Re: Huffy Cranbrook Project
Actually I believe the photos are all of the front mount, not the rear. I'm not a fan of 'U' bolt style mounts like that one but if done right they will suffice. The extra length needs to be trimmed off so it can be tightened better.
What I see is a very loose chain. The droop is obvious in the second photo. I'd start by tightening the chain. You want 1/2" to 3/4" of slack. More than that, and just a little misalignment with the sprockets and you'll have the problem you're having.
The tensioner can also cause you problems if it isn't aligned with the chain path. Almost without exception the tensioner brackets need to be bent/twisted to get the tensioner wheel to align with the chain. As they come in the kits the wheel will tend to pull the chain off to one side or the other and cause derailment, especially with a loose chain. Have you given any thought to removing the tensioner completely? Some bike frames will allow that and eliminates one potential source of trouble.
From the photo your sprocket alignment looks pretty good. You'll also want to make sure the rear sprocket is perfectly centered on the hub. It must be concentric or it will cause the chain to tighten then loosen as the rear whel rotates. That too can cause a chain to derail from the sprockets.
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Last edited by 2door; 07-02-2014 at 09:52 PM.