Originally Posted by
Carbon Unit
I know this subject has been beaten to death so I am not going to ask about the pros and cons. What I am interested in is anyone that has gone from a triple to a compact, has your front Dr shifting gone down or up?
Much, much, much, much more with the compact. More than 10X more often since every transition from dead flat to a false flat up-hill and back again meant a front shift from 50x21 to 34x15 as speed dropped below 17 MPH and back again from 34x14 to 50x19 once it went back above 19 MPH.
For those of you that have gone from the triple to the compact, do you miss the triple at all?
I dropped the compact in one of my spare parts boxes and regret waiting as long as I did.
While you can get the same range and spacing with a compact crank that you used to get with fewer cogs on a triple that doesn't tell the whole story (I'd been riding 50-40-30 x 13-14-15-16-17-18-19-21 and migrated to 50-34x13-14-15-16-17-18-19-21-23 after wearing out parts because the range and spacing were the same and 2 rings must be better than 3).
When you run the numbers taking into account that a given rear cog acts like one 2 bigger with a 34 ring instead of a 39 and that the middle ring is centered on the rear cluster which provides an acceptable chainline for the smallest and largest cogs you notice that you can put out 90% more power on flat ground using a cassette with the same starting cog before you need to shift to the big ring.
My blanket advice would be that if you're not strong enough to spin a 39x21, 23, or 26 (depending on whether you prefer an 11, 12, or 13 starting cog and assuming only 10 cogs in back - you can add a gear with 11) up the vast majority of climbs in your area and still manage the rest stick with a triple and consider a smaller granny ring. You'll get less front shifting and tighter spacing in back.