double vs. compact double

[songlady]

If I was looking at a bike, how could I tell if it was a double or a compact double? I am assuming it has something to do with the cassette? Is this also what they mean when they speak about a 9spd vs. a 10spd? Thanks for your help :o

[mimitabby]

on the back wheel of the bike is a cassette that consists of a bunch of rings with teeth. The 9 speed has 9 of them. The 10 speed has ten of them.

A compact double is a relatively new bike configuration.
Someone else will help you with the rest of your questions.

[VeloVT]

Yay! Shopping for bikes is so much fun.

1. Double vs Compact Double (vs Triple). This refers to the number and ratio of the FRONT chainrings on your bike. A standard double is usually 53/39 (that's the number of teeth on each chainring, respectively). Some bikes have triple chainrings, with an extra-small chainring allowing lower gears for extended or hilly touring. A common ratio for a triple might be 52/42/30. A compact double basically splits the difference, giving you some lower gears than you'd get with a standard double, but without the additional weight/slower shifting of a triple (though I've read mixed reports on the latter count with compacts). A common compact ratio is 50/34.

2. 9sp vs 10sp (or 8sp!). This refers to the number of gears on the REAR cassette on your bike. More gears gives you... well, more gears... but the important thing to remember is that you are not **necessarily** getting more high gears or more low gears in say, a 10sp vs a 9sp, they may simply be more closely spaced. You'll also see the range of gears in the cassette specified -- it will look like 11/23, 12/25, etc, and again refers to the number of teeth on the largest and smallest cogs.

Good luck!

[mimitabby]

not at all, but the diff between the 9 and 10 speed might have more to do with the age of the bike (for some reason a lot of manufacturers are going to 10 speeds now)

[Grog]

No indeed, 9spd or 10spd or however-many-cogs-in-the-back has nothing to do with being a "compact" double or not.

[Eden]

A compact double refers to the front chainrings - a regular double usually has a 39/53 (39 teeth on the smaller ring and 53 on the larger) on the front, a compact double will usually have something like a 36/50 or maybe even a 34/50 this gives you easier gears on the low end, but does limit your top end a bit.

8/9/10 speed etc. refers to the number of cogs on the rear cassette

wow! look at all those responses in the time it took me to type this one!

[li10up]

A common ratio for a double might be 52/42/30. A compact double basically splits the difference, giving you some lower gears than you'd get with a standard double, but without the additional weight/slower shifting of a triple (though I've read mixed reports on the latter count with compacts). A common compact ratio is 50/34.
That ratio you specified for would be a triple ...which is what I think you meant to say. Just wanted to clarify so as not to confuse anyone.

[songlady]

Thanks ladies, very helpful!

[Eden]

(for some reason a lot of manufacturers are going to 10 speeds now)

Mainly just because that is what is available in the newest technologies - you can still find some 9 speed equipment new, but it is becoming more scarce.

[VeloVT]

quoted:
That ratio you specified for would be a triple ...which is what I think you meant to say. Just wanted to clarify so as not to confuse anyone

yup, that's what I meant ;) . just edited. oops!

[KnottedYet]

Rivendell sells 6,7,8, and 9 cassettes. I have 8's on each of my bikes.

They also sell the wider chain for those cassettes.

As long as I can keep getting 8's, I have no plan to switch anything to a 9 or 10 (shifters would have to be replaced, too.)