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Old 05-13-08, 09:41 PM   #1
Lurker1999
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Nashbar basic mountain crank triple into single?

I rarely shift out of the large chainring on my daily commute, preferring instead to use my rear derailleur (partially because my front derailleur sucks). The large 42t chainring on the crank is probably going to survive just this chain replacement before it's due to be replaced as well. I was thinking of going from a triple to a single chainring up front.

I read through Sheldon Brown's single speed page but it mainly focuses on the rear where I'd prefer to keep my 7 speed cassette. However I could ditch the front derailleur, shifter and the inner two chainrings. Any place I could read up on how to do this? Any problems people forsee with this?

Also does Nashbar sell a 42t chainring? I see them listing a 44t chainring replacement on the website but it's currently out of stock.
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Old 05-13-08, 09:59 PM   #2
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Also does Nashbar sell a 42t chainring? I see them listing a 44t chainring replacement on the website but it's currently out of stock.
I think I have two 42-32-22 cranksets removed from my two MTBs so I could add a trekking crankset (48-38-28) to each bike (2003 Giant Rainier, 2005 Raleigh M50-DX). Neither has much use.

If I am able to separate the rings, I may be willing to part with the 42 for beer money and postage
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Old 05-13-08, 10:00 PM   #3
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For better chainline with a 1x7 setup, may want to think about putting the 42T chainring in the middle position of the crank. Whether you put the single ring in the outer or middle position, you'll need shorter, single-speed/BMX chainring bolts. You can get them from your local bike shop.

No need to buy a whole new crank, especially if you're only going to use one chainring. Any 42T chainring with 4-bolt, 104mm BCD should do.
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Old 05-13-08, 10:07 PM   #4
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Mount your 42 tooth ring in the center and put one of these http://www.ebikestop.com/raceface_ba...olt-CR6719.php on the outside. Granted, $30 is kind of spendy. But I didn't really shop around looking for the picture. And there might be a cheaper used one on Craig's list.

I ride a 1x8 drive train on my Crosscheck... a 42 ring on the inside of a 5 bolt road double, with a Spot brand bash ring on the outside.

DanO
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Old 05-13-08, 10:14 PM   #5
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This thread has me thinking about going to one ring to rule them all. I've relied on triples for so long here in hilly Colorado, but I am using the granny ring less than 5% of the time now, I'd estimate. The 48T ring would kick my ass on hills, especially since I just went to a 11-26 cassette.

Riddle me this - can I remove the small ring, leaving me a 48-38, without making too drastic of mods to the shifter to prevent me from accidentally shifting the chain off the sprocket?

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Old 05-13-08, 10:31 PM   #6
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Riddle me this - can I remove the small ring, leaving me a 48-38, without making to drastic of mods to the shifter to prevent me from accidentally shifting the chain off the sprocket?
You'll need to screw in the low-limit screw. To do it right, you should tighten the cable so you use position 1 of the shifter for the middle/inner ring and position 2 for the outer ring.
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Old 05-14-08, 11:20 AM   #7
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You can pull two of the three rings, put the one you want in the middle position, and adjust the limit screws on your FD to keep it in place as a chain guide. You might not need to do this if your commute is smooth riding, but it's helpful if the terrain is dicey and you don't want to drop your chain. Or you could buy a function - specific single-ring chain guide.
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Old 05-15-08, 03:04 PM   #8
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Thanks for all the feedback. How do I go about acquiring the parts to mount a 42t chainring in the middle position? Also how can I find out whether a setup will fit my existing 68mmx113m bottom bracket?
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Old 05-15-08, 04:55 PM   #9
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Thanks for all the feedback. How do I go about acquiring the parts to mount a 42t chainring in the middle position? Also how can I find out whether a setup will fit my existing 68mmx113m bottom bracket?
All you need is shorter, BMX/single-speed chainring bolts. Just go to a bike shop. Or, here's the first eBay item that popped up: http://cgi.ebay.com/Odyssey-Silver-B...QQcmdZViewItem

If you're not changing the crank, don't worry about the bottom bracket. You're essentially just using the middle chaining only and it happens to be larger than normal. The middle ring can work okay with all the cogs in the back. One concern though, since the middle ring will be bigger than usual, make sure it doesn't get too close or touch the chainstay.
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Old 05-15-08, 06:16 PM   #10
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This thread has me thinking about going to one ring to rule them all. I've relied on triples for so long here in hilly Colorado, but I am using the granny ring less than 5% of the time now, I'd estimate. The 48T ring would kick my ass on hills, especially since I just went to a 11-26 cassette.

Riddle me this - can I remove the small ring, leaving me a 48-38, without making too drastic of mods to the shifter to prevent me from accidentally shifting the chain off the sprocket?
Wouldn't it be nice to have the granny for that 5%? What's the benefit of removing it?
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