what's the difference between compact and regular road bike cranks?

Answer 1

This allows the bike to be configured for flats or hill by simply changing the cassette - bypassing the need for a triple crank, which will require new Front and Rear mech and in the case off the new shimano Ten speed product, new shifters as well.

You loose all the complex gear overlap of the triple for a cleaner shifting double configuration.

The promise from compact is the 50/11 combo is a high gear than the 53/12 on the common 12~25 and 12~27 shimano cassettes... Sram is doing a Ten Speed 11~26 and 12~26 but, to get complete satisfaction get the 11 tooth cassette and you won't loose any top end.

While it doesn't go as low as a 30/25 or 30/27, it's low enough to get you up the hill!

Like mentioned above, the quality suffers due to the bolt pattern on the spider... it's 110mm. Which really makes the reach to the 50 tooth a stretch from the 34 or 36 that would make u pthe crank. Make sure, if you are going to make the jump, to get a 7075 aluminum chainring. The softer generic chainrings simply push over with front der. and chain and really have poor shifting compared to the 7075 big ring.

Bottom line, you get what you pay.

Answer 2

There are a number of regularly happening BCDs in use (Bolt Circle Diameters.) maximum conventional highway cranksets use one hundred thirty for the outer 2 jewelry and 74mm for the indoors, granny ring. The compact gadgets take an internet site from one in all the different standards, the a hundred and ten/fifty 8 regularly happening. because of the fact that compacts are merely a double, they use the a hundred and ten BCD and don't problem appropriate to the fifty 8. The upshot is that the a hundred and ten BCD can settle for smaller diameter, and for this reason decrease the tooth count quantity, chainrings than the regularly happening one hundred thirty mm jewelry. the two way, there's no longer something distinctive appropriate to the crank *palms.* Mirage, I also have a a hundred and ten/fifty 8 set. the vast ring is 56T and that i understand for a reality Vuelta makes them a minimum of as super as 60T.

Answer 3

The difference is in the chain ring size. A compact crank will often have a 50/36 configuration rather than a 53/39. It is not as easy as changing the rings however. Since the bolt patterns need to be smaller, you need a separate crank.

The are gaining popularity because you can get very close to the effect of adding a "granny" gear or triple chain ring, without having to change the cassette or derailleurs.