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Converting a full front and rear derailleur to only a Rear derailleur.

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Converting a full front and rear derailleur to only a Rear derailleur.

Old 01-13-13, 01:57 AM
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TrebelC
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Converting a full front and rear derailleur to only a Rear derailleur.

So as a project I'm planning on doing, I want to convert a bike of mine from a 21 speed to only a 7 speed. So it'll have 7 gears on the rear derailleur and only one chainring replacing the front derailleur. How would I begin to do this? And what tools might I need for a painless as possible conversion. I also will need a chain guide similar to this:


Thanks a lot guys.
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Old 01-13-13, 05:02 AM
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I've never done this conversion but I always assumed you just take off one shifter, the front derailer and the chainrings, then you put on a single chainring of your choice on the inside of the spider? If you don't have a chain guide before the conversion, why would you need one after? Or are you going to use the bike for downhill afterwards?

I actually did this conversion on my road bike that I made fixed gear, come to think of it.
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Old 01-13-13, 05:19 AM
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i have a 1x7 and you do need something to keep the chain on the front ring, especially when riding off road. that chain guide looks like it would work.. a bash ring and an chain guide mounted like a front derailleur would also work
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Old 01-13-13, 11:32 AM
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If you don't have a chain guide before the conversion, why would you need one after? Or are you going to use the bike for downhill afterwards?
Yeah that was my intent to do some downhill and whatnot. And the chain slipping and slapping is getting on my nerves.
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Old 01-14-13, 02:23 AM
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Remove shifter/cable/housing/derailleur (obviously) and remove the small and big chainrings.


Helping to clarify for us what the bike is and the parts on it would help. Do you want to run a bash ring or not? Full upper and lower guide, or upper only? If your bike is old enough to have 7 speed parts - think carefully about its intended useage vs. what you want it to do. How much do you want to spend? What's the BCD of the cranks/rings you have on there?

http://www.jensonusa.com/Chain-Tensi...-Guides?pg=100

Just a sampling of what's out there, to buy complete, or peice together the bits you need to make something work with whatever you've already go.
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Old 01-14-13, 05:04 AM
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One more thing: just taking off the small and large chainrings is a suboptimal solution because the middle ring has shortened teeth with odd profiles and whatnot to aid shifting, which you don't need. Best to switch to an actual single chainring with full size teeth.
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Old 01-14-13, 07:00 AM
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Originally Posted by xlDooM View Post
One more thing: just taking off the small and large chainrings is a suboptimal solution because the middle ring has shortened teeth with odd profiles and whatnot to aid shifting, which you don't need. Best to switch to an actual single chainring with full size teeth.
Less a big deal though, if he's on a budget and wants to really use a guide. I've done plenty of single ring and SS setups with ramped rings. So long as your chainline and guide setup is good, no trouble. Replace the ramped ring once it dies with a SS ring.
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Old 01-14-13, 11:54 AM
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If you're really on a budget, leave the front derailleur on and lower it closer to the chainring. You could even bend the sides of the cage inward to help keep it lined up.
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Old 01-16-13, 12:01 AM
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your front derailer will work as a chain guide, just use the adjustment screws to lock it over the middle chain ring. I had to do this on one of my bikes until I got an unramped chainring for it.
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Old 01-16-13, 01:58 PM
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Recheck chain length too. If you are taking off a big ring( assuming you have a triple) , you will want to shorten the chain.
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