39t or 50t for my 9 speed mod

39t or 50t for my 9 speed mod

Postby Bugs71 » Sun Sep 15, 2013 5:43 pm

Hey guys,

Looking for some advice and wisdom about gearing options for one of my Comet hack roadies I have. I have a 9 speed cassette (11-25) but can't decide on the chain wheel size between 39 or 50. My commute is pretty flat bar two hills that have me on the 39 but they're doable with the 50 in 23 or 25. I love to hit to speeds so I'm worried I'll be spinning like crazy on 39. Should I just bite the bullet and go the 50 up front? Have any others gone from 27 or 18 to a 9 speed with a single chain wheel. If so what size chain wheel did you go for?

Bugs.
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by BNA » Wed Sep 25, 2013 1:23 am

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Re: 39t or 50t for my 9 speed mod

Postby Dragster1 » Wed Sep 25, 2013 1:23 am

The 50 would be fine for the road specially if most of it is on the flat
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Re: 39t or 50t for my 9 speed mod

Postby elantra » Wed Sep 25, 2013 11:57 am

Dragster1 wrote:The 50 would be fine for the road specially if most of it is on the flat


My experience with running single chainrings up front is that you must use an inner chainring as the one and only chainring.

Outer chainrings have shallower profile teeth and the chain tends to come off if there is no front derailleur cage, which is quite a nuisance.

It is not that hard to find inner chainrings as big as 44 teeth.

even better have 2 inner chainrings mounted on the crankarms, say one that is 39 teeth and one that is 44 teeth, that gives you the option of manually selecting which is the more appropriate for the riding conditions you are faced with on the day.

Hope i have not confused you there, i have a bike set up like that which i use for light touring. can photo if need be.
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Re: 39t or 50t for my 9 speed mod

Postby Dragster1 » Wed Sep 25, 2013 2:28 pm

elantra wrote:
Dragster1 wrote:The 50 would be fine for the road specially if most of it is on the flat


My experience with running single chainrings up front is that you must use an inner chainring as the one and only chainring.

Outer chainrings have shallower profile teeth and the chain tends to come off if there is no front derailleur cage, which is quite a nuisance.

It is not that hard to find inner chainrings as big as 44 teeth.

even better have 2 inner chainrings mounted on the crankarms, say one that is 39 teeth and one that is 44 teeth, that gives you the option of manually selecting which is the more appropriate for the riding conditions you are faced with on the day.

Hope i have not confused you there, i have a bike set up like that which i use for light touring. can photo if need be.

Agree best of running two chain rings but If your worried about dropping the chain leave the cage on. I would out spin a 44 and 11 no problems and the bike is about 13kg with 2" tyres. I run a 52 28 chain ring 11 32 cassette hardly ever use the 28 only on steep hill climbs.
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Re: 39t or 50t for my 9 speed mod

Postby rkelsen » Wed Sep 25, 2013 3:37 pm

Depends on what you want out of it.

My 1x8 has a 42t chainring. 42/11 is enough for me to hit 50kph on the flat, but that is because I struggle to do much more than 105rpm.

At 100rpm with 39/11, you'd be doing about 45kph.

Obviously, you'll spin out if you want to go much faster than that.
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Re: 39t or 50t for my 9 speed mod

Postby Dragster1 » Wed Sep 25, 2013 4:24 pm

Dragster1 wrote:
elantra wrote:
Dragster1 wrote:The 50 would be fine for the road specially if most of it is on the flat


My experience with running single chainrings up front is that you must use an inner chainring as the one and only chainring.

Outer chainrings have shallower profile teeth and the chain tends to come off if there is no front derailleur cage, which is quite a nuisance.

It is not that hard to find inner chainrings as big as 44 teeth.

even better have 2 inner chainrings mounted on the crankarms, say one that is 39 teeth and one that is 44 teeth, that gives you the option of manually selecting which is the more appropriate for the riding conditions you are faced with on the day.

Hope i have not confused you there, i have a bike set up like that which i use for light touring. can photo if need be.

Agree best of running two chain rings but If your worried about dropping the chain leave the cage on. I would out spin a 44 and 11 no problems and the bike is about 13kg with 2" tyres. I run a 52 28 chain ring 11 32 cassette hardly ever use the 28 only on steep hill climbs.

Forgot to mention I have a 26er
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