johnnyluv
Rock Crawler
This is not going to be impressive, by any means, since I'm one of the least experienced scale builders, or even model builder. Seriously, I didn't build models, legos, or anything, growing up, because I never wanted to stay indoors. However, here I am, decades later, getting into scale RC crawling, and I end up picking a custom, short wheelbase build as my first kit. Talk about choosing the hard road.
It all began in the early spring of 2014, before I had a working crawler. I purchased an SCX10 JK kit from Tower Hobbies, during a good sale, heeding the advice of many, that building a crawler would provide an invaluable level of knowledge and self-sufficiency. The kit arrived a week later, but as I was not ready to start the build, the box was gently stowed beneath the bed. Shortly after that, while perusing through a thrift store, I found a Nikko FJ Cruiser on the used toy shelf. I didn't even know, at the time, that it was, or had been, a highly sought after RC hard body, so I whipped out my phone and Googled it, to make sure I wouldn't be wasting $6.00. Within a few search results, of course, I discovered that I had found a gold nugget in a stream of useless sediment, and quickly grabbed it with both hands and proceeded to the checkout. I got home, removed the body, disassembled the chassis, and discarded the useless pieces. The body had working headlights, which tested positive, but now I could only shelve it, until some time in the future, when I figured out what to do with it.
As the months wore on, I researched, reading many forum threads and watching many YouTube videos, but it wasn't until mid summer, that I learned about the STRC Short Wheelbase Conversion Kit. Seeing that summer was most likely going to pass before I could dig into a custom kit build, I chose to spring for an RTR SCX10 Deadbolt, so I could jump into crawling, and learn what it was about. My plan was to get an STRC swb conversion kit, to supplement my SCX10 JK kit, for a short wheelbase build, later on, in the fall season. I had wanted to do it before winter, but was having too much fun getting out with my current truck. Also, I took the Rubicon body (and links) from the JK kit, painted it up, and swapped out the Deadbolt body with it.
As it commonly goes, I ended up waiting until winter time, to finally begin the kit build, having almost an entire week off work, which really helped me get focused. That was over the Christmas week.
Now, since I was building a new SCX10 kit, and not performing a conversion, as the STRC kit instructions are based on, I had to fill in the process gaps, myself, and go back n' forth between the SCX10 build guide and the STRC conversion guide. It wasn't too bad, for getting the axles & tranny built, and putting the frame together, until I chose to start with my FJ Cruiser body, which had a greater than 9.8" wheelbase. You see, I had been lucky all summer, finding additional toy RC hard bodies, and a couple of them would've fit the 9.8" wheelbase that the STRC kit provides, but I wanted to do the FJ first. Therefore, I had to figure out the wheelbase on my own.
Frustrating enough, I got mixed measurements, since, when I first measured it, it seemed 10.75", but later it looked more like 10.6". Then, as I worked with it, I settled on 10.75", because of the front wheel well. If you look closely at the Nikko FJ Cruiser body, you'll notice that the back side of the front wheel well is more straight than both sides of the rear wheel well, which are more slanted. Because of that, the front wheel needs to set a little further away from the back side of the wheel well, to avoid rubbing under articulation, seemingly.
Now, since I'd never done this before, I used wooden skewer sticks to mock up my links. This was a pain, at first, because even with some paper shims, the sticks kept falling out of the rod ends. Being greatly upset, I had to walk away, and leave it for the next day.
I went ahead took care of waterproofing my new servo, a PowerHD 1501 MG, which I had also purchased, many months before, from ValueHobby. It's not shown in the picture, but I added a good layer of marine grease on top of the topmost gears.
To overcome the challenge of my wooden links falling out of the rod ends, I cut small strips of a rubber balloon, and pulled each one tightly over the end of the stick, before inserting into the rod end. This provided a gripping effect. It also helped to turn the chassis upside down, and once getting the links in place, using rubber bands to pull the axles in toward each other. This probably sounds nuts, but it worked for me, and kept everything in place, for transporting it up to my in-laws, where I got help from my father-in-law, cutting and threading steel links from a 3/16" steel rod from Home Depot. We threaded it using an 8-32 thread die, and tapping the rod ends the same. By the end of New Year's Day, I had all my permanent upper & lower links in place, and was very satisfied.
I felt it best to note that I used two MIP Rear C-Drive "Dig" shafts, due to their short length (thanks to Lobonyc). Consequently, the MIP shaft uses a set screw, but neither my transmission or axle outputs had flat spots, so I had to match up the holes, to make sure the set screw would at least have some indentation to hold against.
I don't have the body mounted yet, but as it sets, it looks like I nailed that wheelbase. Not too bad for a Johnny-come-lately.
The chassis was now ready for the receiver box, battery tray, and finally, the electronics. The STRC kit recommends using their optional STRC aluminum rear brace, but I used the SCX10 plastic brace. In the conversion kit instructions, they use servo tape to mount the ESC down on the rear brace, because the aluminum STRC brace is flat & smooth. The stock plastic brace didn't provide that, but as I looked at my spare parts on the table, I noticed I had an unused stock metal front servo plate (since the STRC kit provides its own servo plate, which also serves an upper link mount, for a front 4-link setup, which I did). Soooo, I tapped three holes in the plastic rear brace, and mounted the servo plate on top, which provided me a nice smooth plate to mount my esc. Speaking of esc, I took the AE-5 off my RTR Deadbolt chassis, since it has a smaller footprint, and a new Castle SV3 will take its place.
I decided to use the Titan12T brushed motor that came out of my Traxxas Son-uva Digger, since I was most likely going to toss it, sooner or later, so why not use it? Since it is a lower turn motor, I simply put on the original 14T pinion that came with it, which was perfect, because it reduced speed significantly, and added sufficient torque, as far as I can tell. I haven't been able to get an outside test, yet.
Just for an initial test, I mounted some Pro-line 2.2 Dirt Hawgs, intended for the 1/16 Traxxas E-Revo, since their overall diameter (OD) matches the FJ Cruiser's wheel wells, almost perfectly. However, I have a set of heavyweight, 1.9 alloy beadlocks, that will be going in their place, with some rock crusher style tires that measure about 94mm OD, just a wee bit larger than the Dirt Hawgs, but with good crawler tread.
And with that, I'm going to publish this thread, as I'm now waiting on a special 1.5mm hex socket driver, in order to use my new beadlocks, which I'm expecting to arrive later this week. I've also got some brainstorming to do, regarding the body mounting, and other stuff, like tail lights. More to come, for certain, as time allows. ;-)
It all began in the early spring of 2014, before I had a working crawler. I purchased an SCX10 JK kit from Tower Hobbies, during a good sale, heeding the advice of many, that building a crawler would provide an invaluable level of knowledge and self-sufficiency. The kit arrived a week later, but as I was not ready to start the build, the box was gently stowed beneath the bed. Shortly after that, while perusing through a thrift store, I found a Nikko FJ Cruiser on the used toy shelf. I didn't even know, at the time, that it was, or had been, a highly sought after RC hard body, so I whipped out my phone and Googled it, to make sure I wouldn't be wasting $6.00. Within a few search results, of course, I discovered that I had found a gold nugget in a stream of useless sediment, and quickly grabbed it with both hands and proceeded to the checkout. I got home, removed the body, disassembled the chassis, and discarded the useless pieces. The body had working headlights, which tested positive, but now I could only shelve it, until some time in the future, when I figured out what to do with it.
As the months wore on, I researched, reading many forum threads and watching many YouTube videos, but it wasn't until mid summer, that I learned about the STRC Short Wheelbase Conversion Kit. Seeing that summer was most likely going to pass before I could dig into a custom kit build, I chose to spring for an RTR SCX10 Deadbolt, so I could jump into crawling, and learn what it was about. My plan was to get an STRC swb conversion kit, to supplement my SCX10 JK kit, for a short wheelbase build, later on, in the fall season. I had wanted to do it before winter, but was having too much fun getting out with my current truck. Also, I took the Rubicon body (and links) from the JK kit, painted it up, and swapped out the Deadbolt body with it.
As it commonly goes, I ended up waiting until winter time, to finally begin the kit build, having almost an entire week off work, which really helped me get focused. That was over the Christmas week.
Now, since I was building a new SCX10 kit, and not performing a conversion, as the STRC kit instructions are based on, I had to fill in the process gaps, myself, and go back n' forth between the SCX10 build guide and the STRC conversion guide. It wasn't too bad, for getting the axles & tranny built, and putting the frame together, until I chose to start with my FJ Cruiser body, which had a greater than 9.8" wheelbase. You see, I had been lucky all summer, finding additional toy RC hard bodies, and a couple of them would've fit the 9.8" wheelbase that the STRC kit provides, but I wanted to do the FJ first. Therefore, I had to figure out the wheelbase on my own.
Frustrating enough, I got mixed measurements, since, when I first measured it, it seemed 10.75", but later it looked more like 10.6". Then, as I worked with it, I settled on 10.75", because of the front wheel well. If you look closely at the Nikko FJ Cruiser body, you'll notice that the back side of the front wheel well is more straight than both sides of the rear wheel well, which are more slanted. Because of that, the front wheel needs to set a little further away from the back side of the wheel well, to avoid rubbing under articulation, seemingly.
Now, since I'd never done this before, I used wooden skewer sticks to mock up my links. This was a pain, at first, because even with some paper shims, the sticks kept falling out of the rod ends. Being greatly upset, I had to walk away, and leave it for the next day.
I went ahead took care of waterproofing my new servo, a PowerHD 1501 MG, which I had also purchased, many months before, from ValueHobby. It's not shown in the picture, but I added a good layer of marine grease on top of the topmost gears.
To overcome the challenge of my wooden links falling out of the rod ends, I cut small strips of a rubber balloon, and pulled each one tightly over the end of the stick, before inserting into the rod end. This provided a gripping effect. It also helped to turn the chassis upside down, and once getting the links in place, using rubber bands to pull the axles in toward each other. This probably sounds nuts, but it worked for me, and kept everything in place, for transporting it up to my in-laws, where I got help from my father-in-law, cutting and threading steel links from a 3/16" steel rod from Home Depot. We threaded it using an 8-32 thread die, and tapping the rod ends the same. By the end of New Year's Day, I had all my permanent upper & lower links in place, and was very satisfied.
I felt it best to note that I used two MIP Rear C-Drive "Dig" shafts, due to their short length (thanks to Lobonyc). Consequently, the MIP shaft uses a set screw, but neither my transmission or axle outputs had flat spots, so I had to match up the holes, to make sure the set screw would at least have some indentation to hold against.
I don't have the body mounted yet, but as it sets, it looks like I nailed that wheelbase. Not too bad for a Johnny-come-lately.
The chassis was now ready for the receiver box, battery tray, and finally, the electronics. The STRC kit recommends using their optional STRC aluminum rear brace, but I used the SCX10 plastic brace. In the conversion kit instructions, they use servo tape to mount the ESC down on the rear brace, because the aluminum STRC brace is flat & smooth. The stock plastic brace didn't provide that, but as I looked at my spare parts on the table, I noticed I had an unused stock metal front servo plate (since the STRC kit provides its own servo plate, which also serves an upper link mount, for a front 4-link setup, which I did). Soooo, I tapped three holes in the plastic rear brace, and mounted the servo plate on top, which provided me a nice smooth plate to mount my esc.
Speaking of esc, I took the AE-5 off my RTR Deadbolt chassis, since it has a smaller footprint, and a new Castle SV3 will take its place.
I decided to use the Titan12T brushed motor that came out of my Traxxas Son-uva Digger, since I was most likely going to toss it, sooner or later, so why not use it? Since it is a lower turn motor, I simply put on the original 14T pinion that came with it, which was perfect, because it reduced speed significantly, and added sufficient torque, as far as I can tell. I haven't been able to get an outside test, yet.
Just for an initial test, I mounted some Pro-line 2.2 Dirt Hawgs, intended for the 1/16 Traxxas E-Revo, since their overall diameter (OD) matches the FJ Cruiser's wheel wells, almost perfectly. However, I have a set of heavyweight, 1.9 alloy beadlocks, that will be going in their place, with some rock crusher style tires that measure about 94mm OD, just a wee bit larger than the Dirt Hawgs, but with good crawler tread.
And with that, I'm going to publish this thread, as I'm now waiting on a special 1.5mm hex socket driver, in order to use my new beadlocks, which I'm expecting to arrive later this week. I've also got some brainstorming to do, regarding the body mounting, and other stuff, like tail lights. More to come, for certain, as time allows. ;-)
