› Pro-line Powerstroke HD Shock Shafts for Traxxas X-maxx
Super-sized shafts to make your X-maxx an even mightier machine
Pro-line’s been on top of the X-maxx since Traxxas first dropped the super-sized monster on the RC scene, and the PL crew hasn’t limited themselves to bodies, wheels, and tires. I tested the trick Ultra Reservoir Caps for the X-maxx’s fat aluminum shocks back in the October 2017 issue, and now Pro-line has an equally dialed bottom end for the dampers. The Powerstroke HD shafts are a complete shaft/piston/seal cartridge assembly that features significantly thicker shafts, new spring perches (with shaft guards—nice), and new rod ends to accommodate the thicker shafts. Here’s how it all goes together and performs.
Pro-line assembles the shaft units for you and says, “Just install and go.” You can do that, but I took apart the seal cartridges and coated the O-rings and shaft guides with Protek Premier
Blue seal grease. I had to take everything apart for photos anyway, and seal grease is a particularly good idea on a heavyweight machine that’s really going to work the shocks. Pro-line makes it easy to get to the seals: Just unscrew the lower aluminum cap, which has flats if you need to put a wrench on it (you’ll need a 20mm). The thick O-ring seals are widely spaced, and a pair of shaft guides help reduce shaft deflection. I left the installed moldeddelrin “1.6” pistons in place since they match the stock pistons. Pro-line also includes
“1.4” pistons if you want firmer damping. Before installing the shaft assemblies in the bodies, I slid the cartridges up and down the shafts to see how much resistance the seals offered, which was very light, so operation will be extra slick. The only thing I missed from the stock shock setup was the shaft-wiper boot that fits over the bottom of the seal cartridge, but that’s not a deal breaker. I’m happy to trade the shaft wiper for the stouter shafts.
Since the 6.5mm Pro-line shafts are 25 percent thicker than the stock 5.2mm shafts, they also displace quite a bit more oil than the stock shafts when the shock is compressed. And so I installed Pro-line’s Ultra Reservoir Caps to provide extra volume compensation. The Pro-line shafts can be used with the stock bladder-equipped caps, but I wanted to test an all-pro-line build. That includes the springs, with a set of red “firm” upper and lower coils from the 6299-00 set replacing the single-rate Traxxas springs. The Powerstroke shafts aren’t meant to change handling feel, they’re just meant to be more durable, so there’s no “they felt better than stock” component of this test. And while I can say I didn’t break the Pro-line shafts, I haven’t broken any stock shafts, either—but there’s no way the Pro-line shafts aren’t stronger, given their increased thickness straight through the threads. I was pleased to see the titanium carbon nitride (TICN) shaft coating still looks new after putting a bunch of time on the shafts, and I haven’t seen any weeping at the shaft exit or where the cartridge threads into the body. What did make a noticeable difference feel-wise was the dual-rate springs, which are very supple over smaller bumps as the softer, upper springs do their thing. You can mix and match the soft, medium, and firm upper (primary) springs with the soft, medium, and firm lower (secondary) springs to really dial in your setup. As for me, I just went firm because I’m all about big hits when I’m in X-maxx mode.
More nice suspension stuff from Pro-line; they’ve really got the Powerstroke lineup dialed in. Fit and finish is excellent, and all you have to do is look at them to know they’re going to outlast the stock parts. As expected for high-qual stuff in a large scale, the HD shafts aren’t cheap. But spending the extra dough sure beats replacing broken stock shafts, a job that is low on anyone’s list of favorite RC activities, no matter much you love wrenching. If you find yourself with a broken X-maxx shock shaft, skipping the stock replacement in favor of upgrading to Powerstrokes is a smart way to go.—peter Vieira
The Powerstroke shafts arrive assembled, complete with a tall shaft guard.
62 Here’s the Powerstroke shaft next to the stock Traxxas X-maxx shaft.
I assembled the shocks with Pro-line’s Dual-rate Springs (6299-00) and Ultra Reservoir Caps (6293-00, as tested in the October 2017 issue).
Pro-line–equipped versus stock. Looks pretty trick, right?
The stock X-maxx seal cartridge contains one X-ring seal, while the Pro-line unit contains two fat O-rings and a pair of Delrin shaft guides (I left one out in this pic—oops). An aluminum cap holds it all together.
The 6.5mm Pro-line shafts are significantly beefier than the stock 5.2mm shafts, and coated with TICN to reduce friction. Note the fat threads, too—there’s no step-down to the threaded portion of the shaft.