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Horizontal dropouts + chain tensioner = suspenders & belt?

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Horizontal dropouts + chain tensioner = suspenders & belt?

Old 03-06-15, 09:07 AM
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Horizontal dropouts + chain tensioner = suspenders & belt?

I will be installing an IGH on a vintage frame with horizontal dropouts. My existing cassette-hub wheel axle sits entirely at the back of the dropouts, which gives me room to run a 38mm tire. When switching to an IGH, I would like to retain my clearance for a 38mm tire. This means pulling the axle to the far back of the dropouts. This seems to indicate that I will have to run a chain tensioner, unless I am able to get lucky enough to achieve sufficient chain tension when the axle is pulled to the back of the dropouts. As a first-timer to setting up an IGH, I have been searching for information on the ideal chain tension, and have not done too well. What is the rule of thumb for measuring adequate chain tension?

Also, if I go a little slack on the tension, but have a bash guard outboard of the chainring and a drop-stopper inboard, and the Shimano cog on the hub with the dual chain guards, am I OK without a chain tensioner if the chain does not end up with the ideal minimum tension?

Forgive my ignorance on all-things-chain-tension, since I have been a derailleur man for all but my first few years of bicycle riding.
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Old 03-06-15, 09:12 AM
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half link can adjust the chain length so as to Not use the axle all the way back in the dropout..
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Old 03-06-15, 09:28 AM
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Adequate chain tension is no tension (some slack) at the tightest point. You should always be able to move the chain about 1/4 to 1/2 inch up and down with finger and thumb. Excess tension will result in excess chain, and possibly cog, wear.
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Old 03-06-15, 09:51 AM
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Originally Posted by dsbrantjr
Adequate chain tension is no tension (some slack) at the tightest point. You should always be able to move the chain about 1/4 to 1/2 inch up and down with finger and thumb. Excess tension will result in excess chain, and possibly cog, wear.
+1 the right tension is zero tension or some vestigial slack at all times. Someone riding fixed gear will want the minimum slack possible (but some slack) to reduce the "backlash" when reversing torque. But you want to see visible sag in the chain. Take a look at these heavy duty chain drive systems One thing they all have in common is noticeable slack in the chain.
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Old 03-06-15, 04:40 PM
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you might want to look into, if you haven't already, what a 1/2 link in either 3/32" or 1/8" width, depending on the chain you will be running, will do for you.

if you replace one link with a half link, and i understand your problem (not a given ), you may still be able to run the tire you want and get adequate tension.

here's a pic in case you are not familiar with them.

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