VS 4-S Build, Volt Up Gear Down

[HumboldtEF]

Ok I'm late to the VS4-10 party but still want to have some fun

I had planned to get the VFD tranny for a scratch build but after they released it in a slightly more Incision spec I decided the most affordable way to get it how I wanted it was by just getting the damn kit.

The chassis went together nicely, the only surprise I found was with the rear axles binding. I examined it and found the issue, I posted a separate thread here Clearancing the VS410 rear axles

Copied and edited from that thread:
Last night I started to dig into building the axles on the VS410, the front went together very nicely. It was refreshing to build an axle and not have to disassemble shim test, disassemble shim test and so on, this one was flawless and smooth.

The rear on the other hand had one issue. I could see after chucking up the axles they are just a tiny bit out. When they are installed I was getting some binding. I took it apart multiple times to see where it was coming from and I eventually found that the tangs near the end are 7mm and the bore of the axle is 7mm so as the slightly out of true axle rotates it would rub up against the inside of the housing.

I sanded it a tiny bit last night and Its already smoother and I can no longer hear metal on metal rubbing.



I spent a bit more time today finishing these off. I ended up sanding .3mm off the tangs though they started to feel better with just .1mm or so removed. So I did likely remove more than necessary but I dont see it hurting anything.

Now they have no binding at all, nice and smooth like the front

Drilling out the axle housing instead is likely much easier but I didn't have a bit that was only a touch larger, all I had was a bit thats 1mm bigger.




I found that the steering link wasn't the right length if the rod ends were screwed down all the way (the Manual kind of dropped the ball on the link lengths, no lengths are listed just images that were not to the same scale as the individual parts). Anyway I printed up a spacers to allow me to fully thread the rod ends on and satiate my OCD.


On to the volt up gear down part. I decided I'd like to try out 4S and looking at the VFD design I had a good hunch that I could slap a much larger spur gear on once the spur cover was removed.
I ordered some Protec 4S shorties and a handful of spur gears before I even had the rig. Lucky for me it all worked out.
I didn't bother doing any math to see what the gear ratio would be after all I didn't know what ratio I even wanted. I just decided to get a few spur gears to play with so I could feel it out.

I started off with a 64T spur gear from RC4WD, plenty of space for a big spur gear in there.


I had to slot the motor mount slots a bit more to account for the larger spur gear, I hogged out an extra 1.5mm. After that I was able to mesh a 9T pinion though I think i could fit maybe an 11T or 12T too, or you could slot the holes a bit more.

I designed a new spur gear cover because I've seen how my Wraith (with its gear in the same area) turns into a stick eater when I'm out in the woods. I wasn't sure how I was going to copy all of the contours without a scanner. In the end I was able to get it pretty close and then print some small cross sections to test fit. I ended up with a 2 piece design since the spur gear is larger than the back side and wont go together that way.



You can squeeze the back half and get it to clear your spur gear or remove the spur gear and put it on (then re-install the spur).

Squeeze it and slip one side past, then the other








I think this should allow up to a 66T spur gear in theory based on the size of the cover.

I also worked up a electronics tray as I didn't feel like installing 50 screw just to mount the stock one. Seriously did they have to use so many screws!!!
I plan to weigh the screws I didn't use to just to see what it is.

This screws down to some factory holes (the ESC is fastened to the tray first)


I built in some stand offs to raise the ESC over the hump where the outter portion of the sliders fasten.



And of course I could help but redesign the battery tray even though I plan to use the Hurtz dig kit once its in stock again and the tray will be in the way. At least it can be useful for those who dont plan on running dig and also use shorties.

The tray sits about as low as it can in this location. It mounts to the sliders using existing holes.

[odomandr]

Damn j miss the like button. This is cool. Thank you for sharing

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[soze]

Nice man! I'm going to be following this one too!

[HumboldtEF]

I forgot one piece, I made a brace to keep the front body posts aligned. They were leaning towards each other and made it difficult to drop the body on. So this spreads the posts to the proper width and holds them.






There are holes on each side so it can be fastened to the posts with a M3 driveshaft pin/body post pin





I also forgot to mention that spur gears that use Axial's 3 bolt pattern work with the VFD tranny. So most made for the AX10, Wraith or the old 3 gear tranny should work. Kimbrough makes some affordable spurs but the one I received was not true it had some wobble but I heard they were good. I was surprised that the RC4WD spur was actually better or more true rather.


Oh yeah and here's the truck lol

Originally Posted by odomandr

Damn j miss the like button. This is cool. Thank you for sharing

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Originally Posted by soze

Nice man! I'm going to be following this one too!

No problem, Thanks guys!

[Voodoobrew]

I have a bunch of kimbrough 96t spurs that wobble. I alwayse assumed it was from my mounting job or the slipper eliminator. I will have to try some other brands I suppose. Kimbrough is alwayse so highly rated.
I tried 2 Robinson racing gen 3 80t spurs that did not seem perfect as well.

These were all 48p and functional. Some of them do have an audible warble. And only the worst ones seem to have a performance loss at the slowest initial start speeds.

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[JohnRobHolmes]

Nice build! I like the way this is going

[B-MOW71]

Liked and subscribed!

I like the standoff you printed for the top of the slider. That is something that I was considering for my PRO to make mounting the ESC a little easier!

[Brandon]

Nice design work on the spur cover to work with the larger spur gear

[HumboldtEF]

Okay time to test drive......DOH leaky shocks already! The shocks had been assembled for maybe 5 days and already had a few drops of oil pooling on the rod ends and axle. I can overlook a bit of leaking but they also felt very inconsistent on each corner. Quick side note, these came assembled and one shock had its x-ring and spacer stack out of order (which I fixed).
I will say that I was impressed with how the shocks go together, the bladder is a huge plus and they felt surprisingly good for being such small shocks. I used 60wt oil. Its unfortunate that they went from feeling great to not so great so quickly.





Anyway I tore the shocks down for a rebuild. I got some measurements of the spacers so I could play with thicker spacers. The idea being If I can get a thicker spacer in while still keeping the shocks feeling smooth they might not leak.






Stock spacers are .50mm




I 3D printed some new spacers in a few different sizes and settled on .60 which since its 3D printed isnt super accurate, it actually measures .62mm -.65mm or so.






One shock was not happy with this sized spacer and was just too stiff with it installed. I used the stock spacer here and marked the shock so I could use this one as the control so I can compare later on.


I eventually got out to test late last night on my rock pile and it was pretty cold, 40 degrees or so. I tried out a few different tires and sizes starting with the stock tires which didn't fair well in the cold on the rocks and had a fair bit of body rub. I then tested out some G8 ProLine Flat Irons which were good but I was getting tons of body rub again.






Then I tested the tires I had originally wanted to run, the Proline TSL's (non XL's). I had though they looked a bit too small in the Origin's giant fenders but after installing and running them my tune changed and I'm now totally okay with running them. These tires did pretty well and had zero body rub issues.





Locked Up RC Recluse wheels




I honestly dont feel like I was getting the best performance out of the VS4-10 but It was wet and very cold so I wont hold that against it. Next run I want to have another rig to compare it to.

Originally Posted by Voodoobrew

I have a bunch of kimbrough 96t spurs that wobble. I alwayse assumed it was from my mounting job or the slipper eliminator. I will have to try some other brands I suppose. Kimbrough is alwayse so highly rated.
I tried 2 Robinson racing gen 3 80t spurs that did not seem perfect as well.

These were all 48p and functional. Some of them do have an audible warble. And only the worst ones seem to have a performance loss at the slowest initial start speeds.

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When I mounted up one of my Kimbrough spurs I felt like I tightened the screws a bit too much and I may have warped it. I backed off the screws and checked again and it was still out but not as much. I think the thinner middle section on these spurs might be why these wobble.

Originally Posted by JohnRobHolmes

Nice build! I like the way this is going

Thanks, You've definitely had a big oversized novelty hand in inspiring this build.


I forgot to mention the motor, I had a Holmes Hobbies Magnum 540 built in a 20T configuration which isn't a normal option for these motors. I emailed Holmes Hobbies to see if they could make it and sure enough they had everything on hand to do it. I thought a 20T might be better on 4S and work well with the whole gear down idea. Thanks again John!

Originally Posted by B-MOW71

Liked and subscribed!

I like the standoff you printed for the top of the slider. That is something that I was considering for my PRO to make mounting the ESC a little easier!

Thanks, I'll probably share the design once I wrap up.

Originally Posted by Brandon

Nice design work on the spur cover to work with the larger spur gear

Thanks, I was really happy that I was able to make it work. This design will likely get shared later on too.

[Topher Builds]

I like the little swampers on there. Flat irons look very big in contrast.

[HumboldtEF]

Yeah I was just trying to fill in the fenders with those flat irons, I guess either way isn't making the fenders any smaller. I'm pretty sure I'll be sticking with the swampers, they are one of my favorite tires.

I got a bit more run time this morning and its doing a lot better since I can use all the throttle I want now. Last night I was just trying to crawl as slow and quiet as possible so that may be why I wasn't overly impressed.

Gearing wise I think I overshot the mark a little, its super slow maybe 3-4 mph. So I'm gonna try a larger pinion and possibly go down on the spur gear size. For being 4S it sure doesn't feel like anything out of the ordinary with this gearing.

[JatoTheRipper]

That's a bummer about the shocks! Have you contacted Vanquish to see if they can offer any unique tips, besides the usual, to get them to stop leaking? This is unacceptable on a high end, expensive kit like the Origin.

What's your thought on the Tekin servo? I'm thinking about getting the T-360 for mine.

[HumboldtEF]

Originally Posted by JatoTheRipper

That's a bummer about the shocks! Have you contacted Vanquish to see if they can offer any unique tips, besides the usual, to get them to stop leaking? This is unacceptable on a high end, expensive kit like the Origin.

What's your thought on the Tekin servo? I'm thinking about getting the T-360 for mine.

I probably wont bug VP about the shocks. I'm used to leaky shocks and have some back up Dravtecs I could use.



As for the servo I dont feel anything revolutionary about it though I need to take a closer look at its fine control to see if its any better. It uses DPE digital magnetic encoding instead of a potentiometer. It does have one interesting feature, it can do a full rotation since theres no mechanical stop inside. This means you can set the center point anywhere (using hot wire) and not have to worry about running out of throw on one side because it can freely rotate everywhere. Probably not really necessary for any regular crawler but good for some extreme situations maybe. You could also make it into (the most expensive) servo winch with no mods.
Power wise it seems to feel like the specs are accurate.



The servo horn provided is a nice metal clamping stye horn which is nice, though its completely straight with no offset unlike most that raise up a bit. Due to this I wasn't able to use this horn on the VS4-10.


I should also mention I have some sort of glitch going on where the servo makes a ticking noise every 2-3 seconds on the dot, this is with no load so its not trying to center itself. I'll be sending a video to Tekin soon, I already called and they said "just run the hell out of it" lol.


I'll probably go back to the 2290 for my overkill servos in the future though.

[durok]

Just curious... Are those the beadlock rings you are planning to use with the LURC Recluse wheels?

IIRC, those are inner rings.



Otherwise, looking great!

[HumboldtEF]

Originally Posted by durok

Just curious... Are those the beadlock rings you are planning to use with the LURC Recluse wheels?

IIRC, those are inner rings.



Otherwise, looking great!

Thanks Durok



Yeah this isn't the way they're intended to be assembled, those are the inner rings. I just thought the inners looked better.
The outer rings dont have a sandblasted finish that matches the wheels. This also meant I didn't have to use 60 screws. I'm not a huge fan of the bedazzled look you get from beadlocks that bolt on the ring from the outside.


I took it out for a trail run yesterday with my Sister and Nephew. My Nephew is 2 and he loves trucks, he was being pushed around in a stroller so he could watch me drive. He would command the truck pointing down the hill "it should go down dere", "its coming back up". Then whenever the truck lost forward progress for more that a millisecond "stuck" or he'd say "control it up here with your hands" (meaning use the TX), upon a roll over "crashed it".

lol he's a funny little guy

[HumboldtEF]

I have to come clean here, from what I've experienced so far with the VS4-10 I'm pretty unimpressed. I was looking forward to a rig I didn't have to customize for once, but I really think I'll need to do something to make the VS4-10 competent and fun to drive.

I though at first it was the weight that was holding it back but its really not that heavy. After a bit more driving I think I can see whats holding it back, its a lowrider!
The skid is very low, the sliders are as well. Low CG is nice but not at the expense of poor ground clearance. Its constantly getting hung up dragging on the skid and sliders. I find myself taking what I'd consider the easy lines instead of challenging it. Its performance seems much closer to a scale truck than that of an all out performance truck.

Yes I am using some smallish tires (4.5") but even if I size up to 4.75" I'll only gain 1/8" of clearance.

Now I'm thinking about ways to raise the truck up which is not something I've ever considered before.

Once the VS4-10 is on a simple flat-ish slope it does just fine, it grips well and behaves very nicely. Its only when you get to rocks taller than the skid or sliders that it starts to suffer. I'm used to being able to push through those situations but when I try that with the VS4-10 I often end up rolling it.

[svt923]

Originally Posted by HumboldtEF

Its constantly getting hung up dragging on the skid and sliders. I find myself taking what I'd consider the easy lines instead of challenging it. Its performance seems much closer to a scale truck than that of an all out performance truck.

We all have our interpretations on the way a truck drives but this is the exact opposite of my experience. I'm running the OG VS4-10 aluminum bumpers that everyone complained got hung up on everything and even had 4.19 tires for a while with no issues of ground clearance or getting hung up. Since going up to slightly larger PB Rock Beasts (4.45 in versions), the VS4-10 Pro is probably my most capable 1.9 truck outside of the Capra.

[Topher Builds]

Interesting feedback Humboldt, and not the first time I’ve heard of that.

@svt I was not a fan of the original bumpers, they didn’t necessarily get hung up but I did have to approach lines differently just because of the bumpers and I did not like that. It’s good to know you’re having a positive experience with the Pro. I’m on the fence with which direction to go with the kit I bought but am thinking some D44s and rock beasts as well.

[Voodoobrew]

Originally Posted by HumboldtEF

Gearing wise I think I overshot the mark a little, its super slow maybe 3-4 mph. So I'm gonna try a larger pinion and possibly go down on the spur gear size. For being 4S it sure doesn't feel like anything out of the ordinary with this gearing.

There are diminishing returns on volt up gear down. The diffrence is like 99% at initial startup speeds, torque and punch. Being geared so low crawlers don't need more punch (I turn mine down for smoothness)

Extra torque once your actually moving a little bit also isn't necessary. Mostly this lowers the initial start speed through gearing and you need the torque when the motor is under 500rpms. The benefits are mostly there if your litery crawling at a snails pace.

I like to be able to do that in the workshop, honestly I don't do it too much out side in a big rock pile. But I also don't drive over 4mph outside either. So I keep it geared low and slow for the extra throttle sensativity.

This adds tons of usability on cheaper 540 motors in my opinion. On my 550 10t crawlmaster I have it at about 66:1 ratio but have the throttle capped in the radio on a switch so it kinda shifts between 3 speeds 100%,66% and 33%. Im almost alwayse in the middle speed.

The 4s helps a little on the torque and to buy the top end back. The extra torque from the voltage means you don't need to gear down as much to get the same power at 500rpm.

Opinions on when the low throttle control is good enough varies from person to person. And 3-4 mph is my happy place. My 1;1 toyota has dual transfer cases and crawles super slow so it can almost idle up anything. This way I'm not bashing into some toughrt rocks trying to bounce up them, that breaks stuff fast. I wanted my rc to do the same thing.


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[Voodoobrew]

Capra axles will increase the ride height, taller shocks. Obviously increases the cog though. But can you increase the ride height to match the skid clearence while still retaining better cog then other vehicles?

I imagine angling up or narrowing the sliders my help. Might require a different body.

Btw love all the details in your writeup and criticism. It's very appricated.

Some of the recent chassis like the vs4-10 and trx4 increased the frame arch over the axles. This is great to lower the skid especially if your running Portals you need that clearence. But your also raising the chassis mounted servo weight higher and anything mounted next to it.

In my opinion with a straight axle the scx10 arch height was plenty. And the vs4-10/trx-4 arch height is good for Portals or smoother terrain.

My hotrod crawler is super long, heavy and low. It drags on everything , or slides over, the petg is pretty slick. It has light weight springs that ride fully compressed, this means all the articulation is the shock extending. Maybe you call this droop, I don't know. But it has a narrower chassis and maybe boat sides. It has exceptional performance though. Blows my mind how well it crawls. But there are some things it want do well, like going up sharp ledges, I can usualy bump it over fine, but I don't like driving that way. Also being so long it dosent exactly turn on a dime. But crawling uphill both ways? That's what gramps hotrod crawler was made for...

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