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Old 09-20-10, 11:26 AM   #1
bcemail
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Downsizing from 21 gears?

Hi,
I have a Giant MTB that I ride on either roads or fairly benign trails. Not jumping over boulders or pedaling straight up a mountain or anything. My bike has 3x8 gears, and I find myself not using the majority of them. Also, I think a lot of the time a shift of one gear is pretty useless, and I would rather just pedal a little harder or easier than shift through a few gears.

So, is it feasible to switch from this set up to something with 8-10 gears? I was looking at sites that sell derailleurs, but wasn't sure what I would need. Could I leave the front derailleur as is and just use the middle hub, then switch out the rear one, or will I need 2 new ones? What should I look for as far as number of gears, ratios, etc.? I'm don't know a whole lot about this stuff, but would like to get something that works for not too much $$ (don't need anything super fancy, lightweight, etc.).

Any help or ideas you can provide would be greatly appreciated! Thanks!
Brian
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Old 09-20-10, 11:31 AM   #2
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You could just toss the front shifter and derailleur and only use the back; just position the chain on the middle chainring on the crank.
Some cranks are set up to have removable chainrings, so you could save a couple of ounces by tossing the two unused ones.
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Old 09-20-10, 11:32 AM   #3
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The simplest option would be to choose one of the chainrings, remove the front derailleur, and use the rear as-is, creating a 1x8 setup. Of course, this will limit the range of gear ratios available, but if you spend most of your time on one chainring, it shouldn't be much of an issue.
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Old 09-20-10, 12:04 PM   #4
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Yes , the Middle chainring is the right location If you reduce to just one , adjust the size of that chain-ring to suit..

figure out the ratios with this site: http://sheldonbrown.com/gears/
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Old 09-20-10, 12:19 PM   #5
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3x8=24
You don't really have 24 useable gears now but with a single ring you will have 8 gears available.
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Old 09-20-10, 05:45 PM   #6
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Thanks for all the help! (and JanMM, thanks for the math lesson, d'oh!)

I was considering just losing my left shifter, but if I did switch out the rear derailleur, are there ones that have a larger range/ratio? What kind of ratio should I look for to give me a wide range of sizes over 8 gears, to cover some hills and some power?

I'm still working on figuring out my current ratio with the Sheldon Brown calculator...

Thanks again!
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Old 09-20-10, 06:46 PM   #7
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Just don't shift into gears you don't use. Problem solved at no cost!
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Old 09-20-10, 06:47 PM   #8
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The rear derailleur is the cage like thing with 2 pulleys that makes the chain move from cog to cog. Changing that will do nothing to your gear ratios.
What you appear to be asking about is swapping out the cassette (the stack of cogs on the rear wheel) to a wider range. Depending on what you have on there now, you may already have about as wide a range as is available in a cassette. Seeing as it a MTB, this is probably so. In that case, if you don't have enough gear range you will need more than one chain-ring on the front to get the range.
To be honest, I don't think this is really worth putting any money into. Just leave the front in the middle ring and shift two gears at a time for the rear. I think that as you ride more you may find yourself wanting those closer steps in the shift pattern. I know that on my road bike with a much narrower cassette range, there's still a couple of steps I'd like to tighten up if I could only get strong enough to ditch the larger cogs.
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Old 09-20-10, 06:59 PM   #9
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Quote:
Originally Posted by waldowales View Post
Just don't shift into gears you don't use. Problem solved at no cost!
+1
Leave it alone! Changing derailleurs will NOT change gearing.
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Old 09-20-10, 07:04 PM   #10
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If you ride more and in new places you might want the missing gears. Lust leave it in the middle ring if you like.
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Old 09-20-10, 10:01 PM   #11
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I could get buy on a 1x7 set up something like a 44t front and a 11-13-15-18-21-26-34
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Old 09-21-10, 07:46 AM   #12
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How long have you been riding? You certainly can do this to your bike with no harm if you like, but, this is usually a question asked by people who don't ride much. Later on they get used to the gears.
Everyone is different, riding conditions vary too, but the 1x7 might work for you, there's no way to be 100% sure by reading a description on a forum. Your description of your riding conditions is very good, better than most, but, no one can be sure exactly what is right for you without trying it. What size is your middle ring now? I'm guessing that's guiding you to your idea for a 44t front. Sounds about right.
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Old 09-21-10, 08:43 AM   #13
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this really doesn't make sense to do. if you dont' want to use the gears, don't use them! what would probably benefit you is changing your casette on the back. do you know what the tooth counts are? i have an 11-32 on my road bike my gf has 12-25 on her bike. I put her wheel on my bike and it was weird shifting and not really feeling th edifference in gearing. on my bike there is definately a jump in the gearing.
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Old 09-21-10, 08:55 AM   #14
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Going with a 1x drivetrain is pretty popular, and it works for many situations.

Try riding with the chain in the middle ring up front, and ride as you would, but only use the rear derailleur. See how you like it.
If you do like it, you can clean up the drivetrain by removing the extraneous rings and the cables. You'll need to either keep the front derailleur as a guide or use something like this http://www.paulcomp.com/chainkeeper.html to keep the chain from derailing when in your lowest and highest gears.

You can fine tune the ratios, as has been mentioned - say a 44T front with an 11-32 cassette.

That's the best way to do it on the cheap.

If you want simplicity and utility and a similar gear range, an internally geared hub is an elegant solution, but at a cost.
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