Leslie Posted February 1 Share Posted February 1 Hi there I've not long been given a HiSpeed 1/10 monster truck with brushless motor, and the problem is I hold the buggy off the ground and accelerate the wheels go round no problem. But when I put it on the ground it just judders and doesn't move, I have checked most things drive cups etc all tight any ideas ,???? Motor maybe Quote Link to comment Share on other sites More sharing options...
Fred barlow Posted February 1 Share Posted February 1 What's happening is called cogging, I'd check the motor connections but if you give it a push it'll start going it's due to the gearing been to high ratio (pinion too big) or because there's too much resistance in the drive system, remove the motor and if everything moves free I'd check the motor, if it's running ok I'd check the pinion tooth count and get another one with fewer teeth (but make sure it's the right one for the spur) 1 Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 1 Author Share Posted February 1 I have just changed the pinion and spur as I thought it was that, but still the same. The pinion and spur was changed like for like 17T / 64T Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted February 1 Share Posted February 1 Cogging can also stem from an inadequate battery. The motor wants to run, but the battery can;t supply the amps. Revving the motor with the wheels off the ground is under no real load, so it goes fine. Things are breaking down under load....so if it;s not the gearing putting too much load on, it could be the battery. What motor/ESC combo do you have in the truck and what battery type and rating are you using? A 1/10 scale could easily be running a brushless setup able to pull 60 or so amps. Run it on a 3000Mah 7.2V NiMh pack, and it won't be happy 1 1 Quote Link to comment Share on other sites More sharing options...
Fred barlow Posted February 1 Share Posted February 1 It's sounding like a motor kv too high so it's not got the torque to move the car, as nitroholic suggested lack of power from the battery or a bad esc, if you've got known good motor and esc I'd swap and work from there 1 Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 2 Author Share Posted February 2 The motor is a king Kong 3650 brushless 4500kv plus a 60A esc, and the battery is a lipo 7.4v 5200Ah 50c Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 2 Author Share Posted February 2 13 hours ago, Fred barlow said: It's sounding like a motor kv too high so it's not got the torque to move the car, as nitroholic suggested lack of power from the battery or a bad esc, if you've got known good motor and esc I'd swap and work from there Hi today I took the drive shaft off and tried the buggy and everything working OK except no front wheel drive and no juddering, as soon as soon as I put the drive shaft back in it goes back to wheels locked and the buggy juddering. I have checked the front and rear diff they are turning as they should. So do you think I it still maybe the motor I do have a motor to go in just got to find a battery different connector Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted February 2 Share Posted February 2 That motor is higher KV than I would go on a 4WD off roader. I would say it is almost certainly the motor not being right for the buggy. Taking out the drive to the front wheels would reduce the torque load, and as soon as you did that...your car was happier and the cogging stopped. I would try another motor. I would go for a 3600Kv or lower motor. That would have more torque. 1 Quote Link to comment Share on other sites More sharing options...
Fred barlow Posted February 2 Share Posted February 2 The kv is a bit high but not too crazy Stupid question time, are both wheels running the same direction when you have it off the ground? Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 3 Author Share Posted February 3 13 hours ago, Fred barlow said: The kv is a bit high but not too crazy Stupid question time, are both wheels running the same direction when you have it off the ground? Hi not a daft question, I have just checked this and the back wheels are going forward and the front wheels are going in reverse, so when I got this it must have had something done to the rear diff I'm guessing now. I have asked guy who I got it off, was anything done to the rear diff, he said he isn't sure as someone looked at it for him. So how do I go about sorting this Thanx for the not so stupid question Quote Link to comment Share on other sites More sharing options...
wolfie1 Posted February 3 Share Posted February 3 1 of the diffs has been put in upsidedown, take 1 out and turn it round, to tell which 1 it is lift the wheels of the ground go forward on the control and see which 1 is going in reverse and then turn that diff around in its casing 1 Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 3 Author Share Posted February 3 5 minutes ago, wolfie1 said: 1 of the diffs has been put in upsidedown, take 1 out and turn it round, to tell which 1 it is lift the wheels of the ground go forward on the control and see which 1 is going in reverse and then turn that diff around in its casing Thanx for the swift reply I will check this shortly it doesn't look like the rear or front is upside down maybe something in side.???? Quote Link to comment Share on other sites More sharing options...
Fred barlow Posted February 3 Share Posted February 3 1 hour ago, Leslie said: Thanx for the swift reply I will check this shortly it doesn't look like the rear or front is upside down maybe something in side.???? It's a easy mistake someone's made if the part of the diff the teeth point to is put in using the wrong side of the gear in the case it'll rotate the wrong direction, when you've found which axles run the wrong way all you need to do is flip the differential 180° and you'll be good to go 1 Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 3 Author Share Posted February 3 Hi there well the buggy is working as it should now, it was the rear diff put in the wrong way, I would not have sorted without all the replies Thank you 1 Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 3 Author Share Posted February 3 23 hours ago, Nitroholic said: That motor is higher KV than I would go on a 4WD off roader. I would say it is almost certainly the motor not being right for the buggy. Taking out the drive to the front wheels would reduce the torque load, and as soon as you did that...your car was happier and the cogging stopped. I would try another motor. I would go for a 3600Kv or lower motor. That would have more torque. Hi if I get another motor with a lower kv, would the 60a esc i have already be OK for it Quote Link to comment Share on other sites More sharing options...
wolfie1 Posted February 3 Share Posted February 3 Try it now that both wheels are going in the same direction and see if its still doing the same Quote Link to comment Share on other sites More sharing options...
Leslie Posted February 4 Author Share Posted February 4 11 hours ago, wolfie1 said: Try it now that both wheels are going in the same direction and see if its still doing the same It's OK now and everything is work as it should Thanx Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted February 4 Share Posted February 4 Good to hear you are sorted. If you did decide to go for a lower KV motor, there is no need to change ESC unless the motor you chose was likely to pull more than 60A. Most motors in the size you need would be fine, but it;s always goot to check before you buy. Should be in the description/specs. 1 Quote Link to comment Share on other sites More sharing options...
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