1985 1/9 Suburban scratch build

[adamsfly]

I love seeing a full custom build right down to a hand made chassis?"thumbsup" I too know how it feels to start a build only to have a manufacture make something similar just after starting. My 40 series Land Cruiser was over shadowed by RC4WD's model.

I used the chain link for my shackles only because they looked scale but the aluminum ones you have built look good and I'm sure will work fine. Very nice start on things.

 

[JoeThePro]

Looks good currently, I would drill a few optional holes as once the body is placed your leafs are bound to compress. You may need to adjust the placement of the rear shackle to compensate for the sag. Much easier to drill the holes while the chassis can be placed back to back and drilled at the same time to ensure consistent placement.

Good idea, Ill make sure I do that before it all goes together.

I love seeing a full custom build right down to a hand made chassis?"thumbsup" I too know how it feels to start a build only to have a manufacture make something similar just after starting. My 40 series Land Cruiser was over shadowed by RC4WD's model.

I used the chain link for my shackles only because they looked scale but the aluminum ones you have built look good and I'm sure will work fine. Very nice start on things.

Its kind of a crap feeling, eh? But hey, it will be unique regardless of how well or crappy it turns out! Ill probably make copies of the shackles Im currently using out of thicker aluminum that isnt riddled with holes. These things bend if you sneeze near them. Thanks for the nice words!

Well I finally made some progress worth sharing. Since I snapped one of the steel rails I just remade them both out of aluminum. Cut and bent up some C channel to use as cross members, made some mounts for the leaf springs on the axle (not sure exactly how it will work with the screws since there is literally no clearance under the mount, but Ill figure something out), and made some spring hangers.

Got the Tamiya High Lift leafs in, and holy $#!+ they are stiff. Mind bogglingly stiff. Here they are next to a homemade one I did, you can see they are thicker and wider. Doubt they will work for what I want. Ill either go with super soft RC4WD springs, or keep working on these homemade suckers and make some accessory leafs for them. My only concern is they are pretty narrow, so Id probably have to use like M2 screws to not totally compromise the steel, and Im not sure how I feel about that.

The 10" drill press also recently arrived, so nice to finally have.

Hoping to get the leaf mounts situated next, bend the front of the chassis in a bit so the wheels dont hit the leafs when turning, and get the drivetrain/electronics mounted. Could be next week, could be next month. I can never tell how these things will go. Im always having to do things 3 times because I designed poorly the first 2 or messed something up!

Oh, and my wife got me a little 66 'burban as a valentine. :lol:

 

[JoeThePro]

Got some more done during a few way-too-late nights. More cutting, drilling, and filing, then scrapping and re-cutting, re-drilling, and re-filing... But I had some help from Jack swagger and Jax.

Got the front springs bent up (after about 3 failed attempts and incorrect length cuts, good thing I have lots of springs steel), really hoping these work out when its all said and done. They will all need at least one helper spring which I've cut to size as well.

Cutting the plastic spring loop bushings.

Jax ended up just shooting holes in the aluminum.

Hangin' the hangers. If you look closely you can see the 2 holes where they mount to the chassis are uneven, that was a fun surprise. They were actually off more than it shows here. I guess the drill bit... er.. bullet... drifted when I... uh I mean Jax... was making the holes. It took alot of control not to break the chassis over my knee, but it ended up not really being a problem. Just annoying!

Jack, overseeing the work. Its hard to tell here, but I narrowed the front of the chassis for the wheels to clear the leafs at full turn. This is also why the hangers/shackles are in line with the rails and not offset to the side like they are in the rear.

The springs are not mounted to the axles yet, gotta make those mounts, and Im also waiting on my M2.5 screws/nuts to arrive. REALLY hoping that my holes are perfectly aligned to the axles sit straight. I'm going to expect them not to, but I'm not sure how to fix it at this point if they are off a little bit.

I think I need a break. I'll probably take a few days off and just let it sit and clear my head for the next round of building. It's getting close to roller status!!!

 

[Itali83]

Keep up the good work. Hate to be picky and a bearer of bad news but the angle you have your shackles at won't work. As the spring compresses it lengthens, and the shackle needs to move rearward to accommodate that. The shackles swing on an arc and if they are resting more than 90 degrees towards the front of the truck, they will bind because the weight of the truck wants to flatten out the springs and move the shackles rearward but since the shackles are in the front side of the arc, it actually has to lift the truck, or bend the springs to arc rearward. Clear as mud? Just redrill your top shackle bolt holes forward and you'll be all set.

Ben



This is my chassis I'm building. I hated putting the front spring shackles intront of the springs but with the ride height I wanted and the bend of the frame I couldn't get the ride height I wanted with the shackle angle.

 

[JoeThePro]

Keep up the good work. Hate to be picky and a bearer of bad news but the angle you have your shackles at won't work. As the spring compresses it lengthens, and the shackle needs to move rearward to accommodate that. The shackles swing on an arc and if they are resting more than 90 degrees towards the front of the truck, they will bind because the weight of the truck wants to flatten out the springs and move the shackles rearward but since the shackles are in the front side of the arc, it actually has to lift the truck, or bend the springs to arc rearward. Clear as mud? Just redrill your top shackle bolt holes forward and you'll be all set.

Ben

This is my chassis I'm building. I hated putting the front spring shackles intront of the springs but with the ride height I wanted and the bend of the frame I couldn't get the ride height I wanted with the shackle angle.

I definitely know what you mean, and I was a bit worried about it as well. At the end of the day its just my inexperience with this stuff that resulted in the shackle placement. I had thought that, when sitting with trail-ready body weight, the shackle should be vertical, so I put them a little extra far out to accommodate this. Though, the front shackles butt up to the frame near full compression already, so its kind of a good thing I gave them that little extra room to swing, otherwise I may have run into clearance issues. If I decompress the springs past where they normally hang with no weight, the shackle will bind up, but as-is they don't bind.

If I run into issues I will just put an M2 screw next to the shackle as a hard stop at the binding point. Thanks for your input, its stuff like this that keeps me thinking and helps me learn.

As a side note, there appears to be alot of front to back movement of the axle when the springs compress because of the shackle movement. Is this normal? I imagine this can cause wheel well clearance issues, Im a little worried about it. I tried to minimize it by placing the shackle at the point which puts the axle in the center at mid spring compression... we'll see how it goes.

 

[Itali83]

The truck I'm building is my first leaf spring truck too so I'm learning as I go for sure. The biggest thing for spring placement is having the spring as level as possible at ride height. Thatway you've only got rearward movement of the spring flattening out and not the arc of the spring because the front spring mount is higher or lower than the rear. Leaf springs just naturally have front to rear movement of the axle throughout its travel. But setting wheel base at ride height and spring compression will put the axle in the middle so only a little rearward movement when compressed and a little forward when unloaded. Hope this helps and keep on working. Don't scrap it!

Ben

 

[JoeThePro]

Yeah, if it comes to it I can just fab some new hangers to put the spring a bit farther forward. This will flatten the spring out a bit, and also bring the center line more to where it should be. Once I get the axles mounted Ill be able to determine if its bad enough to warrant this. I want this to be heavy and lumbering, but Im just not sure my springs and shackles/hangers are sturdy and tight enough to handle axle shear forces. Will be fun testing, though!

 

[JoeThePro]

My M2.5 screws and locknuts finally arrived, so I finished the rear axle leaf mounts and got it all put together. No help from Jax this time. At this point, I realized either the axle or the chassis was not aligned, couldnt tell which was the culprit. I realized it was probably those aluminum cross braces I made a while back, and decided to cut and bend some nail plate steel and make a nice fat brace to base the rails on.

This worked out MUCH better, everything snapped into alignment after some minor tweaks to the chassis, straightening out some tiny bends and twist. I really took my time with this, spent about 3 hours just carefully mocking it up and measuring and bending and all that. Drilling, then re-measuring, re-mocking it up, then finished drilling. It feels so good when patient effort pays off. I was really worried that all my tiny errors and tolerance issues here and there would end up with an axle misalignment that was not salvageable. Luckily that was not the case

Test fitting the brace.

Done! (Well, need to trim the bottom bit flush with the chassis)

Some shots of what I worked out for the leaf mounts on the axle.

The motor-to-driveshaft adapter also arrived, so I was able to connect my 3:1 gear reduction unit to the transfer case. I may need a shorter shaft though. I have no idea if that reduction unit will last or if it will shred itself due to the size/weight of the vehicle when its done. The motor there is a stock CC-01 540, no idea how many turns it is, but I'm guessing mid 20s.

 

[Rickleo]

Looks like the chassis is coming along nicely. Glad to see you're putting Jax and Jack Swag to work lol.

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[JoeThePro]

I'm a little concerned about wheel size. If I go 1.55, that will be like having a 14" rim since this is 1/9 scale. If I go with 1.9s, that would be like having 17" wheels which is OK but definitely bigger than the 15s that these came with at the time.

1.7" wheels would be the perfect size, but they are all proportioned for semi trucks and probably wouldnt look right on this.

Any suggestions?

 

[BigSki]

There's a few 1.7 bead locks and tires out there for scale rigs, mostly from rc4wd.

 

[Rickleo]

Just seen these on ebay

RC4WD 1.7 Stocker Beadlock Wheels

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[JoeThePro]

There's a few 1.7 bead locks and tires out there for scale rigs, mostly from rc4wd.

I actually decided on just using 1.55 stamped steelies from rc4wd.

Just seen these on ebay
...
RC4WD 1.7 Stocker Beadlock Wheels

The offset looks pretty intense on those, would probably push the wheels too far out for my liking, but thanks! Pretty cool looking.

---

A little teaser of some of the stuff I've been doing. Made the motor mount and the front axle leaf mounts.

Looks like a...

Dont worry, I trimmed the top down.

It puts the leafs up a bit higher than I wanted, but its not a big deal.

Also picked up some traxxas driveshafts for the center.

I'm frustrated with the front axle. The shackles are a bit lower than the hangers (my fault), so this tilts the axle back and drops the pinion a bit. I'll see if it becomes a problem and make longer hangers, if so. Not ideal, but Im just kinda over it at this point. Once I get it running and get some satisfaction out of that, it might be time for a break from this to recharge and come back fresh to fix some of the issues. Now all that's left is to get the servo and electronics in and we're running.

 

[JoeThePro]

After a little more work, I got most of the mechanical/fab stuff finished. I had to cut out a bit of the inside of the traxxas yokes at the transfer case side as they are meant for shafts that are flat on both sides. The t-case I have has round shafts with a flat spot a couple millimeters back, so I had to also file the round part flat all the way out to the tip (sorry, forgot to take pics).

Basically it was like --___--| and I made it like ____--|

Anyway, the motor is mounted, the t-case is mounted with the shafts, the chassis stiffened up a bit because of it, and things are looking good. All thats left is the servo and electronics! And yeah, the motor sits up a bit too high, I'll probably adjust the mount to get it maybe 1/2" lower, we'll see. Also the rear pinion angle is now a bit sharp, but some of that is due to how the traxxas yoke fits on there a little sloppily. It sage down just a tad. Im not super worried about it for now.

I'm just absolutely loving the suspension bounce this sucker has, its so freaking smooth and responsive. I doubt I'll even put dampers on it, its just too much fun to watch it bob up and down unlike any RC I've had before. (Video a bit further down) Prepare your web connection, lots of pics ahead.

(Those are 1.9 landies for the time being until I get my 1.55s)

And I was seriously surprised at the flex it has. Really shocked me. Not like I'll be needing it for how I'll be running it, but damn.

J and J stopped by to help tune the suspension.

Jack dropped the chassis on Jax shortly after this photo was taken.

He was pretty nonplussed about it.

Here's a little clip of the suspension bounce. Maybe I'm just inexperienced and havent seen enough in person, but this feels extra smooth and soft to me with great rebound. Going into this, I always had the idea in the front of my head that this was not going to be another stiff bouncy build, but that it would have this soft plush feel to it so that it would look less toy-like off road. I'm feeling hopeful that I've accomplished this. (The tool at mid chassis is just there to even out the weight distribution for the vid.)

https://www.youtube.com/watch?v=H8cZthwpJwI&feature=youtu.be

Next steps are obviously the servo, and then to solder the xt60 connectors to LiPo and ESC, tune the sidewinder 3, and get it all mounted. Really wish that front diff was open, turning radius is beyond abysmal! :lmao:

 

[JoeThePro]

I added a leaf to each axle for more support because its only getting heavier. By the light of Zeus, these things are a pain in the butt to make. The drilling is the worst part because they are such hard steel, gotta manage heat very carefully or you'll kill the spring. Took me a few tries to get it right.

I also mounted the servo, went smoother than I expected for never having done that before. Scrapped the first attempt and used better steel in the end. Proper Planning Prevents Poor Performance

We're having some fun at work with a drawing I made on a whiteboard in the kitchen. People have been adding to, and I feel a Christmas tree strapped to the roof coming. :santanana:

I've got to lower the motor a bit, the shaft going to the t-case is just too high, especially since I dont have a tranny to keep it low. The axle wrap is also very real, since these springs are really soft. I actually removed the 3:1 gear reducer, and just tuned the ESC max power down a bit to keep the speed in check, and its actually kinda cool how it just cruises smoothly up to speed. Its actually having to work to pick up speed now which is cool, much more realistic looking.

Finally I'm debating changing this to an '89 Scottsdale, because after seeing some pics I just love the front. I'm a little confused about the headlight styling on these things. Its like they reverted to the 1980 headlight style for the Scottsdale in '89, unless I'm just not familiar enough with the styling of different trims. Anyway, looks sick to me, so I may replicate this bad boy.

More pics here, at bottom.
1989 Chevrolet Suburban Photos