My ebike frame cracked? Help!

Oh, so you did crash it. I suspected something other than normal use had been done.

I just suggested a bmx because of your wheel size. Maybe just stop crashing, and a decent quality folder will still work for you.

I don't suggest re lacing into 26" rim, because you will very likely then have the wrong speed motor for 26" rim to work well. We can figure out if your motor is too fast for 26" or not, by measuring the speed it runs with the wheel off the ground, or perhaps just by the speed you had before the crash.

A new motor intended for use in 26" rim will work, if you upsize to 26" bikes.
 
The other thing that having my bike stolen did was make me unwilling to buy used bikes. It's way too easy to sell a stolen bike. We could end bicycle theft if we stopped buying bikes with undocumented origins.
 
No I never crashed it until the frame cracked. Other than that I didn't ride it very fast until that day, so I think it was just too much power for the bike.
 
Looks like it broke right where it was designed to break. Problem is it was good for most 100-125 pound riders to last 500-1000 miles. I bet you are well above that. Get a good name brand a few years old that is a bit heavier and more over built. One with a Full Triangle frame. Steel is best, but well designed aluminum will last a bit. $200 -300 buys a good bike if your patient.
 
IMHO, a motorized folder should not exceed 20mph. Your asking for trouble down the line. In my case, the handlebar stem snapped leading to a classic endo crash.

Your search for a new frame is on. I think it's a great time to learn what's your next best step. Figure out what type of riding you want to do, then find a suitable frame. From there, I think everything else falls into place (hopefully). After reading post after post of suggestions from members here, I now have that keen eye when I walk into a plethora of bikes (be it walmart or a LBS or craigslist) and can assess whether it's a suitable candidate for electrification.
 
Kagamoosha said:
Would any of these work for an adult?

http://www.academy.com/shop/browse/recreation-leisure-bikes-bmx-biking/_/N-855499797
Click to expand...
Change your parameters IMHO. From "20inch BMX" to "24inch BMX" and your frames and wheels start to look doable. Your almost telling the search engine to stop looking at "kids BMX" with crappy welded frames to "adult/pro BMX" with beefed frames made for drops. What I've seen at the LBS with 24" BMX bikes, the drop outs are outstanding for easy motor placement. I've always thought about gluing a set of Doc's torque plates onto one for my own adult electric BMX build, but I like suspension and the longer wheelbase.
 
I think I'm going to get the Mongoose Beast and try my 20in wheels with that frame, or maybe I'll use the wheels that come with it, but it was a comfortable ride at Academy!
 
Hopefully a stronger frame there now. Is it steel? I've been tempted to fat tire my longtail, just to make it look cooler.

You'll learn real fast to keep the correct pedal up in the corners. If you bend that crank, it was going to need replacing nearly immediately anyway. Tin foil steel gears on it I bet. The mongoose is no surly. I was just looking the other day at a fat tire huffy at WM, in a beach cruiser frame. Looked cool for sure, perfect if riding on a beach is legal.

I wouldn't spend a ton of money re lacing that 20" motor. It's real likely to perform like a turd if you put it in a 26" rim. Figure out what you will do with that bike, and select the right winding for that use when you buy a new motor. If you will ride in deep sand real slow, then you need a slow winding. Or put a cromotor on it, and ride through deep sand at 40 mph.

For now though, if it rides ride it. It's hilarious looking, but that heavy front tire should tame the wheelies some. It will handle weird, with the rake changed that much.
 
:lol: Didn't take you long to get the bike and set it up...

I'm willing to bet that mongoose's bottom bracket is a 68mm. If so, that would be a great start off point for the recent mid drive options from GNG & 8Fun. Then you can keep that original rear tire. :idea:
 
Definitely another good option to consider, especially if you will be riding a beach now and need that low gear.
 
Bike.JPG

This is what it currently looks like!

I haven't decided what to do yet, but I might keep it like this if I can't figure out a way to mount the motor on the new wheel.
 
What's your current motor rpm on 36v? If it's above 330 rpm, it will suck in a 26" wheel.
 
How do you STOP?
 
Oh my, I didn't notice that in the small picture. That thing has a rear coaster brake, and now it's gone. :lol: Looks like a gearmotor too, so forget regen brakes.
 
I'm going to put a different 26 or 29 in wheel in front instead of the fat tires. They weigh too much and it is hard to turn without my feet hitting the wheel. Overall this bike frame is a cool choice for a lowrider style bike! :mrgreen:
 
Remember that thing about eBike weight/speed? All the more reason to rarely, if ever to use a platform lacking provisions for seriously adequate brakes.

Single coaster brake can be a NIGHTMARE if/when chain derails or breaks. I love 'em power slides but will never ride a coaster brake bike fast lacking a serious front brake. Unfortunately, those design elements aren't commonly found on single brake beach cruisers.

Kitting an eBike, brakes are among the 1st things to consider since they will be much more important and stressed than ever considered/designed.

Now some folks will probably advise using clamp-on brake mounts and/or welding, etc. Much easier to just choose more wisely in the first place, IMO.
 
I plan on using the e-brakes that came with my last bike, and getting a 26 in wheel for the front and attach brakes to it eventually. Maybe even invest in a different fork for the front.
 
Kagamoosha said:
I plan on using the e-brakes that came with my last bike, and getting a 26 in wheel for the front and attach brakes to it eventually. Maybe even invest in a different fork for the front.
Click to expand...

Please let us know how that works out???
 
If you go to a skinny tire in front, then it will be easy to put a fork on it with the mount for front disk or v brakes.

If the frame is steel, buy a disk brake mount and have it welded on.
 
retro fit mount
sunp0039.jpg
 
What size axle do I have in the front? I took it off the Mongoose wheel to make my 20 inch fit on the fork; just to test it out but I want to purchase a new one so I can keep the Mongoose wheels as they are and sell them on Craigslist. Anyone have knowledge of how big a 4 inch wide axle would be? I'm looking into a 26 inch wheel in the front so I can at least pedal the bike.
 
it is time for a new frame because who knows when or where else the frame could fail and could happen high speed on the road.

and it looks like it broke completely off not a crack
 
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