I mounted a set of ActionTrax brand traction matts on the STC rear molle panel yesterday. I prefer the material of the ActionTrax (more flexible) than the MaxTrax (more rigid). Had a medium blue set that we thought would look slick with the gray camper and then had also bought a black set as we wanted a total of four. Ended up liking the black set better and considered putting those on the outside and blue on the inside, but fickle us decided all black would be more our taste so another set of black are on the way.
As for mounting, STC has four holes in the rear molle specifically spaced for Maxtrax brand traction boards. Of course the ActionTrax use a different pattern. Blah.
MaxTrax uses 890mm (35.0394") by 270mm (10.6299).
ActionTrax uses 873.125mm (34.375") by 266.7mm (10.5").
The width is juuuust close enough that it will work, though not as smooth as if the width was exactly appropriate. I wanted to only re-drill two holes rather than four plus there was not a good place to re-drill all four without overlapping at least two of the new holes with existing holes (effectively making an oval or an 8 shaped hole) which I wanted to avoid. I chose to mount the mounting pins in the two existing lower molle panel holes and then redrill only the two top holes. That would also space the new holes far enough away from the two existing top holes that the holes would not overlap. I put a scrap piece of Hardie Plank siding behind the molle while drilling to avoid marring the camper after the drill bit passed through the molle panel. Marked the center of the needed holes by mounting the boards on the two lower pins and marking the center of the holes with a marker, removed the boards, center punched the molle panel so the drill bit wouldn't drift, drilled the hole first with a midsize bit then with the final sized bit.
If I'd planned way further ahead, I may have inquired if STC could drill the board holes at the needed ActionTrax spacing rather than Maxtrax spacing. They could potentially update their pattern and have one panel for ActionTrax and one panel for MaxTrax, or, perhaps a single panel that has holes for both spacing but offset far enough to have all eight individual holes. ActionTrax are becoming as popular, if not more so, than MaxTrax, so might be worth STCs consideration, which I intend to mention.
I used Maxtrax brand board holder pins. They make make three versions (standard boards, extremet boards and hybrid) and each can be purchased with 17mm studs or 40mm studs. I had the standard pins set with 17mm studs. The 17mm will fit on the STC molle panel without requiring the stud to be cut off like on longer studs. They come with a washer and nylon lock nut, but I also used loctite.
The ActionTrax standard boards are slightly deeper than the Maxtrax standard boards . On the Maxtrax pins that will hold two or four boards, two ActionTrax will not allow the knob to close for two boards; you have to use the 4 board knob and then there is quite a bit of play (see image below). ActionTrax says the standard board pins will hold 3 ActionTrax. The longer pins, meant for four Maxtrax extreme boards will carry four standard ActionTrax boards. I'll likely swap out to the longer pins when we get back from our April trip, but for now, they are mounted and I'll bring only 3 boards rather than 4.
Freshly-drilled set of upper holes for ActionTrax which are slightly narrower and shorter than Maxtrax hole spacing.
This shows the spacing with two pair of Action Trax. They are thicker than Maxtrax so I can't close the 2-board pin; only the 4-board pin and that leaves a gap. Three ActionTrax will fit with the 4-board pin closed and I'll add the third board next week. Meanwhile, I'm using two Giant Loop brand Pronghorn straps to keep the boards from moving.