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Compact Crankset vs. Traditional Crankset?(9 posts)

Compact Crankset vs. Traditional Crankset?spoke
Nov 27, 2003 7:22 PM
A newby just getting into road biking and trying to learn as much as I can before selecting a bike and components. What are the postives and negatives of compact cranksets versus that of traditional cranksets? Thinking of the Fuji Team Super Lite bike. Thanks!

Ken
re: Compact Crankset vs. Traditional Crankset?Rusty Coggs
Nov 28, 2003 6:10 AM
Gearing.So get a gear inch chart and figure it out.
re: Compact Crankset vs. Traditional Crankset?glia
Nov 28, 2003 6:43 AM
Compact cranks are designed to give you a greater range of gears on a double setup at somewhat greater gear spacing. So it will only benefit you if you live in a hilly area and need one or two smaller gears. Don't go there if you live in the flatlands! If the regular 12/25 cog with a standard crank 39/53 is not going low enough for you (41.2 ratio) then going to a Compact crank (34/50) will give you two extra smaller gears with 39.1 and 35.9 ratios. Now those are almost granny gears that should get you up any hill. I personally use a compact crank with an 11/23 or 12/23 cog. I still have an easy gear that is just a tad easier than the 12 on a regular crank (39.1) and with the 11/23 I still have the same hard gear than with my 12/25 on a regular cank (120.1). One advantage if you are into saving weight, you'll shorten your chain and shave off about 30g of chain weight. Also the compact carbon crank that FSA sells is only 520g at a very affordable price.
Ritchey, FSA have announced alloy compacts for 2004eflayer2
Nov 28, 2003 12:09 PM
If you don't want to pay big bucks for 4 ounces less weight with carbon, it looks like these guys are both going to be doing 110 bcd compacts in alloy -- coming soon.
Thanks all for the info. Much Appriciated! (nm)spoke
Nov 28, 2003 3:11 PM
re: Compact Crankset vs. Traditional Crankset?lithiapark
Nov 28, 2003 2:44 PM
I have the FSA compact crankset on my bike, with their ISIS bottom bracket also. I like the looks, it shifts well with a standard double front derailleur, and it helps me get up the 3 pretty good climbs that lead out of the valley I live in without having to go to a triple. I can pedal it up to 40mph downhill before I'm spun out which is fine with me, I'm not a racer. I use it with a 12/27 cassette. I don't mind the slightly larger gear spacing, my background is MTB, so I'm used to even wider spacing. I have heard some say it leads to more rapid chain wear because the chain has to go around smaller sprocket up front, but I think since you always have smaller sprockets on the cassette, and hence greater angulation at each link anyway, it must make a very small difference. Chainrings on MTB's are smaller yet and I'm not unhappy with how fast they wear.
Faster chain wear, more drivetrain friction, otherwise OKKerry Irons
Nov 28, 2003 5:32 PM
Since you are always on smaller cogs in the back, your chain and cogs will wear faster - fewer teeth engaged and a sharper angle for the chain to wrap. That sharper wrap also means higher drive train friction. For this, you save very tiny amounts of weight. If it was a great idea, it would have replaced conventional chainring sizes long ago.
Faster chain wear, more drivetrain friction, otherwise OKlithiapark
Nov 29, 2003 6:51 PM
I believe I read somewhere that for sprockets more than 14 teeth the differences in frictional loss secondary to greater angulation of the chain links is extremely small. I can't remember where I read that, has anyone else seen that type of information? If the alternative to the compact drive is a triple and if sprockets up to 30 teeth had significantly increased friction, then the 50/34 combo would be a better choice than having to ride for significant distances up hill in a 30 chainring, wouldn't it? If your usual conditions didn't warrant a triple, there probably wouldn't be any need to consider a compact drive crankset, it would seem. Does this make sense?
The goal of a compact systemKerry Irons
Dec 1, 2003 4:57 PM
The compact system was pushed as a way to save weight, not as a way to get lower gears. The rules are still the same - the bigger cogs you can run the chain around, the less friction and the less wear you'll get. Most riders should ditch any gears greater than 100 inches (front/rear tooth ratio = 3.8) as something they will not effectively use, and then look hard at how best to get the low gears they need for the hills they climb. All else equal, it's better to get those low gears with bigger cogs rather than smaller rings, though smaller rings are obviously required at some point.