I have a Razor Dirt Quad that needs more "Oomph". I tried installing a YK43B speed controller and going to 36v but that just destroyed the stock 350w motor (2 of them actually). The stock gear reduction motor had good torque and speed with that setup but it only lasted about 5 minutes before dropping speed/power with a burning smell! So, I am considering installing the 750w (non gear reduced) motor available at TNC OR the 36v 600w gear reduced motor. Given the YK43B I already own, what would you recommend on the dirt quad. It's not really a matter of fit as I will custom fab whatever brackets I need. It's really a matter of what's going to give me the best performance. We need more torque for our yard which has some moderate inclines and a little more speed than the 24v 350w stocker can provide. Another option would be to start over with the 1000w 36v "kit" available at TNC (matched speed controller and throttle). I've already spent way too much on batteries, chargers, burned up motors, speed controllers, etc. so I'd like to hear from someone who can recommend a good 36v setup that will perform well and last a long time!
Thanks in advance for the help.
I ran some gear ratio calculations for a 2800 and 3000 RPM motor with 11 tooth sprocket running with an 80 tooth rear sprocket, such as our item # SPR-2580, and found that it would have a top speed of 15-16 MPH. This is a good gear ratio and top speed for a 750-1000 Watt motor to have and would be a good choice in my opinion. Our 80 tooth rear sprocket is for #25 chain, and our 36V 750W motor has a #25 sprocket on it, however our 36V 1000W motor has an 8mm sprocket on it which can be replaced with a #25 sprocket (item # SPR-2511C) to make it compatible with the 80 tooth rear sprocket.
The 750 Watt motor has over twice the power of the original 350 Watt motor and would definitely give it more "Oomph".
Here are my gear ratio calculations for both the 36 Volt 750 Watt and 1000 Watt motors:
Please let me know if you have any questions.
First....you are awesome. That's exactly what I needed to know. Could I go with the 9 tooth front sprocket and a smaller rear sprocket (I think I saw a 72 tooth or something like that) which would keep around the same gear ratio but have a smaller diameter on the axle sprocket. I ask because that big rear sprocket reduces the ground clearage on the Razor dirt quad quite a bit. It's probably not a big issue in my yard but if it's all the same, more ground clearance is better. I measured the diameter of the tires at 12.25 for whatever that's worth.
I ran a gear ratio calculation for the Dirt Quad using our 36 Volt 750 Watt motor and an 80 tooth axle sprocket. Here are the results.
The top speed is 14.37 MPH with this setup which is fairly high gearing for a 750 Watt motor to be a hill climber. It would go pretty fast on flat ground, and be able to climb hills but lug slowly up the steeper ones and not be able to climb the steepest hills at all. Using a 1000 Watt motor would provide 25% more power than a 750 Watt motor though so that might be something to consider.
To make a steep hill climber with a lower top speed but that would climb anything with ease, a gear motor such as our MOT-36600G would be needed. I ran some calculations with this motor and a 34 tooth axle sprocket.
I would have hoped for a top speed of around 7 or 8 MPH however with the only sprocket we have that works with this motor and fits the Dirt Quad axle the top speed winds up being 5.27 MPH. At this speed it will have a tremendous amount of torque though and could climb the steepest hills with ease.
If you are looking for a low speed high torque setup like this but want a slightly faster top speed then there are online sprocket makers who custom make sprockets and could make practically any size axle sprocket that you need for any top speed that you want. Rebel Gears is one of these sprocket makers that our customers have had great luck with.
That is pretty much it. I would expect as with all custom projects that there might be something needed which is missing from this list, but these are definitely all of the major parts that will be needed for the job.
I notice that the red and black wires in the Dirt Quad's charger port connector will need to be reversed to match the wire colors of the controller.
It will be easier to get a little more chain than is needed and cut the chain to the required size after the motor and axle sprocket are installed than to try to figure out what size chain is needed before installing these parts.
I could make a kit out of these parts with matching and labeled connectors so everything would plug together right out of the box. I would just need to know what size batteries, sprocket, and chain you want to use.
Please let us know if you have any questions.
i have dirt quad v#3- and would like to know if these 48v 1800w kits would work