2017 - Arrma Granite
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A couple years ago I built an ECX Ruckus to use as a loaner vehicle for kids to drive. It worked well enough for that purpose, but it sat around the rest of the time because I had no interest in driving it for my own enjoyment. In the interest of getting more use out of it, I decided to replace it entirely with a similar vehicle -- the Arrma Granite.
I knew I would enjoy running this vehicle during the 362 days of the year that it's not on-loan to my girlfriend's family, because I already have an Arrma Raider as well. I'm not going to go over every detail of my new Granite, because I built it about 95% the same as my Raider (build thread [url="http://www.rctech.net/forum/electric-off-road/885284-build-complete-arrma-raider.html?highlight=build+complete%3A+arrma+raider"]here[/url]), but there are a few differences that I thought were worth mentioning.
First and foremost, this truck appears to be much more durable than the Raider; the Raider's weak point is the exposed shock towers that will often snap clean off if the buggy lands upside-down. Since the Granite has a full-cover body shell and big squishy tires, I haven't had to reinforce the shock towers with extra braces even though I've been doing my best to beat the tar out of this truck in preparation for what the kids will eventually do to it. So that's a nice change. I did opt for the factory-upgrade red braces, though, because they're thicker than the stock parts, and the front tower still didn't come with a brace.
Second, instead of hunting down Team Durango shocks that would fit the Granite, I decided to give the STRC aluminum shock bodies a try. I've loved them on every other vehicle I've installed them on, and this one is no different; they're smooth, durable, consistent, and don't leak. I did replace the O-rings in the lower seal with spare O-rings from Tamiya shocks, because the stock O-rings looked kinda cheap.
Third, because I couldn't find CVDs or universals that would fit the Granite, and had to stay with the stock dogbones, I replaced the stock ball-stud turnbuckles with Traxxas captured-ball turnbuckles. Early in my testing, the truck landed funny on one of its rear tires, which popped the turnbuckle loose, ripped the ball-stud out of the rear hub (I never found the ball-stud), and sent the dogbone flying. The Traxxas turnbuckles won't let that happen again, because they're bolted solidly in-place at both ends, with locknuts on the ends that attach to the hubs for extra security.
Fourth, because this truck is a wheelie-monster with with its rear weight bias and super-low 9/58 gearing (to limit it to 30mph top speed), I knew I'd need a wheelie bar. The used Granite BLX that I bought to scavenge upgrade parts had a broken wheelie-bar, and it was clear that the breakage was the result of the truck landing directly on the wheelie-bar, which in stock form has no flexibility at all. The solid mounting of the wheelie bar is good insofar as it prevents parts from getting lost, but I didn't want it to break when the kids somehow manage to get it to land on the wheelie-bar, so I replaced the upper support with a pair of MST touring-car shocks. The shocks are fitted with the stiffest HPI Pro4 springs available, and filled with 2000wt oil, to make sure they have sufficient shock-absorption capability to handle the weight of a monster truck crashing down on them. After installing these, I proceeded to test them by dropping the truck from about a foot in the air straight onto the wheelie-bar several times, then I spent an entire battery pack jumping over a speedbump and punching the throttle in the air to tilt the truck backwards so it would land on the wheelie-bar. So far it has shown no damage or premature wear on the shock bushings.
Lastly, because this truck is going to be run by kids who only have a vague grasp of the concept of "brakes", I have the ESC programmed to apply 35% drag-brake -- the highest setting I can get without causing so much drag that the truck spins around backwards when coasting into a corner. I have a couple Traxxas Tellurides configured for trailing and light crawling, and they run 50% drag-brake, which has worked extremely well for the purpose of preventing kids from breaking bystanders' ankles when they forget to use the brakes. Also, this truck is connected to a Spektrum DX2L radio that has a three-position throttle-limiter switch, so this truck can be easily slowed down to 20mph from its natural top speed of 30mph, to make things even easier for younger kids (and safer for the people standing nearby).
I've only put a few packs through this truck and I've driven it in a way that normally makes me cringe, but I can tell that I will enjoy bashing this truck much more than the ECX Ruckus it's replacing. It should hold up well in the hands of squealing hyperactive children, too.
Minor update to this vehicle: I upgraded the slipper clutch to the Team Associated VTS unit. I already had a Team Associated spur gear, high-torque slipper pads, outer slipper plate, and pressure spring from the SC10, but because I have the gearing on this truck so low (for Maximum Wheelie Action!!!), the pressure spring was bottomed-out and the slipper clutch was still not quite tight enough.
The VTS slipper clutch replaces one of the stock slipper pads with a retainer that holds two slipper pads and a friction washer between them, doubling the contacting surfaces from 2 to 4. This setup lets me tighten the slipper clutch enough without bottoming-out the pressure spring and losing the fine adjustability that should've been available.
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