Making the tank run straight?

[Jib]

Apologies if this has already been answered elsewhere, I searched the forums here and didn’t see much.

I’ve always had issues where the tank (Taigen, Torro) either ran straight already, or was easily fixed to run straight using the remote that comes with the tank, and then when I upgraded the card to the Elmod FusionX, it always leans to one side or the other.

Radio trim on my aftermarket radios do almost nothing to fix this. I started out with a Flysky i6x, now I have a Radiomaster TX16s. Is there any other workaround for this? Motors I’m using range from stock 380s up to 540s.

[Jimster]

Unequal track tension maybe? Try recalibrating the joystick. Just some off the cuff thoughts and I hate troubleshooting annoying stuff like that. Good luck.

[Jib]

It just sucks that you buy this near $300 card that’s great in all other aspects, and on every one of my tanks I’ve put it on the tanks goes from running straight to somewhat off center.

[tankme]

I would have a hard time accepting that it's the card. The ESC (electronic speed control) portion of the car just delivers current to the motor depending on the stick position. It is affected by the trim settings...slightly on a tank. I would go through the entire drive train to make sure there were no track pins catching, that the wheels/idlers/sprockets were all properly lined up, and that no suspension arms were working their way loose. I have had a gearbox that was intermittently spinning the final drive gear connected to the output shaft under load. That was causing the tank to pull to one side. The final gear is press fit on some gearboxes. It is tight enough when stripped to move the gearbox with the tracks off the ground, but under load slips.

There are several ways to troubleshoot the issue.

First, remove the upper and hand rotate the tracks to see if they are catching anywhere and observe the gearbox teeth to ensure none of the gears are missing any teeth. Second with the upper still removed, put the tank on the carpet or some surface with resistance to it. Hold onto the chassis while giving it full throttle forward. If one track moves pretty freely and the other stops and stutters, you know it's a problem with the gearbox that is stuttering. That problem could be a bad motor or the press fitted gear has come loose. Third, with the upper still removed, turn it over and run the tracks at full speed. Observe the tracks. Are the flapping wildly? Or seem to be moving in and out? Are the sprocket screws tight? When you spin the sprockets by hand is there a lot of play in them before the gears turn? Fourth, swap in your old electronics to see if the issue is still there. I know that may be a royal pain, but it may be a coincidence that this issue started around the time you swapped boards. Fifth, remove the drive sprocket and make sure the shaft of the gearbox isn't stripped or the inside of the sprocket isn't stripped/broken.

That's about all I can recommend without seeing the issue first hand.

Good luck!

[Jib]

Thanks for the suggestions. I will look it over and give these a shot. I think that the track might be running in the inside of the side skirt on one side near the idler wheel. Any idea how to get it to give the track a little more clearance? Using a heat gun to bend it away from the track a little or is there a better way?

I just replaced the gearboxes and the motors and it’s doing the same thing it was doing before I replaced them, so I don’t think it’s that. But, I will check and see just in case.

[Rad_Schuhart]

Well, maybe that is just me, but I found not a single one of my tanks runs perfectly straight. Either they lean to one side when driving slow, or they do it when doing it fast. And if I manage to correct it, it eventually keeps leaning to any side. There is a lot of things involved there, wear, tear, dirt, dust, human hair and so, so many things, that I ended living with it.

Said that, I found while installing elmod boards I experienced the same issues. I happened to have 3 on my hands, and tested on the same tank, the same day, over the same surface, and the tank leaned to different ways with different intensities, so in that case, I think there was something board related.

I corrected it with the radio, using the trim. You can adjust A LOT with the trim, you can enable extended limits in your radiomaster, and even program some curves and adjust so many different things, that it should be running straight at the end of the day.

[Jib]

Yeah, I didn’t think about doing something with curves. These are all good suggestions, I’ll try to give them a shot when I get some time.

It would be nice if there was something in the software that let you regular how much power went to each motor individually. Seems like it would be easy for them to implement, but I’m not educated on the subject at all so, maybe not.