Sub-Par Super Build- MT

[Crawl in Az]

I’ve had my MT for some time and have been trolling on here for a few months. Curiosity got the best of me, so I went to a comp a few weeks back. It was humorous to me how HORRIBLE my crawler did (hence the thread title). I had recently broken a rear axle housing, due to lack of time to fix, the rear steer was taken off. I knew having no dig or rear steer would be a big hurdle, but the real surprise to me was the COG issue. The crawler was sitting real high and didn’t side hill at all! In short, the other 3 supers made this thing look like a Sh!t Missle. LOL!

Keep in mind this build has been and will continue to stay on the cheap!

The beginning:

I picked up a Mad Torque almost 2 years ago after a friend stumbled across the crawler. The original intention was to enjoy while out camping. After about a year, the first attempt of modifications were; narrowed the chassis, body & stretched the wheelbase. With a 6.5” belly, 118.5” wheelbase and straight links, the rig looked more like a stick bug than a crawler. The shocks were mounted on the links (movable with some pressure) making for a tunable wheelbase and belly height. The only other upgrades included a RC4WD ESC so I could run 3S Lipo, Solar 772 servos and a Stick controller for the rear steer.
Looked goofy though:



Last fall I made my first Body-less design. I really liked the lines of the Superjuice. Thanks to a $2.98 cutting board and some dremmel work I came up with this:





I used a brake line bender from Harbor Freight and made some bent links. All the obstacles I typically found would have a real sharp break-over so the goal was a lot of clearance in front of the rear tires and I clocked the rear motor up quite a bit.



1/4" aluminum rod was used for the cross braces. The shocks had multiple mounting locations to dial in the ride and articulation. In the end the shocks were at the end of the chassis to get the lower mount off the links. The front links also received a bend for more clearance.

[Crawl in Az]

Next up were tires & wheels: Size was the main goal. I had some 40 series truggy wheels I narrowed to 1.5” (total width) 1.25” (bead to bead). I used the Gorilla impact resistant super glue. I didn't get a pic of the narrowed wheels.





For tires, I wanted a cheap set to learn on. It took a ¼ tire extra to fit around the truggy wheel.



The wheels were a standard offset (I think) from Proline and helped match the original track width after the hub conversion. The Mad Torque wheel hex is REALLY long but have close to a zero offset wheel. Here is what the new wheels looked like on the stock hex.



But there was noticeable height difference.



To get rid of all the scrub I went to a standard truggy hex using a spacer to adapt the 4mm axle to the 6mm hex.



To dismount the old glued pin tires, I used an old cake pan on the top shelf of my grill at 425* for about 18 minutes. Watch them close though! A few spots started to melt. Could probably go 400* for 16 minutes. Be sure the tires are laying flat on the pan, mine weren’t and the pressure points are where I had some slight melting. (These pin tires will be the next cut-n-shuts I build.)

For tire foams, I used the Joann Fabrics foam and was able to squeeze 4 tires out of the one square. I cut a paper template and traced out with a sharpie marker. The retractable razor knife worked pretty well to cut through the foams. To help the tires flex, I tried shaping the foam slightly as well. Final height came in just under 7.5” tall.



The size was nice but the traction was still pretty disappointing. I tried cutting the tread blocks in ALL sorts of directions with no noticeable change in traction. I understand the compound is the biggest factor but the sidewalls don’t flex or mold around obstacles at all. The sidewalls were too stiff! So I shaved the sidewalls with a 4.5” angle grinder and flap wheel disk. (Makes a pretty good mess.)



The tires will bag a little now, but the traction can’t be that great as the small 3rd gear still holds up fairly well.

Turns out the springs are WAY too stiff, so took them off and used tubing to limit the articulation.



This brings me to the present.




I don’t suspect the looks will change much other than ride height, but have the following goals on the list to improve this POS.

On the list:

Axial Chub on rear axle- mounted on 4 points
Rear servo between the axle tube and motor for lower COG and good tie rod angle.
Bully knuckles (on rear at least for now)
Exceed u-joint style axles modified to 55* ish steering
Front & rear dig- and bias with a dual ESC. (on the cheap for now using 2 stock ESCs)
Lower ride height to about a 3.5”-4” belly
Shocks mounted to axle- (shock cap mod with bent rod ends & Losi mini T springs)
Cut-n-shut pin tires
Knuckle weights

I'm open to suggestions and advice, the items listed above should help with the traction, COG and steering radius.

Thanks for reading.

[Crawl in Az]

Took the shocks loose and moved the rear upper links inboard and was able to slam the ride height down quite a bit. I think the bends in the rear links are a bit excessive but will work for now. Down the road I will probably try a long radius style curve with 1/4 aluminum.

Before the belly was 5.0" at the front of the chassis and 6" at the back of the chassis.



Now the the belly is 3.5" at the front of the chassis and 4" in the back of the chassis.



The top of the chassis is now even with the top of the tires; 7.5"

The instant center of the rear links now appears to be pointing down to the front tires instead of up through the windshield. Not sure if anti-squat numbers play into RC but I'm sure it can't hurt!

After I get some bent rod ends and modify the shock caps the plan (my only option I can see) is to mount the shock on the outside of the axle link mount.

[bquin]

three things you're going to need to be competitive. Rear steer, dig and drive time. Other than that you are on the right path Sean. Dlux has a ton of options as far as parts for that super at good fair prices. Keep showing up to comps.....new faces are always welcome...especially someone with a super. BTW......Krawlfreak is an Az native as well....pm him and maybe get yourself a genuine Super juice.

[Crawl in Az]

Thanks for the input, I'll send him a pm.

Rear steer is done, progress pics soon to come.

[2WheelFlyer]

Nice to see someone from AZ building a Mad Torque. I'll hopefully get one soon (got sidetracked with a short course truck for a bit) , or put it together from parts.
Keep building and driving!

[Crawl in Az]

Rear steer is in! Had this in before but couldn't find a clean way to mount the servo with the axle clocked. I like the packaging of the servo between the axle tube and motor, so I wanted to give it a try. I'm really diggin' how straight/level you can get the tie rod.



I gained 1/2 inch in total width. The rear now sits 14" outside tire to outside tire. (Front is currently 13.5" for the math impaired ) Bad thing is, the extra with is all scrub. (1/4" per side). If I don't like the added scrub I can always change it when I upgrade the wheels. I'd be interested to hear thoughts on how the scrub will affect the rig and handling. At this point, the amount of work I put into modifying the rear axle tubes for the servo and C-hub I'd be better off doing some custom tubes. Here is the mock up I used to fit the servo in. I took about 1/3 of the tube out, so I'm curious how long it lives. (still feels pretty stout though)



The servo is slightly exposed, I will probably use shoe goo to protect the servo wire.



I modified Bully knuckles and clocked the axle with the AX10 CHubs. I've seen DLux recommend mounting the CHub at 4 points- I found out the hard way 2 mounting points is not enough....



For axles I used the Exceed Universal Shafts Part #51C00-81023 I didn't mess with disassembling the u-joint to clearance, so I just did the best I could with a dremel to get in the 55* ball park. I used old inner shaft and did a rough cut and weld. (it's not bling, but it will work)



For bearings I found 8x12x3.5mm on nitrorcx- part #16P-23627. The bearings come in packages of 6, and turns out I"m using 3 per side. An inner, and two outers. The second outer acts as a spacer and makes the wheel hex fit snug against the bearing. Down the road I could refine this by re- drilling the stub shaft to remove the extra outer bearing and reduce the scrub. But I would probably opt for longer tubes and better wheels instead. I think I'm off by one tooth on my servo horn though. For steering I"m getting 45* one way and 55* another. I'll probably have to adjust and make a new tie rod. This is the 55*



But even at 45* rear you can see it's noticeable over the modified stock stubs in the front (machined out .010" by a friend some time ago).

[Crawl in Az]

Originally Posted by 2WheelFlyer

Nice to see someone from AZ building a Mad Torque. I'll hopefully get one soon

These things are a blast! They are perfect for just playing around. I never intended to go to comps, but will see how it does. Definitely an affordable starter crawler.

[nappahdog]

I've been eyeballing the mt for a while now i think it could be made to work well ; wish I would have looked at your rig at the comp, I've been wanting to build a super again and the mt axles are cheap enough to give it a shot, Keep showing up to comps and doing what you're doing, it can be easy to get discouraged at first but to me the step by step progression at the beginning is FUN,
curious as to how the shafts hold up as that looks like a great option.

just ordered some bully knuckles (on sale and discontinued) for my mt build haha

[2WheelFlyer]

After all this mods the performance over the stock MT must be really impressive, looks comp worthy. I'm just wondering about that servo hanging down there, maybe an aluminum skidplate to protect it and have a smooth transition from axle/servo/motor?

[Crawl in Az]

Originally Posted by nappahdog

I've been eyeballing the mt for a while now i think it could be made to work well ; wish I would have looked at your rig at the comp, curious as to how the shafts hold up as that looks like a great option.

I plan to be at the comp this coming weekend, maybe I’ll see you out there. Agreed, the build up is fun, I look forward to the tuning and small subtle changes.
I think the axles should hold up pretty well. I had thought of using a sleeve and welding them, but for simplicity I was able to clamp the shaft in a piece of aluminum angle and weld it. The only other concern would be the small pin on the u-joint. So, time will tell.

Originally Posted by 2WheelFlyer

After all this mods the performance over the stock MT must be really impressive, looks comp worthy. I'm just wondering about that servo hanging down there, maybe an aluminum skidplate to protect it and have a smooth transition from axle/servo/motor?

Still need dig and preferably some kind of front/rear bias, I had hoped to have this done before the next comp but I’ve had delays with a receiver and programming cable.
As far as the servo, I’ll keep a close eye on it first time out. I’ve thought about using a spacer to raise the servo slightly. Still pondering on that one though.

[Crawl in Az]

Modified and relocated the shocks to help with ride height. I used bent rod ends and mounted the shock outside the axle link mount.



The Lower Links are now turned around with the bend closer to the axle instead of the chassis. The rear shocks are exposed and not protected by the link, so I'll need to keep an eye on this until different links are made.



The Losi Mini T springs fit over the stock shocks similar to the Traxxas Big bore shocks. I went with the Losi rear springs to match up with the longer shocks. To limit the travel I used a piece of nitro fuel line, 20mm long over the shock shaft. The springs are just a tad long, to minimize the spring pre-load I left about 3mm of threads showing on the shock shaft. (5mm thread engagement) or 12 turns when threading on the bent rode end.


Ride height now sits as follows at the belly:

(Back of chassis/ front of chassis)
Ride height- 3.875" / 4.375"
Full compression- 2.875" / 3.375"
Full droop- 4.25" / 4.75"

Basically 3.5"- 4"

[Crawl in Az]

For comparison, here are some Mad Torque Shock dimensions/ specs:

Stock Shock:
Total length (eye to eye)- 4.5"
Shock travel (exposed shaft)- 30mm
Total shock & spring weight- 28g




Modified shocks:
Total length (eye to eye)- 5.25"
Total weight - 20g

[Crawl in Az]

Picked these up from V84x4-



Big Props to Rick on the fast shipping! He answered multiple PMs, and after receiving payment in the late afternoon still mailed out the same day. Thanks again!

[motomaster132003]

Nice build, love the orange links.

[Crawl in Az]

Decased two stock Mad Torque ESC's. Removed the cases, extra motor wires, and on/off switch. To mount the combo behind front axle.



Smashed ESC with a Castle BEC - 91 g
2 stock ESCs - 164 g

[nappahdog]

looked good today keep it up ; nice meeting you

[Crawl in Az]

Thanks, nice meeting you too KJ. Going to do the Hack on the GT-3B this week and get it configured. Still trying to decide how I want the controller set up.

[Erik D_lux]

There is some pretty cool stuff going on in here!

I like the idea of putting the AX hubs on the stock tubes. Man, that makes it cheap and effective.

If you ever have a problem breaking tubes where you moved the servo forward into it, try moving the motor back next time and see if you can leave the tube. God forbid you ever had to replace the expensive tubes though huh?

If you want to try and get those shocks out of the way you could reduce their overall length just a touch to do this. It looks like you have external limiters on the shock shaft so maybe you could simply screw the shock shaft as far in on the rod end as possible? This makes the shock shorter and also acts as a limiter. You could also cut down the bottom one. Maybe you have already done this....? Shortening the shock will do a lot to get it above the link and bring the height of the car down.

Originally Posted by Crawl in Az

I gained 1/2 inch in total width. The rear now sits 14" outside tire to outside tire. (Front is currently 13.5" for the math impaired ) Bad thing is, the extra with is all scrub. (1/4" per side). If I don't like the added scrub I can always change it when I upgrade the wheels. I'd be interested to hear thoughts on how the scrub will affect the rig and handling. At this point, the amount of work I put into modifying the rear axle tubes for the servo and C-hub I'd be better off doing some custom tubes.

Ever since I reduced my scrub I wont go back. Its a much better setup for me. I even built my sporty with that in mind and I am loving it. I wish I could do it with my Berg but there are other compromises.

Custom tubes could be your best bet. You could reduce the scrub with some plate style wheels but then you would probably be too narrow.

Great build so far

[cabron]

how long are those universal axles? from the universal pin to the dogbone pin
do the fit into the bully knuckles? what bearings?