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Old 04-14-2017, 04:44 PM   #21
Hal
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Default Re: Belly Dragger Sawback

How do those tires do in rocks?
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Old 12-13-2017, 07:01 AM   #22
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Default Re: Belly Dragger Sawback

Rescued from the Photobucket fail, here's a few pics of the Belly Dragger as built and on it's test run...






While I liked the super stability of such a low rig, it hung up pretty much everywhere. Low chassis + aluminum skid = rock anchor.

Sat on the shelf after the first run until I figured out what to do with it. Inspiration struck the other day while looking for something to wrench on, and started hacking away...

So here's the biggest problem. Though the boatsides covered it visually, the chassis hangs down in the center a ton..


So of course, busted out the aluminum and made a new set of chassis rails eliminating the center drop. Used the old chassis as a template to keep the body posts and suspension mounts in the same locations.


Fitting into the body...just needed a slight trim on the floorboard area. Not really noticeable from the top.


A new trans mount/boatside plate was fabbed up. I made it out of aluminum initially, though I may go back and redo with a steel plate at some point so it slides better. Can see the difference already with the old chassis up top.


Now nice and flush on the bottom! (Well, will be when I countersink everything) Gained over an inch of center clearance. Since I only had about 1.5 inches, that's a huge difference,


Now the challenge is to stuff the driveline under there. Under the hood is no problem, but the t-case is going to be tight. Not a lot of room under there... I checked out a few options for front motor/tcase setups and think I found one that will work - just waiting for the UPS driver!
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Old 12-13-2017, 07:01 PM   #23
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Default Re: Belly Dragger Sawback

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How do those tires do in rocks?

Sorry I missed your question, been a while since I've been in this thread. Only ran them through about a pack, but there were not too bad on first impression. Good on rocks for sure. Didn't run it enough to really get a better feel for them though - or even really break them in.
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Old 12-16-2017, 04:36 PM   #24
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Here was plan A - sourced an MST front motor conversion kit. Great little transmission and t-case combo.


However, after assembling the trans and mocking everything up, turns out it was a tight fit. The trans hangs so low and far back, there's no real way to connect it to the t-case, and the shaft to the axle would have hit the transmission. So on the shelf the trans goes - it's a nice setup - I'll find a home for it eventually.



I didn't have a plan B per-se so I set the truck on the shelf for a while to let it percolate. This morning while digging in my transmission box, I came across an old R2 trans from my TLT days and a 1:1 t-case. Hmm. The R2 drobbed right into the frame rails, and the t-case is low enough to go under the body. Like it was meant to be! Also kinda wishing I had this brilliant insight before dropping $70 on a new trans, but oh well.


The R2 actually lines up perfectly with 2 existing holes on the chassis, but it put the motor too far forward. So I drilled some more further back and mounted it as far forward and low as I could get it. Chassis is super short - bottom of the axles to the top of the trans is only 3.5"


T-case lines up perfect now, and all the driveshaft angles are (well, will be) smooth. Plenty of clearance under the trans for the axle shaft now too.
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Old 12-18-2017, 02:31 PM   #25
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Default Re: Belly Dragger Sawback

Moving right along!

T-case filled with red and tacky bolted up. I shifted it to the left as much as possible to keep all the drivelines centered.


Took apart the R2 and cleaned out all the old moldy grease. Added more red and tacky everywhere to hopefully quiet it down a little. Dropped in a 12t pinion so it matched the ratio of the Sawback trans and made a thinner cover for a bit of driveshaft clearance. Lopped off the front output too. Ready to go!


Trans mounted up and mated to a stock gmade driveshaft...not the strongest, but it's what I have for now.


Needed a servo mount....could have cheated and used standoffs and just drilled them to the chassis, but decided to take some thick bracket and make an actual mount. Didn't really clean it up much - function over form. Smoothed most of the edges and called it good. Not my best work, but it's super solid.


Servo mounted, and shock towers and body mounts bolted on. It's super tight, but everything fits.


and by super tight, here's an example - bolts are touching the motor. If I want to use a larger pinion down the road, I'll have to think of something.

Last edited by OSRC; 12-18-2017 at 02:36 PM.
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Old 12-18-2017, 02:46 PM   #26
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Default Re: Belly Dragger Sawback

Battery tray, rest of the chassis parts all bolted on...ready for axles!


Robbed the upgraded leaf bushings from my other sawback (which is now a pile of parts) - they really make a nice difference as far as smoothness and slop goes.


Rear axle mounted up. Might need to re-space the batt tray a bit higher as the axle only moves up about 1/4 inch. There's not a lot of flex on this rig, not sure if they'll make contact or not. I'll see once I get all the weight on it. I'm sure I will though. Shocks towers braced at the top as well. This chassis is much stiffer than stock overall.



Last edited by OSRC; 12-18-2017 at 02:49 PM.
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Old 12-20-2017, 06:29 AM   #27
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Default Re: Belly Dragger Sawback

Started work on the front axle. Hard to see in there, but it's modded with R1 gears for overdrive. Both axles have the brass inserts as well. Really helped with my stock Sawback as they tend to be quite top heavy. Should really make a difference now since everything is so much lower.


Plenty of clearance for the motor...


Learned something about Junfac shafts...the indexed part of the female shaft only extends in about 1/4 inch, the rest of the inside is round. I went to shorten it a bit and cut off the indexed part and ruined the shaft. Whoops. Had to order a new one. Lesson learned!


The white body fell victim to my not so great bodywork skills...I went to dovetail the rear, and kinda sorta cut too much off. Basically ruined the body. Between the body and the driveshaft, I'm on a roll here. So I stole the blue body from my other Sawback...I won't be needed it anytime soon since Sawback #1 is in a million pieces. I'll build something from it eventually.
[

Last edited by OSRC; 12-20-2017 at 06:39 AM.
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Old 12-20-2017, 06:33 AM   #28
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Default Re: Belly Dragger Sawback

Before I hacked it up, I mounted some OG Flat Irons on....could be a heck of a scale rig, I really like the look. Should perform too...hmm...maybe an option for Sawback #2?



But I like the agressive look of the body sitting low with the fenders trimmed, so went ahead and trimmed it up. Very carefully this time..


What the...? Whoops! Wheeled this axle through 2 packs and never noticed the missing bearing. Was letting the axle slide around laterally - fixed that up.


Almost got a roller here! Not sure if the TSL's are staying or not, got a few options to mess with.


Low and mean...might lower the servo a bit too so I don't need the spacer on the link.


Had to do a little dremel work to get the body sitting just right, but loving how it came out. Prefer the white body instead of the blue, but now it's what I got. A little flex shot of course. Using all three leafs at each corner, suprised at how much articulation I get.


Guess it's not much of a belly dragger anymore....Lowered the CG and increased ground clearance by over an inch. Win win!


Mounted my usual suite of high end electronics....kind of a tight fit, but it all stuffs in there. Still have to clean up the wiring a bit - it's right on top of the driveshafts, prefer to have a little space there somehow.


New driveshaft is on order, still need to figure out bumpers, sliders, etc. Fun little project so far.

Last edited by OSRC; 12-20-2017 at 06:40 AM.
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Old 12-20-2017, 07:10 AM   #29
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Default Re: Belly Dragger Sawback

Gear Head wheels belong on everything.

How in the world did you get that much flex with all of the leafs installed?
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Old 12-20-2017, 08:20 AM   #30
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Default Re: Belly Dragger Sawback

Doesn't yours flex like that? It will actually go more once I get the driver and battery in - might have to look into internal springs for the shocks to stiffen it a bit. Can't really hack more of the fender off in the back.
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Old 12-20-2017, 08:42 AM   #31
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Doesn't yours flex like that? It will actually go more once I get the driver and battery in - might have to look into internal springs for the shocks to stiffen it a bit. Can't really hack more of the fender off in the back.
Mine probably flexes something like that, but I don't think I use 3 springs ever since I installed the ant-wrap bars that have really minimized bent leaf springs.
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Old 12-27-2017, 08:59 AM   #32
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Default Re: Belly Dragger Sawback

Front driveshaft came in...got it mounted up and had to take a test drive.


The balance on this rig is incredible...can sit sideways even with the heavy driver up top.


Found the steering horn hit the chassis before going full lock. Will have to lower the servo a bit to clear. No problem, was planning on doing this anyway


Had to throw in a battery and go try it out. The ground clearance made a ton of difference - immediately went up and over places I would have never thought of before. I use my parking blocks as a standard test of sorts, and it passed over with flying colors! Would have never even come close with the old chassis layout.


Out in the rock garden...


Have some severe tire rub up front...need to think about what I want to do here.



Failed on my test climb...has a lot of driveline lash - so much so it hopped terribly. Twisted a leaf as it was bouncing so hard. No good!


Brought it back in and tried another set of tires...still rubs.



So some mixed results on the test run...it was super stable and the power and gearing was spot on. Steering needs to be fixed though, and the driveline lash was just awful...need to investigate what's going on. Heading in the right direction though.
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Old 12-29-2017, 06:15 AM   #33
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I love your builds, so much homegrown engineering and tech.
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Old 01-06-2018, 08:41 AM   #34
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Default Re: Belly Dragger Sawback

Very well done. I built an ascender with the same idea, made as much myself as I could, everything super low and a flat belly. Really works great and surprises many with where it goes being so low and on leafs all four corners. I'll keep watching and seeing how this ends up.

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Old 04-06-2018, 01:08 PM   #35
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Damn you OSRC!! My only currently working crawler and now I want to start cutting it up! Found the same trans you are running got a transfer case... Shit here we go....
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Old 04-06-2018, 03:28 PM   #36
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Default Re: Belly Dragger Sawback

I hope there's not too many people copying my jalopies... lol.

Really need to finish this. Found the drivetrain last was due to a bad output gear on the R2 trans. Need to pick up another one next time RPP has a sale. Have a new body on it too - same, just unpainted.
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Old 04-18-2018, 03:28 PM   #37
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Default Re: Belly Dragger Sawback

Been a few months on this one... Still plugging away at it. Kinda.

Went ahead and tried another dovetail. Came out kinda rough...but since I've never done one before, I can honestly that it really is the best work I've ever done! Body is kinda beat, so didn't feel bad about hacking it up.




Replaced the output gear in the R2 and swapped in a matching t-case as well. I've already got OD in the front axle, so it went in pretty much standard.


Put the TSL's back on..I think they really fit the stance nicely. Not sure what I'll do about the tire rub - I'll figure something out. Added a few scale details here and there, the winch from my Deadbolt and finally got a window in. And by scale details, I mean a few stickers to hide the holes. I'll need to figure out some kind of bumper too. The winch kinda hangs out there.



Found out I was getting so much flex before because my axles were a bit loose on the spring perches (which is what twisted a leaf). Tightened them up and suddenly, not much flex anymore. This is all she's got at the moment. Not going to mess with it for now, just drive it as is and make some changes later.


Hunter Dan is clearly dressed for our very chilly spring weather...

Last edited by OSRC; 04-18-2018 at 03:30 PM.
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Old 09-07-2018, 06:48 AM   #38
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Default Re: Belly Dragger Sawback

Gave the spring under Sawback some love.. not quite finished, but now I can drive it anyway. Did a bit of work out back in the battery area to get some more suspension travel. Very happy with it overall now - leaf trucks shouldn't have a ton of flex imo, that's part of the charm.


I had a ton of play in the drivetrain stil, even after swapping the t-case. Combined with the leaf springs, it was a disaster waiting to happen - hopping all over the place. I found the t-case had a ton of internal play, so I swapped it with an MST t-case. Tightened up the entire driveline, and the 2:1 reduction worked out perfect.


Love the layout of this thing, can't get the motor any lower in there, and still have good suspension and breakover.


Went out to to some testing. The 1.9 Flat Iron XL's did very well. I have no weight in them, and I've found that Sawbacks do better with some weight. The brass axle inserts help for sure, but that cage and driver figure up top combined with the relatively narrow track makes it somewhat tippy on sidehills.





Couldn't do the 55d ramp. :( Though with the R1 gears in the front diff, it never tried to flip itself, just sat there and spun. Very good trail runner, but climbing is not it's forte apparently.


Swapped on a set of weighted wheels wish Axial BFG's. Noticed the weight made it much more stable, but holy cannoli, these tires did terrible. Stuffed with dual stage foams, I think the foams are just too stiff for the closed tread.



For round three, I bolted on some siped/cut 2.2 Flat Irons. I think the Sawback body is just big enough that they don't look too out of scale. Even though they are an older compound, they do pretty good - they are the same height as the 1.9 XL's, but much wider. Having a huge contact patch helped for sure. Not sure if they are staying on, but of the three sets I like the way these drove the best. They just look a bit too fat to my eyes though.




Breakover is incredible with this truck. I'm thinking a steel bottom would work much better as I think it would slide better....been mulling it for a while, but haven't done anything about it. That's for the next round of mods. Needs a front bumper and sliders for sure, and going to lose the winch. It's just there for looks anyway.

Last edited by OSRC; 09-07-2018 at 06:51 AM.
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Old 09-07-2018, 10:53 AM   #39
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Steel belly skid huh? How thick did you have in mind? I finished my own belly skid/boatside template (cake box) just need to cut out the final product now. I have 1/8" aluminum, and 1/8" steel plate on hand, and might even be able to get a large enough scrap of stainless to use, but I was still leaning towards aluminum. I know the aluminum won't slide nearly as well since it gouges easily, but it's the lightest, and certainly the easiest of the 3 options to work with. A friend of mine brought up the point of having more active suspension with more sprung weight, and suggested using mild steel for the belly pan. I think SS would be sweet, but boy is it a pain to work with compared to mild steel or aluminum when using basic tools! I'd even considered making the whole thing out of UHMW-PE, I'm just not sure if it would give the necessary rigidity at the same 1/8" thickness. Since you've been mulling this over longer than I have, what are your thoughts?
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Old 09-08-2018, 06:47 AM   #40
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Default Re: Belly Dragger Sawback

Steel belly pan for sure. Good slide factor and adds a bit of weight at the lowest point in the chassis. All good stuff.

As far as thickness, no idea. Doesn't have to be super thick, the chassis rails add the most rigidity - the plate will just tie them together. I have 2.5mm thick aluminum under there now and it's solid as a rock. Probably could go thinner. I'm just going to swing by Home Depot or TSC and pick up a piece that looks about right.
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