Big Mother FUCA (forward upper control arms by Mountain Pass Performance)!

RobertWarren · Nov 19, 2025

Finally got around to installing my @MountainPassPerformance Mountain Pass Performance forward upper control arms!! Easy instal. Much beefier than stock.

Tesla Cybertruck Big Mother FUCA (forward upper control arms by Mountain Pass Performance)! PXL_20251119_180434800

Tesla Cybertruck Big Mother FUCA (forward upper control arms by Mountain Pass Performance)! PXL_20251119_190032430

Tesla Cybertruck Big Mother FUCA (forward upper control arms by Mountain Pass Performance)! PXL_20251119_194857931

Tesla Cybertruck Big Mother FUCA (forward upper control arms by Mountain Pass Performance)! PXL_20251119_185522466

Baldyloxx · Nov 19, 2025

Very nice classic look. Bravo

Tallgeese179 · Nov 19, 2025

I'll probably get flack for this, but without FEA modeling the loads that arm sees I'm not convinced the aluminum control arm is better for the application. Things like steels 3x stiffness and 2x strength along with that edge flange going back to the back onboard bushing is what sows some doubt for me. Second moment of area is why I-beams are common instead of a solid rectangle and the reason I add edge flanges to all of my sheet metal parts when the room is there.

One other consideration, some control arms (like the trailing arms on rear BMW suspensions) are made to act like a fuse in an overload situation, preventing load transfer to more expensive parts downs stream by yielding first.

Again, just an educated guess but I could wrong. Love the anodizing though

Gaximus · Nov 19, 2025

Tallgeese179 said:
I'll probably get flack for this, but without FEA modeling the loads that arm sees I'm not convinced the aluminum control arm is better for the application. Things like steels 3x stiffness and 2x strength along with that edge flange going back to the back onboard bushing is what sows some doubt for me. Second moment of area is why I-beams are common instead of a solid rectangle and the reason I add edge flanges to all of my sheet metal parts when the room is there.

One other consideration, some control arms (like the trailing arms on rear BMW suspensions) are made to act like a fuse in an overload situation, preventing load transfer to more expensive parts downs stream by yielding first.

Again, just an educated guess but I could wrong. Love the anodizing though

I was wandering the same. Not sure if that is aluminum, definitely looks like it. My first thought was “that’s going to bend on the first pot hole, or even hard corner”. Maybe I’m wrong. It looks cool.

ZillaVilla · Nov 19, 2025

It looks cool, but what's it do? Has anyone broken a Cybertruck stock upper control arm ever?

RobertWarren · Nov 19, 2025

Tallgeese179 said:
I'll probably get flack for this, but without FEA modeling the loads that arm sees I'm not convinced the aluminum control arm is better for the application. Things like steels 3x stiffness and 2x strength along with that edge flange going back to the back onboard bushing is what sows some doubt for me. Second moment of area is why I-beams are common instead of a solid rectangle and the reason I add edge flanges to all of my sheet metal parts when the room is there.

One other consideration, some control arms (like the trailing arms on rear BMW suspensions) are made to act like a fuse in an overload situation, preventing load transfer to more expensive parts downs stream by yielding first.

Again, just an educated guess but I could wrong. Love the anodizing though

I was hesitant until I read their response to a thread on here. I considered the fuse angle as well, but if I hit something hard enough to damage the casting vs bend an A arm it would probably be an insurance claim at that point anyway.

Tallgeese179 · Nov 19, 2025

Gaximus said:
I was wandering the same. Not sure if that is aluminum, definitely looks like it. My first thought was “that’s going to bend on the first pot hole, or even hard corner”. Maybe I’m wrong. It looks cool.

Almost certainly 6061-T6 if I had to guess. I'm only aware of aluminum and titanium that are commonly anodized. Could be a 7075 grade aluminum which is significantly stronger than 6061 and something I've used in the past if designing large flat sheets without bends (rare, since I prefer geometric strength and steel is a good substitute at that point if corrosion isn't an issue).

Tallgeese179 · Nov 19, 2025

The only reason I question it is because I remember this segment from Munro mentioning how the upper control arm in this design isn't carrying much load and is mostly resisting bending from camber in/out loads. Which that big inboard edge flange would do a great job at managing. There might be some other unexpected load paths though that are experienced.

There are still times I get caught in the "worked in CAD" trap. No replacement for real-world testing, ultimately. As Mike Tyson said, everyone got a plan till the get punched in the face.

Cyberskunk · Nov 19, 2025

UCAs sell. With the Raptor and others people upgraded as much or even more so for more travel.

typically removed sway bars and longer travel shocks needed more angle at the upper ball joint at full droop or extension. So they go to a uni ball joint and even 1" of lift requires caster change so they made each inboard mount adjustable to allow both caster and camber.

I have yet to get mine in the air and see what the down travel limits are and why.

HickoryGoose · Nov 19, 2025

I installed these to allow for camber adjustment - the mountain pass performance parts do that. My front camber was off on both sides and accelerating tire wear - these parts and checking the tire wear every 4k should help.

Nidavellir · Nov 20, 2025

Tallgeese179 said:
I'll probably get flack for this, but without FEA modeling the loads that arm sees I'm not convinced the aluminum control arm is better for the application. Things like steels 3x stiffness and 2x strength along with that edge flange going back to the back onboard bushing is what sows some doubt for me. Second moment of area is why I-beams are common instead of a solid rectangle and the reason I add edge flanges to all of my sheet metal parts when the room is there.

One other consideration, some control arms (like the trailing arms on rear BMW suspensions) are made to act like a fuse in an overload situation, preventing load transfer to more expensive parts downs stream by yielding first.

Again, just an educated guess but I could wrong. Love the anodizing though

I think they look great and I like it. Personally I would just get the originals powder coated in whatever color I wanted. That is just my opinion.

Tallgeese179 · Nov 20, 2025

All great points brought up! I had not considered camber adjustment since it's a truck, though I should have since I've been OBSSESSING over rear tire camber and toe on my BMWs in order to avoid eating up tires from excess inner shoulder wear.

I even got SPL adjustable front upper control arms for my 370Z Nismo, since for some reason it comes with 0 camber adustablilty from the factory

. Apparently SPL is good enough that Nismo just licensed their design and asked for a red/silver colorway.

BrockN · Nov 20, 2025

Well, the Big Mother FUCA name alone should sell plenty!

Scrambler · Nov 21, 2025

Just ran across this build running the FUCA's incase anyone was interested :

Leifmb · Nov 24, 2025

RobertWarren said:
Finally got around to installing my @MountainPassPerformance Mountain Pass Performance forward upper control arms!! Easy instal. Much beefier than stock.

Looks weaker than stock to me-the mounting hardware, size of bushings etc! Am I wrong?

Big Mother FUCA (forward upper control arms by Mountain Pass Performance)!

RobertWarren

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