# 1X setup on 2X crank



## V1Rotate (Jun 29, 2017)

Hey all! New here so I apologize if this is covered elsewhere but a search was fruitless. 
Anyway I have a 2017 rockhopper pro 29er that has a 2x crank that I'm converting to a 1x setup. Where I ride has lots of steep climbs/etc so I'm replacing the current 22/36T setup with a single 30T chainring that. The plan currently (since the crank is brand new) is to simply remove the larger chainring altogether from the 104 bcd position and replace the 64 bcd 22T with the 30T 64 (absolute black) until I wear out the current crank and upgrade to a dedicated 1x. I like the chainline from the 64 bcd position better than the 104 and it would be a direct swap instead of spacers, etc. Doing so will leave the holes in the crank where the larger chainring mounted. Is there any reason this isn't desired other than aesthetics? Any way to fill those holes to make it look less goofy other than adding washers to the original chainring bolts and putting them back in there? Thanks!


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## mack_turtle (Jan 6, 2009)

what crankset is this? you might be able to replace the big ring with a bash ring. I thought there were some 104 BCD 30t rings on the market, probably with some spacers so the chain will clear the spider arms.


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## Slash5 (Nov 27, 2011)

Should work fine. Make sure you have clearance at the chainstay for a 30T in that position. Put a bash guard on the outer position.


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## V1Rotate (Jun 29, 2017)

mack_turtle said:


> what crankset is this? you might be able to replace the big ring with a bash ring. I thought there were some 104 BCD 30t rings on the market, probably with some spacers so the chain will clear the spider arms.


Specialized stout xc crankset. There are definitely a few 104 BCD 30T rings out there I just like the idea of not having to buy different bolts and spacers to adjust the chainline. Sounds like a bash guard may be the way to go to fill the void.

Looking at it I should definitely have room for a 30T in the 64 bcd position but if for some reason I don't then that'll make the decision easy I guess


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## Crazy_Nate (Jun 18, 2017)

Isn't the large chainring on a 2x setup the "middle" position? I put a raceface NW 30T (104 BCD) on mine (2014 rockhopper comp 29er). I went with a Sunrace 11-42 ten speed cassette in the rear, which worked fine with my stock derailleur. I did have to buy some bolts to do the chainring, but it wasn't too pricey. I didn't need any spacers for mounting it up on my crankset (check it here: https://www.raceface.com/media/Narrow_wide_ring_installation_guide.pdf )


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## V1Rotate (Jun 29, 2017)

Crazy_Nate said:


> Isn't the large chainring on a 2x setup the "middle" position? I put a raceface NW 30T (104 BCD) on mine (2014 rockhopper comp 29er). I went with a Sunrace 11-42 ten speed cassette in the rear, which worked fine with my stock derailleur. I did have to buy some bolts to do the chainring, but it wasn't too pricey. I didn't need any spacers for mounting it up on my crankset (check it here: https://www.raceface.com/media/Narrow_wide_ring_installation_guide.pdf )


Thanks for the link to the chart! I'll look again at the chainline from the 104 front position to the back of my current 11/36T. I feel like either way would accomplish just about the same thing at this point, mounting to the 104 bcd position definitely gives me more options though


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## V1Rotate (Jun 29, 2017)

Crazy_Nate said:


> Isn't the large chainring on a 2x setup the "middle" position? I put a raceface NW 30T (104 BCD) on mine (2014 rockhopper comp 29er). I went with a Sunrace 11-42 ten speed cassette in the rear, which worked fine with my stock derailleur. I did have to buy some bolts to do the chainring, but it wasn't too pricey. I didn't need any spacers for mounting it up on my crankset (check it here: https://www.raceface.com/media/Narrow_wide_ring_installation_guide.pdf )


Also, what size bolts did you buy for the new RF chainring? According to the chart without tabs it looks like 8.5mm works. Googling "single chainring bolts" it seems the popular size is just a bit smaller than that at 7mm or so, perhaps the difference being the design of the RF ring itself. The 30T 104bcd appears to be threaded as well as some built in spacer tabs so I just wanted to make sure those will work


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## J.B. Weld (Aug 13, 2012)

Crazy_Nate said:


> Isn't the large chainring on a 2x setup the "middle" position?


Actually the small ring is usually near dead center of the cassette and the big ring is several mm's outboard. A lot of times the 104 bcd position spaced slightly inboard works better for various reasons but the 64bcd position can be perfect in many circumstances. As mentioned some rings have built in spacers.


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## eb1888 (Jan 27, 2012)

You'll want to retain your front derailleur or go narrow wide ring with a plus rear derailleur which hopefully you've already got.


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## cjsb (Mar 4, 2009)

If you want lower gearing AND narrow wide to prevent chain drops, consider keeping the 22T as is and replacing the 36T with a 32t narrow wide (or similar). If you have really steep climbs you can manually move the chain to the 22T. Just my own preferences, but 30t is too low for normal riding but not low enough for very steep climbs.


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## J.B. Weld (Aug 13, 2012)

cjsb said:


> If you want lower gearing AND narrow wide to prevent chain drops, consider keeping the 22T as is and replacing the 36T with a 32t narrow wide (or similar). If you have really steep climbs you can manually move the chain to the 22T. Just my own preferences, but 30t is too low for normal riding but not low enough for very steep climbs.


That works but then you have to live with the 32t being in a sub-optimal chainline position because it can't be spaced inboard.


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## cjsb (Mar 4, 2009)

J.B. Weld said:


> That works but then you have to live with the 32t being in a sub-optimal chainline position because it can't be spaced inboard.


That's the drawback, but I figure no different than the OEM setup with respect to chainline.

I'm not in my 42T in the back much for the normal trails I ride so the chain line trade-off is minimized for me. I like having the 24t for really steep climbs.

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## V1Rotate (Jun 29, 2017)

eb1888 said:


> You'll want to retain your front derailleur or go narrow wide ring with a plus rear derailleur which hopefully you've already got.


Definitely getting a narrow/wide ring whichever bcd I go with and yep, I'm currently running an XT shadow plus RD so should be set.



cjsb said:


> If you want lower gearing AND narrow wide to prevent chain drops, consider keeping the 22T as is and replacing the 36T with a 32t narrow wide (or similar). If you have really steep climbs you can manually move the chain to the 22T. Just my own preferences, but 30t is too low for normal riding but not low enough for very steep climbs.
> 
> Sent from my iPad using Tapatalk


At the 3 places I ride most often I haven't used the 36T even once.. seems the overlap just isn't worth the hassle. With that said I only heavily use the smallest 5 or 6 cogs of my 10 speed cassette and don't have a problem with spinning out really. In my mind a 30T would actually widen the number of cogs I use in the rear due to needing to use the remaining 4 or 5 larger cogs I don't currently need to use for climbs but also give me more speed on the other end compared to the 22T. I Will probably pick up a 34T as well to have around for trips to more open/faster/flatter trails.

I think I've decided on the RF 30T 104bcd narrow/wide ring since it also allows me to use some existing hardware since the 30T ring is threaded and it's spaced for an acceptable chain line from that position.


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