Gearing Question

[rplace13]

Hello,

Long time biker but new to the fixie craze. I am digging my new (old) bike revived as a fixed gear machine. So much so that I am going to attempt my anual MS 150 on it. I am currently able to struggle up all the toughest hills in my area with a 42/16. But it is a bit lacking on the flats in the speed department.

The MS 150 I do is on the Eastern Shore of Virginia and is pancake flat. This weekend I was playing around with my multi speed bike and figured that a 53 with a 15 or 16 was about right for me on the flats with slight inclines or small hills for keeping it between 17 and 20MPH. That is about the speed my flat land friends I visit in VA maintain for the MS 150.

So on to my question. Does it ultimatly matter how you come up with the gearing you want as long as you get what you want? Or do I need to change both the front and the rear? Not sure the numbers are exact, but for the sake of argement is a 53/16 the same as a 50/15 or a 47/14 or a 42/13? If there is a difference why; and is it better to arrive at that gearing with a smaller chainring and smaller sprocket or bigger chainring and bigger sprocket? I currently have a 39, 42 and 53 for that particular crank so it would be nice to swap my 42 for the 53 and be done.

Bonus question. I have an ENO hub on the bike (vertical rear dropouts). I have yet to need to flip it over and use my freewheel. It happens to be a 17 tooth. Anybody have any experiance in knowing how many teeth difference you can take up the slack on an ENO hub?

Thanks!

 

[joblue]

Its pure algebra...divide the chainring number by the cog number...you will get a gear ratio. You can now compare that with any other combination (the higher the number, the harder it is to pedal)

 

[mircozorzo]

Hi, for transmission's efficiency is better the combination with the major number of teeth.

Hi, Mirco

 

[oldbobcat]

That 53/16 combination is going to be a leg-breaker on any sort of incline or headwind. With cadence training you should be able to hit that 17-20 mph range with the 42/16. The lower gearing and higher cadence will give your legs the torque to power through hills and headwinds. 42/15 will give you a little more top end for downhill or downwind.

For my fixed-gear training rides on rolling terrain, 44/16 gives me enough top end that I'm not spinning out on the downhills. I started with the 15 that came with my wheels, but it was just too much gear.

 

[Akadat]

Gears are there for the takin. No harm in takin what's available for better enjoyment. A fixed gear is for a fixed environment either internal or external.

 

[benson]

I have a 53/39 crankset that can't be removed (majorly stripped threads). What's the best cog size to make this a single speed? I live in a hilly area. Thanks!

 

[alfeng]

Originally Posted by benson .

I have a 53/39 crankset that can't be removed (majorly stripped threads). What's the best cog size to make this a single speed? I live in a hilly area.

Are you saying that you can't remove the chainrings?

Regardless, choose a gear combination & ride around with your current bike without shifting ...decide what cog works for whichever chainring you are using for the most of the inclines you encounter. Try another combination. And then, another. One will be better than the rest.


BTW. Whereas oldbobcat has a 44t chainring & a 16t cog, I happened to choose a 50t chainring & an 18t cog on one bike to achieve basically the same gear ratio.