Infinite Gundam

Went bashing with my emaxx today, it had barely made the first round back to me when it somersaulted, and landed nicely on all fours. Rats, something just popped up from the ground and tripped it, i thought. Pressed the throttle, it didn't respond. I walked over to my emaxx, but was surprised to see nothing sticking out around the area that could have tripped it. Pressed the throttle again, heard the motors struggling, it was trying to move but unable to, seemed like the drivetrain got stuck. I flipped it over but didn't see anything wrong, and all wheels could spin freely. So i removed the body, and realised that something has ripped through the chassis, right in front of the evx, and got stuck there! My cvd pin !!! So an r/c can also trip itself over [sm=surprised.gif]!

Infinite Gundam

Btw, anybody knows what's the use of roll-pins that are included in the mip hardware package?

E-maxx0976

Sounds very rough! I dont have center-drive CVD's, although i do have rear drive CVDS and i ALWAYS lose the pin, i think it is a bad design. I do not know the use of the roll pin, although i do know that i have purchased roll pins and literally wedged them into the CVD pin place, they dont rotate quite as freely, but they are NOT coming out, put it in though and you will not get it out, so dont take the risk if you dont want to, if there is a little of the roll pin sticking out of the cvd still i just used a bench grinder to take it down. I kept losing the pin every time i would spray lube into the coupling, so i litterally wedged it in! i had to hammer it in and gring it down, the roll pin made itself fit through. I dont know if i reccomend it, but i did it and it seems to work.... you almost will never get it out.

That is so rough though about your center drive, totally sorry! what are you going to do?
I had to go CVD's on the rear at least because thats where all the torque goes and i have snapped A TON of plastics.... either on landings or stupid people who do not know how to flip over a e-maxx and do it when the wheels are still going fast, and toss it over and then it doesnt drive in the rear[X(]

GOOD LUCK, Happy Radio'ing!


AL

Infinite Gundam

Yeah mip should have put a groove in the middle of the pin for the set screw to bite into. I saw this design fault as a potential cause of trouble when i first assembled them, but since i haven't heard of anything disastrous other than a few people losing their pins, i said forget it keep things the way they are, and it happened to me [sm=angry.gif]. So it was also my fault for not doing something about it.

Anyways, when i get the replacements, i will rebuild all my cvd pins, make grooves in the middle so the set screws can bite firmly onto them. Thanks for sharing your idea on the roll-pins.

AlexGT

Something similar happened with my revo it lost one of those C shaped clips in the drivetrain and the center shaft came loose, I replaced it and put some CA on all C clips, haven't lost one since.

Maybe some CA or silicon sealant on each end to help them stay put would help.

AlexGT

Infinite Gundam

Good idea with the sealant, i have also heard of using shrink tube to wrap around so the pin won't come out easily, these are great strengthening methods.

Infinite Gundam

I emailed pro-line regarding the roll-pins and got their reply:

Thank you for supporting Pro-Line/PROTOform products. The black pins are included for use in the axels (where the hex nut attaches).

I wouldn't use them though, seeing that they are hollow and constructed of thin metal, i doubt their strength .

E-maxx0976

I would doubt their strngth alot also! what i swrong with the stock pins, i have aluminum hex nuts and they would squish the roll pin it seems, especially once you put the lug on.... maybe they should counsider not even handing them out, or at least say what they are somewhere....


Al, Newark NY

Infinite Gundam

Precisely...

i8tweety

My Feedback: (11)

The spring steel roll pins are stronger than you give them credit for. I've never had a failure (or even bent one) during use. One really nice feature of a roll-pin is that it will not fall out and get lost in the grass when you are swapping tires at the track.

E-maxx0976

I switched to Aluminum Hexes with the set screw holding the pin in anyways! GPM makes them from my LHS... I am currently not running now waiting for my Novak Brushless motor to come from California with a new signal Harness installed on it, i ripped the other one off in a Body-Less Wreck.



Have fun at the Track

Infinite Gundam

My bad [sm=tongue.gif]. The roll-pins may not be as weak as they look, still i don't dare to use them with my jumbomaxx tires. I was thinking if i put both stock hex pin and roll-pin on the table, then treat them with a hammer, i would think the roll-pin would be squashed flat, not sure though how much relevance this test of strength has with regards to the intended use.

Infinite Gundam

I finally fixed the problem. The damages were more than the bent pin itself, the pin-hole on the cvd bone and the sliding-hole in the hub were deformed when the pin came loose and wrecked havoc, so stock 2.4mm pin cannot fit in properly anymore. I bought some 2.5mm pins, redrilled the pin-holes and the coupling, and filed down the sliding-holes, in the process clearing up the deformities, and the new pin fit nicely in.

I also rebuilt all cvd pins, filed indentations on them for the set screws to bite onto. This can be done easily using a round bar file, go easy on the initial strokes, making sure the file stays in the middle by good eye-ball-ing, and apply more forceful strokes when the dents are deep enough, stop when 1/5th of the diameter has been filed off. The pin must be securely held with pliers so it doesn't turn with the file strokes. Each pin took only 2-3 minutes to file.

I have run my emaxx with the newly fixed pins and they worked flawlessly, no more worries for cvd pins coming loose! Hope this helps people with similar problems.

E-maxx0976

Not a bad ideeer, I am looking into different CVD's As i write, I am not a huge fan of the MIP ones anymore, i have seen some with total different couplings that i like better, but hey glad you made it work! We hit up our local go-Kart Track that has been abandoned today, WOW! it was prettty fun with road tires and a lowered truck, Only damage done was a hard hit to the wall breaking the front bumper mounts on the Bulkhead, and a twisted plastic shaft, as i only have CVD's on the back, i broke a front. All fixed and ready to go break again, i also did a pretty well sacrafice to the body with some road burn. All in All, a worth it trip!


Have fun E-Maxxin'

Al

cchrider

That sucks. BTW. I am new to monster truck nitro RC so can someone explain to me what exactly a CVD is or what it does?
Thanks
chase

chaoticlife

My Feedback: (1)

Thats why I check the set screw(s) before and after I run, and always use threadlock.

E-maxx0976

A CVD, for a Nitro and Electric is a Constant Velocity Drive, Simply put, A Metal Drive Shaft with a coupling instead of Plastic Half-Shafts with a Universal Joint... Also Less Maintenance and Much Higher Strength, I have broken a Number of plastic ones with my Brushless Motored E-Maxx and CVD's, Steel or Titanium are much heavier Duty.



AL

ThunderbirdJunkie

My Feedback: (3)

I'm with tweedy on the roll pin..I've used nothing but and never had a problem. Also, i've never lost a CVD pin, have you guys been threadlocking your setscrews?

Infinite Gundam

I inspected everything carefully after the incident, the set screw remained incredibly tight in there, somehow the pin just managed to bolt its way out! Definitely i had threadlock on all the set scews, and i was pretty sure i screwed them in with all my might, less breaking the driver of course . I think weak friction between the pin and set screw was the cause of the pin coming loose even when the set screw was locked down. I am not taking any chances anymore.