Chainring sizes

[sayek1]

Hi,

Looking at a couple of different bikes I am trying to understand how much difference there will be between a bike that has a 50x36 chainring and another that has 50x39x30

Most of the time (95%) I never use the lowest chainring of my current three, but I do have a few hills once in a while?

The bike with only two chainrings is in Halfords and therefore I am unlikely to be able to give it a good testride.

Any thoughts

Thanks
K

 

[davidg]

are the cassettes the same on both? and what is the cassette size?

when I was looking it was argued that a triple has much move overlap and therefore quite a bit that you wouldnt need while a compact is much more straight forward....most compacts are 50x34 which is why I ask about the cassette.

also the extra low gears on the triples I have looked act have been around 10% easier, so not crazy amounts easier and only for really steep hills imo


I would look at your current set up and the ratios on there, see what the lowest y ou have ever used is and then you have a ref point...

sheldon brown can help with the ratios if the rings/cassettes are not the same
http://www.sheldonbrown.com/gears/

 

[jay clock]

I have a compact double with 50-34 and a triple with 50 40 30. In fact I find the latter good as I can use the 40 a large amount of the time without changing ( I can get up to 30kmh easily)