sthus Silver Spring loaded chain tensioner for 49cc 50cc 66cc 80cc Engine Motorized bike

works good but need to use 2 springs to keep tension or a different load spring all together.

Awesome keeps my chain snug not tight to keep it from stretching , also means I don't have to cut link's from chain stretching ! Good Job on this product , Thank You !

It's fairly simple to install but I felt they stamped the parts out the wrong way as the nice side was against the casing and the rough side was facing outward, otherwise it needed to have two washers for the roller so that it didn't drag the whole wheel and end up with wear spots on the pulley wheel, but I had some , also the Allen head bolts stick out so if you plan on this application you will need the extra wide pedals or you can't pedal as the pedal arm hits the bolts of the chain tensioner

Keeps your chain on your 66/80cc bike from jumping off, a dreaded occurrence, lol. I had a cheap stock tensioner bend and break a lower frame member (yikes!!!), and also had the chain jump off once on another motorized bike before I bought this tensioner. I've had zero problems since. I moved out of state for college and had to leave my motorbike behind, but i'm building a new one and so I just ordered another one of these tensioners. I would NOT feel safe on a 66/80cc 2 stroke motorbike without one of these. If you have a cruiser frame, the pedals should clear the allen bolts that hold this tensioner on, but if you have a mountain bike, you might or might not have to install wider pedal cranks, depending on the bike/brand.

It is what it is. For the price, I didn't expect much, and it delivered. Probably okay for some applications, but inadequate for mine; it's awkward to mount and flimsy. Sorry to leave a 3-star review -- I should have known it wasn't going to be the answer to my prayers!

Had a defect in mine but customer service is so good they replaced it even ordered a second one for my wife’s bike saves on the chain from hiring the frame and keeps it tight .

Upon first using this to tension my chain I was very pleased. It seemed like a much better solution to the stock tensioner. However, after only 3 rides the pulley nearly fell off twice and now has melted into a ball of plastic from tightening to prevent falling off the bike.

The design is good, but the spring fails. I would recommend replacing the supplied nuts with proper nylon locking nuts, as well as replacing the weak spring with something more rugged. My main issue would come from starting the bike. Since it's basically a pop-start, it's extremely harsh on a tensioner. It basically pulls all of the slack from the chain till you spin that rear wheel. So, if your spring can't handle that load or excessive travel, it will definitely fail - either by snapping or stretching. Either get a beefier spring, or go with a fixed tensioner.

Stop thinking about it and just buy it totally fine piece of Steel spring and plastic ...at least you won't lock up your back tire with the one provided better option I think

This chain tensioner is alot better then my defacto tensioner. I got it installed with a slight modification to my bicycles crank arm and replaced one of the screw, as the crank arm kept hitting on that one screw on the the tensioner plate.

Crochet du ressort tendance a ouvrire si ressort étiré trop..faire attention que votre chain tombe pas trop longue et que sa referme trop..proche du sproket du moteur. La bolte qui tien la roullette..a changé pour une un peu plus longue et enlevé lock pour un meilleur qualité et une note lock..double sécurité..assuré vous que votre roulette ne soit pas trop serré pour un max de roulement si non ne tournera pas et use la roulette prématurément..si non une merveille

Only way to go

Missing spring, requested refund, no response