Karldar

Yesterday, my ride partner and I hit a local trail after work. About halfway back to the boat ramp(where we had parked) on a dry, flat(but rocky) creekbed, my buddy's rear derailleur gets in the spokes and plays contortionist. He bent the hanger(how, I'm not sure, but this is the second occurence-first time he broke the hanger in two) and we decided it would be easiest to remove the der and shorten the chain for the ride back to the parking lot. Obviously this didn't work well and we had no half-link or tensioner, so my question is:

How would you have handled this from a repair standpoint?

I'd like to think it won't happen again, but past experiences suggest otherwise. I'm going to try keeping a closer eye on his gear combos. He's new to mountain biking and still has some issues with timely shifting for conditions.

Bikewer

That's usually the sort of emergency fix that's cited, but as you note getting the chain tension right might be difficult. How about getting the chain "about" the right length on a smaller cog, then manually shifting it up onto the next bigger one. That should snug it up enough for the ride back.

BostonFixed

Uhh, dude, that's a singlespeed, not a fixed gear. BIG difference.

Retro Grouch 

Depends. I've had good luck in the past with just bending the derailleur hanger back by hand. If you can do that, it lets you keep the derailleur arm to tension the chain. I've even had success getting the derailleur to shift again although somewhat imprefectly.

Karldar

Sorry. Why don't you 'splain it to me, then? Seems to me that we "fixed" the bike in a single gear even though it still had multiple gears-well, we tried, anyway. I thought a ss was one chainring, one rear cog.


I didn't get a chance to try it, but I had thought about pinching two links together and using my chain tool to bind up the pins to approximate a half-link. Think that would've worked a little better?

Bikewer, I don't quite understand the manual shifting idea--not that we really tried it. First time I ever had to make this kind of repair and I guess I just expected the chain links to allow a perfect fit on some available gear combo.

Gonzo Bob

Fixed-gears have no freewheel. If the rear wheel is rolling, the cranks are turning (unless you've dropped the chain

thechamp

if all you're trying to do is ride home you shouldn't need that much chain tension, just find a managable gear and break the chain accordingly. I guess that didn't work though. moving the chain up or down one (rear) cog might have made all the diffenerce. between 2 or three front rings and 7 or 8 in the rear you should be able to find some combination that works.
And of course the real solution is to properly adjust the rear derailer so it doesn't catch the spokes. Help your friend get that right and he won't have this problem. maybe even adjust so he can't access that big ring in the back.

boots

yah, as long as your freewheel is still spinning your chain can be slack as poo

Karldar

Hmm, thanks for the info.


I found out last night that he actually took a hit on the derailleur and/or hanger coming down the hill before the flats. It's a nasty one, covered with loose rocks as well as large embedded stones That's a risk on the trails around here. He might just need to pick better lines. We were gonna ride today, but he had to order a hanger and it won't be in 'til Monday. We're gonna try to straighten the old one out today. Pretty iffy, tho--the threads for the der bolt got chewed up a bit.