Mongoose CX24v450

I have no idea what rock I have been living under, but never knew the Mongoose CX24v450 existed until last week, when one in pretty good shape popped up on CL for $50. From the pics I knew the front fork was bent pretty badly, and assumed the batteries were shot, but still worth it to me since it looked REALLY cool.

Here is the pic from the CL ad:


My son is only 5 right now, so it will be a couple years before he will be throwing a leg over this one. He does ride his Razor MX350 quite a bit at the park across the street from our house. I had been using a Mongoose M350 scooter as my chase vehicle, which I just sold to replace with this bike.

My LBS had a set of moderately used RST Gila T4 forks that they let me have for $10. While I prefer the look of the triple tree forks, even a "cheap" set of downhill forks with suspension was more than I wanted to pay at this point, so there ya go...



Trued up the front and rear wheel, adjusted the brakes and chain tensions, and waited for my new 12v 12ah batteries to arrive from Chrome Battery (through Amazon).

The batteries arrived yesterday and I am quite pleased with the performance of this bike. I am 195 lbs and it carries me better than I had anticipated. I even rode around the backyard with my son on the back, and he adds another 62 lbs (he is a pretty big almost-6-year-old). This thing would scoot pretty well with someone age/weight appropriate on it, lol.

The biggest issue currently is the crank arm on the chainring side is bent. Since it saw virtually no use by the previous owner, I think someone backed into it with a car in the garage, which would explain the bent forks and the crank bent into the lower swingarm. I was able to use some heat and puuuuuulling to bend the crank arm out enough to clear the swingarm so it is rideable, but I need to actually take it off the bike and to the neighbor's with a bigger vise to bend it the rest of the way.

You can see the swingarm dent here, I think structurally it is still ok:


It really is a very neat ride. I would like to say that I am going to fight the urge to modify it, but I have little doubt that once I make a little more progress on my China Girl, that this one will be next.

Uh oh... getting the itch to modify this bike... LOL

It has been running great, added bolt on passenger pegs to the rear so my son can ride around with me to the community pool and such. With me at 195 lbs and him at 62, it is definitely taxing on the poor bike, but she still pulls us up the slight hills around here. It is definitely crowded in the saddle when he is with me and I cannot pedal, but still fun.

BUT, my neighbor just gave me his old weed eater that died. Probably just a gummed up carb, but we will see. I am thinking about adding it to the front wheel as friction drive, to help with the top end. It would be a snap to attach the weed eater motor rigid to the fork brace, but I would really want a gravity clutch, so that would take some doing. I would probably use a lever to lift the motor off the wheel, and some sort of adjustable hook to lock the lever in place?

And for the throttle, just use a shorty bicycle brake lever mounted backwards and keep the twist throttle for the electric motor.

LOL, those are 20" wheels. It is probably meant for someone around 12 - 16, our neighbor has a 12 year old and it fits perfectly and the power if plenty for him. I fit on it and can pedal just fine since it is taller than a BMX bike, but definitely not made for an adult.

Now there is someone who has theirs online that modified it to fit an adult and it turned out really well Denise Eckert's 2006 Mongoose CX 450

So with my 195lb carcass on it I slightly outpace my son on his Razor MX350, so it does maybe 14 MPH? It really is fun to ride. There is a good chance that by the time my son can ride it I will have taken it to 36 or 48 volts, put on a higher wattage motor and controller, and gone lipo.

goldengales said:

I bought this exact bike over a year ago from a store that was going out of business. They had it in their storage area in the back. They had 2 of them. I bought it around $175 which I thought was a great price for an electric bicycle. I bought it specifically for a teenager, but my girlfriend & I split up. I hadn't given it to her kid yet. Anyway, now I have it. The charger is still sealed up in the new packaging. I put it up for sale on Craigslist for $125 just to get rid of it. It was taking up too much garage space, besides it's an eye sore since we are no longer together. Do you think I am asking too high, too low, or a good price for it? It is in perfect, new condition. Also, I'd like to hear how you have souped it up. I would like to share this with others who might be interested to buy it.

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If the batteries have not been charged, and I think these were just made in 2009, they are toast. SLAs do not like to sit discharged, and if they even take a charge now they will not hold it very long. The bike takes 2 12V 12AH batteries, which you can get shipped for about $55 from Chrome battery through Amazon.

FWIW, I think $175 was a great deal for this bike new, as is $125 if is just needs new batteries. The bad news is that this bike is less of a dedicated adult eBike and more of a toy for a teen. An adult can ride it just fine as long as you stand when pedaling, I am 5' 11" and 195 lbs and ride ours all over the neighborhood, but the range with me on it is about 6 miles on mostly battery power.

So I think that price is a fine deal, but the audience is pretty limited. It can be modifed pretty easily to go faster/farther, but that is an even more limited audience.

Ours just has a new front fork since the stock forks were bent badly when we got it, and I added new batteries and put on passenger pegs so my son can ride with me when he does not feel like riding his own electric motorcycle.

If I were to make any modifications at this time, it would be going to 36V for a little more top speed. The stock controller can usually handle a 12V bump over what it is intended for, but will carry more heat and go poof sooner. When the stock controller dies, new 36V controllers are cheap. If I was serious about making it a "real" eBike, I would go with a higher wattage motor, 48V controller, and 48V LiPo batteries. But since it is intended to go to my son in a few years, it is going to stay SLA until he wants to mod it himself

Good luck with your sale. It is a very cool bike. As beefy as the frame is, I wonder how well a Morini would stuff in there? Put a real downhill triple tree front fork and upgrade the rear and you have the makings of a poor-man's Boxer!

Crap, I wish you had not put that idea in my head... LOL

Okay, so since my HT exploded and I sold off my 2 stroke parts to fund my son's go-kart restoration, I have been puttering about the neighborhood on the Mongoose. It really is a neat bike, and since I put on the rear pegs actually carries me and my 65 lb. 6 year old son around pretty well, surprisingly.

But I am so tempted to up the voltage. I would love to get 20 - 25 MPH out of the bike, with just me on board.

It comes with the Currie 24V 450W geared motor. I would really like to keep the stock motor and drivetrain if I can help it and just put in a 36V 10AH or 15AH LiFePO4 battery pack and maybe a higher amp 36V controller?

Is that doable with the stock motor? And should I try and go with the stock 24V controller first, or just assume it will smoke over time? I would definitely like to avoid smoking the motor in short order, if possible...

I do still have a free weed eater motor that I was contemplating putting on the front wheel as a friction drive to get more top end, use the electric motor to get going and the gas at higher speed, but would definitely prefer the simplicity of an all electric solution.

Edit:
After thinking about it more, I think to hit over 20 MPH I would probably need to go to 48V, which would mean switching out the motor too... They make a 36V 450W version of the same motor so the mount would be the same, so I would just go with a 48V battery pack and controller, but wondering if the low wattage would be holding me back?

I have been hanging around on Endless Sphere recently, and think that I would rather just go 36V with the Mongoose and keep the pedals and stock motor. I originally bought it for my son to grow into, which he should be big enough for in about 3 years. I am eyeballing the 36v 15AH LiFePO4 Ping battery. That should make for a fun 18 - 20MPH runabout.

And for me, I am planning on building a hub motor electric bike, probably based on my current pedal bike, a 1993 KHS Montana Summit. It looks like a 48V 1000W yescomusa rear hub kit and 14s LiPo should get me just north of 30 MPH on my short errand running route. And that leaves me room to add new batteries if I need more AH or change out the controller and add batteries for more speed later on down the road.

This will be a post-Christmas project, so will start a build thread when I get rolling.

Quick update, moving forward with the process to eventually release the magic smoke from the little 24V 450W stock motor

I ordered 9s 15AH worth of lipo from Hobbyking (3 x 4s 5AH bricks and 3 x 5s 5AH bricks). Since the US warehouse was out of stock of the 4s lipos, I ordered everything from the international warehouse. It just shipped, so I figure maybe another 2 weeks?

I was torn on getting lipos since the additional risk involved, and if my kiddo eventually inherits the bike I will put something more forgiving in. I already picked up a Hyperion 1420i and 500W Mean Well power supply. I will probably pick up a parallel charging board from EP Buddy soon.

We will see how the stock controller handles the extra power! Some people say they work fine, others say they do not operate at 36V at all. If not, I can always order a 36V controller.

BUT... if that goes well I am considering switching the stock 20T sprocket to a 16T. That should put me in the lower - mid 20's, which is about where I want this bike.

I will update this thread as the bits come in

16v4nrbrgr said:

I highly encourage you to try a Razor MX500/650 throttle and controller, it will be trouble free.

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I figured I might as well try the existing controller first. Are you suggesting an "official" Razor controller, vs. a generic? I figured I would just get a 36V 30A controller and throttle from tnc scooters.

BTW, my batteries arrived yesterday, much quicker shipping than I had expected!



I am running them through 5 charge/discharge cycles each on my Hyperion charger, so far they are all looking pretty healthy. Still waiting on my custom wiring harness and 16T rear freewheel to show up, but will at least try to go for a little test run with a single 9s pack this weekend to see if the stock controller even operates at 36V...

16v4nrbrgr said:

Yeah get an official one if you go that route, the generic one is garbage, the official one will be durable even at 48v.

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Prices look pretty comparable too, do you have any idea of how many amps those stock Razor controllers put out? I cannot seem to find any solid info on it. Hopefully comparable or better than the stock Currie controller on the Mongoose, I would hate to lose torque.

Quick update, got the charge/discharge test cycles done on the batteries and all tested good!

Put together a test 9s 5AH pack (~36V), temporarily mounted and went for a test ride. WOW, the difference in feel is amazing. My old SLAs would voltage sag pretty badly when going up the slight hills aorund here, but not the lipos. I was cruising at 22 MPH on flat ground and 21 MPH up slight hills.

And the stock controller is holding up well so far, but only rode about a mile.

I should have the rest of the parts I am waiting for in this week, and am working on a nice way to mount the batteries. I want to make the battery box easily removable for charging off the bike and in case fire breaks out on a ride!