Szczerba's 3rd CXT, Build #57

[CM9000]

3k diff fluid wow. I bet that thing will crawl like a mountain goat!

[Szczerba]

Originally Posted by CM9000

3k diff fluid wow. I bet that thing will crawl like a mountain goat!

I had had 7k diff fluid on the outer 4 non-sprung shocks but that was too much, as it slowed the action too much. I replaced with 3k fluid and it's much better. The outer four shocks are just for suspension dampening and suspension travel tuning.

I also extended the the total wheelbase from 19" to 20". Looks more proportional now. I am waiting on some new tires to decide if I want to trim the front fenders or not, that coincides with making tube fender protectors as well. I'll be working on the electronic mounts and front inner fenders until then.

[CM9000]

sounds like a good plan. have you tried 2k fluid? and maybe a smaller piston?

[Szczerba]

Originally Posted by CM9000

sounds like a good plan. have you tried 2k fluid? and maybe a smaller piston?

I only have 3k, 5k and 7k on hand. 3k seems like a better starting point than the 7k. I'll just have to wait until I drive it around to tweak the suspension and shocks.

[CM9000]

technically the 7k would in turn be 14k?? one on each end of the bar. so 3k could be 6k? in a sense. am I wrong?

[Szczerba]

Originally Posted by CM9000

technically the 7k would in turn be 14k?? one on each end of the bar. so 3k could be 6k? in a sense. am I wrong?

Are asking cause there are two 7k fluids on each end of the beam? I am not sure but I believe that would still be 7k.

Although, my outer shocks are angled in at the top so 7k is not really 7k in relation to the suspension cycling. The shocks would have to be 100% perpendicular to the beam at full compression for it to be 100% 7k resistant. Same theory for shock springs, you start laying shocks down and the suspension interacts with them differently, ie, less force is needed to compress them when they are not vertical. Really depends on how they are mounted in relation to the chassis mount and lower link/axle link mounting. Confusing to type out. Picture in my 2nd CXT build though.

[BigSki]

You're touching on the subject of force vectors. Sine or Cosine of the force applied at a given angle to calculate the net force for each vector.

[Szczerba]

Originally Posted by BigSki

You're touching on the subject of force vectors. Sine or Cosine of the force applied at a given angle to calculate the net force for each vector.

Correct! Coincides with rising and failing rate shock/link setup and positions. A lot can done to setup a rig correctly for it's intended application. I try to balance out setting a truck up correctly but my patience to keep moving can lead to shortcuts.

Made the electronics mounts and inner fenders from black 0.060 styrene. Also made some front lower links from 1/4 steel tube, 8/32" all-thread and revo rod ends.

[CM9000]

so if vertical. each shock on one end of the beam, filled with 7k. pivot point being the middle of the beam. tilt it cw or ccw one shock compresses and one decompresses resulting in 14k or 7k? just a thought I want to clear in my head.

cause if you had say.. put fluid shocks on a clod 8 of them all the same setup it would take more force to flex than just 4 of the same setup, correct?

[Szczerba]

Originally Posted by CM9000

so if vertical. each shock on one end of the beam, filled with 7k. pivot point being the middle of the beam. tilt it cw or ccw one shock compresses and one decompresses resulting in 14k or 7k? just a thought I want to clear in my head.

cause if you had say.. put fluid shocks on a clod 8 of them all the same setup it would take more force to flex than just 4 of the same setup, correct?

I am definitely not super schooled in all aspects of suspension geometry, so don't take my word for everything. I am not 100% sure but the two ends of the beams are operating in opposite forces almost all of the time. So, I would assume 7k total for system. Don't quote me on that and this kinda cloudy for me as well. I just know that 7k was too much. lol

Also, in response to your term "vertical", it would be better described as "the shocks perpendicular location to the lower suspension link at full compression". When the shock and link are in that shock cycling position range of movement, 7k oil would be 7k oil and a 20lbs spring would be a 20lbs spring. This maximizes your springs and oil dampening. Lets the spring work as designed, in a consistent linear fashion until full compression. Resists bottoming out if correct spring is chosen. Important for race rigs and heavier trucks.

If you notice on pure comp trucks that are lightweight, guys lay the shocks down a ton. That is really lowering the spring rate, as there are just not soft enough springs for the type of feel they want.

Picture from my 2nd CXT Dakar build.

[CM9000]

thanks for the input. its something im studying. like how much force does it take to compress 2 springs of the same rate over a single spring of the same rate. and the same with shock fluids.

[chino63]

Very nice work sir. You always seem to make cool things that work. I have s similar rear suspension design festering in my cranial gland but with leafs. Awesome work as usual, looking forward to a video.

[Szczerba]

Originally Posted by CM9000

thanks for the input. its something im studying. like how much force does it take to compress 2 springs of the same rate over a single spring of the same rate. and the same with shock fluids.

Report back.

Originally Posted by chino63

Very nice work sir. You always seem to make cool things that work. I have s similar rear suspension design festering in my cranial gland but with leafs. Awesome work as usual, looking forward to a video.

Thanks, we'll see how this works before too long.

Getting there.


Rear sponsor tunnel. Need to make an inner frame for it.

[chino63]

It looks so short for a 20" WB. Must be the giant size of everthing.

Any plans for A-pillar toobage? I'd hate see it get smashed if it takes a hard tumble.

[Szczerba]

Originally Posted by chino63

It looks so short for a 20" WB. Must be the giant size of everthing.



Any plans for A-pillar toobage? I'd hate see it get smashed if it takes a hard tumble.

The wheelbase and look is a balance of looks and drivability. Any longer and performance starts to suffer. Any shorter, it starts looking stubby.

I think I am done with the metal work. I debated front tube fenders but think Ill leave it as it sits. Maybe.
Going off of this rig. Don't see many newer model, long nose trials rigs.

[CM9000]

now that it looks nearly complete, I like the fenders.

[Szczerba]

Originally Posted by CM9000

now that it looks nearly complete, I like the fenders.

Still working like a dog on this thing.

Back end work. Mudflaps, tow point and Carter Fab & Machine 5" metal light bar.

[CM9000]

I have a mudflap "fetish" I guess you could say. I love mudflaps. mudflaps on rally cars dragging on the ground especially. I put mudlfaps on everything. mudlfaps.

they look good

[Szczerba]

Originally Posted by CM9000

I have a mudflap "fetish" I guess you could say. I love mudflaps. mudflaps on rally cars dragging on the ground especially. I put mudlfaps on everything. mudlfaps.

they look good

My second 2nd CXT had double the amount of mudflaps this 6x6 CXT does.

Indulge.
Szczerba's Second CXT Build

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[viper6171]

so am I gonna get to see this thing terrorizing the Disney terrain