jgedwa

Not sure to ask this here or in the mtb forum.

I am contemplating buying a cheap crankset set up for my fixed gear snow bike. The crank I am thinking of comes with a narrow wide chainring (every other tooth is wide so that the chain does not slap around and jump off a set up without a front derailleur). The chain ring has an even number of teeth and so is meant to pair with even-numbered teeth cogs in back. Otherwise it will get out of cycle and get a wide tooth jammed into the alternate narrow chain gap. I currently have a cog on the rear with an odd number of teeth.

So, here is the question: Will the wide teeth of the chainring fit in both the narrow and wide gaps of a single-speed chain? Will it work? Any downside otherwise?

Thanks,

Jim

TejanoTrackie 

I think you will be OK with a 1/8" chain.

jgedwa

That is my hope. But has anyone actually tried it?

Jim

TejanoTrackie 

No, haven't tried it, but mathematically it should work. A narrow-wide chainring is designed to work with a 3/32" chain, and the wide teeth will be wider than the narrow teeth by about twice the thickness of the inner chain plates, which is less than the 1/32" difference between a 3/32" chain and a 1/8" chain.

jgedwa

That sounds pretty convincing to me. Thanks. Jim

squarenoise 

Even number of teeth up front, but shouldn't matter in the rear since these narrow/wide chainrings were designed 1x setups, right? I've never seen anything stating the rear cogs also have to be even numbered.

I'm super curious now because I was thinking about purchasing a narrow/wide for my 1x9 commuter setup.

Edit: Found some info on the MTB forum...

"The only way a chain can become out of sync is if the chain is lifted off the chainring and was placed 1 tooth away. It doesn't matter how many teeth are on the cog."

"The only issue I'm aware of with narrow-wide rings is that they don't play nice with half-links."

Digger Goreman

Sorry to highjack the thread, but could you elaborate on your 1x9 setup? I'm eventually headed this way but am struggling with gear inches vs hills.

veganbikes

Not to hijack your question but my 1x9 hybrid is a 38x11-32. Not great for hills should have gone with a 34+ but in the end it is not a hill bike it is a round town "beater" bike

jgedwa

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Geez. You are right. I am a bit embarrassed to say that I ws repeating something I had read somewhere but had not bothered to pause and think it through. Thanks for pointing it out. Jim

squarenoise 

It's very much a combo of personal preference, ride strength and types of roads/trails you'll be riding. All my road/touring triples are setup 50/40/30 up front and 12-28 rear and my compact doubles are 50/34 with 11-28 rear. On my triples, it's rare that I use the 30 up front and on my double I've only used the 34/28 combo on the toughest climbs. Soooo for me, a 1x9 setup of 40t chainring w/ a 11-32 cassette is just about perfect.

Around town and not a "hill bike" is exactly how I use my 1x9. It's mostly been a kid hauler, cruise to the park bike for me.

It's definitely a brain teaser and I had my doubts as to what the right answer was, haha!

Digger Goreman

Thanks Veganbikes and Squarenoise

My current commuter runs 22/32/42 with 11-32 on a Trek 800 Sport. That gets me 18-99 gear inches. A setup of 40 and 11-50 would capture most of that but exceed my derailleur (45 tooth). To please my CFO, I think I will eventually go with 36 up front and expand the cassette to 11-46 when it wears out.

The interim would give me 29-85 gear inches. I'm mostly ok with losing the rarely used 99 g.i. My operational range is mostly 24-84 gear inches with occasional dips to 20. An eventual 36x11-46 would give me 20-85.

Potentially stupid question: Is there a significant difference in effort to pedal 22x21 (27 g.i.) and 32x32 (26 g.i.)?

squarenoise 

I can't see it being super noticeable unless you were at your limit on a climb and needed just the tiniest bit more help.

Rolla

Yes. I've used a 1/8" chain on a narrow-wide chainring without any issues. But it kind of negates the advantages of the alternating tooth profiles.

BK268

I'm wondering if a narrow wide chainring will help for my issue,

I recently brought a cheep aluminium folding bike for a bike/train touring trip, (Dahoon v8)

i was anticipating selling it on my return, but I've actually somewhat fallen for it, but there are two big failures in the design,

1. The break and gear cables routes are ridiculous- I've sorted that,
2. the chain comes of the front chain ring occasionally when on he biggest rear sprocket, not because of chain jump, but because the chain angle is too much.

Will a narrow wide chainring solve this? or does it just solve chain jump on rough terrain?

I've tried changing the spacing on the rear wheel, but then it comes off on the smallest rear sprocket - it seems the change angle range between biggest and smallest spoken is to much for the chain ring.

any thoughts appreciated

TejanoTrackie 

Assuming you have a single chainring in front (no front derailleur), then definitely a narrow-wide chainring will help avoid unwanted chain drop. I had this problem with a 3x7 setup that I converted to 1x7 and removed the front derailleur, and a narrow-wide chainring cured it.

tombc

usually a folding bike has a 50+ tooth front sprocket to keep the gearing reasonable with the small wheels. I've been out of the folding bike store for a couple years now but I am not aware of any narrow wide chainrings in that size range. May exist though! I would also recommend a 10+ speed chain to prevent drops, cut as short as you can get away with to take out the chain slack. Clutch derailleur may be a good upgrade if you are running 8+ speed as well.

BK268

thanks really useful suggestions ill give them a go and get back to you

Nipo

Yes.

Also: In single-speed and fixed setups a narrow-wide chainring has no special value if the chainline is already straight (as it should be) and chain tension adjusted (as it should be).

But, what if one already has a narrow-wide chainring in a fixed bike? I guess it works just fine.

It could be good if the chainring and rear sprocket of a single-speed or a fixed gear bike had a hunting gear ratio.

That would be certain if the chainring had a prime number of teeth.