Bomber Crawler Refurb

[elRayRay]

Hi all!

I'm doing the unthinkable and rebuilding my upgraded Bomber RTR into a custom scale-focused crawler. The mod list is already pretty deep: JEC Racing shock towers, stainless TA's, and Anti-Roll Bar; VP Stage 1, CVD's, Diff gears (U/D rear), and Ti links; LURC FI Spools, OT axle shafts, and 2.2 wheels; Gmade XD Rock Shocks; and SSD driveshafts.


In emphasizing "Scale," I'm switching to smaller tires (4.75 OD, probably stretching 1.9 XL's on the 2.2 wheels), shortening the WB (it's already about 12mm shorter than stock) with JEC Twin Hammers stainless TA's, and a full-depth Wraith interior. I also have a full complement of aluminum body panels from Barndog, AMF, DMG, and Carter Fab that I'll be painting.




I've already built an all HR Wraith transmission with dig and mounted it on the stock skid with the DMG plate. I think the interior will fit even with the dig servo, though I don't have it yet to mock up. I'm planning on using Voodoobrew's dash panel to fit the Wraith interior. I still need to cut the receiver box down to clear the new spur/pinion configuration.



At this point, I'm still collecting parts. I still need suspension links, I ordered the TA's earlier today and I'll be waiting for those before taking measurements for the other link lengths for the desired wheelbase (probably around 350mm).

I'm only undecided about axles and powertrain, at this point. I'm pretty sure I want to go narrower and smaller than an AR60 pumpkin. I'm leaning towards AR44's with Wraith-splined brass tubes in XR10 width. My concern is for replacement axle shafts. Will they continue to be available? Fronts and rears are a bit hard to find, already. I'm also considering a metaphorical second mortgage and fitting the VP Currie portals. Then there are the SSD portals that are trickling out...and the Redcats.

Regarding powertrain, I'm not sure if I want to go brushless. If I do, it'll be a MX and a Revolver so I can go 4s and get a ton of power. If I go with VP portals, I'll most likely do this as there is more reduction in the axles. Brushed will be a MX (or BR-XL) and TorqueMaster Expert 550.

Then there's lights...front and rear running lights, brakelights, headlights, light bar, KOH lights, AND rocklights. These will be switchable from AUX channel(s).

I'm probably gonna do a winch too, but I'm already in a pretty big (and expensive) project. It's slowly coming together, though.

Stay tuned...let's see if I get it finished!

[elRayRay]

Update #1 - 01-03-2019
I received my new trailing arms today. Here's a comparison photo:


These will hopefully get me around 350mm WB, but I think I will shorten the front as well and get down to about 325mm.

I got servo wire, connectors, all 3 parts bags for the Wraith interior, and some other odds and (rod) ends at a couple almost-LHS yesterday. Took off and went shredding my friend's 2wd Slash with his brother today.

Update #2 - 01-12-2019
Received, assembled, and installed my new links today. Definitely impressed with them, initially. Custom lengths, mixed materials (front lowers are stainless, uppers are aluminum), great fit and finish, and INCLUDED Revo ends for ~$40 US.


And installed:


My rough math/measurements should get me close to target wheelbase, although it ultimately depends on which axles I go with, to some degree. The skid will probably have to be clearanced around the lower link mounts and I still need to figure out what I need to do to the stock receiver box to clear the motor gears and (now) the shorter angles between the upper links.

Update #3 - 02-08-2019
I went ahead and pulled the trigger on a set of AR44's today. I wanted the SSD's, but they're backordered and I figured that I could at least use the Axials to mock up and get the SSD's later.


My link lengths turned out to be a little short. I added M4 nuts on the rod end screws to space them out a bit. Pinion angles look good and wheelbase measures out to 326mm.


I don't have the correct driveshaft for the front yet, a Bomber front should work. I also realized that the receiver box/front cage support will have to be completely sacrificed due to the centered pumpkin. This leaves me looking for somewhere to mount the ESC.


And a side profile. I think the axle locations are pretty ideal relative to the cage lines.


One thing I should have foreseen is the link/shock mount width. I'll have to mount the lower shock ends outside of the double shear mounts in order to have the shock lowers outside of the upper mounts, and still hope the shocks clear a couple cage tubes. On the rear, this should be fine as it will allow me to use the double shear mount for my anti-sway bar (now mounted in factory location!). On the front, I'l probably just use a spacer in the double shear. I'll eventually be upgrading to brass items in key locations, also.

The biggest issue I can see right now is that the front corners of the Barndog side panels will likely prevent much steering angle. They have a new side panel that "inverts" that corner, and also reduces the battery box...hmm.

*Incremental update at Post #18

*Incremental update at Post #19

Update #4 - 02-28-2019
I received, built, and installed my new shocks, the other day. Gmade XD Piggyback, 93mm front and 103mm rear. I also went ahead and got some hard springs for them in anticipation of the weight of this truck when it's finished.



I also put 40w oil in the front with 4-hole pistons and 50w with 2-hole pistons in the rear. Suspension action feels very nice and I think I have plenty of up-travel with the shorter shocks up front. I also really like how the reservoirs peek out of the rear side panels.


A friend recently gave me a screaming deal on a 2-3 pack old Mamba X with a 1415 2400kV sensored motor, so I put it in. It should be great for 3s, I suppose. I definitely intend to go 4s, though.


And then it goes in this (along with 4s)...


Incremental update at post #33

Update #5 - 10-21-2019

After making the decision to have a custom cage built to solve suspension geometry and tire clearance issues, I promptly sent the relevant parts to a cage builder. This has spurred me to start getting the rest of the build list sorted out.

I've acquired some choice wheels that I'm keeping close to the chest, for now, but here's the bulk of it:


I built the tires up on some nice wide wheels with scale hardware (short a dozen screws) and the DW foams with an inner tuning ring cut down to ~3.5"...looking pretty plump.

I've got hubs on the way, I can complete the spare build (stock foam), get that last dozen screws, etc. I'm basically just waiting to get the cage and I'll be able to build it to a roller. Then it's on to interior and lights. Custom light controller on the way!

To be continued...

[MasteroFlego]

Have you thought of using trx4 axles?

Sent from my SM-G960W using Tapatalk

[LSXGMC]

Sweet. You’ll love the TH length TA’s. I installed them on mine as well, it looks so much more scale accurate.



Good luck with the build. Really curious to see how it turns out with the smaller axles!

[elRayRay]

Originally Posted by LSXGMC

Sweet. You’ll love the TH length TA’s. I installed them on mine as well, it looks so much more scale accurate.



Good luck with the build. Really curious to see how it turns out with the smaller axles!

Nice looking truck! That pic confirms that I will be shortening the front links, too.

*edit* what rear driveshaft are you running? Stock geartrain?

[elRayRay]

Originally Posted by MasteroFlego

Have you thought of using trx4 axles?

Sent from my SM-G960W using Tapatalk

Sorta...how wide are they pin to pin?

[durok]

We think somewhat alike - I'm planning on stretching XL 1.9" Proline tires on 2.2" wheels myself, and I have that killer AMF "Deluxe" hood panel on mine...

But I like to think of mine as more heading towards a LWB rock bouncer style and away from the KOH replica, and I can't bring myself to install even the stock Bomber interior.

Too much hassle to remove...

Am watching your build with interest!

(Shit, totally forgot - I am also running the Revolver/Mamba X combo with 3S/4S power, it's an excellent choice!)

[elRayRay]

Originally Posted by durok

We think somewhat alike - I'm planning on stretching XL 1.9" Proline tires on 2.2" wheels myself...

...

(Shit, totally forgot - I am also running the Revolver/Mamba X combo with 3S/4S power)

I caught your question about the tires a while back. I'll probably buy a set of tires and give it a shot. The LURC wheel design seems conducive to stretching the bead.

Also aware of your powertrain. Your videos and one posted in another thread last week actually got me considering brushless, providing I get the reduction from the VP portals.

[elRayRay]

Project update Post #2

I received my new trailing arms today. Here's a comparison photo:


These will hopefully get me around 350mm WB, but I think I will shorten the front as well and get down to about 325mm.

I got servo wire, connectors, all 3 parts bags for the Wraith interior, and some other odds and (rod) ends at a couple almost-LHS yesterday. Took off and went shredding my friend's 2wd Slash with his brother today.

[elRayRay]

Ordered new custom links from American Machine Works Ohio via eBay. He allows custom lengths. I ordered 112mm rear uppers, 100mm front lowers, and 96mm front uppers. They should get my wheelbase to around 325mm.

[elRayRay]

Project update Post #2

Received, assembled, and installed my new links today. Definitely impressed with them, initially. Custom lengths, mixed materials (front lowers are stainless, uppers are aluminum), great fit and finish, and INCLUDED Revo ends for ~$40 US.


And installed:


My rough math/measurements should get me close to target wheelbase, although it ultimately depends on which axles I go with, to some degree. The skid will probably have to be clearanced around the lower link mounts and I still need to figure out what I need to do to the stock receiver box to clear the motor gears and (now) the shorter angles between the upper links.

[elRayRay]

I'm probably going to scoop up some SSD Pro44 axles. I need something that I can get a servo mount for. I think either the BP Custom mount or KNK brass truss will be the ticket. I'm hoping the width works out, I'm a bit worried about going too narrow and not having full tire clearance for articulation and steering. I also don't want to go with crazy-wide hubs for the wheels in order to keep steering sensible. Anyone with more experience with 1.9 Wraiths/Bombers have any input?

Paint scheme for the body panels is decided, I think. I need to make some modifications to the Barndog roof and sides, and drill mounting holes in the rear number plate panels. I'm going to get to work on the interior soon, too. All the parts have been acquired, I just need to cut, paint, assemble and fit it. What might be the best color for the floor and dash? I was thinking silver to mimic steel sheet, but I'm thinking rubber undercoat spray would be nice for durability and to (maybe) quiet down the likely very noisy motor just a bit. I was also thinking of using undercoating on the aluminum body panels but I don't think paint will stick to the undercoating well.

Car got totaled while parked in front of my house and I'm getting a proverbial windfall as I'm not concerned about replacing it soon. Hopefully get this buttoned up.

[MAC FAB]

Why paint the body? Raw aluminum just has that "coolness multiplier" look. First time on its lid and the roof and nose of the hood will get all scratched up. By going skinny on the track width ( if I read correctly), will your tires be into the body at full lock/twist/bump?

[elRayRay]

Originally Posted by MAC FAB

Why paint the body? Raw aluminum just has that "coolness multiplier" look. First time on its lid and the roof and nose of the hood will get all scratched up. By going skinny on the track width ( if I read correctly), will your tires be into the body at full lock/twist/bump?

I'm planning a real "racing livery" paint scheme that will only look better once it's scratched up a bit.

And yes, I am concerned about the tire clearance. I want to narrow it, but I still need the tires to clear the cage during articulation and steering.

[NitroDarwin]

Im wondering how you are going to run the sway bar, I have been thinking of running shorter trailing arms but have axial sway bar and like it how it handles

[elRayRay]

Originally Posted by NitroDarwin

Im wondering how you are going to run the sway bar, I have been thinking of running shorter trailing arms but have axial sway bar and like it how it handles

I'm not quite there yet. I'm running a different anti-sway bar that mounts at the rear of the cage and it might allow me to use longer links to reach the relocated axle.

[elRayRay]

Project update Post #2

I went ahead and pulled the trigger on a set of AR44's today. I wanted the SSD's, but they're backordered and I figured that I could at least use the Axials to mock up and get the SSD's later.


My link lengths turned out to be a little short. I added M4 nuts on the rod end screws to space them out a bit. Pinion angles look good and wheelbase measures out to 326mm.


I don't have the correct driveshaft for the front yet, a Bomber front should work. I also realized that the receiver box/front cage support will have to be completely sacrificed due to the centered pumpkin. This leaves me looking for somewhere to mount the ESC.


And a side profile. I think the axle locations are pretty ideal relative to the cage lines.


One thing I should have foreseen is the link/shock mount width. I'll have to mount the lower shock ends outside of the double shear mounts in order to have the shock lowers outside of the upper mounts, and still hope the shocks clear a couple cage tubes. On the rear, this should be fine as it will allow me to use the double shear mount for my anti-sway bar (now mounted in factory location!). On the front, I'l probably just use a spacer in the double shear. I'll eventually be upgrading to brass items in key locations, also.

The biggest issue I can see right now is that the front corners of the Barndog side panels will likely prevent much steering angle. They have a new side panel that "inverts" that corner, and also reduces the battery box...hmm.

[elRayRay]

More tweaks to the suspension hard points. I mocked up some RTR shocks to see if I could get suspension geometry sorted out.
Full shock extension:


"Static" ride height:


I had to get creative with the front lower shock mounts and rear link mounts.
The fronts used an extra Revo ball on each and a longer screw to mount outboard of the double shear mount and in the top hole. I also had to clearance the rear of the c-hubs and grind off the panhard mount.


For the rear, I had to flip the link mounts, which extended the wheelbase to 328mm; put the anti-sway bar link in the double shear (and clearance the RPM long rod ends that comprise its links); and the trailing arm outboard of it. (sorry for the blurry pic)


I may still space the rear out more, it's definitely not the ideal solution, though. Anyone have any thoughts? I'm assuming the greater the "negative camber" orientation of the shocks, the better for sidehilling, right?



And the belly shot:


Overall, the suspension seems to articulate well. No binding front or rear. The rear has more up-travel than my main Bomber and seems to have more twist, also. Up front, I think I'm going to a shorter (93mm Gmade) shock to get more up-travel, even though the servo on the axle will no doubt be my travel limiter when it contacts the winch plate that will be in soon. I still need to get the steering clearance figured out...when I get rolling stock.

[elRayRay]

New shocks ordered. Gmade XD Piggybacks, 93mm front, 103mm rear. I also bought a Mamba X combo with a 1415 2400kV that had a couple packs through it from a friend. The coupon code for a free CastleLink was even still valid! The motor is a tight fit but should work out. At least for a while. Worst case, I can upgrade my newly acquired Baja Rey and go 4s in that.

I did end up spacing out the rear trailing arms with one more Revo ball on each side. I don't think it's ideal, but I think it will be fine, especially after I get some brass link mounts.


I also received my Wertymade winch plate. It will require trimming my Carter Fab inner fender panels, so I haven't fit it, yet.

[MAC FAB]

Crawl only, no bashing? Otherewise you'll be breaking stuff. Trying to think of the guy who did a scratch build TT doing this and it wasted the housing. Link needs to be double shear to live. I run the 1415 in mine, wish it were sensored. Castle link programming may help there.