Originally Posted by
Cody Broken
On one hand the tensioner is a simple device, and so little or no maintenance should be required. The vertical dropouts allow for a quick release skewer hub and so indeed no wrench required.
You can run a quick release skewer with horizontal dropouts too. Vertical dropouts are really there to allow you to remove a wheel from an index shifting bike, put it back, and have the gears still aligned right.
Originally Posted by thdave
I don't have a tensioner on my internal hub. Disadvantages: you have to wiggle the wheel back one side at a time to get the chain just right, after you remove the wheel. Also, I suspect you get more chain wear, but I haven't noticed that yet. The chain hasn't sagged or fallen off. I've got about 3000 miles on mine--so I might be speakin' too soon.
You can only wiggle the hub back like that if you have horizontal dropouts. This is why a vertical dropout bike needs a chain tensioner. There is no reason why you should get more chain wear. An infinitesimal amount less, if anything. All a tensioner does is to tension the chain - exactly the way a derailleur does. Older single and 3 speed bikes never had them, and never needed one. You just have to have it adjusted right. In point of fact, you are far MORE likely to drop the chain if you have a chain tensioner, because it allows loads more play and flex when you go over a bump. Horizontal dropouts FTW.