Lookin' to buy a Kong RC CA-10 kit, couple Q's

[JennyC6]

This thing looks astonishing and nobody I've talked to about it on Reddit or Discord has had anything bad to say about it vis-a-vis quality, so I'm most likely gonna be buying one here soon. Fingers crossed, with my tax return in the next couple weeks. But there are a couple things I'm already looking to upgrade with it.


* Springs. Every video I've watched one of these things in has shown them to be INSANELY stiffly sprung, to the point it's questionable to even say they have suspension. I've watched them carrying 25 pounds of cinder blocks in the bed and still not be on the bumpstops. It's damned impressive, but I also don't have any need for that sort of carryweight, and the stiff springs come with a startling lack of flex. I want to soften the springs up, make it ride more like the Tamiya trucks. From what I can research, it weighs about 6.4 pounds unladen and I'll likely never put more than that in the bed(If I carry anything at all with it), so I'm fine with the springs being quite supple indeed. At most I might put a fifth wheel on it, build a flatbed, and use it as a scale semi-truck. Will the Tamiya springs work in this thing?

* Tires. Every sign points to these things using off-the-shelf TAmiya truck tires. This correct? 12mm drive hexes? Front axle shafts the same diameter as Tamiya truck axles? I like the idea of having scale brake drums and hubs bolted to the axles and then bolting the rims to those drums similarly to how the real thing is done, if they'll fit here I'll do that with this truck.

* One of the draws that brought me to this truck is the working rear diff, and I'm never going to hard lock it. But I might want to go the viscous LSD route. I'm thinking, maybe 75w90 would be goopy enough to stay in there if I want a low amount of posi traction, perhaps ye olde wheel bearing grease for a stronger posi. Sound good? Or perhaps I might be better off saving up and installing one of those cable-operated lock-on-the-fly diffs floating around?

* Is there enough room in this thing for one of those Tamiya 3-speed gearboxes, or perhaps an RC4WD 2-speed/CVT? I'd like it to have a bit of top end too, it won't be spending every waking moment in the brush after all. I'm probably gonna fit it with a brushless system roughly equivalent to a mod motor for 1/10 ST or buggy racing, rather than a >45t brushed crawler motor, and I'll be running 2s 7400mAh batteries.

* How hard would ya'll reckon it'd be to fit this thing with a fifth wheel? A pintle hook would be pretty easy I think, but a fifth wheel would be better on driving it...ya know, backing up and all that...I'd rather do a fifth wheel than a pintle hook.

* I've noticed scale truck trailers are LUDICROUSLY pricey. Like, a basic little 40' dry van is $200 bucks?! A container trailer is nearly 500, with the 40' can itself another $250+? Lowboys into the thousands?!?! Ludicrous. I'm thinking of building my own and I'm pretty sure itt'l be a hell of a lot cheaper than buying one already on the market. There any merit to that?

 

[1tonscout]

Off topic. Your screen name reminds me of a guy on youtube that does a bunch of motorcycle projects. are you that guy?

 

[JennyC6]

Nah, it's taken from a particularly memorable run of Fallout: New Vegas I did. 'Tis the name of the protagonist in that run.

 

[sig_p232]

Let's try to answer your questions, mine is not built, but is is open on the table.

* The leaf springs look extreme, but nearly all the leafs are actually plastic. I was a little disappointed in this, but if they were all metal, there would be zero suspension. The leafs measure 4.77" eye to eye in the rear and 3.73" eye to eye in the front. Tamiya leafs may fit in the rear, but they would be just as stiff. For the front, I think you would need to build custom leafs for a recoil spring off an old lawn mower or similar.

* The tires are a standard 1.7" inside diameter, thus Tamiya semi truck tires should fit. The rears have a 12mm hex and the fronts appear to use standard 5x11 bearings. The wheels are similar to vintage wheels of the period. I think all the rims are the same, but the hubs are different.

* For the diff, I have not opened it yet, but I would bet that it would not be suitable for filling with oil without having major leaks. The funny thing is something like silly putty may go along way to provide a somewhat limited slip action. Try to find posts from the 2007 time frame when people would building crawlers using TLT axles, you might get some ideas. Your best bet would be to find a cable lock rear axle, but as you mentioned, they are pricey. The axle width is very similar to that of a Tamiya semi axle.

* With minor mods you would have plenty of room for a three speed. I just finished a custom tamiya semi with a 3-speed and to be honest, even with the stock 27T motor, low gear is still pretty fast.

* A 5th wheel mod would be cake. I plan on making mine into a box truck. With an aluminum plate and a tamiya 5th wheel, it may take an hour.

* The last 5th wheel trailer I built cost me $150-180 in materials. I hate to say the cost of aluminum is not as cheap as it was 15 years ago.

Nate

 

[JennyC6]

* The leaf springs look extreme, but nearly all the leafs are actually plastic. I was a little disappointed in this, but if they were all metal, there would be zero suspension. The leafs measure 4.77" eye to eye in the rear and 3.73" eye to eye in the front. Tamiya leafs may fit in the rear, but they would be just as stiff. For the front, I think you would need to build custom leafs for a recoil spring off an old lawn mower or similar.

Hmm. Would it be plausible, then, to soften the springs a bit by dismantling them, snipping the plastic leaves down until they're just spacers, and reassembling it? Obv it'd be one at a time until I got to a softness setting I liked, and I'd soften the front far more than the rear.

* The tires are a standard 1.7" inside diameter, thus Tamiya semi truck tires should fit.

Mm, good, confirms what someone else on here said, and it makes tire choice easy. I've already found a set on eBay with a pretty meaty tread I like that should work far better than the military style tread they have factory.

Specifically, https://www.ebay.com/itm/1-14-all-t...282126?hash=item48a627f64e:g:I7MAAOSwAaJaM-wO these ones.

The rears have a 12mm hex and the fronts appear to use standard 5x11 bearings.

Should be able to use pretty much any crawler rims I want on it, then. Sweet!

The wheels are similar to vintage wheels of the period. I think all the rims are the same, but the hubs are different.

Yeah, I noticed that, especially when RCSparks uploaded an unboxing video of one. I love that the hubs are separate parts, that the wheels bolt onto the hubs, and honestly I probably won't change the wheels themselves. That's a change I would make if I got a Tamiya truck, or really any trail rig, and it's nice that they have this thing set up as such right out of the box.

I wonder if the bolt pattern on these wheels matches some of the other hubless 8-lug 1.7" truck wheels on eBay...

* For the diff, I have not opened it yet, but I would bet that it would not be suitable for filling with oil without having major leaks. The funny thing is something like silly putty may go along way to provide a somewhat limited slip action. Try to find posts from the 2007 time frame when people would building crawlers using TLT axles, you might get some ideas.

Right, best bet then is to stuff the diff itself right full of wheel bearing grease until it oozes out every orifice, then give the ring-and-pinion the proper level of grease. That'd probably give me enough of a posi action to be fun to drive.

Your best bet would be to find a cable lock rear axle, but as you mentioned, they are pricey. The axle width is very similar to that of a Tamiya semi axle.

Mm, might hold off on this until I decide to convert it to 4WD. Looks like it wouldn't be that hard, though the ride height may need some tweaking on one end or the other to get the stance and the linkage/driftshaft angles just so.

* With minor mods you would have plenty of room for a three speed. I just finished a custom tamiya semi with a 3-speed and to be honest, even with the stock 27T motor, low gear is still pretty fast.

Mmm, nice, nice. If this stock trans decides to crap out I have an upgrade path~.


On that note, does the stock trans use 32p, 48p, or some metric gear pitch? In the cart-o-odds-'n-ends I have saved on amainhobbies.com, I've got a 9t, 10t, 11t, 12t selection of pinions in 32p so I have some options vis-a-vis gearing.

* A 5th wheel mod would be cake. I plan on making mine into a box truck. With an aluminum plate and a tamiya 5th wheel, it may take an hour.

Whoo!

* The last 5th wheel trailer I built cost me $150-180 in materials. I hate to say the cost of aluminum is not as cheap as it was 15 years ago.

I've been browsing eBay and, honestly, it's the axles that seem to cost the most. Rarely, someone'll throw stock Tamiya trailer axles up for 20-30 bucks a piece but usually the only things that show up are those fancy CNC aluminum ones that go for 70-80 a pop.

I'm probably gonna go for a basic sliding tandem flatbed 53 scale feet in length. I don't know if that's gonna be in 1/12 to match the truck, or 1/14 to match the tires. Haven't decided. 1/12 makes the measurements easy!

Nate

Those look boss!


Oh, while I've got your ear...where'd you say the best place for the electronics in the CA-10 to go? I'll be using an AR-600 receiver and a Castle SV3 ESC, with a pair of Gens Ace 2s 5000mAh lipos in parallel. Hitec HS-77 will provide steering, mostly since I can't dial in the scale-like steering slowness these old trucks had using my radio's software, and I threw a servo saver into the cart to protect the servo from bumps and tumbles.

 

[sig_p232]

As for the leaf packets, I am sure if you start trimming the plastic leafs out, you should be able to tune your suspension some amount. Remember it is a leaf sprung big rig, so don't expect insane results. There is going to be a big trade off between scale looks and performance. You might search the chino mod for leaf springs.

You might have issues using crawler rims on the front as they run on bearings and not hexes, but any Tamiya semi wheel should work.

The gears are 32 pitch.

Finally, I would consider making a toolbox to hide the battery and maybe other storage containers to hide the other electronics. The gas tank does open and appears to have room for the rx and esc.

Nate

 

[JennyC6]

I've done plenty of searches on Youtube for the real thing, found that 99% of them rode SIGNIFICANTLY lower in the front than the model does. Model's ride height is typical for an AWD variant. Good video of the real thing in action, it's raked severely and the front tires have their tread almost exactly at the bottom of the fender arches.

https://www.youtube.com/watch?v=BpkGvjA8nso

I was thinking of mounting the batteries beneath the box as if they were under-the-bed toolboxes. They're hardcase lipos, so no worries about impaling or crushing them out on the trail.

Nice to know I guessed right on the gear pitch. Those four pinions should give me more than enough wiggle room to fine tune it and keep from overheating the powertrain I've chosen. Castle says 2s and 6.5lbs for 2wd buggy/short course, I'm right at 6.5lbs and running 2s but there's a lot more gear reduction at play here. And if I need to I can put a cooling fan on the motor.

 

[frizzen]

Limited slip diff - just get silly putty and silicone shock oil. Add oil 1 drop at a time to the ball of putty, work oil in, try it, add another drop, work it in... More oil = more open. It won't leak out over time like your grease will. Eventually it does start to break down and diff opens up.

They seemed really tall to go 5th wheel and make a trailer using tamiya semi parts, plus wouldn't pintle be closer to realistic for them?
ZIS 150 Complete Kit - RC Truck and Construction

It's very much a scaler of a heavy duty truck, not a crawler.

 

[JennyC6]

Either or is prototypical. Russia sold them as tractor trailer units under the ZiS 120N moniker, as well as the version depicted in our kit as ZiS 150. Really, they used these things for just about everything, I can find images of them hauling logs, of three axle versions, found some towing artillery pieces, half track versions, mobile cranes, hell I've found several images of the cab of one of these things transposed onto a light tank hull to make a fully tracked vehicle. I've pretty much got a blank check in that regard, anything I can think of would work.

And, indeed, if I did put a fifth wheel on it, my trailers would be designed for that height. I'm scratchbuilding no matter what, due to the exhorbitant cost of ready made trailer kits. I can get a 12 foot stick of steel c-channel in the right size for about 40 bucks, more than enough to make a trailer(Really a couple of trailers, these never pulled 53 footers), I can get used Tamiya trailer axles for a pittance on eBay, leaf springs...yah, shouldn't be that pricey to scratchbuild trailers compared to buying readymade.

However, I'm probably gonna leave the box on it and go with a pintle hook. Found this on Shapeways and, coupled with who I'm gonna have in the cab(Gordon Freeman will be driving, Duke Nukem riding shotgun), I felt that would be a perfect thing to put in the bed. They also have plenty of spare ammo crates to put in there as well. It's pricey AF so for a while I'll be running the truck empty, but it will look amazing in there, and with that gun in the back I've got no choice but to run pintle hook for trailers.

And, yah, I'm more of a scaler than a crawler when it comes to this aspect of RC. Not much appeal to me for a truck that twists itself into a pretzel clambering up boulders. I'm more for a driveable replica of something that can drive down a highway reasonably well, but is also capable enough off-road. Happily there's a huge overlap between scalers and crawlers!

 

[durok]

RC4WD makes a lot of variations on semi-truck wheels & tires.

They also make a hub adapter that should make most bearing-equipped free-wheeling front wheels accept a 12mm hex drive.

 

[JennyC6]

Yah I've oogled RC4WD's wheels and tires many times. Honestly I don't think I want different wheels, these come with a lovely set of aluminum wheels that bolt onto seperate hubs with 8 lug bolts, which is an upgrade path I was already planning on doing before I learned of it being a factory feature. And I can buy them seperately, too, so any trailers I build will have matching wheels. Rear dual wheels come with the hex hub and front single wheels come with the bearing hub.

Tires, though. Yeah. I don't have high hopes for the military style tread on the stock tires, especially after seeing DJMedic's unboxing video and hearing his comments on how hard the rubber compound is. I'll run it with them and see before I commit to buying tires, it isn't difficult to debond CA from an aluminum wheel after all(And I only glue in four points on each bead rather than the entire bead, it's held on my nitro touring car for >6 years itt'l hold fine on this) so if these tires live up to expectations I'll grab some suitably knobbly replacements. I've also pondered RC4WD's CVT transmission on more than one occasion, and if I ever convert it to 4WD I'd need an x-fer case which they offer. And I'm planning on at least one winch, their hi-lift bumper jack would look boss in the bed....mm, they have tons of lovely things for me to use with the CA-10.