Compact Chainsets/Ultra Narrow Chains

[threebikesmcginty]

Just after a tad more info if anyone could assist.

Do you have to use an ultra narrow chain with a compact chainset?

Are there advantages other than weight?

That special tool you need to fit one seems bloody expensive!!!

Thanks in advance folks.

 

[John the Monkey]

The "Compact" refers to the fact that the chainrings have fewer teeth than a standard double chainset (e.g. 50/34 as opposed to, say, 52/42)

The chain width is dependant upon how many gears the bike has. 9 and 10 speed (and I assume 11 speed) drivetrains need progressively narrower sprockets to accommodate the extra gears on a 130mm spaced freehub wheel. In turn those narrower sprockets use a narrower chain.