Spring loaded chain tensioner from spare parts

[Moto]

Hi everybody, this is my first post, I have had my motorized bike (the third one I've built) for a few weeks and I have been running with no chain tensioner but the chain keeps coming loose. I came up with this tensioner from parts just hanging around my garage, the only thing I had to buy was the spring. The clamp is from the rear mont of my old motor, two long bolts hold it on. The arm with the pulley is an old motor mount I made, the pulley is from a scrapped derailleur. Works GREAT so far!!!

 

[waistofhumanspace]

After I got the high speed hub that trued the sprocket I did not have a need for a chain tentioner, you might like to check this one out for ideas... It's the best I have seen

 

[2door]

Moto,
Not a bad idea but if that derailer sprocket is plastic it probably isn't going to last too long. Keep an eye on it. They do make metal (aluminum) derailer sprockets with bearings but even then the wear rate is going to be high.
If you weren't having chain to frame interference and could run without a tensioner, there was other reasons why the chain would come off. My guess is incorrect alignment and tension. Get those right and you can eliminate the tensioner.
Tom

 

[kla63]

Hi everybody, this is my first post, I have had my motorized bike (the third one I've built) for a few weeks and I have been running with no chain tensioner but the chain keeps coming loose. I came up with this tensioner from parts just hanging around my garage, the only thing I had to buy was the spring. The clamp is from the rear mont of my old motor, two long bolts hold it on. The arm with the pulley is an old motor mount I made, the pulley is from a scrapped derailleur. Works GREAT so far!!!

did that didn't last long broke under presser !!!! sucked chain into spokes !!!! bad idea !!!! get something better !!!!