Monday, November 1, 2010

How To - Build a Super Class Crawler...The Easy Way


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How To - Build a Super Class Crawler...The Easy Way
By Tony Arnold -

Super Class rock crawlers are the big brothers of Axial AX10 sized rigs and are typically all custom. Super Class crawlers are huge with massive 7 inch ProLine Moab XL tires and long 18 inch wheelbases, however building one was... a super huge pain. It involved chasing down parts from everywhere and still being stuck with a bunch of fabrication. RCP Crawlers has now made it easy for anyone to bolt together a competition level Super Class crawler complete with RCP's famous national competition winning Team Carnage Hustler chassis.

RCP Crawlers' kit comes in ready-to-assemble kit that only needs electrics and a few easily obtainable parts. This is a HUGE step forward. Previously you needed to buy a complete $400 Clodbuster kit, strip it to just the axles, upgrade to bearings, find diff lockers, buy all the miscellaneous screws, make all the links, fabricate a chassis, and figure out what you are going to do for wheels and tires. All these parts were available from separate vendors and then hope it all worked. Tamiya now sells a kit with only two complete Clodbuster axle kits - yeah. But RCP has gone a step further and offers Tamiya's Clodbuster axles with 95% of the parts for a Team Carnage Super Class crawler all in a couple bags.

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To complete the chassis, you will need RCP Clod diff lockers and (Mico Engineering) servo mounts, motor adjustment plates, and their Clod specific pinions. One easy transaction later and we had everything we needed to finish the build.

[IMG5.JPG & IMG6.JPG]{GROUP - CAPTION - Mico Engineering Motor Mount}


Build the familiar Tamiya Clodbuster axles with the included full bearing upgrade and add RCP's dif lockers. Assemble the heavy-duty links with the included E-maxx rod ends, attached the chassis and axles with the included hardware, set up the droop shocks, assemble the wheels, and the build is about 90% complete. All that sounds like a mouthful, but its all relativity painless. If you do get a little confused, the support from RCP Crawlers is great.

IMG2.JPG (875295 bytes)[IMG2.JPG]{CAPTION - RCP solid billet diff lockers compared to stock Clod difs}

------------Call Out-------------
Kit Inclusions:
* Hustler Tube Chassis & body panels
* Full Set Of Suspension Links
* Steering Kit
* Internal Shock Springs For Droop Set Up
* Lower Link Shock Mount
* Tamiya Clodbuster axle kit
* Axle bearing upgrade & RCP Dif Locker
* Bender Customs 12mm - 23mm wheel adapters
* Proline Moab XL 40 series tires & Cheyenne Beadlocks
* Traxxas Maxx shocks
* Trinity 110 WT shock oil

RCP Clod Differential Lockers $25 Servo & Motor Mounts & Pinions $60
(2) Tekin FX-R ESCs & 55T Motors $125 each
Hitec CRX Spectra 3-Channel Synthesized RX/TX $270
Hitec 7955TG Servos $120 each
A123 3S 9.9V Battery Pack $60
Punk RC Programmable Computer $80

Total $1444

The "tube-style" Hustler chassis is consistently one of the top chassis in competitions due to its rugged steel cage design and low center of gravity. Supplied are Lexan body panels that can be painted like any typical body – mine of course were hit with a Tonka logo and then plastered with stickers.

As is typical, our RCP Chassis features a 4-link suspension design that provides plenty of articulation, however instead of a sprung suspension; the entire chassis uses a "droop" style suspension that greatly improves crawling performance. Install the supplied springs under the Traxxas Maxx shock pistons filled with Associated 110Wt oil and the shock stays compressed unless articulation or "droop" /clearance is required.

[IMG3.JPG]{CAPTION - Droop suspension is improved via under piston springs}

The drivetrain is a slightly upgraded Tamiya Clodbuster drivetrain with locked differentials and bearing upgrade, however I did a standard clod axle steering increase modification and clipped the steering limiters.


Narrow Cheyenne Beadlocks and enormous 7" Pro-Line XL Moab tires are included along with Bender Customs 12mm-23mm wheel adapters to make the hub to wheel connection. To up traction I
added 12oz of weight to each wheel for added traction and lower CG.

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We bolting in Tekin Crawler Combo ESC/55T Motor kits powered by a shared 3S 9.9V A123 pack. To steer those big fat wheels around with authority, Hitec 7955TG servos were used featuring 333oz/in., titanium gears, heat sink, and coreless digital power.

IMG16.JPG (2197223 bytes)[IMG16.JPG]{CAPTION - Beefy HiTec 7955TG servos mounted into the Mico Engineering Servo mount front and rear.}

Typically, serious competitors use a 4-channel stick system to provide fully independent steering and motor control of each axle, however driving with a dual stick TX is an art form I can't comprehend, so I stuck with my feature rich Hitec PCX 3-Channel pistol style synthesized RX/TX system. Being the RC nerd I am I couldn't do the easy thing and just use a servo reversing splitter. To imitate the function of a 4-channel system, I used a PRC-PC (Punk RC Programmable Computer). This little gadget allows you to use the third channel as a trigger to change operating functions on the fly – now with just a three channel TX/RX, I can initiate changes from two-wheel, to four-wheel, to crab walk steering modes, and still enjoy both front dig for some mind blowing maneuvers. Punk RC is adding new programs all the time and will even take custom requests. Ah, I love technology.

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[GROUP IMG8.JPG & IMG9.JPG]{NOTE THESE CAN BE VERY SMALL IMAGES - CAPTION - We use the sophisticated programmable RC PC from PunkRC, however simple four wheel steering is easy with just a standard airplane Servo Reverser and three channel transmitter.}

The performance increase over smaller 2.2 rigs is stunning with tires nearly twice the size and even rear-independent steer. Since super class crawlers yawn at challenging 2.2 courses, so I set up some extremely aggressive courses using Pro-Line's new Gatemarkers.

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The RCP kit performed like a nuclear powered goat. Unless I attempted near vertical lines, I simply could not find an obstacle that could not be cleared with the kit. With a little extra tweaking and a more competent driver, some of those near vertical lines would even be possible.

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RCP did a great job with pulling together the basics of a custom Super Class rock crawler. Sure we needed a couple extra parts and some electrics, and perhaps a direction or two, however RCP's kit is worlds better than finding all this stuff separately. According to Brian at RCP, "we want to have the best service in the crawler industry and kits are a great way to eliminate the guessing game for customers." RCP fielded my questions and personally helped to assure I had a successful build. As expected of this nearly $1500 build, the performance was stunning, awe inspiring, and mind warping. These big Super Class crawlers are not cheap, but can do things that just are not possible anywhere except the scale world of RC. With more easily assembled kits like RCP's hitting the market the Super Crawler class is sure to heat up. See you on the rocks...with the Tonka Trunk I have always wanted.



IMG7.JPG (869005 bytes)[IMG7.JPG]{Hitec PCX 3-Channel Synthesized TX & Syth DX RX}

IMG9.JPG (1209703 bytes)[IMG9.JPG]{2 - 7955TG Servos

IMG20.JPG (910443 bytes)[IMG20.JPG]{2 - Tekin Crawler Combos}

IMG21.JPG (1101226 bytes)[IMG21.JPG]{A123 Racing 3S 9.9V Lithium Ion Pack}


SOURCES: RCP Crawlers –, Tekin –, RC Guy –, Hitec –, Pro-Line –, A123 –, Bender Customs –

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