry this way is actually better.


H-R rear hubs are here. God I hate that company but it’s what was already on there, so now I have one spare. That outer bearings was NOT happy lol and came out in about 5 pieces. Ended up with a 0.5 shim on right side and 0.7 on left.



Changed to the 4wd shock (stock length) with 4wd spring in rear mounted in same position. This allowed me to get a even better ride height with one less large preload spacer. We will see how it handles. I think this is more appropriate for the heavier motor, all metal components in back and trans, and wheelie bar. The spring pic compares a 4wd spring (from 110mm shock) to a 2wd rear spring (105mm shock).

 

[slick2500]

“Fixed” my 45a Tazer ESC by internally bypassing it. Brother was right, somewhere in the board is an open (probably at whatever regulates the power from the lipo batt input down to 5a or whatever it should be at the diagnostic port). Next time we get together he can laugh at my soldering and we can see if we can find the original problem and address it but for now I have what I want back a test mule.

View attachment 7963View attachment 7964

Addressed the camber arms popping off by flipping what side of the rear hub they bolt to. My other choice was to go m3 spacers on the inside mount and that made the angle even harsher. I can go through the whole suspension range of motion without it hitting anything or binding - since I made a change I did end up checking the rear camber and I did need to shorten them up 1/2 turn or so to get back to -2 so that tells me the geometry this way is actually better.

View attachment 7966
H-R rear hubs are here. God I hate that company but it’s what was already on there, so now I have one spare. That outer bearings was NOT happy lol and came out in about 5 pieces. Ended up with a 0.5 shim on right side and 0.7 on left.

View attachment 7967View attachment 7968

Changed to the 4wd shock (stock length) with 4wd spring in rear mounted in same position. This allowed me to get a even better ride height with one less large preload spacer. We will see how it handles. I think this is more appropriate for the heavier motor, all metal components in back and trans, and wheelie bar. The spring pic compares a 4wd spring (from 110mm shock) to a 2wd rear spring (105mm shock).

An M3 washer under the screw head helps prevent the rod ends from popping off the pivot balls, I had to do that on my 3s Typhon or else the shocks would pop off.

 

[95PGTTech]

An M3 washer under the screw head helps prevent the rod ends from popping off the pivot balls, I had to do that on my 3s Typhon or else the shocks would pop off.

Green arrow where you mean? Traxxas sends M3 screws with the 3741x turnbuckle kitwith a really large diameter head that I think is probably getting after what you're referring to (third pic, red arrow). Yellow is what I meant, because the root problem seems to be that camber link is hitting the rear shock tower at certain parts of suspension travel and the plastic end is being driven off of the articulating ball...opposite the process of pressing them to install (although these came assembled). There are pretty clear witness rub marks on the camber rod ends from the shock tower. Second pic is the left side which I've never had fully come off but you can see how it's been driven off the articulating ball and is just riding on the head of the mounting screw. Probably would have come off except for the axle being there. I only noticed this after a cartwheel knocked the right completely off and I was in there fixing it.



I chose not to go with putting washers in the yellow arrow indicated area simply by trial and error, I would like the camber rod to be as parallel as possible to the lower control arm's movement. Washers at yellow put it on more of an angle than simply flipping the distal end to the other side of the knuckle. I ran it through full compression and extension and it seemed nowhere close to hitting anything, but it's really probably just a go run it and see how it does type thing. I'm going to keep your washer idea in mind, that's a good idea. I'd rather have a partial failure like in that second pic than it come completely off like it has twice on the right - got lucky so far, but it's only a matter of time until there are more casualties than just pressing the rod end back together.

 

[95PGTTech]

Remember when I posted that video of the rear wheel play a few posts back? I showed the pics of the absolutely lunched outer bearing, but also included a part of what kind of play happens without axle shims or a hex that clamps to the axle.

I'm going for 0.1-0.2mm endplay (axle in and out) with new bearings in it. I needed 0.5 shim on the right and 0.7 shim on the left to achieve this. I've run it at zero and that's really hard to tell if its true zero or preloaded, and I think that contributed to early bearing failure. For sure, running too much allows the axle too much freeplay which will eat bearings and then steel bearings and axles eat aluminum suspension components (see previous aspects of this thread). It would be pretty dope to find someone making a knuckle setup with tapered roller bearings inner and outer so we could run some preload like 1:1 stuff and get a really tight low drag fit with some margin for error on bearing wear.

 

[95PGTTech]

Did the foam wheel mod for my DumboRC X6. Also calibrated it to the ESC and set endpoints, much better throttle response. Foam wheel isn't anything life changing, but for $9 does feel pretty good.

Weights arrived - first tried in the cubby where the radio transmitter and steering servo is, but there wasn't enough room for much, so I zip tied progressively more to the area behind the front bumper in 2oz increments. 8oz seemed to be the happy place, and now all 4 of the wheelie bar settings have some use. I'm going to put more driving time on it. I haven't decided where it's going permanently yet - I'd like it as far forward and as low as possible, because that means I can run the least amount possible (lever) and it does the most benefit possible.



Theres a little more work to do before finalizing the weight, most importantly aluminum front wheel hubs and gearing. Pinion is "only" 21T now, the higher I go with that is typically thought of for increasing top end but the gear ratio also reduces torque off the hit via the taller ratio. So I don't want to smash a bunch of weight on there permanently now and have it be too much in the future. It would be pretty dope to do it in a weight bar type system where more can easily be added or removed given the conditions.

So I went out and ran the crap out of it in long straight pulls through the grass back and forth, got maybe 20 laps of a 500ft section in and experienced a sudden loss of power and the high pitched whirring like a plastic gear had been stripped. Took off the clutch cover to find the clutch disks completely melted. Ambient was 75F and motor was only 150F with no fan on it, barely too hot to touch, ESC was 90F.



So what's crazy is my notes say I had it full tight minus 1/2 turn. That's super tight by most standards they say start at 1 to 1-1/2 turns out. But looking at how that failed, it looks like it got hot. It only gets hot when it gets loose, right? One disk actually spun on the spur it didn't stay locked in to the flat spots. I scrubbed all the old crap off the spur got it super clean even acetoned it, new clutch kit.

 

[95PGTTech]

This is the video I've always used to adjust my slipper. The other method of park it on carpet or other high traction surface and measure how far the car slips before grabbing is far too ambiguous for me to figure out:

Here's my truck

First test slipper full tight then back off 1 turn = pure slip
second tightened it another 1/2 turn = zero slip pure wheelie (alarmed the lipo lol)
third test loosened it 1/4 turn (3/4 turn loose from full tight) = some slip, still big wheelie...compressing the wheelie bar wheels.

that's enough heat into the clutch for now. I might try 1/2 again later and then something between 1/2 and 3/4 but take the wheelie bar completely off so I get a good idea really how high it's going. Whats super stupid about all of this is the original setting that I was outside running it on was 1/2 turn from full tight. So how TF did that happen to the clutch? Nylon locknut backed off? It was a new one with the last clutch. Maybe instead of the nylon locknut I'll do a washer and double nuts (lock them together) and loctite

EDIT: tried a bunch more settings, one or two at a time then long cool downs. Settled somewhere around 5/8 turn off full tight. Did a washer after the spring and 2 nuts locked together and loctite. Took it all apart at one point to check on that inside disk. Made sure the spacer was there others mention forgetting. Weird. Ordered up some more stock clutches

What’s kinda annoying is that one time, a specific setting (let’s say 3/4 turn from full) would be super slip. Test that setting again back to back and it slips a little more each time, makes sense a little heat. Let it cool make some adjustments and go back to that setting later and now it’s half slip or seemingly no slip at all max wheelie. Annoying. Had to test each multiple times and get an “average feeling.” I tightened the nut down fully each adjustment and counted my turns each time, I didn’t just add and subtract from the last. We will see how this holds up I guess tomorrows weather looks promising

 

[95PGTTech]

The clutch lasted about ten minutes of me trying to put as much heat in the motor as I could again. I think the tall grass and the grip of the prolines just has it in a constant state of partial slip.




I made friends with a guy Martin Wright through the ECX group on FB and he sent me over these pics then hopped on the video chat with me and James. He glues his stock pads in, he used some cotton balls to make a dam around the pad to glue it to the spur. Ditch the locknut and just run two nuts jammed together and loctite, and basically run it at full tight stop adjusting it. I’m out of stock clutches here except for one on a plastic spur, so he said just go ahead and make one out of whatever gasket material I have in my car shop (pics and info used with permission).

 

[95PGTTech]

I had either cork on hand or a grey fiber gasket, went with that. Cut it out using the backing pad from the stock one as a pattern. Left more infill than the stock disks do. Superglued the disks to the spur. I don’t envy the next guy. I went real try hard and I hit the disks and the pressure plates with 150 grit before installing. Double nuts loctite and 1/8 off full tight. I swear I’m not actively trying to break stuff. I swear.

All my hard work was rewarded with such a violent wheelie it bent the m4 bolt mount.



And after about 15 minutes of running it, far longer than any stock clutch has lasted, I was rewarded with a clicking sound similar to a card in bicycle spokes. Paused to inspect for body caught on tire, small stick in axle etc. and kept running it. Noise quickly increased until we got the familiar sudden loss of power and then dead in the water.

Went to blow it all out after the run and popped the clutch cover off. It’s not the clutch.

Took the axle pins out, it’s not the axles the pins or snapped trans output shafts (all of which I’ve broken before, LOL!!!). When I use two pins to hold the output shafts from moving (you need to hold both for an open diff), we can see correct function of motor pinion spur clutch input shaft yet no movement at outer. Appears the diff housing is spinning. So power in no power out, something inside the trans went. It’s the game of upgrade stuff and just find the next weakest link.

Silver lining is we finally got a clutch to hold?

 

[95PGTTech]

I’m getting really good at getting this transmission in and out and apart. I’m not sure that’s something to brag about your RC about.





So, that sun gear has about 1.5 teeth left. I’d have to look back in this thread and my build sheet for the trans but I think I remember putting 30k in this diff and it was clear going in. Other planetaries and sun look okay. I have two good suns I was able to pull out of the original diff. Found the teeth in the bottom of the diff housing, they beat it up pretty good and put a few new windows in. The diff cases are not interchangeable.

Rags, soap and water, brake clean, air compressor everything is sitting clean and ready to go for tomorrow. I enjoyed the locker in the ax10 trans. The H-R one hasn’t been available for some time and ones like the Slash are going to take a bit of work to make work. Tomorrow I’ll either chemically weld this one (epoxy) or mechanically. Probably the latter. I could go to a crazy thick diff fluid like a million, but this 30k was supposed to be super thick for high power 2wd bashers. Why would I expect another fluid solution to be any different?

 

[95PGTTech]

The more I thought about welding it, the more I thought about the ax10 trans that we broke at the differential output pins and I considered how putting that much heat into a part that small was going to make the whole thing super brittle. I was at the pharmacy anyway, so I picked up some silicone earplugs. These are supposedly equivalent to 20 million diff oil, which would take a week to get here. I cut them up into very small pieces and packed about 3 plugs worth in. I needed to use my vice as a press and just wiped up the little bit that squished out. superglued the diff bolts for the ring gear and put new red and tacky in the trans itself.



All back together, clutch set at 1/4 turn from full tight. Replaced that bolt in the wheelie bar that was bent



Its raining out so ran it for a few minutes on a weather break. It seems to be fine, it's clearly a locked diff. Managed to rattle free another left rear wheel nut and a left front knuckle shoulder bolt, standard Ruckus affairs. Didn't want to run it too much, conditions like this there isn't much worthwhile data to gather and crap just breaks and gets dirty. I'll clean it up charge some batteries and we will have at it a nicer day.








Did get this pretty dope shot though. Wheelie bar at work for sure. Without it, the next frame is a cartwheel end over end on its right side

 

[95PGTTech]

I’ve been working on the 4WD lately so this one has just been getting driven. No problems to report, but we are also not thrashing on it.

Tonight I got a gap of time so I started working on the new ESC plate for the nose. 1/8” plate

 

[95PGTTech]

In the cavity left over by the stock transmitter location is where I'll be putting the wheel weights for now. 27 fit in there pretty good @ 1/4 oz each is 6.75oz. When we tested before, zip tied in front of the shock tower, 8oz seemed to be the sweet spot. It should need more in this location since it's further back, but I'm hoping that's offset by moving the ESC, and the plate being heavier than the original ECX grey nose triangle thingy. They fit pretty snug, I'm not really afraid of them bouncing around, and it's a solution that still allows me access to the two screws for the steering saver if I ever need to access them again. Once we have a setup we like, I may do something moldable that can pop in and out quickly.




ESC removed, I need to replace/extend the wires, plate primed. Took a fair bit of time dialing in the last little bit to get it perfect, there are a couple complex curves up there it's not totally flat. The ESC and transmitter test fit okay where I wanted them (flat, centered so I can use the gyro).

 

[95PGTTech]

Moved the ESC and the receiver to the front. It's a little tight but doable.


Made a new battery hold down with provisions for securing the battery and ESC wires. I may add the lipo alarm to it.


Took six weights out of the front so now I'm down to 21x0.25 = 5.25oz to compensate for what I moved foward. Still flies really, really balanced so I may continue to remove some each time.

Noticed with the increased weight up front the shocks almost sit on the bump stops at the far end of their travel just sitting on the bench, that's no good. Put 4wd springs and lower perches in the front.



Got it sideways and cartwheeled it, ripped the wheelie bar right off via the bottom rear bumper mount. Looks like I'll be building a metal one for this one too. For now, I just ordered the replacement parts they are cheap.

 

[95PGTTech]

In primer, installed. works pretty good. I generally charge the battery in the car (I know, I know), but if you did want to take it out it's pretty quick. With the new springs it's TOO much in the front, it hardly ever compresses them, which definetely doesn't help the wheelie situation. I'll add some more weight back and put the prolines with aluminum hubs back on the front. Trial and error. It's basically undriveable without the wheelie bar, you can't do more than 25% throttle. I think 30mph was all we were able to muster. It had a few topples and only popped off that one right rear camber arm again. Ever since I loctite'd the wheel nuts they haven't been a problem. Not ideal in my mind, but it's working.

 

[95PGTTech]

The good: two sessions today, back to 26 weights in the front and the prolines with the aluminum hubs again. It's actually relatively controllable even without the wheelie bar. It can still be a handful and get out of shape quick, but at least you can use most of the throttle and occasionally go full throttle once under way. The suspension is compressed a bit more, still a tad too tight but not near as bad.





The bad: towards the end we noticed a bad wobble in the right rear. It's bearings AGAIN.



The excess runout the driveshaft was allowed to do wore marks into the rear hub again, but in a purely cosmetic area, so I just knocked down the sharp edges. I'm going to put Traxxas XO-1 rear hubs and bearings on it like I did the 4wd...it uses a 12mm outer diameter (the ECX uses a 10 and a stock slash uses an 11). The XO-1 uses a 6mm axle so you can't use the stock bearings, I ordered up 5x12x4 conversion bearings. Same exact setup I'm using on the back of the 4wd (with these axles) with zero problems. For a minute I considered using the aluminum upgrade ECX 4wd rear hubs since I already had them but two problems - it uses a much bigger inner wheel bearing (15mm OD) and a 5x15x4 bearing doesn't exist as far as I can tell, plus if I was ever to destroy one of these, they are very very very difficult to obtain.


I had 4x4 slash rear hubs (aluminum upgrade) on hand for mockup, which I know from our 4wd build are dimensionally similar to the XO-1 hubs (the difference being you can't run a 6mm axle on these). As you can see, they are narrower at the LCA pin mount than the ECX 2wd hubs (by 3.3mm). I mocked it up with some washers.



You can see in this pic how I (painstakingly) filed down 4mm nylon spacers I had on hand to 3.3mm. I chose to shift the hub to the rear most position. There isn't any noticeable difference in driveshaft angle, but that's 3.3mm more length of wheelbase we now have. I'd really like to flip that camber arm, but even with this hub farther back it STILL hits the shock tower the other way around.

I did consider doing what I did with the 4wd and just putting slash lower control arms on this, negating the need for a spacer. I measured the ones I have on hand and they are about the same distance (within 1-2mm) length from pin to pin, however the slash arms are MUCH wider at the inner mount to the chassis. Unlike the 4wd model, the way the pin mounts to the rear of the 2wd ECX, making my own pins and pin brace is not an option. I do find it odd how the 2wd LCAs are moving forward, pretty considerably. This shortens the wheelbase and puts the axles on an angle from the transmission. Maybe I'll flop them side to side when I'm bored and see if I could think up a shock mount that would work...probably a good 20mm difference in wheelbase, which would not only help antiwheelie in and of itself but it would also shift the center of mass more forward in relation to the rear axle.





The other note would be due to the geometry of the hub, if I was running a stock rear (non-adjustable) camber arm, there would be a ton of positive camber. Since I have an adjustable arm, this won't be a problem to align after it's done. This is the final mockup with bearings installed. XO-1 parts take a minute to get, so what I may do is end up stealing it off the 4wd for now.

 

[95PGTTech]

While I had it apart anyway, started taking apart the wheelie bar and trying to figure out how I'm going to make the next version. It seems to be perfectly fine when operating the RC forward and forces hitting it how it's intended, it's when the RC rolls like a cartwheel and it gets hit from the side that stuff breaks.

First time I've had the clutch cover off since making the DIY clutches and checking them shortly after building them, still holding up great.




Final pic is a hint of things to come.

 

[95PGTTech]

@WoodiE @X can one of you move this to the Ruckus forum and change the title to "1/10 2WD build"? This thread has gotten a bit far off of a member introduction and it would help people in searches better. Thanks

shortened the camber link simply by going to a RPM end on the inner side.



Of note, Traxxas uses a floating lower rear hub pin with a set screw where I'm pointing my allen tool. DO NOT install said set screw using it on our ECX control arms with our fixed pin. You will cause a bind and possibly wear out where the pin goes into both control arm ends




This is what I mean about the control arms. Loctite bottle is pointing to front of vehicle



This is them overlayed on each other, with the sharpie marks marking the backside of each, representing how much wheelbase would be gained if they could be flipped - roughly 12mm.



What I was hinting at, belted 3.8s arrived.

 

[95PGTTech]

These belted 3.8s are more of a joke and an experiment than an actual serious mod. It's pretty comical to see. I thought this would be the end-all-be-all antiwheelie mod to prove a point. The gearing effectively should be much taller - going from 4.7 to 6.8 tall, which should effectively kill torque off the hit. By putting them only on the rear, it should cause a pretty dramatic forward rake too.



Traxxas 17mm adapter kit. I'm still running the ECX rear hub on the left and the Traxxas rear hub on the right to see if the slightly larger bearing helps before the XO-1 stuff comes.



If I were to keep these (I won't, the truck feels like they are going to snap off at any moment), I'd need to cut the back of the body up even more it hits on full suspension compression. This is using the wide offset hubs too, I can't even imagine how bad the front would hit. it would be cool to see. It does look really good in the grass and it's making me think maybe on the 4wd when we are really trying for speed I may throw a set of 4 on for short blasts.

 

[95PGTTech]

FAIL!

In a very unexpected result, the truck wheelies much harder. My only guess is it’s dead hooking. The greater width of the tire plus the incredible rotating mass has zero slip whatsoever. I’ll need to slow down video of past runs but I’m betting that there is a lot of wheelspin even as the truck wheelies previously. Regardless, the exercise of trying a taller tire to limit torque off the hit and increase the trucks rake didn’t help. I couldn’t get it above 25% throttle without putting it on the rear bumper.

My fear that grass plus this rotating mass would really heat up the motor fast never became an issue. I couldn’t get into the throttle to really load it up and it only ran about 5 minutes. I couldn’t get enough throttle in it to tell if it would help with a speed run. Theoretically it should.






Cartwheels are always $$$. The huge mass of the wheel and the offset of the adapter and the hub snapped the hardened steel 5mm axle right at the pin. I’m not terribly upset, they had developed a bit of slop at each of the joints from all the power lately so they were a ticking time bomb as it is. Just a bummer I didn’t get more run time to goof off.

 

[95PGTTech]

Carnage shots...I was fortunate to be able to get the pin and the stub of the axle out of the 12-17 adapter kit. Poor 5mm hardened steel axle had zero chance. Also noticed I managed to pop the left rear camber arm...previously it had only been the right side.




New parts have been here for a minute, but we've been working on the 4wd mostly. That is, until we sent the diffs and the slipper into another dimension. Sunday my wife was exposed to someone who tested Covid positive on Monday (who called her immediately), so she started quarantine and got really symptomatic by Tuesday morning and tested positive herself. I had the three kids all to myself this week, but we had already been exposed to her and I started to get really symptomatic Friday night. By this morning, 2 of the 3 kids are as well. So as hard as being 1vs3 was, 2 sick parents caring for 2 sick kids plus one is less fun, LOL. Life. This too, shall pass. It did buy me lots of quiet time to do phone research for the other truck, and I carved out some time with James today to work on this one a little and go outside for an hour trying for some semblance of normal. In the pic you can see the XO-1 rear hubs arrived.



With the 4WD down for probably awhile, I just stole these off of it. I'm running the same hardened steel slash axles, the same xo-1 hubs, same bearings, same bronze 12mm hex, and I already had it a lot apart so I said screw it and just stole them off of it, it's already shimmed the way I like it. Sorry, no bearing shots, but if you look close you can see how much beefier the area around the hub is to accept a 6mm axle and the bearing needed for that (6x12x4). I am running a 5x12x4 bearing to convert to the slash aftermarket axle. The stock rear hub uses a 5x10x4 and I was torching them like nobody's business. Bigger bearing means same force and same amount of heat applied over a larger area hopefully = greater durability. This is both the inner and outer bearing, FYI. You may also notice that you have two choices of rear toe based on which side you install it on the vehicle. I opted for 1.5 degrees of toe in (per side). I do not believe there is any toe built into the stock rear bulkhead or rear lower control arms, but I will doube check once it's on the ground. the XO-1 hubs and the slash aftermarket aluminum hubs share a lot of the same geometry, so the camber link should be fairly close.






One small issue I did run into was with the slash hub installed there was a bit of play at the bottom of the lower control arm (my bitter hatred of even slight suspension mis-tolerances is well documented) so I pulled out those 3.3mm spacers I painstakingly made and put 4mm ones in, figuring maybe the RPM plastic just spread over time. No change, so decided to wait until I got the XO-1 arms in. No change once in. Visible gap with 3.3mm installed (I would assume now from me having the 4mm installed for a couple days has spread the control arm). Pulled it all apart and dry fit the pin in the hub outside the vehicle...2.5mm pin in a 3mm hole. Every pin I dealt with/cut/bent/replaced/fabricated on the 4WD was 3mm so I guess I just assumed these were too, and neither my eyeball nor my hand is precise enough to feel 2.5mm vs 3mm unless I'm looking for it. Drilled out the control arm hole to 3mm to match (go slow, it doesn't go completely through!!!), and put a piece of stainless stock in it for mockup (the pic you see above).

Side by side of a stock slash 3mm pin vs the ecx rear stock 2.5mm pin. I obviously cannot use the slash shorter pin, so I will need to make one. I will check my 4WD stuff to see if there is a stock one that will work, or I have this stuff (tungsten carbide) in 3mm to make one. I bought this because I was making stainless steel 304 pins for the 4WD and bent a couple of them.



Going to try and get it to a roller tomorrow and run it around a little, me and James need some fresh air. I took measurements for the lower control arms, I didn't see a very quick way of flipping them or swapping to something else to gain wheelbase.