Stubs Sub-3lb build

[stubs179]

Goal is the have a top performing car under 3lbs with battery and proper front weight bias.

I have wanted to build this car since I got my first pair of prototype Superlite’s back in 2012ish. I got that car down to 3lbs 3oz but that was with almost zero knuckle weight. That parts just didn’t exist then to get a car that light and work. Things have changed….

A build like this requires weighing every part as every gram counts.

Built list-
OG all Delrin Superlite’s (still the lightest axles
Custom DJM Skeena chassis
Custom DMJ ultralite wheels
Scx10 shocks with ultralite add-ons
Dlux “Team” Stumpys
Shift RC GT3s LP servo
Hiper Apex escs
Aluminum rod end balls
7075 lower links
Custom carbon upper links
Al and TI hardware
Modern SAF gears
Narrowed OG Voodoods front
RC4WD pins rear
CI foam

https://imgur.com/a/0ayZdvP

https://imgur.com/a/0ayZdvP

 

[stubs179]

The wheels can be glued or the faces can screw on and the tire only has to glue to the center. I have screws in the fronts and the rears are just glued.

https://imgur.com/a/MUH1Tqr

Complete rear wheel

https://imgur.com/a/RiktUty

 

[stubs179]

7075 links are a little lighter than Ti and the aluminum balls help too

https://imgur.com/a/i5UsKPg

 

[stubs179]

This is about as light as I could get the scx10 shocks. Dlux ultra soft springs.

https://imgur.com/a/VC3Q6nv

 

[stubs179]

I was able to get all the electronics on the front axle. The Hiper Apex ESCs make it nice because they have a built in 12a BEC to run the Shift GT3s. I run 3s (especially in this light car) so direct power servos are a no go.

I made some custom skids to hold the ESC’s and cover the motors.

https://imgur.com/a/4Wnt9Cw

 

[stubs179]

As far as the axles go there I no other option really. Unless you build your own axle you can’t get anything lighter than a V1 all Delrin Superlite.

-Weights with hubs-
V1 Superlite rear with SAF gears - 140g
Current Superlite rear - 175g
Dlux XR10 rear - 190g
Axial XR with VP - 220g+

With Ti and Al hardware, Delrin hubs, my own upper link mount and some other small mods I have the rear axle down to 135g. I am really happy with the weight of the rear axle and this really helps keep the overall weight of the car down.

210g ready to go with motor and everything.

https://imgur.com/a/74ZrVDV

 

[stubs179]

I was able to stay under my goal very well. 2.8lbs (1320g) with a battery. The weight bias came out at 64%ish with 2oz of knuckle weight per side in the front. I have a few more things to do so I am hoping to keep the same overall weight but add 0.5oz to 1oz more knuckle weight per side.

https://imgur.com/a/CJbwJTq

 

[Chingon]

That is pretty wild, thanks for taking the time to post! I would have never guessed you could save over 10 g in just rod end balls.

What receiver are you running? Looks like it might be even more compact than the FS2As I have been running on my builds.

 

[stubs179]

I use a lot of the Dlux rod end balls with the built in 2mm spacer. So the AL really cuts the weight down.

I run Radiomaster. There ER4 is insanely small. I direct soldered the servo to the esc. So only the two plugs for the escs remain.

 

[Gula]

Sweet! Now you just need to let all the air out the tires and fill with helium....ultra lite....or add holes to things to lighten stuff, if any more needs to be...

 

[Chingon]

Where are you sourcing your aluminum and titanium hardware? It seems I have enough of a problem stripping out normal screws, how bad are the aluminum ones?

 

[Gula]

You're using aluminum screws/bolts? Wow, brave! Are they strong?
I've had MAD problems with stripping stainless, so I went back to black oxide....
I've never used ti screws/bolts in this size, as they are usually $XX.xx for, like, 2 pieces..... how strong is the ti? Can it be removed multiple times without issue?

 

[dude26]

Nice

but in my opinion all the tricks is in the foam setup

 

[stubs179]

You're using aluminum screws/bolts? Wow, brave! Are they strong?
I've had MAD problems with stripping stainless, so I went back to black oxide....
I've never used ti screws/bolts in this size, as they are usually $XX.xx for, like, 2 pieces..... how strong is the ti? Can it be removed multiple times without issue?

Where are you sourcing your aluminum and titanium hardware? It seems I have enough of a problem stripping out normal screws, how bad are the aluminum ones?

You're using aluminum screws/bolts? Wow, brave! Are they strong?
I've had MAD problems with stripping stainless, so I went back to black oxide....
I've never used ti screws/bolts in this size, as they are usually $XX.xx for, like, 2 pieces..... how strong is the ti? Can it be removed multiple times without issue?

Aluminum from fasteners express. Titanium from multiple online drone stores. You have to use a MIPs driver and be very careful.

If it was cheap and easy everyone would be running a sub3 pound MOA. It’s definitely not a drive it hard and put it away wet car. But I’ve learned a lot building it and it’s extremely fun to drive.

 

[stubs179]

I have been testing these and they are holding up. I am not sure they would make sense as a production piece but they are pretty cool. I’m not sure you can get a link any lighter?

They are 3mm carbon with a printed insert that snaps in and I’m running aluminum rod ends.

https://imgur.com/a/C1HSWkG

 

[Chingon]

So which CI foams are you running in this thing? I run their soft outer in my rigs which weigh significantly more and I am curious if that is too firm for something this light. It would be cool to get some action footage of this thing!

 

[stubs179]

I have a couple videos on YouTube. The weather has been crap up here in Seattle for weeks now so I haven’t been able to get a lot of good crawling in.

 

[stubs179]

Got around to making a video going over the car.

 

[JatoTheRipper]

Yeah buddy! That's a super impressive, vertical climb!

 

[DickyT]

Sick build Jeremy! Under 3lbs is crazy. I remember when we were chasing sub 4.