Structo dumptruck conversion
 

I wanted to build a light dumptruck, this is mostly based off of the tonka conversions of smallhaul and several others i've seen on here. (Steal oll the ideas!)

For the donor, I picked up a 1/16 Redcat rock crawler. 4wd, solid axles, locked diffs and trans, and axle hexes were about the width i needed.

Originally i wanted to convert my 1930s style nylint, but once i had axles it looked too narrow with the fenders, so I grabbed a 1960s Structo hydraulic dump truck tandem axle with the pow-r-r-r motor noise maker.

http://imgur.com/8tDrDAvh.jpg

My plan was to just go quick and dirty on this, use the original stamped frame and try not to get too crazy in hopes of making the indy show.

Tires are just the modified stock hard rubber that's been under it since it left the factory.

I ordered a set of tamiya semi springs, but what i got is too long. it's like 3 inch eye-eye. I can't figure a way to get my front axle under the fender and not have to chop off the front bumper to get spring shackles through it.

http://imgur.com/ZhdbmASh.jpg

Pics will be here as soon as photobucket starts playing nicely. Photobutt is awful and should feel bad.

http://www.tnttoytrucks.com/Structo602.html. it's pretty close to this truck.

Re: Structo dumptruck conversion
 

http://rsmg.pbsrc.com/albums/v413/fr...h=480&fit=clip


http://rsmg.pbsrc.com/albums/v413/fr...h=480&fit=clip

The 20 min edit rule isn't good.

Re: Structo dumptruck conversion
 

So i'm painfully aware now that tamiya # 9808091, 9808092, 9808094 was the wrong type of spring. 4.75" long spring was way too big, but it's what amazon had.

Anybody know what springs i was actually wanting to buy?

Re: Structo dumptruck conversion
 

i think you want the ones for the tamiya highlift (f350 or tundra)

Re: Structo dumptruck conversion
 

the springs for the hilift are longer than the semi set, you might want to modify the ones you have.

Re: Structo dumptruck conversion
 

I curled up the 'b' helper springs, and got the front end looking a little better. Once i got the front of the springs mounted, and played with shackle lengths on both ends.

http://i.imgur.com/ib442O9h.jpg

And mangled a hole in the chassis, got the trans mounted up to some brackets.

http://i.imgur.com/s9WunDEh.jpg

http://i.imgur.com/4yK3ptAh.jpg

And i still have some suspension travel when it's got a load of dirt on.

http://i.imgur.com/79mOqQGh.jpg

Cab mounts i went really easy / lazy: I stuck a bolt through the bumper rivet holes and cab, threw a nut on those, the bolts slide into the original chassis rivet holes, then the stock tabs slide into the original slots.

Re: Structo dumptruck conversion
 

Bottom view

http://i.imgur.com/uGd7NKYh.jpg

Got the interior back in. Trans clearance wasn't as brutal as i expected it to end up.

http://i.imgur.com/j8tXKDoh.jpg

I know by the stunned silence you've all been wondering who would run such a modern, immaculate, classy, and well preserved vehicle in their fleet?

http://i.imgur.com/AkD8BjLh.jpg

I haven't come up with a great company name yet... We better hope i get creative before my dragline crane becomes part of that guys other division Mike Oxbig Erection and Mining. :cop:

Re: Structo dumptruck conversion
 

Much fun at the Indy 2016 show on friday!!!

http://i.imgur.com/tg2g3lph.jpg

http://i.imgur.com/cvEnE7Sh.jpg

shook a spring loose, hit the shop
http://i.imgur.com/CjkVU2Uh.jpg

hit the general store for lunch
http://i.imgur.com/n3xV48kh.jpg

http://i.imgur.com/AmTEhOCh.jpg

Re: Structo dumptruck conversion
 

Here was the truck before i started modding, i had yanked one of the tandem axles off since it only had enough retainer clips for one rear. I was hoping for a stance more like this than my big lifted truck.

http://imgur.com/8tDrDAvh.jpg

Re: Structo dumptruck conversion
 

So lessons from indy:

Rock crawlers aren't fast. Taking the 3.770 tall tires off and replacing them with 2.315 tall tires means that you need to pull over and let everyone pass. Seriously, everyone passed me. I can reach top speed in under a yard. I have more torque than the tires could ever use. Must regear the trans!

Drilling brass bushings from round stock by hand makes a really wobbly setup. I need to either redo wheel pin drive using tubes, or grind the tires to the new round, or get different rim/tire combo.
I also learned its possible to have a car shake the rear suspension apart, um, in like 1 battery pack. :lol: but the crowd seemed to like it

Setting the suspension up for heaping load of dirt doesn't work that well for crumb rubber. Full load of rubber, no movement.. this didn't help the out of round tire situation since there's no real spring or any dampening. Once i got home I loaded the bed with soda cans, and learned the rear springs didn't get near max out until 6 pounds, i need to pull a leaf..

My transfer case still needs lowered since my drivelines are horrible, i need to shorten the rear springs. i need to put deans plugs on so i can use better battery and charger. I need some lights, a trailer hitch, and mudflaps. i've also got a few ideas for some interior detailing...

Kinda getting tired of talking to myself though.

Re: Structo dumptruck conversion
 

If anyone may be interested in these donors, here's a bit more i've learned.

Turns out I used a 1965-66 only configuration Structo hydraulic dump truck. I still have no clue if it's supposed to be based on any kind of real truck, or just a generic truck.

Stock steering on the Redcat Everest / Exceede Maxstone donor is kinda bad and understeers a lot, here's the biggest part of the fix:
http://www.rccrawler.com/forum/newbi...tuning-10.html
Redrill knuckles for zero ackerman, make new draglink and tierod. Eliminates tire scrub, it's still turning a 4 locked truck, but atleast you can steer the same direction.

On the trans, up to 370 brushed motors fit, and stock esc will support them.

The differentials have a 14t pinion, 38t ring. Which is 2.714 to 1.

The motor pinion is 14t. i don't yet know the spur size, or the trans total ratio.

Any specs or dimentions that might be helpful?

Re: Structo dumptruck conversion
 

So what's the most important part for a DUMP truck to have?

Yeah, you'd really think so...
http://i.imgur.com/aX4GW14h.jpg

But instead of getting that part so it can DUMP: i made light mounts, hacked servo board so the lights can be activated from the tx, made a trailer hitch, started working on a trailer, and made the steering wheel i'd thrown in there look less like a round servo horn.

Other than softening the rear suspension a little by pulling the smallest helper spring, i haven't done much of the planned mods.

Thinking i may try adding Plastidip to the tires to see if it helps with the traction situation. I knocked more rust off the hubcaps, but didn't try for too shiny, this trucks not about that life.

Re: Structo dumptruck conversion
 

I picked up a Helion (4300 rpm) 370 motor to replace the stock 260. So i moved up from an inline 6 to a flathead v8. It took making the motor mount holes ugly ovals, and a little file work on the skid mounts, and taking a ridge off the side of the trans.

Stock pinion is 14t, to 61t spur. not sure about 3 gears in trans. Axles are 14t pinion, 38t ring

I also picked up a delrin cutting board to use as spacers for a t-case drop.

Re: Structo dumptruck conversion
 

Nice work on getting the ol' girl running again!
The hood/fender contours link like a 65-66 Chevy/GMC, but that grill looks like an IH…

(My cocks big Hauling)
 

Thanks roadranger, it's getting there. Most of the driveability issues were because i wanted to keep the stock wheels, or rushing to be able to drive at Indy.

I'd put out the help wanted signs a while ago, these 2 nicely dressed germans inquired about jobs while i was at RuralKing. They said they overspent on christmas and agreed to work for me at half price just to have a job.
http://i.imgur.com/fxL6ZKvl.jpg

They look awful clean cut for Mike Oxbig, but we know the interview isn't usually the real guy anyway. We'll see how they work out...

Re: Structo dumptruck conversion
 

Haha. Nice!

Re: Structo dumptruck conversion
 

Frizz,

Could you post a few pictures of the underside of your truck? I'm going to abandon the independent suspension and try something more like yours.

I need pictures and design ideas for the axel and suspension and drivetrain. Not sure if or how I am going to be able to use my dromida truck diff parts since they are NOT solid axels, but I'm gona see if I can figure out something...

Jim

Re: Structo dumptruck conversion
 

Post 6 has a pretty good top view, and post 7 has an ok bottom view. The t-case has been dropped, and spring shackles changed to aluminum since then.

Anything specific you'd like when i grab some better pics?

Re: Structo dumptruck conversion
 

I don't know how I didn't see those? I thin the post 7 is what I need. How did you attach the axel to the leaf spring, some sort of U bolt? Is that in one of the pictures in the thread?

Thanks!

Re: Structo dumptruck conversion
 

The leafsprings i used had 3 holes already drilled. Axle to leaf attachment was just a bolt through the leaf into existing hole in the top of the diff, post 6 kinda shows on front.

U-bolts would look better and be more scale, this was just trying to reuse existing hardware from the donor crawler so i didn't have to hit the hobby shop.

Re: Structo dumptruck conversion
 

Hopefully these help some

http://i.imgur.com/TWL2xx1h.jpg

http://i.imgur.com/0QxcMKzh.jpg

http://i.imgur.com/wxM2PwQh.jpg

Re: Structo dumptruck conversion
 

Frizz, ya that helps a bit. You probably say in the thread, did you use taymia axels on this?

Today I bought a yeti Jr. 1/18 or maybe it says 1/16 but it turns out to be NOT the perfect donor for a dump truck. The rear axel is solid, but it has open diffs and the front end is independent suspension and not a solid axel.

Jim

Re: Structo dumptruck conversion
 

Well, what sucks is when you click on edit because you are under 20 min, but by the time you finished typing the new stuff it is past 20 min limit and it screws you...

Re: Structo dumptruck conversion
 

No, tamiya axles are way too big, and expensive.

This is a 1/16 scale Redcat Everest / Exceed Maxstone rock crawler. 4wd, Solid axles, spools in both, standard hexes, lots of axle mount options, 3 gear trans, no center diff, 2 ch radio. They go for $100-120 on most hobby shops or amazon. Some better parts are available or adaptable, lots of tweaks to make things work better.

Re: Structo dumptruck conversion
 

Frizz, did your motor swap take care of the slow speed issue? Or did you also change gears?

Jim

Re: Structo dumptruck conversion
 

The motor swap got me up to the speed of semis in the city layout, plus a bit. I'm sure they'll still drop me easily in the open in higher gears, but i'm driving a single speed beater dump truck not a ratrod. The 370 really helped.

http://www.scale4x4rc.org/forums/showthread.php?t=58173
Said that i either needed Losi Mini Crawler or 1/16 Redcat everest axles if i wanted to tuck anything under fender or bed

My new 'steelies' gave me more grip and a touch more speed than my 'whitewalls', and fixed the wobble/shaking. I'll probably try to find some street or rally tread instead of the hard slicks it comes with.

I have not done a regear, and probably won't since it did petty well at lebanon. I might consider it on a nicer looking truck to really dial it in. I can easily haul 5 cans of soda in bed, and another 6 in a trailer, so i've atleast got enough torque i want.

Re: Structo dumptruck conversion
 

http://i.imgur.com/6CRuAX9h.jpg
Took the the Dump and Sandloader trailer to play. I didn't think to get pretty posed pictures.

If you do something like mine, watch out for driveshaft bind on the front. It has a horrible angle, short shaft, and leaf springs are harder to fix yoke angles than linked axles.

Re: Structo dumptruck conversion
 

Ah, hadn't thought about the steering geometry issues.

I would love to see some good pictures of your rig pulling the sand loader! Do you have the loader powered? I may have seen one of those, but it has been YEARS, probably played with one as a kid in the sand box! :p

Are there pictures of your dump solution? Did you use an actuator or what?

Jim

Re: Structo dumptruck conversion
 

Frizz,

You handing out near the keyboard today?

Do you recall any specs on the leaf springs? How long eye to eye, width, shackle length, height unloaded?

I'm gona try 1/4" wide and add a helper under the rear ones for sure. I'm using strapping to start with. They might be a prototype until I get a little further into it.

AND, anyone else following along, if you have done leaf springs and have any tips I'm ALL ears!

Thanks,

Jim

Re: Structo dumptruck conversion
 

The tamiya leaf spring i gave p/n for in beginning are 0.260" wide, mains were 4.5" eye to eye, and have several helper springs available. forward got cut down to 2.3" eye to eye, both got a helper spring. I'd like shorter rear springs to push the axle a little further back, it now sits between the original tandems.

On mine rear shackle is .700 eyes, mounted aft side of spring. Front shackle i just used some bike chain outer link plates to get it together for indy, also mounted aft side. The shackles should be close to vertical but pointing toward the axle at rest. Set your fixed eye to center the axle, then shackle length tunes the spring rates. (Ignore the lightning holes in my frame, they were for testing)

For dumping i'm still planning a figreli / actuonics unit. I got confused trying to make sence of what i needed, and instead spent the actuator budget building a VW bus so i could operate 3 machines at the show.

Loader isn't powered other than the hand crank, but maybe somewhere down the road. I'd like to do a belt drive with a generator hiding components.
http://i.imgur.com/7bHV0pnh.jpg

Re: Structo dumptruck conversion
 

That loader looks cool behind the truck! Thanks for all the measurements and install tips! I'm headed to the shop now, hope to get the axels mounted today, I'll post some pics, I think I started a build thread for mine, but I have more of my truck in your thread at this point! :p

Jim

Re: Structo dumptruck conversion
 

It's all good, seems like i tried doing a lot of my crane in your thread.
We're having fun and exchanging knowlege.

Re: Structo dumptruck conversion
 

I still think I'd like to use a figreli / actuonix actuator for the main lift ram.

Bed is 5.20"w by 7"L by 2.5"h. Hinge is 1.5" fwd of the gate, ram attach 2.25" fwd of gate. Original 'hydraulic' ram is an oil damped spring 100mm open, 80 closed, 20mm travel. (Eww, metric) I'm open to suggestions of better ways to do it.

L12- 30mm ranges mount hole lengths from 82 to 112mm

So i'm thinking i need an L12r-30-210, or L12r-30-100. I think the 210 ratio slow speed would fit this look better?

Or there was talk of an L16-30 becoming available and only 14mm longer than the L12-30-.

Re: Structo dumptruck conversion
 

Thanks for forging all the measurements! I think they are the same for me. Your truck was originally a tandem axel? I have one of each but I started with the single axel truck.

I did a YouTube video a year ago or so where I made a screw drive linear actuator, I may try to do something like that and see if it works. It uses delrin rod drilled and taped to fit threaded rod. I used one of the micro gear motors.

Jim

Re: Structo dumptruck conversion
 

Yep, i thought this beat up tandem axle looked coolest of what that antique shop had, and even if I couldn't stick with tandems, it would give me spare wheels for a trailer, plus the bed was bigger and had a tailgate. It came down to either this or a red/yellow Tonka, and i'm pretty sure everyone has seen *that* conversion already. Didn't want "Hey, why does this build suck more that i remember?"

Then i figured out an axle donor, but couldn't find spare axles seperately and didn't want to buy a whole second truck to scrap just for 1.5 axles. Even if the diff matched up enough that i could figure out a pass-through, the rear axle mounting didn't really look like it would work upside down.

I originally was going to do a servo powered cable bed lift with 2:1 or 3:1 advantage, but chassis space got real tight once i had it driving. Winch drum at back of cab, pulley at rear frame, pulley on the lifting arm, dead end at the bed. But the driveshaft and my leaf mounts were pretty close in that area.

https://youtu.be/2R0stfMjJ7w
I don't know, these are 50 throw instead of 30. 100 ratio looks good and quick, but 200 ratio looks good and more powerful too.

I went beyond Cardboard Aided Design, and made a scrap wood actuator template. Then i remembered the motor housing and remade it to correct dimentions. In the stock holes, it'll lay frame, and can go a little past vertical.

http://i.imgur.com/FFAIqv6h.jpg

Re: Structo dumptruck conversion
 

My first operator didn't like the rig and wanted to run other equipment. Taking night classes and all that.

'I quit, and i'm going that way.'
http://i.imgur.com/us80Eael.jpg

So we hired this new guy. So far he's really enjoying the old truck and isn't complaining about not having new stuff.

http://i.imgur.com/syOT0nVh.jpg

Re: Structo dumptruck conversion
 

I hadn't recognized that the mirrors were diy, nice, I should do something like to mine. I also need to do a video of it hauling!

Re: Structo dumptruck conversion
 

Can't back up accurately without mirrors, and most trucks i saw from this era just have the big single mirror on the bracket. So i just grabbed a little Brass sheet, copper wire, solder, silver sharpie. Didn't feel like making them as nice as what the crane truck has.

I didn't know how big of a hit this would be over at the first meet, so I guess i was thinking 'scale points' like at rock crawling events. I thought they seemed to fit the look. It's not nice or fancy, but Mike isn't making a lot hauling since all the bigger trucks got popular.

Re: Structo dumptruck conversion
 

Looks good. When you getting some truck nutz on this thing? Talk about going over well at a meet.

http://www.ebay.com/itm/RPM-R-C-Prod...3D122092382079

Re: Structo dumptruck conversion
 

Hahaha, wow i didn't know those were an rc thing. Probably not for this one, who wants to dump on their sack, or knock it into stuff offroad.
but if i were doing a 'Brodozer' style truck, i'd have to get those. Then make a scale yeti cooler, find either some Tapout or Monster or DC stickers...

Now that i've got a better looking Mike, I still need to figure out more of his look. What's his hat logo? Does he have a trucker tan, some stubble, stained shirt, overweight? Who is he?