Modding Conqueror 1/18 Crawler

[Coelacanth]

I recently picked up one of these 1/18-scale RC crawlers for my daughter. I'm not sure if she'll be into RC so I wanted to start off with something inexpensive, mod it as much as I could, and see how it ends up. These crawlers are all over eBay and Amazon, AliExpress and wherever, under a hundred different names...but I found out about it after buying a similar crawler, it turning out to be a flaming pile of poo, and researching the best 1/18 crawlers. It came up as a "CrossRace 1/18 4WD Crawler", it comes in red, green & blue, but one thing they all seem to have in common is the name "Conqueror" molded into the sides of the plastic chassis tub.

Before I get down to business, I want to first warn everyone to NOT buy this particular model; it's a very similar-appearing item but very inferior quality:

https://www.amazon.ca/gp/product/B07K7BZRJG

I originally chose this one because I liked the aluminum body sides, it looked like it might be built better...but the shocks were atrocious, even for a toy-grade RC. The shock shafts all would bend & bind, especially the left rear one, and not compress properly. I bought two and both had this problem, so it appears to be a design flaw. This metal crawler was also only 2WD. One of them had something rattling around inside the transmitter and the car wouldn't even power up. Lastly, the turning radius was very wide, and steering didn't work properly with one of the two. It would steer somewhat okay to the left, but hardly steer at all to the right. After researching the crawlers and discovering the Conqueror models above, that were the exact same $48 price (under $30 on American Amazon), I decided not to bother with the metal ones, returned both and bought the 4WD Conqueror. This model has excellent reviews and more importantly (for me), it looked like a good candidate for modding.

After I received it, the first impression was MUCH better. It came boxed up nicely with transmitter, 2 x 700 mAh batteries (instead of 1), a wall charger (instead of cheap USB charger), and everything separated into 3 separate inside boxes, instead of everything slapped into 2 halves of a clear plastic clam-shell. The car itself was secured to the main inside box with 4 zip-ties around the axles. As an RC, this crawler has some limitations, but those can be addressed with the modding.

-Throttle and steering are not proportional; they're full-on or off.
-The 700 mAh batteries are AA-size NiCad packs.
-The plastic spring-only shocks are much better than the ones on the other crawler, but still toy-grade.
-Some of the lower shock mounting posts were already cracked, new, right out-of-the-box.

I've seen a lot of people modding these 1/18 crawlers, you'll find some YouTube vids of people replacing the electronics with a decent transmitter/receiver combo (i.e. FlySky), that at least gives you proportional throttle and brake, and I saw a few vids of people hot-gluing a full-size metal servo onto the fronts of their models, and that takes care of the proportional steering...but looks like a real ghetto kludge to me. (I don't know what it is about Russians and hot glue guns...) I also saw some mods for 2S LiPo, but I think that's ridiculous as there's no way these gearboxes can handle nearly twice the 4.8V voltage...not that they're even meant to in the first place, it's supposed to be a crawler, after all. But one thing I noticed from all the YouTube mod vids is nobody addressed the piss-poor suspension. Why go to all the trouble of soldering in new electronics but totally ignore the craptastic shocks??

So here's the crawler itself; let the modding begin!

With wheels off, showing the crappy spring shocks:

And here are the shocks I'll be upgrading to; they're all over Amazon in any color you would want, search for 70mm shocks, part # 736092. At a glance, these have the exact same 63mm uncompressed length, and 50mm compressed length, eye-to-eye:

[Coelacanth]

Upon removing the blue plastic shocks, I was disappointed to see some of the shock mounting posts were pre-cracked:

I decided to reinforce the posts with some spare bushings I had lying around; the posts are about 5mm O.D. so any spacer, plastic or metal with a 5mm I.D. should work:

I reinforced all 8 mount points the same way:

[Coelacanth]

The 736092 shocks come with only a few drops of oil inside, I suspect it's only for lubrication of the seals. You need to fill them yourself. I went with the lightest weight of shock oil I had on hand, Tamiya "Soft", but I have no idea what the weight actually is. Does anyone know? Even with this oil, the shock damping will be a bit too firm. I'd recommend a lighter weight, but since I don't know the weight of Tamiya "Soft" shock oil, I don't know what to suggest.

I encountered the next obstacle when trying to test-fit the new shocks; even though the shocks, side-by-side with the stock shocks when removed from the crawler are the exact same length compressed & uncompressed, I found the new shocks were about 1 cm too long when trying to reinstall them. Clearly the stock plastic shocks are already significantly compressed when installed. That might not matter much for cheap spring shocks, but it made the oil-filled shocks even a bit more firm. I relieved some of the pressure by hack-sawing off half of each shock shaft's threaded end, and cut off a similar amount from each of the plastic shock ball-ends. This shortens the shocks by 6 or 7mm. I want to try a lighter oil before modding the shock piston rings with a tiny hole, and a softer spring might also be needed, but the shocks definitely work much more smoothly compared to the stock plastic ones.

The next obstacle involved how to mount the shocks. The stock shocks have these huge ball-ends that fit over the 5mm O.D. mounting posts. I ended up using all the mounting hardware included with the shocks, plus a bunch of spacers I had lying around, to install the new shocks. One thing I had to do was cut down a few millimeters of each shock end pivot ball, as leaving them the way they were would push the shocks out too far, which would obstruct with the body when re-mounting the body. I just Dremeled them all down and filed the cut ends smooth, popped them back in the shock ends, and used washers on either end, reinstalling the new shocks with the included black mounting screws, which fit nicely right into the original mounting post self-tapping screw holes.

Shock upgrade complete:

[Coelacanth]

Other planned upgrade items to include a 2600 mAh NiMH battery pack, $13.59 on Amazon, that should nearly quadruple the run-time, plus NiMH's are better than NiCad's. The radio will be a FlySky FS-GT2E, $30 and I went with this 20A ESC for under $7, this one should have forward, reverse & brake:

https://www.amazon.ca/gp/product/B07WFHL6BK

[Coelacanth]

I picked up some Losi 15W oil (150 CST), it was the lightest oil the LHS had in stock, looks almost as runny as water. That seemed about right for the shocks, but the spring stiffness still needs to be addressed. The springs with these alloy shocks are 1mm x 13mm x 38mm; I have a package of ten 0.8mm x 13mm x 35mm stainless springs on order from AliExpress that will hopefully be a better softness. I chose 35mm long instead of 40mm because the shocks are already compressed somewhat once installed on the car. I also disassembled the gearboxes to make sure the suspension links and gears got a proper lube with good lithium grease.

[Coelacanth]

My softer springs arrived from AliExpress and they're perfect. Here's a comparison shot of the black springs that come with these aftermarket shocks, and the ones I picked up (qty 10) for $4.78 with free shipping. The wire for the black springs is 1 mm, the silver springs are 0.8 mm. They compress more easily and don't cause a bounce when the fully-assembled crawler is dropped from about 8 inches. Being oil-filled, aluminum and adjustable makes this probably the biggest upgrade to these cars that nobody else seems to be doing.

EDIT: I should also mention when I replaced the shock springs, I opened up the 2 holes in each shock piston ring a bit, using a 1/16" drill bit and just turned it by hand in the existing holes, which I would guess are 1.5mm, just a bit smaller than 1/16". I used 15WT Losi shock oil.

Here's a pic with the upgraded electronics installed. I had to snip off and grind flat 3 of the 4 plastic stand-off posts that the original circuit board is bolted onto, to make it easier to stick in the new electronics with double-sided tape. It took a bit of arranging before the body could be re-fitted onto the tub and bolted on. I'll show a pic of the final arrangement later, I had to move the receiver to be perpendicular to the ESC for the body to fit as opposed to the diagonal position here.

I then reopened the front gearbox and removed and tossed out this metal spring and screw, which serves to center the front wheels and adjust the trim with the original steering motor. This crawler doesn't have a steering servo originally, it has a motor that spins non-stop in either direction when the original transmitter wheel is turned, then when you let the wheel go, the spring makes the steering center link return to the middle. Obviously this is no longer needed with a proper proportional servo and would even resist its operation. On the other videos I saw of guys modding these, none mentioned removing this spring.

[Coelacanth]

Here's the steering servo I bought to upgrade this crawler; it's under $18 CAD, I could've bought others for half that price, but I wanted this to be a micro servo and metal gear as well.

https://www.amazon.ca/gp/product/B07FPJYM5T

A pic of the front end with the steering motor assembly removed; it's a separate part from the front gearbox and removes easily enough. The pic also shows the original steering link to the right (passenger) side steering knuckle, which will need to be removed and a new steering link fabricated.

Plastic steering link removed:

I used this second video as a reference for this mod, but this guy's idea of modding is to slap hot glue on everything...and I don't like how he simply bends a wire to make the link; it gets the job done, but it's a lazy kludge.



For the servo mount, instead of just globbing hot glue all over, squishing the servo down and calling it done, I figured a small piece of Kydex would work much better, with 3 holes drilled to let it bolt down onto 3 of the existing stand-off posts that the original steering motor assembly bolts onto. I used a counter-sunk screw for the front post so the surface for the servo to attach to would be flat. Fabricating a link was easy. I made it from some 2-56 threaded rod and a few ball studs and cups; much better than the video guy hot-gluing pieces of wire to pieces of plastic.

Using the existing plastic posts to mount the Kydex piece actually puts the servo at almost the ideal height for the servo horn's bottom hole to line up with the ball stud, which I simply screwed into the top of the right side knuckle where the original plastic link was attached. I filed the middle front mounting post down a millimeter or two.

[XLR8]

I think the earlier WPL vehicles came with a steering "servo" (gearbox contraption) similar to what your car came with. Many have reported that this was the second part to fail - just after the universals. Anyway, I think WPL have switched to a proper servo now.
As with all things in life, you tend to get what you pay for.
These little RC's are very inexpensive so one can overlook some of their shortcomings. They're fun to tinker with.

[Coelacanth]

I think the earlier WPL vehicles came with a steering "servo" (gearbox contraption) similar to what your car came with. Many have reported that this was the second part to fail - just after the universals. Anyway, I think WPL have switched to a proper servo now.
As with all things in life, you tend to get what you pay for.
These little RC's are very inexpensive so one can overlook some of their shortcomings. They're fun to tinker with.

That's true, I did a lot of research into these specific 1/18-scale crawlers before buying one for my 9-year-old daughter...even stock, these will crawl up objects and steeper slopes that much more expensive crawlers won't. Every reviewer I've seen was very impressed by this $50 (CAD) toy. I'm personally never satisfied with something that can be upgraded, as long as it's not too difficult. This has been time-consuming but not really difficult. And of course, it's the hobbyist in us that can't simply take an RTR out of the box and leave it as-is. I wouldn't have bothered with all the modding if this little crawler didn't have so much potential.

I figure my upgrades probably added about $100 CAD to the $50 cost, but you'd probably be hard-pressed to find a crawler with similar features for the same $150 amount spent ($113 USD).

EDIT: My total cost for the crawler and upgrades added up to $147.73 CAD including all shipping. Everything except the springs were bought on Amazon.ca. That includes:

-Car: $47.99
-2600 mAh NiMH upgrade battery pack: $13.59 (car comes with 2 x 800 mAh NiCad packs)
-FlySky FS-GT2E radio: $35.28
-2 pairs of 736092 shocks: $21.84 (I've since found a 4-pack of these for only $11.22)
-10 springs: $4.78
-ESC: $6.36
-Mini Micro metal gear servo: $17.89

[Coelacanth]

Here's a front-end pic showing the servo and linkage, and the repositioned electronics in the tub for the body to fit:

I drilled a hole through the tub and roof to slip an antenna tube inside, then hot-glued it to the underside of the tub, pretty much right behind the driver's seat. This way, the body can be removed & replaced and receiver antenna wire slid in and out of the fixed position tube.

My daughter finds it much more easy to control now that you can steer and accelerate proportionally. This thing isn't fast but it's not meant for speed. I'll upload some videos comparing the shocks before/after.

[Coelacanth]

Suspension drop test - before spring swap: This drop test is with the aftermarket oil-filled shocks installed, 15WT Losi oil, black 1mm x 13mm x 38mm springs that come with the 736092 shocks:



Suspension drop test - after spring swap: This was done after swapping in the 0.8mm x 13mm x 35mm springs and reaming out the two 1.5mm piston ring holes inside each shock to 1/16", or about 1.6mm; 15WT Losi oil:

[Coelacanth]

Video of proportional steering upgrade; note that although most people modding these by adding a steering servo are simply hot-gluing the new servo right on top of the original steering motor box, they aren't removing the little steering centering spring inside the bottom of the front gearbox, which could negatively affect steering and resist the new servo's motion. To do it right, you should just remove the steering motor box completely, it's only held on with 4 screws anyway...and open up the front gearbox and yard out the spring and screw that are no longer needed.

[Coelacanth]

My 9-year-old daughter has enjoyed her Conqueror crawler since I finished building/modding it for her last summer, but I thought it would be even more fun if my wife had one, and they could bash around together, make a crawler course and see who can navigate it without flipping over, etc. So I bought another one, but it was on the back burner for months. This virus pandemic gave me all the spare time I needed to complete this second crawler. I did all the same upgrades as with the blue/purple one. I removed the silly fake undersized spare tire on the rear. Unlike the first one, I didn't drill a hole for an antenna tube, that was probably an oversight to fabricate an antenna tube because these cars are rolling over all the time and you can see my daughter bent that antenna tube, probably in the first few days of driving it around. I just tucked the receiver wire underneath the body. I don't think range will be an issue because the girls are never more than 10 feet away while driving.

With there being no school for my daughter due to COVID-19, and my wife being at home for at least the next few weeks, the crawlers are getting a lot of use as they're not too fast to bash around the house.

I had only a spare mini servo, but there's plenty of room to mount even a standard-size servo there, if that's all you have lying around. Both crawlers drive beautifully, the oil-filled shocks with appropriate springs for the light weight really work well, and most people modding these don't bother upgrading the craptastic plastic shocks. With proportional throttle and steering, they're very fun and easy to control. I'll upload a video here soon.

[redpixel]

HI,

Cool modification for this little Crawler!
I've been looking for a while for an update for this crawler... till I saw your message in a youtube video... that pointed here.
I would like also to mod the crawler for my son.

I've a couple of questions regarding this mod:
-Which is the length of the new springs? (10mm outer diameter, 0,8 wire diameter, and length? 35mm 40mm?) I would like to order all together in aliexpress.

-About the ESC. The old ESC has 2 connectors for front motor and rear motor. The new ESC has only one connection to motors. Do you connect both motors to the same ESC motor connection?

-Have you thought in upgrading the motors (130 to 180 or... I don't know)? Any ideas?


As I say cool mod and thank you in advance!

Regards from Barcelona,
Redpixel

[Coelacanth]

I've a couple of questions regarding this mod:
-Which is the length of the new springs? (10mm outer diameter, 0,8 wire diameter, and length? 35mm 40mm?) I would like to order all together in aliexpress.

Hi redpixel...the springs I bought on AliExpress were a package of 10 stainless springs, 0.8mm x 13mm x 35mm. 35mm was just a pinch too short, but adjusting the shock collars a few millimeters solved that. You could probably go with 40mm springs instead, but I wouldn't go shorter than 35mm. I bought that spring pack about a year ago. I went back to look at my past orders and this particular item was sold out/not available, but it could be available through another seller now. The spring stiffness and length was just about perfect for the aftermarket oil-filled shocks. The springs that came with the aftermarket shocks were way too stiff for these little lightweight crawlers.

-About the ESC. The old ESC has 2 connectors for front motor and rear motor. The new ESC has only one connection to motors. Do you connect both motors to the same ESC motor connection?

You basically first solder both motor's positive wires together, then both negative wires together, then solder the joined positives to the ESC positive, and the joined negatives to the ESC negative. This video is probably the most helpful one I found and used as a reference:

-Have you thought in upgrading the motors (130 to 180 or... I don't know)? Any ideas?

No, the housings for the motors/gears in each axle/diff assembly is meant to fit that particular size of motor exactly. If you could fit better motors in there that had the exact same size & shape, I suppose you could...but most of the gears are plastic so you'd risk stripping them out with too much power. I think these crawlers have just the right amount of speed and crawling power. They're not race buggies, after all. They're totally fun to bash around the yard or inside the house with a crawling course, and with proportional steering and throttle, they are much more controllable. My 9-year-old daughter loves hers!

As I say cool mod and thank you in advance!

Regards from Barcelona,
Redpixel

You're welcome, Redpixel!