1x9 with Square Taper BB
I came across a very well-cared for 1992 Merlin MTB frame and am looking to build it up. This will be my first time building up a geared bike and I could use some direction.
From what I know, the frame has a square taper press-fit grease guard BB. I know that by keeping it in, my cranksets are limited but its in working condition.
I want to build it up as 1x9 as I never use the front derailleur on my Cross Check and it looks much cleaner. However I can't find any kits that would fit the BB.
Could I simply use a NW ring to replace the stock rings on any 2/3 ring crankset that fits? I have no idea how removing the front derailleur affects the rest of the drive train's compatibility. Would even a single speed crankset be fine?
Anything else I need to be aware of? Suggestions would be great, budget is not an issue as I am taking my time with this.
Thanks in advance.
Posted Dec 18, 2017, 2:07 AM UTC
Yes, make sure to position the new ring correctly to get a good chainline though. Usually in place of the middle ring (of a 3x crankset) gets it lined up.
This should do it. Use the existing crank and slap on a narrow-wide, or even just keep the existing chainring and put on a chain guide (Problem Solvers has one). These systems work best with Type II/clutched derailleur, but I don't think those are available in 9spd. I've done it with a standard 9spd derailleur, normal chainring, and chain guide and it worked out just fine.
Using the existing crank and middle chainring spot, it may look kind of funky with nothing on the outside spot, but you could throw on a bash guard.
Isn't the whole point of a NW chainring to eliminate the need for a clutch in 1 x X setups? That the design prevents the chain from dropping while shifting?
No, the N/W chainring eliminates the need for the chain guide. I think about every derailleur (at least mountain bike, not sure on road) is the type II variety now.
Neat. Thanks for clearing that up for me.
Thanks! I'm okay with it looking funky. There isn't a crankset on it so I've been trying to figure out what to buy. Do I have to worry about the speed labeled on the crankset if I'm only using one ring?
Would something like this be fine with a NW chainring attached?
No.
Yes. But you can probably spend less.
for the price of that thing, you could get a modern shimano hollowtech 2 crankset and BB, assuming the bike's bb shell 68mm is threaded
Yeah for sure, I was just using that as an example. I can find something similar for much cheaper locally. The shell isn't threaded and uses a different type of BB so I can't switch it easily.
You may want to verify this, but I also don't think N/W chain rings exist for 9spd, but a 10spd one should work alright, I think. You'll just need to make sure the dimensions of your chainring will fit the bb.