Step 5: Install dog-bones(drive-shafts) and mount hub carriers (5 min)
Step 6: Assemble Front Frame (5 min)
*** note that the front frame is identical in size to the rear gear box which allows the possibility to upgrade the BFX to 4WD with dual motors if you were to buy an additional gear box and drive shaft assembly.
Step 7: Assemble Front Arms (5 min)
Step 8: Mount Armsto Front Frame (5 min)
Rainy day today, we might have more time to work on the BFX since other outdoor activities have been cancelled.
Step 9: Assmeble front hubs + axles (15 min)
Step 10: Mount front hubs + axles to front frame (5 min)
Step 11: Assemble shocks (15 min)
*** I am not impressed with these dry compression shocks, they are NOT oil filled and use 12mm of cut rubber tubing for the damper. The assembled shock measures about 69mm from the center of the hole on each end of the shock eye mounts. I think I will start searching for a possible suitable replacement or consider ordering the optional upgrade #53280 ($75) or #53155 ($35):
Step 12: Mount Shocks + Bumpers to Front/Rear Frames (15 min)
*** Note that I chose NOT to use the stock shocks that came with the BFX, I installed a "Frankenshock" combination of Kyosho Ultima SC Front Shock Bodies with HPI Blitz Front Springs/Cups with 3mm x 25mm hex screws on top backed with 3mm nuts+washers and 3mm x 12mm hex screws on the bottom of each shock. Further details on the shocks are provided in my "Additional Notes" section after the build photos:
Here is a close-up view of custom shock assembly:
Step 13: Test Radio Components (15 min)
I will be using a Fly Sky FS-GT3B $35 radio transmitter (Tx), however since this Tx has up to a 10 model memory, I am going to use a 6 Channel (R6B) Receiver (Rx) which is technically designed for airplanes, but still works fine for car use. The bind cable must be inserted into the battery slot for the R6B to bind with the FS-GT3B. I have chosen to use the EXI D227F servo which is the fastest servo you can get in the $15 price range. Due to the shape of the battery tray, you are limited to the physical size of battery you can use without making any modifications. I have chosen to use the $21 Gens Ace 2S-25C-3500mAh hard case pack. Although you see a HobbyWing 60A ESC in this picture, this is not the ESC I plan to use for this build, I only used the ESC to test the radio equipment for this step.
Step 14: Assemble/Install Servo Saver (10 min)
The kit comes with 2 horn styles to chose from, Futaba and Sanwa(Airtronics). It turns out that the EXI D227F servo I am using is Sanwa compatible. During this step I also took the time to coil the servo wire over the rod of my screwdriver so the radio install will be as tidy as possible.
***We had to assemble the servo saver a second time after realizing there was slop because we missed a small plastic washer that was hard to see in the instructions. Once the plastic washer was in place, everything fit nice and tight:
Step 15: Assemble Steering Rod Linkages (5 min)
It is not required to have a digital caliper for this step as the instructions have a 1:1 ruler to set the proper distance between the captured rod ends, however a digital caliper will be useful later on when making trim adjustments.
Step 16: Install Servo on Left Chassis + Support Braces (10 min)
Step 17: Install Support Braces + Antenna Bracket on Right Chassis (5 min)
Step 18: Join Chassis Half's together (20 min)
*** normally this step should've taken only 5 minutes, however we accidentally installed one of the battery support brackets upside down which required a complete redo of this step. I also decided to remove the antenna mount bracket towards the rear of the chassis because the 2.4 Ghz Rx antenna is not long enough to reach that far. I also plan to use that area of the chassis as a possible alternate mounting location for the battery pack in "basher mode" to experiment with the center of gravity to make it easier for the BFX to do wheelies.
Step 19: Mount Rx + ESC ( 5 min)
Note the corrected battery support bracket and removed antenna bracket as explained in the previous step
Step 20: Mount Front + Rear Frames to Chassis (30 min)
This step took longer than expected, there were A LOT of screws (16). I decided to reposition the Rx so it's now located on the servo.
*** The Aeolian ESC wires were not long enough to reach the solder tabs on the motor and the Bulllistorm motor did not come with any bullet connectors so I decided to splice solder wires as a temporary solution... I plan to install bullet connectors later.
Step 21: Install Body Posts, 12mm Hexes and Wheels ( 15 min )
*** There was significant slop between the hex pins and the bearing which required 1mm wide shims to be installed. This is covered further in the build video.
Step 22: Install Battery Pack + Battery Brackets ( 15 min )
*** Normally this step would've taken only 5 min, but the Gens Ace battery pack I am using has the wires exiting off center from the pack which required a small modification to one of the battery brackets using a rotary tool to grind away some of the plastic to make additional room. This is explained further in the build video.
Step 23: Paint Body (5 min)
Decided not to paint the body and leave it with the matte black finish
Step 24: Install Windshield (5 min)
Step 25: Assemble Front Bumper + Grille (5 min)
Step 26: Attach Front Bumper + Grille to Body (5 min)
Step 27: Assemble Roll Bar + Rear Bumper (5 min)
Step 28: Attach Roll Bar + Rear Bumper to Body (5 min)
Step 29: Attach Decals to Hood and Tailgate (15 min)
Step 30: Attach Decals to Sides (15 min)
Step 31: Fasten Body to chassis (5 min)
Optional Step: Assemble LED lights (30 min)
It turns out that there are sockets for the headlights which accept standard size LED's which can be wired directly to the Rx!
Total cumulative time spent on the build: 5 hours 45 min
Spare parts left over:
*** Additional Notes ***
Rob says his favorite part of building the kit is searching for parts on the parts tree and cutting them out with side cutters:
Even though we've barely started building this kit, Rob is already asking about what the next kit is going to be!
The axles (bottom 2 are Tamiya BFX) are about the same size as the Exceed DriftKing Axles ($6 for 4), where you may need to add a 2-3mm shim spacer between the bearing and the hex pin which I think might be a good idea anyway as it will slightly increase the overall width of the truck, there is also plenty of room to fit the DriftKing axle in the front hub of the BFX without modification. I plan to use the stock axles initially, however should any of them break, I plan to replace all 4 axles with the DriftKing axles:
The dog-bones that ship with the Blackfoot are 70mm long, these can be replaced from Nitro RCX part #51C00-06006
As an experiment, I verified that the rear hub carrier from the Exceed DriftKing fits perfectly inside the A Arm for the BFX, however I will need to find a shorter dog bone (60mm or 56mm with additional spacers) in order to made this work. The advantages I see by switching over to the Exceed parts would use less expensive and easier to get 5x10x4 bearings as well as ball linkages for the top support of the hub carrier reducing the chance of breaking parts:
After experimenting with several spare parts that I had lying around, I have decided to use the front shock bodies from the Kyosho Ultima SC with the front springs + spring cups from the HPI Blitz. Even though I backed the threaded spring compressor all the way to the top of the shock tube, it still extends about 5mm longer than the stock shock. Fortunately, there are additional shock mount locations on the BFX A-Arms to take advantage of the extra shock length which will further increase the amount of shock travel by 50% more than the stock shock. The picture below shows the stock shock on the left, with my Kyosho+HPI "Frankenshock" in the middle, and the fully extended default length of the Kyosho shock on the right:
If I am happy with this modification, I may consider upgrading to HPI Blitz (front) shocks all the way around as they are about the same size shocks which I am currently using on my Ultima SC's. The only problem with the RTR Ultima shocks is that they tend to leak and need to be re-built frequently.
I found that the front wheels for the Kyosho Ultima SC worked best for street bashing, however I needed to install the Ultima front axles (with 6mm worth of spacers) in the BFX because they are a little longer to clear the steering linkage.
Here is the damage that was caused to the included servo saver. Basically, the plastic "c" shaped ring had over stretched and did not flex back into shape, talk about a piss poor design
I have since replaced this with a Kimbrough #124 Servo Saver:
*** I will continue to update post #1 as we continue the build and uncover any potential issues or modifications we make along the way.
It's the latest Blackfoot chassis in 2wd form & the Duel Hunter, Twin Detonator, Wild Dagger are the twin motor 4x4 version.
The first thing they need are longer (oil) shockers instead of short friction pogo sticks.
Also Full ball bearings & the standard rims are 2.2" so Pro-Line 2.2" Stadium Truck tires fit.
Tamiya Touring Car Hard cup joint set (for gear diff) are the H/D version.
Tamiya CR01 Reinforced wheel axle set, H/D version as well.
A spring loaded servo saver or a H/D version because the standard one is not so good. Cheers
No nothing like the old ORV type chassis. Just the dampers (shockers) need to be addressed on the Blackfoot extreme series, Tamiya went backwards there. Excellent transmission over the ORV Blackfoot's though, the one to buy for performance with the Blackfoot series.
Thanks for the feedback guys, I really appreciate it. Unfortunately, the more research I do, the more confused I get. I really blame JANG for my confusion only because he recently posted some videos on his Axial Wraith and I had no idea that crawlers went that fast! My son is now targeting a crawler instead but I'm not having much luck finding a crawler made by Tamiya
Since we're not looking into a competition ready crawler and it will mostly be for looks and bashing, he's leaning towards one of the Exceed Crawlers and then covering it with a Proline Rock Crawling Body to give it a little more scale appearance.
I may still buy a Blackfoot-Xtreme for me, just so my son has the experience of building a Tamiya, heck it may make for a great review segment to compare the pros and cons between similarly priced models!
I think JANG is wracking his head on trying to figure out how to get his Axial to hit 30mph AND go slow for crawling... perhaps it may be better just to buy two cars each with their intended purpose. Of course I am assuming the Blackfoot can handle a mild brushless system getting it to go close to 30mph, ha!