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Discussion Starter · #1 ·
I was discussing emergency trailside SS conversions with someone in my bike club and had a sudden inspiration. Wondering what the "experts" take on its feasibility.

Your derailleur eats a stick and commits suicide. First thing you do is take the chain off, put it on a straight line connection between the middle chainring and whatever rear cog it lines up w/ best, then shorten the chain as much as possible. Odds are you still have too much chain. What about taking the pulleys out of the dead derailleur, put one on the top of the chain and one on the bottom section of chain and zip-tie the two together loosly.

In theory, the zip tie should still allow the pulleys to rotate and take up some of the chain slack.
 

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Mtn Biker Machinist
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????

I am trying to picture that, but I don't see how the pulleys stay attached to the frame? Where is the tension for the chain coming from? Are you saying zip tie one pulley to chainstay and top section of chain, and the other pulley the chainstay and bottom section of chain?:confused:

More details please

frog
 

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Sounds like it might work as you said, in theory, but I don't think it'd hold on very well since there is no axle to keep the pulley wheels straight, especially on a bumpy trail.

That being said, I'd definitely try it if I had to. Better than pushing.
 

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Discussion Starter · #4 ·
1 cog frog said:
More details please
Zip-ties connect the two pulleys together ... no connection to the frame. As you pull the two pulleys towards each other, it takes up the chain slack. Will have to try an experiment w/ my geared bike to see if its even feasible.
 

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I had to do a SS conversion on the trail. Yes you should definately try it first. My chain was to long when Cut short and wound up jumping to a bigger cog and bent my axle and snapped the chain. My suggestion would be to buy a KMC half link for the skinny chains and carry 1 or 2 with you. Then you are sure to do a safe and reliable fix. I made an order to my LBS and talked them into ordering 24 of them. You can get them for $3.95 a piece online and it would be a safe bet that they would do someone some good rather than having to walk out many miles.
 

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Discussion Starter · #6 ·
EscourtU said:
You can get them for $3.95 a piece online and it would be a safe bet that they would do someone some good rather than having to walk out many miles.
That would be a better option, yes. What this "fix" would be aimed towards though would be how to get out of the woods if you don't have the option of a half-link. The chances of riding w/ someone who carries them is kind of low. Great idea though ... it would be cheap insurance!
 

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Bite Me.
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The trick is to shorten your chain when it is on the middle chainring and the next smaller cog than the ideal cog for a straight SS chainline. Take out as much slack as possible in that set up then manually push the chain onto the next larger cog while turning the rear wheel. You may have to force it a bit but it will ramp on there. That solves the problem for the ride out - the tension may be tight enough to stress the bearings in the hub or BB but as a short term fix it works.
I can't figure out what you're trying to do with the pulley wheels at all?????
 

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I did my fix and got about 50 feet before it jumped to a larger cog. It also jumped 5 more times on flat roads before snapping. I wound up walking out of the woods then trying it on the road and it did last longer before jumping but not much.
 

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Discussion Starter · #9 ·
cutthroat said:
I can't figure out what you're trying to do with the pulley wheels at all?????
Something very similar to the chain tensioner design used by some downhillers (MCR?) that pushes down on the top section of chain w/ one pulley and up on the bottom section of chain w/ another pulley. Just like squeezing the top portion and bottom portion of the chain together w/ your fingers.

Nice idea about making your chain length fit the next smaller cog first. Kind of like how I "discovered" the magic gear on my Klein conversion.
 

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Got the concept now - my question is whether the pulleys would stay in place or get pulled into the chainring or the cassette.

Zip ties are great. I was riding Mack Ridge in Fruita and rode up on a girl who had lost the pivot bolt on the chainstay pivot on her bike. (very cute) She was looking at a 5 mile walk out. I always carry about 20 zip ties of various lengths and sizes. We threaded three zip ties through the bolt hole to link the stays, and she rode off like there was no problem. I saw her in the parking lot later and she gave me a beer!:thumbsup: I now carry a zip lock bag with a variety of bolts, washers, nuts & miscellaneous hardware.
 

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Ghost ring

If you take off one of your rings, you can set that in between the BB and the wheel, so that it rotates as the chain goes around. If you take off your big ring, it will ghost perfectly and take up a ton of slack... But, then you'll need smaller cr bolts eh?
worth the thought.
 

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I tired that in desperation once, and it didn't work at all. The pulleys just twisted sideways until they didn't contact the chain, and it was slack again. I ended up just doing more or less the same thing, just minus the pulleys, and around the chainstay, instead of going over the chain twice. It got me home, though I had indexed pedaling the rest of the way. :D I also had to keep replacing the zip tie, since the chain cut through it. Luckily I carry a bag of bolts and zip ties and such all the time.



I just got an idea. You could take the bushing from an old cheap pulley, and carry that. When your chain breaks, put the the zip tie through the bushing, and put the bushing on the chain, and tighten as described above. The chain would run on the bushing, and while it'd make a horrible racket, it wouldn't wear through the zip tie. Might work if you can't make anything else do the job.
 
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