Bicycle Mechanics - Chain tensioning options with standard horizontal dropouts

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canyoneagle
08-11-10, 01:15 PM
I'm converting a nice 80's road frame to use an IGH and am wondering what other folks have found works to tension the chain.
I absolutely do not want to use a spring-loaded "singleator" type tensioner - I want direct tensioning via a "tugger" type assembly, such as the surly tuggnuts.

However, I know that many of these types of tensioners are specifically designed for track ends and may not work with conventional road-style horizontal dropouts.

Any thoughts or experiences/suggestions from the group?


prathmann
08-11-10, 01:24 PM
Usually no special tensioning device is needed or desired. Just pull the wheel back in the horizontal dropouts and tighten it down.

canopus
08-11-10, 01:42 PM
Tuggnuts aren't going to work on a forward facing road dropout. Period. And they are for axle slippage really, not chain tension.

Unless your hub requires something specific for it, I never had any problems with a good thick serrated washer and locking nut, assuming you have enough length in the dropout to pull the wheel back to tension the chain. The point to all this is to clamp the frame tightly between the hub and the axle nut and not grind it the using the locknut, That is where the serrated washer came in handy.

NOT sharp penetrating washers like these (these usually suck bad after the first removal):
164258

but something like this (This would be nice but you would have to remove the SA specific flat portion by either grinding or drilling it round.)
http://www.sjscycles.co.uk/images/products/sturmeyaxlelockingwasherbig_l.jpg (http://www.sjscycles.co.uk/product-Sturmey-Archer-Sturmey-Archer-Serrated-Lock-Washer-9.5-mm--HMW494-2802.htm)

If you don't have enough length in the dropout, I don't see many options other than half-links/gear combo change to dial in the chain length or something like the singleator.


rhm
08-11-10, 01:49 PM
If you buy a new IGH it will come with the appropriate washers, which are serrated (to dig into the frame a bit) and have an ear on them to keep the axle from rotating (this is crucial to the proper working of the hub). From what I've seen, the SRAM and Sturmey Archer washers look pretty much the same (silvery steel), while the Shimano Nexus hubs come with a small variety of washers all painted different colors so you can distinguish different degrees of offset between the flats and the ear and correctly orient the axle to different dropout angles. And yes, as noted above, this is all you need for correct chain tension. Put the chain on the chain ring and on the cog, and pull the wheel back until it feels right; then tighten up the nuts. Really pretty easy, but you do need to put some pressure on the nuts.

canyoneagle
08-11-10, 02:59 PM
Hmm, I was hoping that I could somehow integrate a better method than pulling back really hard while simultaneously tightening (as I have done many times with my Bianchi Milano). I find I have to first cinch the non-drive side in its approximate final location then use the tire/rim as a lever arm to get enough tension on the chain (I can't get enough tension by pulling on the nuts, and inevitably end up getting slack in the chain once I begin to tighten).

Anyway, I'm pretty sure I've seen some conversions with a threaded tensioner of some kind.

In a pinch, I can just do the ol' pull and tighten, but would prefer a more graceful solution that can get proper tension on the chain.

BCRider
08-11-10, 05:08 PM
If you're levering the chain like that you're putting way too much tension into it. The correct tension for a fixie, single speed or IGH is just barely no tension at all. No slop is good but at no time should the chain ever become actually tight. Everone talks about chain tension but it's really a misnomer. What you really want is just no slack at the tightest spot . From there a touch of slack in the loosest spot is OK.

canyoneagle
08-11-10, 05:18 PM
Yep, I know better than to make it super tight. The problem I run into is that when I tighten the nut, the axle inevitably moves forward in the dropout. I think a decent thick washer (like the one pictured above) should avoid that. My experience is mainly with the stock Nexus setup, which does not work especially well.
I think better quality cranks/chainrings (such as the Sugino 75) also help to mitigate the variation in tension (runout) that occurs with average quality components, minimizing or eliminating the tendency to have tight and slack spots as the cranks are rotated.

noglider
08-11-10, 06:22 PM
Walk the wheel back in the dropouts. Tighten the right axle nut and loosen the left. Pull the wheel back. Then tighten the left and loosen the right. Pull the wheel back and tighten the right axle nut. Is it set right? If not, then reverse the procedure.

canyoneagle
08-11-10, 06:50 PM
Walk the wheel back in the dropouts. Tighten the right axle nut and loosen the left. Pull the wheel back. Then tighten the left and loosen the right. Pull the wheel back and tighten the right axle nut. Is it set right? If not, then reverse the procedure.

That is almost exactly what I have found works best for me. My description above was the abridged version ;)

Jeff Wills
08-11-10, 09:02 PM
Walk the wheel back in the dropouts. Tighten the right axle nut and loosen the left. Pull the wheel back. Then tighten the left and loosen the right. Pull the wheel back and tighten the right axle nut. Is it set right? If not, then reverse the procedure.

Usually it doesn't take more than on iteration for me. If the axle is walking forward when tightening, I'd check the dropout alignment and the contact surfaces of the dropout. Something's not even top-to-bottom. I'd also take the nuts off completely and clean and lube the threads.

DannoXYZ
08-12-10, 12:40 AM
Are you using washers between the dropout and axle-nut? I prefer track nuts with captured washers that spin. Drop a little oil between the axle nut and washer. The axle stays put when you tighten the nut and chain-tension is perfect the 1st time.

BCRider
08-12-10, 12:41 AM
The problem I run into is that when I tighten the nut, the axle inevitably moves forward in the dropout. I think a decent thick washer (like the one pictured above) should avoid that......


Ah, fair enough. I didn't realize that you were getting the axle walking from tightening the nut. Yeah, either that fancy washer they showed or nuts with captured free spinning washers would be a wise mod.