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I've had this idea for a while. Question though, won't pinion brakes heat up extremely fast? That could cause issues. I've seen the mega trucks have the rotors glowing red is the reason I ask.
 

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Discussion Starter #44 (Edited)
I've had this idea for a while. Question though, won't pinion brakes heat up extremely fast? That could cause issues. I've seen the mega trucks have the rotors glowing red is the reason I ask.
Yes it will heat up quite a bit faster, as the rotor is spinning 4-5 times faster than the wheels. That is why I went with a pretty big rotor that is cross-drilled and slotted to help dissipate that heat.
 

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Yes it will heat up quite a bit faster, as the rotor is spinning 4-5 times faster than the wheels. That is why I went with a pretty big rotor that is cross-drilled and slotted to help dissipate that heat.
Backwards thinking. That rotor will dissipate heat less because there is less cast iron to soak up that heat. :homer: Holes and slots have fuck all to do with getting rid of heat.
 

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Backwards thinking. That rotor will dissipate heat less because there is less cast iron to soak up that heat. :homer: Holes and slots have fuck all to do with getting rid of heat.
I might be being :homer: but that makes no sense. Yes a solid disc will absorb and retain more heat energy compared a vented disc of the same size but a vented disc has more surface area which allows for quicker dissipation of that heat energy and if correctly drilled the airflow through the vents is increased, further increasing the ability to dissipate the heat build up. What am I missing?
 

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I might be being :homer: but that makes no sense. Yes a solid disc will absorb and retain more heat energy compared a vented disc of the same size but a vented disc has more surface area which allows for quicker dissipation of that heat energy and if correctly drilled the airflow through the vents is increased, further increasing the ability to dissipate the heat build up. What am I missing?
Nothing. That is spot on. A vented rotor has less thermal mass than a solid one of the same dimensions but is so much better at shedding heat that it makes up for it.
 

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Discussion Starter #50 (Edited)
Backwards thinking. That rotor will dissipate heat less because there is less cast iron to soak up that heat. :homer: Holes and slots have fuck all to do with getting rid of heat.
No I am thinking clearly.. The part I may have not described thoroughly is the pinion brake "kits" that are available for the 14 bolt use a small OEM rotor from a Toyota Corolla-sized car. The rotor I am using is much larger in addition to being slotted and cross-drilled. Should be able to shed heat and perform well.
 

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Discussion Starter #51
Got some cleaning and prep done today on the NP203 range box. Ready for a coat of paint and final assembly. 205 is up next!!





 

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Makes sense on the rotors. I have been wanting to do something similar with 14 bolt diffs but use the axletech planetaries and run like a 50" ag tire being all we have around me is mud. Also thought about 54" claws for if I ever went to rocks.
 

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Yeah I know exactly what you are talking about. I assume when you say G-out, you are referring to grounding out, or bottoming out when landing and the suspension compresses. At that point, yes the chassis is physically much closer to the ground. To help alleviate this problem, and another problem relating to shock efficiency, I am going to have a significant positive caster angle on both the upper and lower A-Arms. Not just the knuckles, but tilting the articulation axis of the A-Arms back roughly 20-25 degrees. This helps keep the front/bottom of the chassis out of the dirt, and focus the dynamics of the terrain into the shock absorbers. For some reason I have not seen anyone do this as of yet in the rock bouncer/KOH world.
Is there a way to expand the information on this? There is caster gain added into my build but not to this level. Maybe just enough to overcome the forward pitch of the frame to the ground. We talk about minimizing the binding of both the IRS/IFS on accel and decel to let the shocks do their thing.

We also know that some SXS IFS' will lift the front end on accel, and why some are known for flipping on climbing. We think the front is going toe-in on accel and forcing the two uprights to steer inward...and lifting the frame. Are you thinking the same thing on braking?? Which would be different from Anti-dive? I am also trying to relate that to trail anti-dive on a motorcycle front. (which is used more on the street apparently)

Some second thoughts: On my offroad bikes I always liked the front to dive on braking thru the trees. It would allow me to turn sharper without actually turning sharper. The caster you are talking about might make turning a chore. Like a dragster with too much negative camber on turning...???

Just a discussion. Always learning new tricks.
 

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Discussion Starter #55
Yes I understand your thinking. And yes, the amount of caster increase I'm suggesting is much more than pitch of the frame during acceleration. Steering will not be as efficient as it would be with 0 deg caster, so I'm committed to 4 wheel steering. See pic below. Note the articulation axis of the front lower A-Arms. Quite a large amount of positive caster, and not just at the knuckle, but starting at the A-Arm itself. Quite drastic!!

 

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Yes I understand your thinking. And yes, the amount of caster increase I'm suggesting is much more than pitch of the frame during acceleration. Steering will not be as efficient as it would be with 0 deg caster, so I'm committed to 4 wheel steering. See pic below. Note the articulation axis of the front lower A-Arms. Quite a large amount of positive caster, and not just at the knuckle, but starting at the A-Arm itself. Quite drastic!!


Mmmm, nylon arm rc10t, oe body and tires too!, i loved beating the shit out of mine for years!
 

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Some coolness there. Maybe a bit much for real tires but in the right direction IMO.

Can you tell us if the top arm is parallel to the bottom arm?? And maybe a picture with the tire turned similar but weight (push down) on the outside corner to simulate body roll?? Thanks. We learned alot by visiting a hobby store one time, and had a very knowledgeable and agreeable owner.

Thanks in advance. Just for learning.
 

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Discussion Starter #60 (Edited)
Some coolness there. Maybe a bit much for real tires but in the right direction IMO.

Can you tell us if the top arm is parallel to the bottom arm?? And maybe a picture with the tire turned similar but weight (push down) on the outside corner to simulate body roll?? Thanks. We learned alot by visiting a hobby store one time, and had a very knowledgeable and agreeable owner.

Thanks in advance. Just for learning.
So there is no top A-Arm, its basically just a tie rod that carries the load and controls camber. See pic below. That being the case, the "leaned back" angle of the lower arm dictates the movement/axis of the arm. For strength, I will just build my top arms at the same angle as the bottoms. Should be super-beef strong!! And Super-Beef Cool!!







For some reason, all the Ultra4 guys are building their suspensions flat w/ respect to the frame/ground. Mine's going to be tilted way back.



 
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