Compact vs Triple - Adequate Replacement ?

litespeedguy said:

Compact cranks have been touted as providing a boost on hills for older riders over the standard double crankset - has anyone gone from a triple to compact and has the compact turned out to be an adequate replacement over the triple for various terrain changes ?

I switched from a triple to a 50/34 front and 12/27 rear (10 speed) and it has been great (lots of hills in north Atlanta area) the 34/27 is almost equal to my bail-out gear 30/25 and the front shifting is smooth as silk. There is also a SRAM 12/28 10 speed cassette but I've never tried it with a Shimano drivetrain.

It really depends on what rear cassette you are using with your triple, and which of the lowest and highest gears you actually need. For instance, if you're largest sprocket is a 25, with your 30t triple, and this is adequate for your riding, you can probably get awfully close with a 34t compact and a 28 - but your spacing will be wider of course. If you're like me and have a 26 (or 27) as the largest sprocket with a 30T triple, AND need every bit of low gearing you have, the 28 cog rear with a 34t compact won't get there; you'll probably feel like you're missing the lowest gear that you used to have.

Another factor whichis significant - to me - is the high end. Your compact 50t won't get you the same high gears as the triple 52t even if you go from 52/12 to 50/11. Again, it might be close enough depending on how you currently use your gears on the high end.

Sheldonbrown.com has a gear calculator which can compare your current set up with what you're thinking of getting so you can see what the new highest and lowest gear would be compared to your current set up, and if it would be meaningful to you.

Obviously I'm a big fan of triples because, other than some small amount of weight, I haven't seen any disadvantage of my triple for my terrain and ability: it shifts flawlessly, it has a very versitile gear set up with very little front shifting needed under normal rolling hills (spend a lot of time on the 42t middle ring), it has both lower and higher gears than I could achieve with any compact, and has narrower jumps for both front and rear shifting to boot. But I'm a middle aged guy who lives in a very hilly area and I like to enjoy the long steep uphills and go 40+ mph downhill.

Camilo said:

It really depends on what rear cassette you are using with your triple, and which of the lowest and highest gears you actually need.

And it depends on the rider. 20 nominal ratios should be plenty, but if you need to go lower than, say, 34/27, you'll probably be happier with a triple.

Regarding the upper end, remember that until the 70s a 14-tooth rear cog was the smallest available. 53/13 was standard until the pros started using 53/12 towards the end of that decade.

I use a 50/36 compact, and the 11 only gets used when I'm going over 31 mph.

Camilo said:

Another factor whichis significant - to me - is the high end. Your compact 50t won't get you the same high gears as the triple 52t even if you go from 52/12 to 50/11. Again, it might be close enough depending on how you currently use your gears on the high end.

For the record, 50/11 is a bigger (higher) gear combo than 52/12.

litespeedguy said:

Compact cranks have been touted as providing a boost on hills for older riders over the standard double crankset - has anyone gone from a triple to compact and has the compact turned out to be an adequate replacement over the triple for various terrain changes ?

Some undoubtedly have but your choice of gearing is specific to you and your needs. No real advantage of compact vs triple with modern shifting systems if you are looking for lowest gears. if a 34-27/28/29(Campag) is low enough, then sure. If not, triple.