Anyone use a Cog 'Sandwich' type guide?- Mtbr.com
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  1. #1
    bmw
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    Anyone use a Cog 'Sandwich' type guide?

    I've had this nagging issue with my drive train that I believe is caused from my chain going slightly off my cog and then popping back into place. Something like this set of guides would keep the chain online if it was big enough to cover a 20t cog (it's for 16t). Anyone know of any other products like this?

    found it here:
    http://www.thefixbikes.com/bikes/pro...A&dept_id=3317
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  2. #2
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    Make your own by grinding the teeth off some old cassette cogs.
    I see hills.

    I want to climb them.

  3. #3
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    i made my own with cogs off cassettes ground down, worked ok for cross but i was always loosing the chain off the front never the rear.

  4. #4
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    Isn't this sort of "treating the symptoms" rather than curing the disease?

    If your chainline is correct, your sprockets have full depth teeth in good condition and your chain is likewise good and, of course, correctly tensioned then you shouldn't be having these sorts of problems anyway.

    It's my personal opinion that all these guides do (and for that matter, bash rings on a SS) is collect all kinds of trail detritus and make it harder to keep the drivetrain clean.

  5. #5
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    Quote Originally Posted by Andy R
    Isn't this sort of "treating the symptoms" rather than curing the disease?...
    +1

    If your chainline is straight, your tension is correct, and you are using single speed cogs (as opposed to stuff designed for derailling), what you are describing is the result of chainstay flex.

    If it's that, it will only happen when you are really putting the pressure on. In other words a frame issue rather than a drivetrain issue.
    As little bike as possible, as silent as possible.
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  6. #6
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    Quote Originally Posted by Andy R
    Isn't this sort of "treating the symptoms" rather than curing the disease?

    If your chainline is correct, your sprockets have full depth teeth in good condition and your chain is likewise good and, of course, correctly tensioned then you shouldn't be having these sorts of problems anyway.

    It's my personal opinion that all these guides do (and for that matter, bash rings on a SS) is collect all kinds of trail detritus and make it harder to keep the drivetrain clean.
    you are mostly correct but bash guards are normally used for protection for the drivetrain. i.e. i run a stainless surly chain ring and without the bash guard it would be better as crumpled wall art. its true that on dedicated ss with correct tension you would never need the guides but lets be honest, thats not always the case, and most tensioners do do very much in terms of actually working.

  7. #7
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    Quote Originally Posted by Stevob
    Make your own by grinding the teeth off some old cassette cogs.
    I 2nd that. Make your own.

  8. #8
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    Quote Originally Posted by thefuzzbl
    you are mostly correct but bash guards are normally used for protection for the drivetrain. i.e. i run a stainless surly chain ring and without the bash guard it would be better as crumpled wall art
    Yes, but those Surly stainless chainrings are as soft as putty.......

    I've, in the past, used a bash guard with a 2x9 setup (to protect the chainring when I was on the granny) and got so fed up with cleaning all the crap out from between it and the chainring that I gave up using it altogether.
    Probably not so bad if you only ride dry, rocky places, but around here they're a waste of time.

  9. #9
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    http://cgi.ebay.com/Wheels-Manufactu...item2eab003f81

    I bought these they work well and they look great. comes with a good number of spacers, 16t and also lock ring.

    U need them to spacer off not only the outside but also the guides away from the 16t. one nagging complain is the spacers are not the fitted type.eg. specifically for shimano type freewheels.so they tend to move a little when u tighten the lock ring. but nevertheless, they look good, wheelmanufacturing makes a good reliable product and i have had at least 2000kms without a chain skip on with a kmc blue bmx chain.

    oh yes.. i use them on a singlespeed full susser.

  10. #10
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    i agree with both sides of what is said here. yes the "cog sandwich" works. yes it's not addressing the real problem.

    if you are using a single-speed (no ramped teeth) cog and good chainline, this shouldn't be an issue. however, if you don't want to spend more money than you have to, then you can do like has been suggested (which i have done myself) and use 2 larger cogs to sandwich things.

  11. #11
    bmw
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    Quote Originally Posted by Jhanney
    http://cgi.ebay.com/Wheels-Manufactu...item2eab003f81

    I bought these they work well and they look great. comes with a good number of spacers, 16t and also lock ring.

    U need them to spacer off not only the outside but also the guides away from the 16t. one nagging complain is the spacers are not the fitted type.eg. specifically for shimano type freewheels.so they tend to move a little when u tighten the lock ring. but nevertheless, they look good, wheelmanufacturing makes a good reliable product and i have had at least 2000kms without a chain skip on with a kmc blue bmx chain.

    oh yes.. i use them on a singlespeed full susser.
    Do you know if the guides are tall enough to cover a 20t cog?

  12. #12
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    Quote Originally Posted by bmw

    Dude, my friend ordered that. I was the one who had to install it. It was our only option for spacers b/c it came as a SS spacer kit. I have made my own out of larger 20+ tooth cogs with the teeth ground off. In fact that was how alot of the first conversions I did were. The home made one works great. I much perfer the homemade variety. Also FWIW, it starts conversation at the coffee shop pretty quick.
    no chain no gain.

  13. #13
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    Quote Originally Posted by bmw
    Do you know if the guides are tall enough to cover a 20t cog?
    There's the rub. No, they're not tall enough for a 20t cog. As a result, one is stuck with "bread" on their sandwich that doesn't cover the "meat."

    But I have no problem grinding the teeth off other cogs to make my own bread, if I'm so inclined.

    There used to be a company that made tall "bread" pieces, it was called Discos, but I haven't seen them around for a few years now. I think they made their cog/chain guides out of plastic, and they worked well. Perhaps not esthetically pure, but they worked well nonetheless.

    --Sparty
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    We get old because we quit riding.

  14. #14
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    The Trek Solution

    Here's a photo of the Trek single version I found on ebay. This went a long way to curing problems on both a Cannondale and a Merlin single speed.

    I suspected the cause of my problem was an off center chainring which required me to leave more slack in the chain than necessary. I don't think I had problems with frame flex on the Cannondale and the chain usually jumped on bumpy ground, not during a high torque hill climb.

    It certainly looks a lot better than many of the other proposed solutions, although it would be best if the cog could be run "clean".

    I was not able to order additional ones though the local Trek store.
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  15. #15
    bmw
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    Quote Originally Posted by Devine Intervention
    Here's a photo of the Trek single version I found on ebay. This went a long way to curing problems on both a Cannondale and a Merlin single speed.

    I suspected the cause of my problem was an off center chainring which required me to leave more slack in the chain than necessary. I don't think I had problems with frame flex on the Cannondale and the chain usually jumped on bumpy ground, not during a high torque hill climb.

    It certainly looks a lot better than many of the other proposed solutions, although it would be best if the cog could be run "clean".

    I was not able to order additional ones though the local Trek store.
    That looks good, thanks for the suggestion. I might try to get one from the local Trek store.

  16. #16
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    where do you get one of these at i contacted bontrager and they dont sell them they only come with there bikes thanks mitch

  17. #17
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    First off I'd double check to make sure your chainline is perfect. The sound is your chain trying to jump of the cog but being snapped back down really quickly, this comes from having a bad chainline. If you've gotten it as close to straight as possible and its still doing it, I'd recomend using a nice big 1/8" bmx chain. When you use a normal 3/32" chain on your 3/32" cogs you have no extra room for side to side play, but if you use a 1/8" chain on you 3/32" cogs then you have an extra 1/32" of play that can be used to make up for a bad chainline, bent cogs/rings, or a twisted chain. I'd also recomend using non-ramped SS specific cogs and rings, but that's not too important. I run a biopace ring, surly cog, KMX 410h chain, and a surly singleator with no bash guards or anything of that such, took it out for a 5 mile ride yesterday and even when I put 220lbs of torque down on the pedals to get over obstacles I didn't get and ckipping or popping.

    -Connor

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