Gear Ratios

[Skipper]

I ride a hybrid with 48-38-28 on the chainring, and 28-11 on the cassette. Is there a difference between 48 front and 24 at the back, i.e. 2 to 1 ratio ..... and 28 front and 14 at the back, i.e. 2 to 1 ratio? Is the smaller chainring easier or harder to ride, even with the same front/back gear ratio? or does it not make any difference?
(technical explanation would be great ..... not just 'I find it easier' etc.)

 

[deanE]

You’ve given the technical explanation. Both are 2:1 and the same. You turn the pedals once and the wheel goes round twice. Whether you might find one easier than the other would, IMO, be all in the mind.

 

[Mile195]

Theoretically the latter would be more efficient. A smaller portion of the chain would be in contact with the chainrings and sprockets, resulting in less friction, although whether or not you'd notice any difference in the real world is a topic for debate.

However, in the latter scenario, the chain would also be slightly straighter I think. This will also result in less friction, as well as giving you better maximum chain, cassette and chainring life.

 

[Kookas]

Theoretically the latter would be more efficient. A smaller portion of the chain would be in contact with the chainrings and sprockets, resulting in less friction, although whether or not you'd notice any difference in the real world is a topic for debate.

However, in the latter scenario, the chain would also be slightly straighter I think. This will also result in less friction, as well as giving you better maximum chain, cassette and chainring life.

Is friction a factor, considering that the chain moves with the cogs and doesn't have to try to slide over them?

 

[Mile195]

Is friction a factor, considering that the chain moves with the cogs and doesn't have to try to slide over them?

The very action of the chain slipping onto the teeth of the sprockets causes friction. Any part that moves against another does. Then again, with the chain wrapped round the smaller chainring, the chain has to flex further to accomodate the smaller circumference, so you could say that would be more inefficient. At that point though, you're getting into differences in friction that scientific boffins would have to measure with scientific gizmos. Not amounts that you could really feel!

Either way, in the real world the likes of you or I would probably not notice any real difference between one configuration or the other whilst pedalling, although it still remains that the straighter the chain, the longer it will last overall.

Still a good original question though.

 

[GrasB]

Larger chain ring & sprockets are more efficient as they don't turn through as tight a corners. However you're looking at about 0.25~0.5% from what someone measured!

Extreme chainlines (big/big or small/small) may over-whelm sprocket efficiency but in he middle of the cassette it tend to be much of a muchness even on triples.