tkvtec
Newbie
I've finally gotten my setup most of the way to where I want it and figured I'd share my progress.
Scroll to the bottom if looking for a parts list, this is a lengthy story.
I started off with the TRX-4 kit, and like many others received one with a bad 24T output gear for the transmission. Basically, the problem on many is that they never finished machining the gears out to the full 10mm needed to fit the bearing. Traxxas had a new one out to me within a couple days and I was able to complete the rest of the build. This only required a less than 5 minute phone call with support, I’m really amazed at the Customer Service.
I had a hobby night planned for Friday with a friend who just bought a Bronco TRX4, and received the kit Monday 3/18 and I was in crunch mode to get the chassis built and fit the body. Going into it knowing I was going to want a strong servo I bought a used Protek 170 TBL that popped up in the classifieds on a forum. I also ordered up the Traxxas metal servo horn to get around any issues with stripping or fitment. Thankfully Protek uses the same 25T splines as the Traxxas stock servo. I read about the fitment of aftermarket servos in the stock mount and needing to trim the servo mounting ears, so I also ordered up the Samix adjustable Aluminum servo mount so I wouldn't have to modify the aluminum mounting ears (I'm just a little funny about that, though I have no problems doing that to cheaper plastic housing servos especially when I know I can get a spare case). Ultimately, the mounting screws actually fit fine and no modification was necessary for this particular servo. My friend had to trim his Savox 1230 IIRC. I also ordered up bumpers that I was hoping to fit the body well. I swapped the front and rear bumper mounts and flipped the front at first and ultimately flipped the rear also. One arrived (rear) before the hobby night, but was really meant to fit something like the defender and was way too wide and straight.
For the transmitter, I had recently picked up a 2nd FlySky GT3C and performed the modifications necessary to reflash the firmware and get 8 Channel capability. I ordered a 6 Channel receiver from FlySky (https://www.amazon.com/gp/product/B01FXLZYMY/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1) to give me independent control of the front and rear lockers and still have an additional Channel for lighting. Now that I'm looking at possibly having multiple lighting controls or a winch, I'll probably up to an 8 Channel receiver. I find that the FlySky receivers for 6 and 8 Channels are designed for Aircraft and the antenna has a metal weight under the red heat shrink. I cut off the red heat shrink and carefully cut away at the metal weight with some small side cutters. I was eventually able to completely remove the weight and was able to slightly route it up into the antenna tube.
I was determined to do an FJ body setup and had seen a couple other people make it happen. I ordered up the HPI FJ body and when it arrived I began my process of trimming up the fender liners with a Dremel to make the body fit. I got a decent fit, but ultimately the body was a little higher than I wanted. I figured if I could center the body a little more forward, as it sits a little too rearward using the predrilled body holes up front, I could get enough clearance to lower the body.
I ended up using a magnetic body post mount setup I had bought for a drift car build to mount up the rear while I figured out all the fitment as that gives me infinitely adjustable positioning at the rear. I ran the truck like this for a few crawls and I have 1 piece of advice... do not run magnetic body mounts (at least in the rear). The setup I had added about 60 grams of weight to the highest location you could possibly go. This made the FJ really tippy despite the body being lighter than my friend's Bronco.
I found that I was going to need to move the body forward, and I didn’t just want to keep trimming the fender liners, so I ordered up some aluminum shock towers as they were the only thing that I could get shipped quickly from a somewhat local hobby shop. I knew these wouldn’t cause any interference and I would be free to line up the body where I wanted and could figure out the body post situation. I somehow also came across some 3D printed parts designed to make the FJ body fit on the TRX4 with the stock FJ bumpers. I ordered up all the parts (Rear post, front bumper mount, rear bumper mount). I liked the idea of these bumper mounts as they would allow me to bring the bumpers much closer to the body and increase the approach and departure angles of the truck.
Early Christmas!
And Christmas day ruined... at step 1 basically this should read 10mm
Finished the rest of the build and just came back to the transmission at the end once I had the part.
Had some Austar Hyrax knockoffs I bought for my son and mounted them up
Body test fit... need to do some trimming
Fender Liners trimmed up
Rock sliders raised with about 13mm of spacers to meet body
3/23: Hobby night couldn’t happen, so we had Hobby morning the next day: I had some Austar Hyrax knockoffs on the truck on some cheap steel beadlocks they came mounted on. I was doing some outdoor crawling and ripping up the course and really impressed with the truck overall. I was there early and my friend showed up with his Bronco after I had done some mud crawls etc… I was struggling with getting up a certain flat faced rock that my friends Bronco just got right up and over… I was like hmmm. Maybe it’s the mud in the tread not clearing out, or maybe those Stock Traxxas tires are really just working well. I didn’t want to glue up the tires, and had planned on getting some beadlocks… well that sealed the deal for me when I found that the hobby shop had the exact wheels I was planning on. SSD D-Hole Black Beadlocks. They also had some Proline Dual Stage Foams. I figured since I was going to go through the assembly process I might as well get those now also, as I was planning to do that later, but wanted to look more into the Crawler Innovations dual stage foams. Anyways, I got the Proline Foams and the SSD beadlockas and got all the tires built and continued crawling for hours (only needed 2x 5000 mAH batteries to accomplish this). Amazed at the runtime.
Impressions: the Proline dual stage foams seem too stiff and don’t provide as much traction in most circumstances, only providing the advantage on side hills and extreme articulation. I will likely be looking into the soft and medium CI foams if I don’t just modify the Proline foams a bit.
3/24: The new new rear bumper came in, and it is a perfect fit for this body. The width and curvature at the corners is perfect. I just folded up the lower flap on the rear of the body at the crease and it was perfect. There was one other bumper out there that I found that might have been a similar design and fit. I did have to slot the mounting holes to fit with the 3D printed bumper mount designed to work with the HPI stock bumpers (40mm mounting width instead of the 43mm Axial and Traxxas uses)
Folded up bottom flap of bumper and you can see the SSD D-Hole Beadlocks installed:
3/25: I measured up the forward offset I wanted at the front body posts and found I needed a little under 9mm. I noticed there was an offset on the rock sliders stock that had them offset rearward by about the same amount, and using the factory predrilled holes on the FJ body, they lined right up. I swapped the rock sliders from left to right and got pretty much a perfect fit. I then modified the front posts, as you'll see in pictures, to basically cut off the bottom half of the posts and mounted them in the mount and bolted the top half to the front of them. I trimmed away material on the lower posts until the front posts were lined up where I wanted them. This ulimately worked out really well, but using this method I definitely couldn't get the body any lower, I'd have to switch to epoxy or custom 3D printed parts. I left it as is for now as the top of the body is still no higher than my friends Bronco, it just looks like the bottom of the body and fenders are really high. I also raised the rock sliders about 13mm using spacers from various plastic parts trees from other builds.
Checking body post offset for properly centering the body, just a little close. Time to modify the front body posts
3/26: My new front bumper finally came!!! It is a perfect fit for this body for the position it currently sits. To get the bumper closer under the body and hide the winch mount brings the ends of the bumper in line with the tires under articulation. There are super narrow front bumpers that would give an even greater front approach angle, but I really like the look of this one, and I’m kind of done spending money on this thing… �� for now
3/28/19: Added Brass outer portal covers, which were an easy install. I ordered the below kits thinking I could use the various weights from the Ultimate kit and customize the weight balance front to rear and play with adding more weight overall, or just keeping it a little lighter.
Out of the box I added the portal covers front and rear and added the 47g inner weights to the front as well. This seemed a bit much and very nose heavy, also the drag brake in crawl mode was not enough to stop the truck in its tracks anymore. I removed those and liked the balance overall. After removing the 47g weights from the front, the truck has a 53% forward weight bias, which happens to be the same as the TRX-4 Sport out of the box. I'm going to roll with this a little and mess with adding weight when I can get to the crawler course again. Overall, the Brass portal covers made a big improvement in getting the tires back down to the ground. I think the truck is about 8lbs 3ozs now.
...
Scroll to the bottom if looking for a parts list, this is a lengthy story.
I started off with the TRX-4 kit, and like many others received one with a bad 24T output gear for the transmission. Basically, the problem on many is that they never finished machining the gears out to the full 10mm needed to fit the bearing. Traxxas had a new one out to me within a couple days and I was able to complete the rest of the build. This only required a less than 5 minute phone call with support, I’m really amazed at the Customer Service.
I had a hobby night planned for Friday with a friend who just bought a Bronco TRX4, and received the kit Monday 3/18 and I was in crunch mode to get the chassis built and fit the body. Going into it knowing I was going to want a strong servo I bought a used Protek 170 TBL that popped up in the classifieds on a forum. I also ordered up the Traxxas metal servo horn to get around any issues with stripping or fitment. Thankfully Protek uses the same 25T splines as the Traxxas stock servo. I read about the fitment of aftermarket servos in the stock mount and needing to trim the servo mounting ears, so I also ordered up the Samix adjustable Aluminum servo mount so I wouldn't have to modify the aluminum mounting ears (I'm just a little funny about that, though I have no problems doing that to cheaper plastic housing servos especially when I know I can get a spare case). Ultimately, the mounting screws actually fit fine and no modification was necessary for this particular servo. My friend had to trim his Savox 1230 IIRC. I also ordered up bumpers that I was hoping to fit the body well. I swapped the front and rear bumper mounts and flipped the front at first and ultimately flipped the rear also. One arrived (rear) before the hobby night, but was really meant to fit something like the defender and was way too wide and straight.
For the transmitter, I had recently picked up a 2nd FlySky GT3C and performed the modifications necessary to reflash the firmware and get 8 Channel capability. I ordered a 6 Channel receiver from FlySky (https://www.amazon.com/gp/product/B01FXLZYMY/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1) to give me independent control of the front and rear lockers and still have an additional Channel for lighting. Now that I'm looking at possibly having multiple lighting controls or a winch, I'll probably up to an 8 Channel receiver. I find that the FlySky receivers for 6 and 8 Channels are designed for Aircraft and the antenna has a metal weight under the red heat shrink. I cut off the red heat shrink and carefully cut away at the metal weight with some small side cutters. I was eventually able to completely remove the weight and was able to slightly route it up into the antenna tube.
I was determined to do an FJ body setup and had seen a couple other people make it happen. I ordered up the HPI FJ body and when it arrived I began my process of trimming up the fender liners with a Dremel to make the body fit. I got a decent fit, but ultimately the body was a little higher than I wanted. I figured if I could center the body a little more forward, as it sits a little too rearward using the predrilled body holes up front, I could get enough clearance to lower the body.
I ended up using a magnetic body post mount setup I had bought for a drift car build to mount up the rear while I figured out all the fitment as that gives me infinitely adjustable positioning at the rear. I ran the truck like this for a few crawls and I have 1 piece of advice... do not run magnetic body mounts (at least in the rear). The setup I had added about 60 grams of weight to the highest location you could possibly go. This made the FJ really tippy despite the body being lighter than my friend's Bronco.
I found that I was going to need to move the body forward, and I didn’t just want to keep trimming the fender liners, so I ordered up some aluminum shock towers as they were the only thing that I could get shipped quickly from a somewhat local hobby shop. I knew these wouldn’t cause any interference and I would be free to line up the body where I wanted and could figure out the body post situation. I somehow also came across some 3D printed parts designed to make the FJ body fit on the TRX4 with the stock FJ bumpers. I ordered up all the parts (Rear post, front bumper mount, rear bumper mount). I liked the idea of these bumper mounts as they would allow me to bring the bumpers much closer to the body and increase the approach and departure angles of the truck.
Early Christmas!
And Christmas day ruined... at step 1 basically this should read 10mm
Finished the rest of the build and just came back to the transmission at the end once I had the part.
Had some Austar Hyrax knockoffs I bought for my son and mounted them up
Body test fit... need to do some trimming
Fender Liners trimmed up
Rock sliders raised with about 13mm of spacers to meet body
3/23: Hobby night couldn’t happen, so we had Hobby morning the next day: I had some Austar Hyrax knockoffs on the truck on some cheap steel beadlocks they came mounted on. I was doing some outdoor crawling and ripping up the course and really impressed with the truck overall. I was there early and my friend showed up with his Bronco after I had done some mud crawls etc… I was struggling with getting up a certain flat faced rock that my friends Bronco just got right up and over… I was like hmmm. Maybe it’s the mud in the tread not clearing out, or maybe those Stock Traxxas tires are really just working well. I didn’t want to glue up the tires, and had planned on getting some beadlocks… well that sealed the deal for me when I found that the hobby shop had the exact wheels I was planning on. SSD D-Hole Black Beadlocks. They also had some Proline Dual Stage Foams. I figured since I was going to go through the assembly process I might as well get those now also, as I was planning to do that later, but wanted to look more into the Crawler Innovations dual stage foams. Anyways, I got the Proline Foams and the SSD beadlockas and got all the tires built and continued crawling for hours (only needed 2x 5000 mAH batteries to accomplish this). Amazed at the runtime.
Impressions: the Proline dual stage foams seem too stiff and don’t provide as much traction in most circumstances, only providing the advantage on side hills and extreme articulation. I will likely be looking into the soft and medium CI foams if I don’t just modify the Proline foams a bit.
3/24: The new new rear bumper came in, and it is a perfect fit for this body. The width and curvature at the corners is perfect. I just folded up the lower flap on the rear of the body at the crease and it was perfect. There was one other bumper out there that I found that might have been a similar design and fit. I did have to slot the mounting holes to fit with the 3D printed bumper mount designed to work with the HPI stock bumpers (40mm mounting width instead of the 43mm Axial and Traxxas uses)
Folded up bottom flap of bumper and you can see the SSD D-Hole Beadlocks installed:
3/25: I measured up the forward offset I wanted at the front body posts and found I needed a little under 9mm. I noticed there was an offset on the rock sliders stock that had them offset rearward by about the same amount, and using the factory predrilled holes on the FJ body, they lined right up. I swapped the rock sliders from left to right and got pretty much a perfect fit. I then modified the front posts, as you'll see in pictures, to basically cut off the bottom half of the posts and mounted them in the mount and bolted the top half to the front of them. I trimmed away material on the lower posts until the front posts were lined up where I wanted them. This ulimately worked out really well, but using this method I definitely couldn't get the body any lower, I'd have to switch to epoxy or custom 3D printed parts. I left it as is for now as the top of the body is still no higher than my friends Bronco, it just looks like the bottom of the body and fenders are really high. I also raised the rock sliders about 13mm using spacers from various plastic parts trees from other builds.
Checking body post offset for properly centering the body, just a little close. Time to modify the front body posts
3/26: My new front bumper finally came!!! It is a perfect fit for this body for the position it currently sits. To get the bumper closer under the body and hide the winch mount brings the ends of the bumper in line with the tires under articulation. There are super narrow front bumpers that would give an even greater front approach angle, but I really like the look of this one, and I’m kind of done spending money on this thing… �� for now
3/28/19: Added Brass outer portal covers, which were an easy install. I ordered the below kits thinking I could use the various weights from the Ultimate kit and customize the weight balance front to rear and play with adding more weight overall, or just keeping it a little lighter.
Out of the box I added the portal covers front and rear and added the 47g inner weights to the front as well. This seemed a bit much and very nose heavy, also the drag brake in crawl mode was not enough to stop the truck in its tracks anymore. I removed those and liked the balance overall. After removing the 47g weights from the front, the truck has a 53% forward weight bias, which happens to be the same as the TRX-4 Sport out of the box. I'm going to roll with this a little and mess with adding weight when I can get to the crawler course again. Overall, the Brass portal covers made a big improvement in getting the tires back down to the ground. I think the truck is about 8lbs 3ozs now.
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