The Tamiya Clod axle has been the reigning Super or Unlimited class axle of choice for a lot of rock crawlers. Its design offers a fairly low center-of-gravity, an efficient motor/drivetrain package, and good durability with a few upgrades as needed.
However, RC4WD recently took the plunge to bring us crawlers another choice in the integrated gearbox arena. They now offer a scratch designed aluminum housing gearbox setup to accommodate the commonly used four-link suspension geometry, and they offer optional steering kit components.
When we received our set of Raptor axles, all the parts were carefully wrapped in protective foam or bags. The main gearbox center section comes pre-assembled and lubed, with aluminum axle tubes and inner axle shafts installed. Ours were artfully anodized in black, and a standard aluminum finish is also available. All parts are CNC machined and stainless assembly hardware is included. The user must assemble the knuckle components and the upper link mount, plus the steering.
We immediately noticed how much smaller the center gear section is compared to that on a Clod gearbox. Then we had to take a quick peek inside the gearboxes to quench our curiosity. Removing the cover revealed a trio of pre-lubed hardened steel gears riding on bearings and bushings. There are no longer two inner axle shafts and a differential chunk as on a Clod, but a single long stainless axle shaft spanning the two knuckle C’s on the axle tubes.
Each gearbox accommodates 32 pitch motor pinion sizes from 8T to 20T to offer overall gearing ratios to 30:1. This gearing may be a little too high for those wanting very slow crawling, but may work well with torquey brushless motors. We’ll soon see. Also, a clear dust cover over a large window on the side of the gearbox makes setting gear mesh easy.
Each Raptor comes with stainless steel axle shafts, full sealed bearings, heavy-duty aluminum knuckles, and an upper link mount that bolts to the top of the gearbox. The width of the Raptor is the same as that of a Clod gearbox. We found the Raptor offered a little more gearbox ground clearance, but only about 1/16”. The weight of a complete Raptor axle from stub axle to stub axle is 547 grams (19.3 oz), compared to a Clod gearbox weighing 376 grams (13.3 oz), so these assemblies will add about ¾ lb. to your crawler….but the weight is down fairly low.
We tested the steering angle of the knuckles and axle shafts and found the assemblies turned about 28 degrees each direction, which is about the same as a stock Clod gearbox with the steering pins cut off the knuckles. RC4WD did a good thing in slightly reducing the size of the knuckle C’s on the axle tubes. Any reduction here means less to grab onto rocks. However, we’d like to see the C’ made even smaller to just fit the knuckles closely. To note, there are holes drilled in the knuckles C’s to allow link mounting above or below the axle tubes. On top, a bolt-on mount is provided to attach upper suspension links.
An optional steering kit (equips two axles, parts for one shown here) is offered that includes a servo bracket and aluminum clamps to attach it to one of the axle tubes. Unfortunately, the clamps hang below the tube and eat up some valuable ground clearance there.
Steering rods are super beefy solid stainless rod with threaded ends, and blingy aluminum rod ends with steel balls complete the linkage. Again, stainless hardware is provided all around.
Overall, we found the Raptor axles to be a solid alternative to Clod gearboxes, offering a locked axle and seemingly strong mechanicals that address some of the vulnerable spots on the stock boxes. The steering is well setup except for the lower bracket issue and we really like the compact size of the center section, offering more clearance for the chassis. With the compact gearbox, there is more room between it and the upper link opening the possibility of custom gearbox clocking for further ground clearance.
If we had one real desire on our wish list it would be an axle that offered significantly more ground clearance at the differential, and offered a compact, ramped leading surface for grinding over rocks.
RC4WD has other Raptor axle variations in the works and is constantly improving their product line. We think they’ve done a nice job on this Raptor, offering a sturdy gearbox with solid features.
Stay tuned and we’ll mount these axles up to a chassis and try them out on the rocks.
