How cheap are those kit 3 piece wide cranks made?

[bikejock]

I noticed a few days ago when working on my build these 3 piece wide pedal cranks seem to be made dirt cheap as in cheap quality. Honestly, I think they could make a better 3 piece crank with the money they are making on these 4 stroke kits. I ordered a few upgrades to improve my 3 piece wide crank so it doesn't feel like I'm pedaling a cheap bike. Everything from the arms, to the bearing cups, axle & sprocket feels very sub par in quality. The arms scratch very easily, the chain ring sprocket feels very flimsy and so does the bearing cup hardware. The only thing I see probably being decent quality is the included bearings. A bottom bracket & crank set should be made of reliable, better quality material otherwise it probably wont last long.

 

[butterbean]

I'm building my own bottom bracket using a moped pedal crank and sealed bearings instead of a bearing cartridge. Once I get all the hardware together, I'll post links.

 

[bikejock]

I'm building my own bottom bracket using a moped pedal crank and sealed bearings instead of a bearing cartridge. Once I get all the hardware together, I'll post links.

Moped pedal crank parts... That's a good idea. I was thinking of finding a pair of moped pedal crank arms that would be better than the kit stuff. I found an axle that allows me to use the original chain ring & bearings and looks like its better quality than the kit pedal axle. Know of a source for quality crank arms & stuff like that? I wanna use crank arms with the same threading as the kit arms because they fit the pedals I wanna use.

 

[butterbean]

I don't know much about what different parts fit together, but I buy all my moped parts from www.treatland.tv I got a rear hub from them and laced it into a 24" bicycle rim.

 

[butterbean]

I don't think a bearing cartridge will work with a moped crank though, the moped cranks diameter is 16mm, and the smallest bicycle crank is 17mm, unless you can find a vintage bearing set, they may have been 16mm at one time but they aren't anymore, it would probably take a lot of searching around to find one that size. Thats why I went with sealed bearings instead, they will last longer than a beating cartridge anyway.

 

[bikejock]

Guess I'm stuck with the kit crank arms until I find better ones that fit. I'm getting an upgraded crank axle from phantombikes so I can use my chain ring that came on the bike & the original bearings & cups. The chain ring from my bike feels much more durable than the kit chain ring. It will need to be durable on my 4 stroke bike because it's HEAVY. I think most 4 stroke motorized bikes come out to around 40 lbs. But my 4 stroke build feels more like 60 or 70 lbs with the motor & other hardware installed. Pedaling on that much weight would be hard on the rear wheel (I assume)

 

[butterbean]

Most cruiser frames weigh at least 40 lbs alone. With a kit, probably closer to 60-65. My last non-kit 4 stroke bike weighed at least 80. The one I'm building now will probably weigh about the same.

 

[bikejock]

Guess I was off on the weight of my current build. My bike is actualy fairly heavy even without the kit. My old 2 stroke was no where near how heavy my 4 stroke is turning out to be. Then again 4 strokes have more parts & bigger parts then 2 strokes. Hope it handles the my weight & the bikes weight.

I might have to rethink my street legal hardware (lights turn signals mirrors etc.) to save weight. Most 12 volt batteries are pretty heavy to even tho they are small it would still add more weight to an already heavy bike.

 

[butterbean]

My last engine only spun 5200 pms. With a heavy front drum wheel, 270lb rider, heavy hydraulic forks, lights, generator, battery, and saddlebags, it still hit it's top speed of 32 no problem. I wouldn't worry about the weight from the lights and battery. The motor can handle it.

 

[bikejock]

I'm around 170 lbs so it should handle my weight no problem. I might upgrade the tires to handle more weight & last longer.

As much as I love the fireball tires on my bike, it looks like I gotta go from a 3 wide tire to a 2 wide in the rear because the chain might be bumping the tire to much. I'm considering moped wheels for increased durability.