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  1. #1
    Lost in the Black Hills mx_599's Avatar
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    I noticed some people convert their MTB to a single speed. I just had the thought of making a bike an 8-speed or something close.

    Do people do this?? Remove the front derailleur and two of the spockets and then just leave the 8 sprockets in the rear? Or are there major drawbacks or issues I am not thinking about?

    Okay...so if people do this and it is not stupid, are the following assumptions correct?

    1) I can remove my front derailleur and shifter assembly from my handlebars.

    2) I can simply have a single sprocket and a bashring upfront.

    3) The best choice of sprocket up front would be the middle one??

    Riding: non-serious XC and goofing around. I was thinking simplifying the 24-speed would be "a change".

  2. #2
    Back in black cydewaze's Avatar
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    I've been thinking about this too - for different reasons.

    I have an awesome hardtail MTN bike that has a braze-on front derailleur. The braze-on broke off a number of years ago, and I had it repaired, but it's been very hard to find a derailleur for it (the old one rusted badly).

    I was thinking of going with a single 30 or 32t up front, and an 11-34 out back. The bike climbs like a billygoat, and I rarely used the small ring up front anyway. I'll be paying attention to the replies this thread gets.

  3. #3
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    My only concern would be the chain line running at extreme angles. But I've never done it. someone here has to know....

  4. #4
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    It is possible(I did once with a 6s), but the chain may occaisionally come off espcially if you don't switcht to a ss chainring. The extra width of the 8s cassette may make this even more likely.

  5. #5
    eert a ekil yzarc SpiderMike's Avatar
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    Quote Originally Posted by mx_599
    ...Do people do this?? Remove the front derailleur and two of the spockets and then just leave the 8 sprockets in the rear? Or are there major drawbacks or issues I am not thinking about?
    Okay...so if people do this and it is not stupid, are the following assumptions correct?
    1) I can remove my front derailleur and shifter assembly from my handlebars.
    2) I can simply have a single sprocket and a bashring upfront.
    3) The best choice of sprocket up front would be the middle one??
    Riding: non-serious XC and goofing around. I was thinking simplifying the 24-speed would be "a change".
    Been there done it. I had a front D poop out on me, and went to "Manual Shifting" for at least 2 years. I have seen "8" or "9" speed bikes (especially in Downtown areas). From the start I thought chain skipping of would be a bad thing...sure it happened but nowhere as frequent as I had thought.

    1. If its broke take em off.
    2. Leave them their, this will eliminate your need to choose which to keep for number 3.
    3. See number 2.

    Oh and I am going to PM ya on the Lyric challenge

  6. #6
    Knows Bigfoot's Momma
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    Quote Originally Posted by ndelaude
    My only concern would be the chain line running at extreme angles. But I've never done it. someone here has to know....
    That's my only concern too, as I've been wanting to do the same on a weight weenie bike. The extreme chain angles in either the high or low couple of cogs could cause problems with excessive wear (both to chain and cogs/chainring). Although some people don't pay attention to it, each chainring is really only comfortable on about 3 cogs it's most in line with...
    nice lugs baby!

  7. #7
    eert a ekil yzarc SpiderMike's Avatar
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    One thing I wish I had was a chain guide, like I've seen on some DH rigs. Something like the Kore Chain Reactor. http://www.kore-usa.com/index.html click Drive and go to Chain Reactor.

  8. #8
    Lost in the Black Hills mx_599's Avatar
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    Quote Originally Posted by TheOtherGuy
    That's my only concern too, as I've been wanting to do the same on a weight weenie bike. The extreme chain angles in either the high or low couple of cogs could cause problems with excessive wear (both to chain and cogs/chainring). Although some people don't pay attention to it, each chainring is really only comfortable on about 3 cogs it's most in line with...
    So I am thinking if I did this to stay away from using the #1 and #8 cog? Then it would probably work good?

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    Knows Bigfoot's Momma
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    Quote Originally Posted by mx_599
    So I am thinking if I did this to stay away from using the #1 and #8 cog? Then it would probably work good?
    Yeah; that would probably work OK if you just kept the middle ring. It would be best if you just used 3,4,5, and 6, - at least as far as chain and gear life goes. I have a road bike set up as a 5 speed, using a single chainring in the outer position, and it's not really happy on the big cog in back... You can see that chain line is pretty far off.
    nice lugs baby!

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    I run a 5 speed block on my commuter and the chain line slightly favours the larger sprockets, it runs perfectly.
    If you do decide to use only 6 of the 8 sprockets it might be worth swapping the largest and smallest into the mix and adjusting their positions on the freehub to get the chainline right.

  11. #11
    Gravity Is Yer Friend dirtbikedude's Avatar
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    Quote Originally Posted by SpiderMike
    One thing I wish I had was a chain guide, like I've seen on some DH rigs. Something like the Kore Chain Reactor. http://www.kore-usa.com/index.html click Drive and go to Chain Reactor.
    The Reactor will take the slack out of the chain but it does float from side to side so you can shift gears and on a big enough hit can allow the chain to drop off. If you do not want to get new cranks then use the middle ring w/a bash guard on the out side. The easiest way to do this would be to get an MRP System 3

    You will get a bashring and a guide but no inner plate which will save some weight. It should bolt right up to your current cranks. I have found some crants wont accept the bash guard with out a bit of filling but it is not much.

    ;beer:

  12. #12
    Senior Member alcahueteria's Avatar
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    A friend of mine's urban bike is like that. The chain only popped off on me once when I borrowed it for two weeks, and that was after a jump. He had an inner and outer bashgaurd, but it didn't really do anything for the chainline.

  13. #13
    Keep Right Except to Pass
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    Here are my thoughts on the matter.

    I'm running sans FD on my freeride bike with 22-32-bash. Sometimes when going up I will manually shift to the 22T with my finger. Getting it back on the 32T is a little harder but not enough to worry about. **Be careful, I don't want someone getting a mangled digit.

    I only lose the chain every once in a while, maybe once or twice per rough ride.

    As far as chainline worries go, how many people are actually thinking about this and shifting chainrings to keep it on the most inline cogs consistantly? Chains are cheap so this doesn't concern me much.

    I would probably be running some kind of chainguide if they weren't so spendy.

    Cheers

  14. #14
    King of the Forest Totoro's Avatar
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    I have done it because I needed the front derailleur for a hybrid that I was building for my son. Anyway, I rode that bike around last summer and I never had any problems with it. Mind you, I kept the chain on the small chainring. For beginners, it may even help force a higher cadence. Beginning mountain bikers should rarely, if ever, use the large chainring.

  15. #15
    one less horse cryptid01's Avatar
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    Quote Originally Posted by mx_599
    Okay...so if people do this and it is not stupid, are the following assumptions correct?

    1) I can remove my front derailleur and shifter assembly from my handlebars.
    Yes, but why is your front derailleur attached to your handlebars in the first place?



    Quote Originally Posted by mx_599
    2) I can simply have a single sprocket and a bashring upfront.
    You will need some sort of chainguide also...I agree with dbd's recommendation of an MRP, but E.13 is also a popular option.



    Quote Originally Posted by mx_599
    3) The best choice of sprocket up front would be the middle one??
    Yep. Your chainline will be okay. You may consider a dedicated DH type ring rather than the stock one (which has ramps and pins to aid shifting and is therefore more prone to dropping the chain), but it hasn't been an issue for me with my System 3.

  16. #16
    Lost in the Black Hills mx_599's Avatar
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    Quote Originally Posted by gastro
    Yes, but why is your front derailleur attached to your handlebars in the first place?
    Okay, I worded that wrong!


    Quote Originally Posted by gastro
    You will need some sort of chainguide also...I agree with dbd's recommendation of an MRP, but E.13 is also a popular option.
    I was looking at that link to MRP. I am not familiar with these items yet. I need to investigate a little more and then probably post another question. But here are some initial questions:

    1) Do you need any specialty tools for installation of these?

    2) Do these items create a lot of drag...or not noticeable?

    3) Currently I have a Bullet Bros Chain tensioner (remember those?). Would this MRP device eliminate the need for the Bullet bros tensioner? Does the MRP as pictured in the link help to prevent chain slap as well?


    Quote Originally Posted by gastro
    Yep. Your chainline will be okay. You may consider a dedicated DH type ring rather than the stock one (which has ramps and pins to aid shifting and is therefore more prone to dropping the chain), but it hasn't been an issue for me with my System 3.
    1) If I were to buy a dedicated DH type are all the fitments pretty standard? I don't want to buy cranks or anything.

    2) What tooth # might you recommend?

    3) As another poster suggested, if I am understanding him right, I could rearrange the #1-8 cogs slightly to take advantage of greater gear variability without subjecting the chain to extreme angles.

    an arrangement of say... 2-1-3-4-5-6-8-7 cogs. Is this possible? A viable option?

    Before anyone says, "Why the hell is he doing all this?" I don't know? I guess when I think about it, I hardly use all 24 speeds so I was just thinking of how I could simplify the bike set-up without going to a single speed either.

    thanks
    Last edited by mx_599; 06-22-05 at 05:51 PM.

  17. #17
    one less horse cryptid01's Avatar
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    Quote Originally Posted by mx_599
    1) Do you need any specialty tools for installation of these?
    You will need the appropriate bottom bracket tool, as your '95 does not have ISCG mounts (three tapped holes concentric to the bottom bracket), and you'll have to sandwich the boomerang (or ISCG adapter) between the bb shell and the bb.


    Quote Originally Posted by mx_599
    2) Do these items create a lot of drag...or not noticeable?
    The MRPs are nearly unnoticeable. The E13's make more noise but I'm not sure if they create more drag.


    Quote Originally Posted by mx_599
    3)Would this MRP device eliminate the need for the Bullet bros tensioner? Does the MRP as pictured in the link help to prevent chain slap as well?

    Yes and Yes.


    Quote Originally Posted by mx_599
    1) If I were to buy a dedicated DH type are all the fitments pretty standard?

    Get the one that matches your crank's bolt pattern...5x110mm, 4x104mm, etc.


    Quote Originally Posted by mx_599
    2) What tooth # might you recommend?
    That's trial and error, dependent upon your bike, trails and personal preference.


    Quote Originally Posted by mx_599
    an arrangement of say... 2-1-3-4-5-6-8-7 cogs. Is this possible? A viable option?
    Yes and No.


    Quote Originally Posted by mx_599
    Before anyone says, "Why the hell is he doing all this?" I don't know?
    You can tell them it looks much cleaner, sounds quieter, simplifies maintenance, and forces you to become a more powerful climber because you don't have the bailout option.

  18. #18
    Lost in the Black Hills mx_599's Avatar
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    gastro....thanks for all that info. I need to look some things up now. Interesting.

    So changing the order of cogs is not something I should do? Does the reason for this have to do with shifting problems?

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    You might be able to shift from 1 to 3 easy enough, but shifting from 6 to 8 might be too much of a jump. Look at your cassette and work out which cogs you can do without.
    If you do stick with it you might want to get a custom cassette to optimise the ratios.

  20. #20
    Senior Member matheprat's Avatar
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    Quote Originally Posted by mx_599
    So changing the order of cogs is not something I should do? Does the reason for this have to do with shifting problems?
    To change the order of the cogs you MUST have a cassette, opposed to a freewheel. I assume you do? Then you'll need to separate the main cluster, probably by filing down the rivet holding them all together, and nocking it out with a hammer. You can, in theory, arrange the cogs in any order you want. However, I think the smallest cog must stay at the outside edge due to it's shape, and the way it fits on. Not sure about this though? If you don't plan on using the biggest cog (gear 1), then take it off and put a spacer there instead. That would look better than having some crazy arrangement of gears.
    And you could just leave your FD on the bike, locked out over the cog your using at the front (taking the cable and shifter off). It would help keep the chain on.

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