Dirt Squirrel 3.0 - The 2nd Mortgage

[the_white_shadow]

Did you not read my post?

The positive? Caster is for crawler stuff. So when you're climbing a waterfall, you might actually be able to steer the rear vs the tires just pivoting in the dirt.

Although I think to make a difference, you'd need more that 2*

Reading comprehension fails me from time to time.

 

[YotaAtieToo]

Reading comprehension fails me from time to time.

Maybe I'm not wording it well? Do you get what I mean?

 

['84 Bronco II]

Jesse Haines said he does 5° on the rear and I have heard others talk about 6°. The idea is that more caster keeps the rear steering from steering into the ground on big vertical climbs as YotaAtieToo mentioned and upsetting the balance of the car when the front is light.

I haven't personally driven a rear steer car, but my experience with rear steer RC crawling suggest that even more extreme rear caster angle may be benificial, but some caster on the rear is definitely better than no caster.

It has nothing to do with return to center or high speed stability.

 

[Sean]

Jesse Haines said he does 5° on the rear and I have heard others talk about 6°. The idea is that more caster keeps the rear steering from steering into the ground on big vertical climbs as YotaAtieToo mentioned and upsetting the balance of the car when the front is light.

I haven't personally driven a rear steer car, but my experience with rear steer RC crawling suggest that even more extreme rear caster angle may be benificial, but some caster on the rear is definitely better than no caster.

It has nothing to do with return to center or high speed stability.

Apologies. I thought I read 2° for the rear somewhere.....

 

[the_white_shadow]

Jesse Haines said he does 5° on the rear and I have heard others talk about 6°. The idea is that more caster keeps the rear steering from steering into the ground on big vertical climbs as YotaAtieToo mentioned and upsetting the balance of the car when the front is light.

I haven't personally driven a rear steer car, but my experience with rear steer RC crawling suggest that even more extreme rear caster angle may be benificial, but some caster on the rear is definitely better than no caster.

It has nothing to do with return to center or high speed stability.

Jesse is a smart man. I will get it off the table and set it at ride height and see where things end up and adjust from there. According to the link calculator ill get around 5 more degrees for the rear at ride height which "should" put be around 5 total.

Front is about 4 degrees of change from bump to ride height. So with it being at 4.5 at bump right now, that will put me at ~8.5 at ride height (i hope). That should put me closer to Jesse's numbers.

 

[Sean]

Here's where I got 2°: Post #246 in Woody's build thread: Build Thread - JHF Trail Chassis

2° rear, 5° front.

 

[Treefrog]

Jesse is a smart man. I will get it off the table and set it at ride height and see where things end up and adjust from there. According to the link calculator ill get around 5 more degrees for the rear at ride height which "should" put be around 5 total.

Front is about 4 degrees of change from bump to ride height. So with it being at 4.5 at bump right now, that will put me at ~8.5 at ride height (i hope). That should put me closer to Jesse's numbers.

I think you might be reading that wrong. With 4.5 at bump, you will have 2.3 at ride.

 

[the_white_shadow]

I think you might be reading that wrong. With 4.5 at bump, you will have 2.3 at ride.

You right. Im dumb. Looks like ill be adjusting the Cs when i get it to ride height.

 

[Sean]

I think you might be reading that wrong. With 4.5 at bump, you will have 2.3 at ride.

Do you mind educating me on how you got 2.3 at ride from the graphs?

 

[Treefrog]

Do you mind educating me on how you got 2.3 at ride from the graphs?

Using the front:

with it being at 4.5 at bump

The pinion is down 2.2 from ride. Or viewed as caster, caster is increased by 2.2 at bump from ride. So 4.5-2.2 gives 2.3 caster at ride and just above 0 at droop.

 

[Sean]

Thanks...I was thinking there must have been some subtraction involved and didn't know if caster could be viewed as correlating to pinion angle specifically, but since they are both fixed, that makes sense.

 

[the_white_shadow]

I started to mockup the brake masters and pedals. Even with the forward swing, they arent where i want them as the rear of the pedal mount hits the down tube. Cant move them any more left. I have a plan though to chop up each pedal and move them over essentially one pedal width and down an inch or so. I dont have much room for my right foot with how they are now. Ill plate them all back up and decide if i want to cut out another pedal on the table or just run it.

 

[Wendle]

All the talk of rear steer caster angle makes me want to go and check what mine is set to that I built half a lifetime ago...

When talking positive ° numbers on a rear axle, does positive relate to direction of travel (pinion up) or relate to the 180° rotated housing (pinion down) ??

 

[Treefrog]

All the talk of rear steer caster angle makes me want to go and check what mine is set to that I built half a lifetime ago...

When talking positive ° numbers on a rear axle, does positive relate to direction of travel (pinion up) or relate to the 180° rotated housing (pinion down) ??

I'm not sure what is positive caster in the rear. I would think it is the same as the front where the top farther back is positive. I do know that in the calculator plots positive is localized to the axle, and positive means the pinion is rotating up in a standard layout with the transfer case between the axles. This does mean that positive front is the same direction as negative rear.

 

[TimJus]

looking from side in my portal axles front is 8 positive and rear is 8 negative .

 

[the_white_shadow]

Cut and kinked the pedals to move them over 1.5" Much more room for my right foot. Still not sold on the configuration. May end up just having one pedal, but will see if i can make it work for now.

Next up is mounting the orbital and steering column/shaft.

 

[chaplinfj60]

just make a plate that slips over both pedals and use like that, then when you feel all cone dodge and need to skid it around remove the pedal. tractors just use a little bar that flips over to each pedal.

 

[Wendle]

looking from side in my portal axles front is 8 positive and rear is 8 negative .

So, 8° pinion down in the rear? Stub axle is closer to the rear of the car than the inner axle?

 

[YotaAtieToo]

Seems like there is not enough room to be able to use just the left pedal. Might be smart to plumb that up to front brakes if you plan to mostly use the rear individually for front digs?

Did you offset the drivetrain at all to the passenger side?

 

[TimJus]

So, 8° pinion down in the rear? Stub axle is closer to the rear of the car than the inner axle?

yes. you could say it like this

 

[the_white_shadow]

Seems like there is not enough room to be able to use just the left pedal. Might be smart to plumb that up to front brakes if you plan to mostly use the rear individually for front digs?

Did you offset the drivetrain at all to the passenger side?

Its offset/angled about 1.5" to the passenger side. Im setting the gas pedal now. But youre right, the left pedal is hard to press by itself. If i keep them where they are, ill have to make the right pedal the rear brake. We will see. May have to use a single pedal and a dildo hand brake for digs.

 

[YotaAtieToo]

How much do the pedals travel?

If you can angle your foot a bit, you might be able to put enough pressure for rear dig. Not like a little brake pressure on the driven axle will hurt anything.

But ya, maybe easier to just add a handle.

 

[the_white_shadow]

How much do the pedals travel?

If you can angle your foot a bit, you might be able to put enough pressure for rear dig. Not like a little brake pressure on the driven axle will hurt anything.

But ya, maybe easier to just add a handle.

Not sure yet on the pedal travel. I’m waiting on the two clevis connections to come in for the masters. Hoping for a short pedal travel.

 

[the_white_shadow]

Gas pedal mounted. I definitely didnt sit in the seat and make vroom vroom noises.

 

[the_white_shadow]

Steering column and orbital mounted. Its a little close to the interior for my liking (its above my feet), but tis the best place to fit it. Ill likely make a shield to protect my legs in the event a line happens to burst.

Also started to mock up the tierods for the steering. I am running some 3/4" heims on the rams and and 7/8x3/4 on the knuckles. I having an internal debate on what size material to use. 1.25 x .120 or 1.5x.25 DOM. The 1.25" just doesnt pass the eye test to me and id hate for them to bend if im bound up and the ram overpowers them. Leaning towards the 1.5" stuff.

 

[the_white_shadow]

I went ahead and used 1.5" for the tierods. One less thing to worry about.

Also built a removable steering column support. It definitely removed some of the wiggle. I may end up mounting my switch pros panel off of it as well. I want everything within arms reach in the event of a roll i can cut it all off quickly without have to unbuckle the shoulders.

 

[mobil1syn]

if the car does not color coordinate with the steering wheel, i will be disappointed.

 

[Crawlin4runner]

if the car does not color coordinate with the steering wheel, i will be disappointed.

I agree… Some crazy 1980’s bass boat paint scheme with them big ol’ flakes lol!

 

[the_white_shadow]

I progressed some over the long holiday weekend.

Added some removable tubes over the engine.

Installed the trans cooler behind the drivers seat. Its a Derale with a Spal fan and is beef. Part Number 65861

You can also see the battery tray that is between the seats. I need to fab up a hold down for it .

I made a tray to mount the power steering cooler and Radial dynamics rear steer valve. They will sit in the dead space under the radiator.

Added some tubes to the rear to finish it out. Tubes still need to be capped.

Started on some filler plates for the front and rear upper link mounts.

 

[the_white_shadow]

I also started to re-drill the unit bearings until the belt on the drill piece took a shit. But i got enough done on one to mount up a wheels and tire. Its a spare with 5" BS but lets me see what its going to look like.

I took a sledge to the Cs and fixed the caster. At bump, im at 10 degrees up front and 7.5 in the rear. This made me move my lower shock mounts which i revised some.

Branik was nice enough to offer 15% off the 32-spline 1550 direct drive outers so i went ahead and ordered all 4 of them for the buggy. Saved me about $510. Thanks Stan. Also ordered a Switch Pros RCR-12. Once i get the rest of the unit bearings re-drilled, i plan on getting the chassis off the table.