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    dbg
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    Value of Horizontal Drops on unsupported tour.

    On a recent group trip we had one bike lose the rear derailer into the spokes on a steep climb. It broke several spokes and destroyed the derailer. Had we been in the middle of nowhere it may have been a big problem. That's when it occurred to me that horizontal drops would have allowed us to temporarily rebuild the rear end as a single speed (we had various options for spoke repair). Maybe it's not common enough to worry about. Anybody else seen problems where horizontal drops would have made things easier? (I'm considering options for future builds)
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    I have horizontal dropouts on my tourer for this reason.
    In every other respect, horizontal dropouts are a PITA but they do get you out of trouble when your rear mech fails.

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    coprolite fietsbob's Avatar
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    I leave "dork-discs" in place on the rear wheels .. aka spoke protectors.

    to do their task..

    my tourer got a 48 spoke wheel, did 1 12 spoke damaging over-shift, on a test ride,
    and learned my lesson.

    so the discs are the lesson learned .. that stroke limit screw has to stay in place.

    The index shifting people rely on, relies on the rear wheel
    always being in the same relationship to the RD ..
    that is why frames with vertical dropouts predominate now.

    friction shifting , rider involvement, hand skills.
    lets things be flexible a bit more.
    Last edited by fietsbob; 08-20-12 at 11:42 AM.

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    Senior Member staehpj1's Avatar
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    It doesn't seem like an adequate reason to use horizontal dropouts to me. If you had to you could ride with a little slack in the chain and limp along with vertical dropouts. If you were really concerned you could take a long a half link and get chain tension to at least a semi acceptable place even with vertical dropouts in single speed mode.
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    Does anyone here know of someone who has converted a bike to SS after damaging and removing the rear derailleur?

    I ask because when I have used old-style cogs in an aborted FG experiment, the chain simply would not stay on the cog because of the tooth offset. I've not tried running a rear cassette as a single-speed and would like to know if it actually works without the RD acting as (a) a chain tensioner and (b) as a guide for the bottom run of chain on to the selected gear on the cassette.
    Dream. Dare. Do.

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    Senior Member staehpj1's Avatar
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    I have seen reports of it working, but have not actually tried it myself. I am guessing it might help if you pick the ring and cog locations that allow the straightest chain line, but again that is just a guess.

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    Senior Member alan s's Avatar
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    Quote Originally Posted by Rowan View Post
    Does anyone here know of someone who has converted a bike to SS after damaging and removing the rear derailleur?

    I ask because when I have used old-style cogs in an aborted FG experiment, the chain simply would not stay on the cog because of the tooth offset. I've not tried running a rear cassette as a single-speed and would like to know if it actually works without the RD acting as (a) a chain tensioner and (b) as a guide for the bottom run of chain on to the selected gear on the cassette.
    Tell you what. I'm installing a new chain today, and I'll give it a go with the old chain on my Surly Troll. I suspect chain tension is the key, as well as using a straight chainline.

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    Quote Originally Posted by alan s View Post
    Tell you what. I'm installing a new chain today, and I'll give it a go with the old chain on my Surly Troll. I suspect chain tension is the key, as well as using a straight chainline.
    Yeah, thanks. Straight chainline is a given, as is FG practice, but I am curious about this.
    Dream. Dare. Do.

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    Senior Member himespau's Avatar
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    Quote Originally Posted by fietsbob View Post
    I leave "dork-discs" in place on the rear wheels .. aka spoke protectors.

    to do their task..

    my tourer got a 48 spoke wheel, did 1 12 spoke damaging over-shift, on a test ride,
    and learned my lesson.

    so the discs are the lesson learned .. that stroke limit screw has to stay in place.

    The index shifting people rely on, relies on the rear wheel
    always being in the same relationship to the RD ..
    that is why frames with vertical dropouts predominate now.

    friction shifting , rider involvement, hand skills.
    lets things be flexible a bit more.
    How much protection do dork disks provide?
    Punctuation is important. It's the difference between "I helped my uncle, Jack, off a horse" and "I helped my uncle Jack off a horse"


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    Quote Originally Posted by himespau View Post
    How much protection do dork disks provide?
    None if the limit screw on the rear derailleur is set properly. I've damaged spokes with overshift after not adjusting the screw properly, but the incident didn't subsequently require me to put dork discs on any of my or Machka's bikes.
    Dream. Dare. Do.

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    coprolite fietsbob's Avatar
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    A belt and braces approach, Shimano's tandem hub still has the Arai drag brake mount threading

    those are RH thread just like freewheels ..
    But a 3/32 Thick, tooth freewheel , is compatible with 5,6,7,8 speed chains
    more than that and the thinner chain roller space presents problems

    But.. other than that. the ability to flip over the wheel becomes practical.

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    Senior Member himespau's Avatar
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    Quote Originally Posted by Rowan View Post
    None if the limit screw on the rear derailleur is set properly. I've damaged spokes with overshift after not adjusting the screw properly, but the incident didn't subsequently require me to put dork discs on any of my or Machka's bikes.
    I don't have a problem with dork disks and I put them on the first two wheelsets I built up because they're going on the first two frames I will have built up as I've never adjusted the RD before, I just didn't know if that flimsy plastic was actually going to provide any protection or not from an event catastrophic enough to damage the spokes.

    Anyway, sorry for the thread derail.
    Punctuation is important. It's the difference between "I helped my uncle, Jack, off a horse" and "I helped my uncle Jack off a horse"


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    Well, if the OP is considering options for future builds and is considering horizontal dropouts as a solution to a problem that rarely occurs, I guess he may consider a more off-the-wall approach. He could have an eccentric bottom bracket installed as is done on the captain's bottom bracket of a tandem. Other than being able to get the slack out of a chain in the unlikely event of shearing off the derailleur, this would also allow one to make small changes in the for/aft location and height of the cranks. I'm not sure why one would ever want to do that, but I suppose it could come in handy some day (sort of like the odds of a horizontal dropout coming in handy).

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    Senior Member staehpj1's Avatar
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    Quote Originally Posted by Rowan View Post
    None if the limit screw on the rear derailleur is set properly. I've damaged spokes with overshift after not adjusting the screw properly, but the incident didn't subsequently require me to put dork discs on any of my or Machka's bikes.
    I agree, but I will say that I know of at least one exception. A guy I rode with on a good bit of the ST had a problem with bending dérailleurs and dérailleur hangers. It happened numerous times in the course of his tour. In that case the dork disk helped even though the limit screw was set fine. He got the bike replaced under warranty and had the same problem again. The dealer seemed to think it was related to the bob trailer and the load on this light carbon fiber road bike.

    Despite that I do not run dork disks and rely on the limit screw doing it's job. If I was prone to bending RDs or RD hangers I might consider running a dork disk.

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    Senior Member Chris Pringle's Avatar
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    Quote Originally Posted by B. Carfree View Post
    Well, if the OP is considering options for future builds and is considering horizontal dropouts as a solution to a problem that rarely occurs, I guess he may consider a more off-the-wall approach. He could have an eccentric bottom bracket installed as is done on the captain's bottom bracket of a tandem. Other than being able to get the slack out of a chain in the unlikely event of shearing off the derailleur, this would also allow one to make small changes in the for/aft location and height of the cranks. I'm not sure why one would ever want to do that, but I suppose it could come in handy some day (sort of like the odds of a horizontal dropout coming in handy).
    Yeah, eccentric bottom brackets (EBB) sound like a much better alternative to horizontal dropouts. Honestly, I don't know if I would use it as a chain tensioner to convert the system into SS. But hey, when touring anything is possible. So, if it's there, one could! For a future build, an EBB's biggest advantage is that it will also give you the option to upgrade to an IGH (e.g., Rohloff ) or even run a belt system if your rear triangle is made for one.

    Last edited by Chris Pringle; 08-20-12 at 06:08 PM.
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    Don't gears for SS have taller teeth on them??? Sure look like they do.

    I have vertical dropouts and horizontal dropouts.I don't worry about either one really.I can limp where I need to go.
    Last edited by Booger1; 08-20-12 at 04:27 PM.
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    dbg
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    Quote Originally Posted by himespau View Post
    I don't have a problem with dork disks and I put them on the first two wheelsets I built up because they're going on the first two frames I will have built up as I've never adjusted the RD before, I just didn't know if that flimsy plastic was actually going to provide any protection or not from an event catastrophic enough to damage the spokes.

    Anyway, sorry for the thread derail.
    Same trip, one rider was breaking in a new bike. He got needled for having a dork disk and removed it at the next break. He immediately started losing the chain on the inside until we adjust his limit screw to fix the problem.
    David Green, Naperville, IL USA "The older I get, the better I used to be" --Lee Trevino

  18. #18
    <riding now> BigAura's Avatar
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    Quote Originally Posted by dbg View Post
    Maybe it's not common enough to worry about.
    Yes.

    PLUS: If you're adept enough to convert your bike to SS on the side of the road, then you probably can cobble together several solutions when presented with a broken derailleur. To build a bike with a horizontal drop just for this "what if" scenario is misguided, IMO. It's similar to the oft stated "my bike frame must be steel because any local welder could fix it".

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    Interesting that this topic came up. I put a spoke protector on each wheel on my touring bikes for this very reason. But, on my last tour, on the next to last day my freehub stopped spinning easily when I coasted. I had the tools to pull the cassette, but decided not to, instead I just avoided coasting on my last day thinking that I would rather fix things when I got home.

    At home, pulled cassette thinking I would have to install a new freehub. But instead I found that all I had to do was pull out the piece of plastic from my busted spoke protector out from where it was jammed between the cassette and hub. Freehub was fine once I removed the cassette and spoke protector.

    So, I was wondering if I should buy a new spoke protector or ride without. In this case the spoke protector caused me some frustration, but after reading this post I think that I will buy another spoke protector.

    Quote Originally Posted by Rowan View Post
    Does anyone here know of someone who has converted a bike to SS after damaging and removing the rear derailleur?

    I ask because when I have used old-style cogs in an aborted FG experiment, the chain simply would not stay on the cog because of the tooth offset. I've not tried running a rear cassette as a single-speed and would like to know if it actually works without the RD acting as (a) a chain tensioner and (b) as a guide for the bottom run of chain on to the selected gear on the cassette.
    Many years ago, I had a bolt back out on an old Campy derailleur (short cage, Gran Sport model, 1950s technology). Several parts scattered on the road. I managed to find some of the parts but not all of them. It was on a century ride so it was not on a convenient day. I did finish the ride as a single speed. Was not fun but it worked. Keep in mind however that we are talking about a 5 speed cluster on the back, the sprockets on those older clusters were thicker than the modern cassettes, so the chain may have gripped the teeth better. I had several people comment about my chain hanging so low as they passed me, I did not have a chainbreaker to pull out any links.

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    Interesting that this topic came up. I put a spoke protector on each rear wheel on my touring bikes for this very reason. But, on my last tour, on the next to last day my freehub stopped spinning easily when I coasted. I had the tools to pull the cassette, but decided not to, instead I just avoided coasting on my last day thinking that I would rather fix things when I got home.

    At home, pulled cassette thinking I would have to install a new freehub. But instead I found that all I had to do was pull out the piece of plastic from my busted spoke protector out from where it was jammed between the cassette and hub. Freehub was fine once I removed the cassette and spoke protector.

    So, I was wondering if I should buy a new spoke protector or ride without. In this case the spoke protector caused me some frustration, but after reading this post I think that I will buy another spoke protector.

    Quote Originally Posted by Rowan View Post
    Does anyone here know of someone who has converted a bike to SS after damaging and removing the rear derailleur?

    I ask because when I have used old-style cogs in an aborted FG experiment, the chain simply would not stay on the cog because of the tooth offset. I've not tried running a rear cassette as a single-speed and would like to know if it actually works without the RD acting as (a) a chain tensioner and (b) as a guide for the bottom run of chain on to the selected gear on the cassette.
    Many years ago, I had a bolt back out on an old Campy derailleur (short cage, Gran Sport model, 1950s technology). Several parts scattered on the road. I managed to find some of the parts but not all of them. It was on a century ride so it was not on a convenient day. I did finish the ride as a single speed. Was not fun but it worked. Keep in mind however that we are talking about a 5 speed cluster on the back, the sprockets on those older clusters were thicker than the modern cassettes, so the chain may have gripped the teeth better. I had several people comment about my chain hanging so low as they passed me, I did not have a chainbreaker to pull out any links. I could not pedal very hard and had to take it slow, but I got home.

  21. #21
    Randomhead
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    Quote Originally Posted by Rowan View Post
    Does anyone here know of someone who has converted a bike to SS after damaging and removing the rear derailleur?

    I ask because when I have used old-style cogs in an aborted FG experiment, the chain simply would not stay on the cog because of the tooth offset. I've not tried running a rear cassette as a single-speed and would like to know if it actually works without the RD acting as (a) a chain tensioner and (b) as a guide for the bottom run of chain on to the selected gear on the cassette.
    I do know someone who tried, and had exactly the same experience. The chain wants to shift because there is a bias to shift towards the spokes built into the rear cogs.

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    Quote Originally Posted by dbg View Post
    On a recent group trip we had one bike lose the rear derailer into the spokes on a steep climb. It broke several spokes and destroyed the derailer. Had we been in the middle of nowhere it may have been a big problem. That's when it occurred to me that horizontal drops would have allowed us to temporarily rebuild the rear end as a single speed (we had various options for spoke repair). Maybe it's not common enough to worry about. Anybody else seen problems where horizontal drops would have made things easier? (I'm considering options for future builds)
    I had one occasion when I destroyed the RD and had to convert it to a single speed. By matching the length of the chain to the best aligned rear cog, it seemed to work OK without skipping (to the best of my memory) although I did not have to travel far after that.

  23. #23
    Senior Member alan s's Avatar
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    Quote Originally Posted by Rowan View Post
    Yeah, thanks. Straight chainline is a given, as is FG practice, but I am curious about this.
    All went well with the conversion to SS. I went with the middle chainring (32T) and second cog (12T) on an 11-32 cassette, although this is probably a little too high a gear if there are any climbs. Rode several miles on roads and over bumps, and the chain ran smooth the whole time without any tendency to shift.

    No problem with tensioning the chain, although a tugnut would have been ideal. The disc brake also slides back, with no loss in braking power. In the unlikely event I need to do this, it's good to know it works.






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    Senior Member staehpj1's Avatar
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    Quote Originally Posted by alan s View Post
    All went well with the conversion to SS.
    Thanks for reporting back on that. Good to know.

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