Compact question for you “gear” heads

[sellsworth]

I’m looking at an ad for FSA compact cranks. I’ve been thinking about the advantages of compact gearing so the ad caught my attention. I’ve been thinking of pairing a 50/34 compact crank with an 11/23 cassette. Right now I have a 53/39 crank with a 12/27 cassette. In the ad there is a little chart comparing compact vs. standard gearing. The chart states that a 34 x 23 combo is approximately equal to a 39 x 26. Is this right? If it is then I don’t see any advantage to the switch in terms of gaining access to a higher gear.

[Dave]

I like my FSA cranks, but there recent ad is mostly baloney, aimed at selling compact cranks.

It's simple to figure out an "equivalent gear". For example, 26/39 x 34 = 22.7 or alternately, 23/34 x 39 = 26.4. This tells you that a 34/23 is a bit lower than a 39/26, but not as low as a 39/27. If you want a lower gear than your current 39/27 you have to use a 12-25 to get the equivalent of a 39/29. In doing that, you also lose top gear.

There is really no advantage to this proposed swap. What FSA fails to mention in their ad is the undeniable fact that the wider spacing will force you to shift one more cog every time you shift chainrings, to make up for the large jump.

They also need a math lesson if they think that cassette with smaller cogs has "closer" spacing. An 11-12 shift for example, is slightly larger jump, than a 12-13.

[bironi]

http://www.bicyclesource.com/bike/gear/

[Samster]

i think this compact thing is mostly full of baloney.

i got my compact cranks because i use an 11/21 cluster and almost never saw time on the 53x11 (big surprise, i know...)

now that i have my compact 48/34, i use my 48x11... almost never.

that said, the shifting works fine for me and i like the way compact looks on my smaller bikes.

and besides that, i spent a ton of money on this and am determined to be happy with the purchase since the return option is long gone...

hey, 48/34 just costs more.
so, 53/39 works just fine.
yo.

[Samster]

but did i mention how much lighter my bike is because of the 3 fewer links and 10 fewer teeth i have to haul around?

that's the techno edge bro...

[Samster]

and no, it never dawned on me to just get a 12/25 like every other normal human being...

[jeffg]

i think this compact thing is mostly full of baloney.

i got my compact cranks because i use an 11/21 cluster and almost never saw time on the 53x11 (big surprise, i know...)

now that i have my compact 48/34, i use my 48x11... almost never.

that said, the shifting works fine for me and i like the way compact looks on my smaller bikes.

and besides that, i spent a ton of money on this and am determined to be happy with the purchase since the return option is long gone...

hey, 48/34 just costs more.
so, 53/39 works just fine.
yo.


48/34 + Shimano = versatility. I can run an 11-23 or 12-25 in relatively normal terrain and break out the 12-27 for the mountains. Also, that is much cheaper than springing for new brifters, crank/bb, FD/RD that you would need for a triple.

With Campy, a 53/39, 13-29 is close to the 34X25, so I went with the 53X39 for a long time and was tempted to keep that since you can put on a 12-25 as well. Eventually, I went to a Campy compact 50/34 and was very happy to have a 34X29 for climbs like Ventoux.

[Climb01742]

34s aren't terribly useful in most terrain (in fact, i've found them to be counter-productive, because you lose useful gears a 39 would give you.) however, once in the mountains or good sized hills, a 34 can be very useful, as jeff and dave know. but unless you do a lot of climbing, i'm not sure a 34 helps you that much.

[Ti Designs]

Sounds like Climb has figured it out. If you live in an area that's all steep hills compact gearing may be for you. I always try to gear people so their "cruising gear" is somewhere in the center of the freewheel in the small ring. If you spend 80% of your time in a tight range of gears, why not have them run clean? By comparison, people running compact cranks are either all the way over on the 12, or every other shift is up front, with a whole lot of shifting in the back to make up for the change. Bottom line - gear for what you do the most, suffer a little on that 0.3% of the time you're on something steep...

[Ray]

Sounds like Climb has figured it out. If you live in an area that's all steep hills compact gearing may be for you. I always try to gear people so their "cruising gear" is somewhere in the center of the freewheel in the small ring. If you spend 80% of your time in a tight range of gears, why not have them run clean? By comparison, people running compact cranks are either all the way over on the 12, or every other shift is up front, with a whole lot of shifting in the back to make up for the change. Bottom line - gear for what you do the most, suffer a little on that 0.3% of the time you're on something steep...
Of if you're weak! I run a 48-34 sometimes with as low as a 12-34 in back, sometimes with a 12-27. Although I very rarely use the extreme bailout gears, the 12-34 allows me to have my "80% of the time" gears on the big ring, which with a 12-34 I can ride easily down to a 48x26, which allows for a lot of rolling hills and gentle climbs without going to the little ring. Things do get steep around here and on most non-epic single day rides I spend a lot of climbing time in the 34x23 and occasionally the 34x26. When I'm doing a long ride and hit the longer 14+ percent hills, often unpaved, I'll occasionally go into the really low 30 or 34. It's basically like having a highly functional 12-26 7-speed (with all cogs accessible from the big ring) with a couple of extreme bailout gears for the rare occasion when I need them. This wouldn't work for someone who likes tight gear spacing, doesn't have any steep hills, or is just strong, but I'm fine with these gaps and I love the versatility of the setup.

-Ray

[znfdl]

I tried a compact crank and then switched back to a triple (52x42x30). I do not mind the few extra grams of weight to have the right gear. I know that when a I ride mountainous centuries, I will always have the correct gear. If you do not mind spending big $, you can get a triple crank and bottom bracket that weighs in the neighborhood of 700 grams (Stronglight Pulsion)

[Samster]

48/34 + Shimano = versatility. I can run an 11-23 or 12-25 in relatively normal terrain and break out the 12-27 for the mountains. Also, that is much cheaper than springing for new brifters, crank/bb, FD/RD that you would need for a triple.

With Campy, a 53/39, 13-29 is close to the 34X25, so I went with the 53X39 for a long time and was tempted to keep that since you can put on a 12-25 as well. Eventually, I went to a Campy compact 50/34 and was very happy to have a 34X29 for climbs like Ventoux.

maybe i came off a bit negative (hey, it was 3 in the morning CST when i typed that message...)

i like my compacts a lot. it's just that for my particular case, i didn't see an improvement in my situation other than i now use the range of rear cogs more (though some may not count that as a real improvement.) but i like the aesthetics quite a bit. so my choice for compact is now vanity-based as opposed to functionality-driven. unfortunately the price of vanity was steep in this case... those record compacts likely provide quite a bit of dealer margin i think...

but i do think i'm getting bursitis in my right hand from all that extra brifter action. sniff.

[CNY rider]

I tried a compact crank and then switched back to a triple (52x42x30). I do not mind the few extra grams of weight to have the right gear. I know that when a I ride mountainous centuries, I will always have the correct gear. If you do not mind spending big $, you can get a triple crank and bottom bracket that weighs in the neighborhood of 700 grams (Stronglight Pulsion)


I went through the exact same sequence. I got one of those beautiful FSA carbon compacts. The bike looked smokin' hot with that thing. And with a huge hole blown through my wallet, I was determined to like it.

The reality though was that I was constantly shifting back and forth with the FD. I never found a really comfortable, easy shifting sequence. So, we're back to the old highly functional but non-bling Ultegra triple.

Oh well.

[schneiderrd]

I switched to a compact on my Serotta because I could not get a triple to work on that frame. I have no problem with a triple if it works, but the compact set up is an acceptable compromise. I agree with many of the draw backs of the compact set up mentioned, inparticular the double shifting. If you can get a triple to work, IMHO it is the better choice.