This forum is in read-only mode. Please continue to browse, but replies are disabled for now. Why?

Razor dirt quad 24v needs more speed!

Hello I have a boy and a girl. The boy rides the razor MX300 Dirtbike and the girl rides the dirt quad. I ride my Bicycle with them on paved trails and the dirt quad is too slow. Is there a rear sprocket I could change out to get us more TopSpeed from the dirt quad. We don't need the extra torque to go off-road. I wouldn't mind getting a couple miles an hour out of the dirt bike either but the dirt quad needs the biggest boost in speed. What do I need to do to get the dirt quad over 15 miles an hour for the cheapest way possible? Veraval speed on the dirt quad would be great so the chances of flipping over while turning would be less likely
The Razor Dirt Quad has a 25 tooth motor sprocket, a 47 tooth rear axle sprocket, and 8mm chain. To increase the gear ratio for a faster top speed a smaller rear sprocket could be installed. We have 44 tooth, 38 tooth, and 36 tooth rear axle sprockets that fit the Dirt Quad.

Here are the gear ratios and top speeds with the stock 47 tooth sprocket, and also with a 44, 38, and 36 tooth sprocket.


The most that the speed could be increased using 8mm chain sprockets is by 3 MPH for a top speed of 13 MPH.

The MX350 has a top speed of 14 MPH so it would still be 1 MPH slower than it but it will be a lot closer to being the same speed than when it ran at 10 MPH.

The 25 tooth sprocket for 8mm chain on the Dirt Quad's motor is the only size 8mm chain sprocket that is available for that motor.

We do have sprockets for 1/2" x 1/8" bicycle chain that fit the Dirt Quad's motor however I ran a gear ratio calculation with the largest motor sprocket and smallest axle sprocket available for this chain size and only got a top speed of 10 MPH.


The Dirt Quad's stock chain has 74 links. If a 36 tooth sprocket is installed then a 68 link chain will be needed.

Here are chain size calculations for the original 47 tooth sprocket and a 36 tooth sprocket.


We sell the item # SPR-836F 36 tooth sprocket for 8mm chain on this page:

We sell item # CHN-800 8mm chain sold by the link and item # CHN-8ML 8mm chain master links on this page:

Please let us know if you have any questions.

So if I order the 36 tooth rear sprocket I need a 67 link chain plus the master link to make a total length of 68 links? Do you guys offer a variable speed controller?
The master link is not included in the chain size calculation because it is not considered to be part of the chain, so a 68 link chain plus a master link should be ordered.

All Razor Dirt Quad controllers are variable speed. Both the version 1-10 and 11+ controllers that we sell for the Dirt Quad are variable speed and they both have a 30 Amp maximum current output rating which is suitable for motor up to 500 Watts.
We do not have a 36 Volt overvolt kit for the Dirt Quad yet, however we do have 36 Volt plug-and-play controllers available for the Dirt Quad which are item # SPD-CT312C1 for version 1-10, and item # SPD-CT312C1-6 for version 11+. These controllers work with the original throttles and plug directly into all of the Dirt Quad's existing wire connectors. With these controllers the only other major parts that would be needed are a 36 Volt battery charger such as out item # CHR-36V1.6A3P, and a set of three 12 Volt 8Ah or 12 Volt 9Ah batteries.

The existing battery pack wiring harness could be reused on the new batteries by cutting the wires off of the old batteries and installing 1/4" tab terminal crimp connectors onto the ends of its wires. The third battery could be wired in between the two batteries in the battery box with long jumper wires to reach it since it will be outside of the battery box. Here is a drawing showing how to wire the battery pack this way.


The blue and green wires in the drawing are only those colors to make them easy to see. These blue and green wires could be a different color such as black so they would blend in better with the ATV and not be so visible.

We could make the wiring harness in this drawing and include it with a kit made from the parts mentioned above if you are interested in buying a Razor Dirt Quad overvolt kit like that?
The chain and sprocket worked out perfectly. I got a 67 link plus the master and was able to remove the loud chain tensioner. I would guess at least 30% fast top end It worked out great thanks.
(621 KB)
(2.35 MB)
I'll try to post another video but just know it was worth it
Great to hear that the smaller sprocket and chain solved the slow speed problem. Thanks for letting us know that it worked and also thanks for attaching the photos and video.
17.2 MPH It's now a 36 razor. New battery and controller
36 overvolted

Awesome, the Dirt Quad looks plenty fast now. That's a nice park that you have to ride it in. Thanks for sharing the videos.

Login or Signup to post a comment