Build Complete: Traxxas Stampede 4x4, wet-weather edition
09-23-2015, 03:50 AM
#1
Build Complete: Traxxas Stampede 4x4, wet-weather edition
Some of my builds have a complicated story of how I built them. This one has a complicated story of *why* I built it.
A couple years ago I got a HPI Savage XS for Christmas. It was a nice truck, but I was never really comfortable with (depending on how you look at it) how fast it went considering its instability, or how unstable it was considering its speed. So I never really used it as much as I would've liked. Eventually I bought an Arrma Raider buggy and it became my go-to brushless high-speed basher, and it could out-handle the Savage XS on pavement any day of the week.
Around the same time, it started raining a lot, so I was really frustrated that I couldn't enjoy my hobby after work, and I realized I didn't have a vehicle that I was comfortable running in wet weather. My Wraith and Summit could handle getting wet -- even completely immersed -- since I take them crawling and fording a local creek, but flowing water is much cleaner than wet grass is. Both vehicles have such complex chassis that cleaning wet grass clippings out of them is an ENORMOUS pain. Also, the Wraith isn't very fast and doesn't handle very well. What I really wanted was something like my Savage XS, but with better ground clearance.
During late winter/early spring of this year, I had bought a Telluride and had modded it to be a trail truck that was safe to loan to kids. I was impressed with how effective it was despite the simplicity of its chassis, and how low its center of gravity was, but the fendered wheels caused it to accumulate tons of crap in the electronics tray during even a short run. Fortunately JConcepts had a ready-made solution in the form of a tray cover, and I'd installed one on my Telluride and found that it worked remarkably well. So when it came time to choose an off-road/wet-weather successor to my Savage XS, I decided to get a Stampede 4x4.
That's the end of the complicated part. I chose the brushed version since I knew I'd be tearing out all the stock electronics, and this way I could share diff gears with my Telluride too. (my Telluride was rebuilt with brushed Stampede diff gears to lower the gear ratio.) The actual nuts-and-bolts of this build are pretty straightforward. The goals were:
1) Make cleaning easy, which is solved just by using the simple Stampede 4x4 chassis;
2) Minimize debris intrusion into the electronics tray, which is solved by using the JConcepts tray cover;
3) Minimize rust, which is solved by using stainless-steel hardware everywhere I possibly could;
4) Make drivetrain maintenance easy, which is solved by using a brushless motor, as well as by solving the previous problems.
All of those problems were fairly easy, though finding stainless-steel shoulder bolts took some digging on Amazon, and installation took some drilling of various parts to accommodate the M4 threads. (the stock bolts are M3.)
Also, after seeing rust building up on the slipper clutch plate, I decided to give the center diff a try instead. Thus far it's been working quite well, and I think it's better for all-around bashing because it helps prevent traction-rolling and traction-flipping. I filled it with 100k diff oil, same as both diffs, and they're all performing just the way I want.
The motor, ESC, steering servo, and radio all came straight out of my Savage XS, which was sold as a roller. Nothing complicated, just a 120 amp sensorless ESC and a Tacon 4000KV motor. (technically 3930KV, but it's close enough as makes no difference.) The servo is a Hitec HS-7955TG, which has a satisfying amount of torque and keeps the wheels pointed exactly where I tell them to.
I made an ESC tray out of a sheet of Lexan and painted the underside black to hide dirt, following the same pattern I used when making an ESC tray for my Telluride this past spring. I included a picture of it on metric graph paper if anyone's interested in copying it. The notch is to allow space for the taillight wires to pass under the ESC tray; you don't have to copy that bit if you aren't running taillights.
The shocks are stock Traxxas pistons, caps, springs, and lower eyelets, upgraded with Traxxas TiN-plated shafts and STRC aluminum bodies. I first tried this combination on my Telluride, and I can't tell you how much better the suspension works with the STRC bodies. The stiction is reduced to basically nothing, and yet they still don't leak. It's a marvelous setup and I recommend it to anyone.
The headlights and taillights are a kit from RC-Lighthouse, and like I usually do I replaced the no-name white LEDs with fancy (i.e. much brighter) white LEDs from my prior hobby as a high-end flashlight collector and modder. I also dropped the headlight resistors from 470ohms to 82ohms so the headlights would be brighter.
The red taillight LEDs were fine as-is, though I sanded the domes off the taillight LEDs so they'd spread their light over a wider angle. I mounted them in a modified RPM step-bumper intended for the T-Maxx, with holes drilled in it to accommodate Axial LED holders. (and yes, I added a pivot-ball to the bumper as a decorative trailer-hitch. That's as far as I'm willing to go, however; no truck-nuts for me.) The LED holders have plastic nuts that hold them in-place, but I superglued them also, for extra strength. I also painted the insides with chrome-silver paint to help more of the light get out of the housing so I can see it at night.
That's about it, really. The lights were the most complicated mod I did, and most of that work was cutting and soldering wires. Other things worth mentioning:
- The tires are vented to make sure any water that gets into the foams can also get out;
- I cut down the body-mount posts as low as I could possibly get them, so the body wouldn't sit ridiculously high;
- I replaced the stock plastic axles with MIP X-CVDs for more strength and lower center-of-gravity;
- I replaced the stock plastic center driveshaft with a Tekno Big Bone aluminum driveshaft because plastic has no place in a truck's drivetrain
- I added a front swaybar to reduce traction-rolling when braking into corners, and the stock swaybar links were rebuilt with stainless grub screws in keeping with the "minimize rust" goal.
I think it came out well.
A couple years ago I got a HPI Savage XS for Christmas. It was a nice truck, but I was never really comfortable with (depending on how you look at it) how fast it went considering its instability, or how unstable it was considering its speed. So I never really used it as much as I would've liked. Eventually I bought an Arrma Raider buggy and it became my go-to brushless high-speed basher, and it could out-handle the Savage XS on pavement any day of the week.
Around the same time, it started raining a lot, so I was really frustrated that I couldn't enjoy my hobby after work, and I realized I didn't have a vehicle that I was comfortable running in wet weather. My Wraith and Summit could handle getting wet -- even completely immersed -- since I take them crawling and fording a local creek, but flowing water is much cleaner than wet grass is. Both vehicles have such complex chassis that cleaning wet grass clippings out of them is an ENORMOUS pain. Also, the Wraith isn't very fast and doesn't handle very well. What I really wanted was something like my Savage XS, but with better ground clearance.
During late winter/early spring of this year, I had bought a Telluride and had modded it to be a trail truck that was safe to loan to kids. I was impressed with how effective it was despite the simplicity of its chassis, and how low its center of gravity was, but the fendered wheels caused it to accumulate tons of crap in the electronics tray during even a short run. Fortunately JConcepts had a ready-made solution in the form of a tray cover, and I'd installed one on my Telluride and found that it worked remarkably well. So when it came time to choose an off-road/wet-weather successor to my Savage XS, I decided to get a Stampede 4x4.
That's the end of the complicated part. I chose the brushed version since I knew I'd be tearing out all the stock electronics, and this way I could share diff gears with my Telluride too. (my Telluride was rebuilt with brushed Stampede diff gears to lower the gear ratio.) The actual nuts-and-bolts of this build are pretty straightforward. The goals were:
1) Make cleaning easy, which is solved just by using the simple Stampede 4x4 chassis;
2) Minimize debris intrusion into the electronics tray, which is solved by using the JConcepts tray cover;
3) Minimize rust, which is solved by using stainless-steel hardware everywhere I possibly could;
4) Make drivetrain maintenance easy, which is solved by using a brushless motor, as well as by solving the previous problems.
All of those problems were fairly easy, though finding stainless-steel shoulder bolts took some digging on Amazon, and installation took some drilling of various parts to accommodate the M4 threads. (the stock bolts are M3.)
Also, after seeing rust building up on the slipper clutch plate, I decided to give the center diff a try instead. Thus far it's been working quite well, and I think it's better for all-around bashing because it helps prevent traction-rolling and traction-flipping. I filled it with 100k diff oil, same as both diffs, and they're all performing just the way I want.
The motor, ESC, steering servo, and radio all came straight out of my Savage XS, which was sold as a roller. Nothing complicated, just a 120 amp sensorless ESC and a Tacon 4000KV motor. (technically 3930KV, but it's close enough as makes no difference.) The servo is a Hitec HS-7955TG, which has a satisfying amount of torque and keeps the wheels pointed exactly where I tell them to.
I made an ESC tray out of a sheet of Lexan and painted the underside black to hide dirt, following the same pattern I used when making an ESC tray for my Telluride this past spring. I included a picture of it on metric graph paper if anyone's interested in copying it. The notch is to allow space for the taillight wires to pass under the ESC tray; you don't have to copy that bit if you aren't running taillights.
The shocks are stock Traxxas pistons, caps, springs, and lower eyelets, upgraded with Traxxas TiN-plated shafts and STRC aluminum bodies. I first tried this combination on my Telluride, and I can't tell you how much better the suspension works with the STRC bodies. The stiction is reduced to basically nothing, and yet they still don't leak. It's a marvelous setup and I recommend it to anyone.
The headlights and taillights are a kit from RC-Lighthouse, and like I usually do I replaced the no-name white LEDs with fancy (i.e. much brighter) white LEDs from my prior hobby as a high-end flashlight collector and modder. I also dropped the headlight resistors from 470ohms to 82ohms so the headlights would be brighter.
The red taillight LEDs were fine as-is, though I sanded the domes off the taillight LEDs so they'd spread their light over a wider angle. I mounted them in a modified RPM step-bumper intended for the T-Maxx, with holes drilled in it to accommodate Axial LED holders. (and yes, I added a pivot-ball to the bumper as a decorative trailer-hitch. That's as far as I'm willing to go, however; no truck-nuts for me.) The LED holders have plastic nuts that hold them in-place, but I superglued them also, for extra strength. I also painted the insides with chrome-silver paint to help more of the light get out of the housing so I can see it at night.
That's about it, really. The lights were the most complicated mod I did, and most of that work was cutting and soldering wires. Other things worth mentioning:
- The tires are vented to make sure any water that gets into the foams can also get out;
- I cut down the body-mount posts as low as I could possibly get them, so the body wouldn't sit ridiculously high;
- I replaced the stock plastic axles with MIP X-CVDs for more strength and lower center-of-gravity;
- I replaced the stock plastic center driveshaft with a Tekno Big Bone aluminum driveshaft because plastic has no place in a truck's drivetrain
- I added a front swaybar to reduce traction-rolling when braking into corners, and the stock swaybar links were rebuilt with stainless grub screws in keeping with the "minimize rust" goal.
I think it came out well.
Last edited by fyrstormer; 11-23-2017 at 02:34 AM.
09-23-2015, 03:52 AM
#2
Oh...in case you're wondering how well the JConcepts tray cover works, here are some pictures from after a run in the rain a couple nights ago:
That run featured an accidental dive down a storm-drain, which required me to lift a manhole cover with my bare hands and climb down to get the thing. I found it upside-down in a puddle of dirty water and god-knows-what-else. The 3M velcro tape (originally intended for holding an EZ-Pass tollbooth transponder to a car windshield) kept the tray cover right where it was supposed to be.
That run featured an accidental dive down a storm-drain, which required me to lift a manhole cover with my bare hands and climb down to get the thing. I found it upside-down in a puddle of dirty water and god-knows-what-else. The 3M velcro tape (originally intended for holding an EZ-Pass tollbooth transponder to a car windshield) kept the tray cover right where it was supposed to be.
Last edited by fyrstormer; 11-23-2017 at 02:35 AM.
09-27-2015, 07:44 PM
#5
Heh. It's a nice basic truck for bashing. Not a lot of tuning options, but it doesn't really need them. The version I got has fixed-camber links, but they can be replaced with turnbuckles. I doubt camber adjustments would really matter on this chassis anyway; maybe on the Slash, or if you were going to lower this and make it into more of a performance truck a-la Jang's Chimera B, but in stock form with huge squishy tires the camber would *maybe* affect tread-wear, but even then only if you drove it on pavement a lot. The MIP X-CVD axles I installed are overkill, but they'll never twist and they lower the truck's center of gravity noticeably. Depending on whether you have a brushless system to drop into it, it might or might not be worth buying the VXL version with a brushless system already installed; in my case I was transferring parts so I went with the cheapest one I could get.
10-09-2015, 04:00 PM
#6
I called this one "finished" a little too soon. I forgot one of the most important things for a vehicle that gets wet on a regular basis: rustproof bearings. After a few runs, all of the stock bearings were rough, and 3 of them were locked solid. So tonight I spent a couple hours taking the truck apart and replacing every last bearing with Boca Yellow Seal ceramic/stainless bearings. I also found a couple screws I missed before when I was replacing all the screws with stainless steel. (they were hidden between the steering bellcranks and the underside of the chassis.)
Okay, NOW it's done.
Okay, NOW it's done.
10-09-2015, 10:01 PM
#7
nice and tidy truck
is it the trackstar sct120 esc ? I have 2 of them and could never calibrate them. did it work for you ?
is it the trackstar sct120 esc ? I have 2 of them and could never calibrate them. did it work for you ?
10-11-2015, 06:07 AM
#9
the sct 120 esc just won't accept the full brake when calibrating. so the calibration is never complete.
it still works, but I got 100% throttle at half the way. what I then correct with the EPA !!
10-23-2015, 04:16 PM
#13
Tech Rookie
thats one nice peded.
11-16-2016, 05:22 PM
#15
Two updates:
I got sick of the center diff leaking, so I decided to buy a Fast Lane Machining aluminum center diff. Unfortunately the FLM diff was slightly too long and pushed the rear diff pinion too far into the rear diff case, but I was able to fit the stiff aluminum cover onto the stock diff cup after cutting away the two tiny alignment tabs on the diff cup. Then I drilled a small hole in the side of the diff cup to allow excess fluid to escape while the diff is being assembled, so there wouldn't be trapped pressure forcing fluid to leak past the seals. The hole is plugged with a M3 set-screw. It works perfectly, the diff is still clean and dry on the outside after several runs, something it could never do before.
Also, I recently embarked on a project to weigh all of my RCs, and combine that info with their top speeds, to calculate the kinetic energy they carry at top speed. (that can be used to infer how hard the motor has to work to reach top speed, on flat smooth ground anyway.) I discovered to my surprise that my 4Pede is unexpectedly heavy, and was running a smaller motor than other vehicles lighter than it is. Furthermore, my 4Pede is intended to run off-road in wet conditions, both of which add extra drag. No wonder the Tacon 540-size motor I installed in it was running so hot. So, I wedged the same 550-size motor I use in my Baja Rey, Wraith MT, and (someday) Ten-SCBE into my 4Pede:
As you can see, it just barely fits, and wouldn't fit at all if it had rear-exiting wires like the old motor instead of side-exiting wires. I had to rearrange the ESC and re-solder the power wires to make everything fit properly, but it was worth it. Now it runs about as hot *without* a fan as the previous motor ran *with* a fan, and the temperature is more stable over the length of the run.
I got sick of the center diff leaking, so I decided to buy a Fast Lane Machining aluminum center diff. Unfortunately the FLM diff was slightly too long and pushed the rear diff pinion too far into the rear diff case, but I was able to fit the stiff aluminum cover onto the stock diff cup after cutting away the two tiny alignment tabs on the diff cup. Then I drilled a small hole in the side of the diff cup to allow excess fluid to escape while the diff is being assembled, so there wouldn't be trapped pressure forcing fluid to leak past the seals. The hole is plugged with a M3 set-screw. It works perfectly, the diff is still clean and dry on the outside after several runs, something it could never do before.
Also, I recently embarked on a project to weigh all of my RCs, and combine that info with their top speeds, to calculate the kinetic energy they carry at top speed. (that can be used to infer how hard the motor has to work to reach top speed, on flat smooth ground anyway.) I discovered to my surprise that my 4Pede is unexpectedly heavy, and was running a smaller motor than other vehicles lighter than it is. Furthermore, my 4Pede is intended to run off-road in wet conditions, both of which add extra drag. No wonder the Tacon 540-size motor I installed in it was running so hot. So, I wedged the same 550-size motor I use in my Baja Rey, Wraith MT, and (someday) Ten-SCBE into my 4Pede:
As you can see, it just barely fits, and wouldn't fit at all if it had rear-exiting wires like the old motor instead of side-exiting wires. I had to rearrange the ESC and re-solder the power wires to make everything fit properly, but it was worth it. Now it runs about as hot *without* a fan as the previous motor ran *with* a fan, and the temperature is more stable over the length of the run.
Last edited by fyrstormer; 11-23-2017 at 02:35 AM.