While the Clodbuster has been around seemingly forever, shaft-driven monsters have recently begun to take off in popularity with the introdution of the Axial Wraith rock racer. Since building one of these monsters takes a little bit to piece everything together, we've written out a step-by-step process outlining all the main components that go into building and running one of these beasts! Whether you have a stock Wraith you want to turn into a monster, or just start a build from scratch, this guideline is a great resource tool!
One of the most important parts to building your truck the AR60 OCP axle! These can be purchased separately or currently come as part of the Axial Wriath, AX10 Deadbolt, and AX10 Ridgecrest. Whether you choose to purchase a brand new Wraith axle set (http://crawfordperformanceengineering.com/product_info.php?products_id=809) or supply your own, the AR60 axles are what makes your truck tick! Also note that these axles come stock with a locked differential. Many people choose to unlock the diffs to improve the turning ability for your monster. These gears are a perfect way to unlock your AR60 axles, and include enough parts to unlock both the front and rear axles. (http://crawfordperformanceengineering.com/product_info.php?cPath=3&products_id=667)
Now that you have your axles we'll move on to the heart of your truck, the chassis! The chassis design takes into accounts things like proper 4-link placement and suspension design, as well as allowing easy installation and access to your electronics used to control your truck. Chassis kits like the Barbarian (http://crawfordperformanceengineering.com/product_info.php?cPath=1_22&products_id=677) are designed to maximize your truck's performance and handle everything from backyard bashing to competitive racing. These complete kits contain all of the components you need to install your Axial AR60 axles to the chassis including things like sway bar arms and mounting hardware.
With your axles and chassis assembled, it's time to move on to adding shocks to your truck. The stock Axial kits come with 4 120mm long oil-filled shocks. Our Barbarian chassis kits are deisgned to use those shocks, but can also accept more standard 4" (100mm) shocks. (http://www.crawfordperformanceengineering.com/product_info.php?cPath=10&products_id=601) We have also had good results using Traxxas aluminum big bore shocks as they operate very smoothly.
Like the Clodbuster, the AR60 axles also use a 12mm drive hex. Unfortuantely, Clodbuster wheels do not clear the steering knuckles without modification. In order to install Clodbuster wheels, an adapter/widener is required. We offer a couple options, but our adapters featuring a drive nub pattern for either Clodbuster or TXT wheels are the most popular (http://crawfordperformanceengineering.com/product_info.php?cPath=7_37&products_id=637). There are also a few wheel options available (http://www.crawfordperformanceengineering.com/index.php?cPath=7_91). Ofna Pirate wheels eliminate the need for the adapters above, but they use a 17mm drive hex and will need our 12-17mm hex adapters (http://crawfordperformanceengineering.com/product_info.php?cPath=7_37&products_id=678) to install properly. For the ultimate in scale realism, planetary hubs and beadlock rings are also available that replicate the look of the full-size monsters!
Since you've now added Clodbuster wheels to your monster, you'll need tires to go with them. There are a number of tire choices you can upgrade your truck with (http://crawfordperformanceengineering.com/index.php?cPath=7_32_139). For hardcore carpet racing, the Pro-Line Destroyer (pictured below) provides great traction. If you want to race or run outdoors on hard dirt/gravel, the Imex Puller or RC4WD Rumble tires are great choices. For deep grass or muddy conditions, we recommend using the RC4WD B&H or Mudslinger (pictured below) tires.
Now that you have a rolling chassis completed, it's time to personalize your truck! Almost any lexan body designed for the T/E Maxx or Savage will work on your monster as well. You have the option to either paint the body to your liking or to use decal kits designed to replicate the full size monsters seen performing today (http://www.crawfordperformanceengineering.com/index.php?cPath=4_34)! If you decide to paint your lexan body, be sure to follow the manufacturer's painting instructions and to use a paint that is designed specifically for lexan/polycarbonate bodies. Not doing so may lead to paint flaking off the body and runing a perfectly good paintjob.
The stock Wraith RTR kits included a 20T brushed motor. This motor can still be used, but they leave a little to be desired in the performance category. When building your Axial monster, you have two basic motor options for your truck, brushed or brushless motors.
- Brushed motors are becoming harder to find, but often allow for an inexpensive way to build your truck. With a race truck, we recommend using brushed motors in the 10T to 15T range. http://www.crawfordperformanceengineering.com/product_info.php?products_id=587 The lower the number of turns, the faster your truck will be. The motors will also require more maintenance as the higher current draw wears brushes faster. A higher turn motor will be slower but will have more torque for climbing/crawling. With the larger size of the tires being used, we recommend using 32p gears on your Axial transmission. Using a 50T spur gear coupled with a 17T pinion will get you in the ballpark for a good torque/top-end speed compromise.
- Brushless motors are maunfactured using the latest technology and do not require the typical maintenance that brushed motors require. Brushless motors also provide a smoother power curve, while producing more power than their brushed counterparts. There are many options available for brushless motors, but typically using a motor in the 3500kv- 5900kv range will give you the best results. (http://www.crawfordperformanceengineering.com/product_info.php?products_id=672). The higher the kv rating, the faster top-end speed your truck will have. In addition, 4 pole motors develop more low-end torque than a comparable 2 pole motor. Again, a good starting point for gearing is to use an aftermarket steel 18 tooth, 32 pitch pinion gear coupled with a 50 tooth 32 pitch spur gear.
8. Electronic Speed Controllers:
The stock Axial kits come with an electronic sped controller (ESC) that is rated for use with the stock 20T motor. Upgrading to a more powerful ESC is definitely required when switching to modified brushed or brushless motors.
- When using a brushed motor, the Traxxas XL5 or Castle Creations Sidewinder (http://www.crawfordperformanceengineering.com/product_info.php?cPath=11_18&products_id=556) are both good ESC options. We recommend using a ESC that has a 60A or higher rating.
- When using a brushless motor, you need a ESC that is designed with brushless motors in mind. Again, the Castle Creations Sidewinder (http://www.crawfordperformanceengineering.com/product_info.php?cPath=11_18&products_id=556) or Mamba Max Pro are both great options. We also recommend using an ESC with a 80A or higher rating due to the added power draw between the brushless motor and Lipo battery.
- Battery: There are two main types of batteries, NimH and LiPo. NimH batteries have been around for years, and are typically what most people have readily available from older R/C vehicles they've used. This style of battery has been surpassed in performance by the LiPo battery however. LiPo batteries both outperform and are lighter weight than their NimH counterparts. We recommend using a single 2S (7.4v) LiPo battery with a 50C+ discharge and a 5000+ mah rating. The discharge rating is how much current the battery is able to draw, while the mah rating describes how long the battery will last on a charge. In either case, a higher number equals more power and/or a longer run time. Dual batteries can also be used, but will simply add weight to your truck and are typically not used in racing applications. Note: We always recommend using a hard-shell or hard case LiPo in your off-road vehicle. Failure to do so may lead to battery damage and possible loss of your vehicle (and its surroundings) due to a battery fire!
10. Radio System:
The radio (or transmitter) is your only control over your monster. Radio functions vary greatly depending on their cost and number of channels, but all radios will control the steering and throttle for your vehicle. We highly recommend the use of a newer style radio featuring a 2.4ghz frequency (http://www.crawfordperformanceengineering.com/product_info.php?cPath=11_18&products_id=279) as these are much less prone to interference compared to the older AM style radios. On our race trucks, we do not use rear steering in order to maximize stability at high speeds. If you run with front wheel steering only, any 2.4ghz 2-channel radio will work fine controlling your truck. You may also choose to install and operate your monster with rear steering. In many cases, a radio having a 3rd channel will allow for control of the rear steering. Some radios are designed and pre-programmed with different rear-steering functions, while others allow you to control the rear steering completely independent from the front wheels.
Hopefully this guideline has been a helpful resource for you in determining the path you want to take in building your Axial-based monster truck! If you have any questions regarding your specific build, feel free to contact us using the "contact us" form on the website or directly via phone during the office hours listed. Thanks!
Crawford Performance Engineering