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Old 09-06-09, 09:54 AM   #1
spiderman 11
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Compact crankset question...

Recently purchased a CAAD 9 with a Shimano Tiagra triple crankset (50/39/30) installed on the bike. I would like to put a compact crankset on in it's place because I don't use the 30 on the triple. I was wanting to put a 50/34 on and was unsure of which company and what specific specs. I need to look for. I'm relatively new to the road bike scene and am looking for some input. Thanks.
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Old 09-06-09, 10:21 AM   #2
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This Shimano should do the trick: http://www.backcountryoutlet.com/out...-Crankset.html
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Old 09-06-09, 10:26 AM   #3
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Ok, but this says 10 speed , what is the difference. I have a 9 speed rear sprocket?
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Old 09-06-09, 10:30 AM   #4
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You can use a 9 speed chain with a 10 speed crank. A 9 speed chain is slightly wider than a 10 speed chain. You should be able to use the existing BB, depending on what you have. If you need a new BB, it will be about $40.

You should be able to adjust your FD.

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Old 09-06-09, 10:46 AM   #5
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Quote:
Originally Posted by spiderman 11 View Post
Recently purchased a CAAD 9 with a Shimano Tiagra triple crankset (50/39/30) installed on the bike. I would like to put a compact crankset on in it's place because I don't use the 30 on the triple. I was wanting to put a 50/34 on and was unsure of which company and what specific specs. I need to look for. I'm relatively new to the road bike scene and am looking for some input. Thanks.
If you do that, what will you have gained?

If you have all the gear ratios that you need using a 39 middle ring, what is replacing it with a 34 ring going to do for you? I've recently addressed the same question. I have a road bike with a 52/42/30 triple that has a granny ring that I haven't used in years. I thought about replacing it with a double crankset but what would be the point?
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Old 09-06-09, 11:37 AM   #6
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If you do that, what will you have gained?

If you have all the gear ratios that you need using a 39 middle ring, what is replacing it with a 34 ring going to do for you? I've recently addressed the same question. I have a road bike with a 52/42/30 triple that has a granny ring that I haven't used in years. I thought about replacing it with a double crankset but what would be the point?
he will gain not looking like a grandpa and having an "acceptable" crank in the road biking community.

seriously, keep the triple. it came on your bike. everything is tuned to it, and there will be one day you'll use the 30 and be thankful you'll have it.
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Old 09-07-09, 01:03 AM   #7
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Also, if you get a compact crank then you may find that you're always cross-chaining (inner chainring and outer cog, or vice versa) and always having to make double shifts (shifting on the back and front at the same time). The 34-tooth ring is too small most of the time, the 50-tooth is too big most of the time. Something in the range of 39-42 would be just right, which is why triples exist. You have the best type of crankset out there, so don't change anything!
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Old 09-07-09, 07:26 AM   #8
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I agree with retrogrouch to a point. as we do not know where spiderman lives we do not know exactly why he wants a 34 but I would look to get rid of the 30 and put the 34 as the granny. also would he not have to change his triple brifter to a double? and the BB? would a wider range cassette solve the issue?

illwafer why isn't a triple acceptable in the road bike community? are you some sort of eliteist?
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Old 09-07-09, 10:06 AM   #9
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Also, if you get a compact crank then you may find that you're always cross-chaining (inner chainring and outer cog, or vice versa) and always having to make double shifts (shifting on the back and front at the same time). The 34-tooth ring is too small most of the time, the 50-tooth is too big most of the time. Something in the range of 39-42 would be just right, which is why triples exist. You have the best type of crankset out there, so don't change anything!
I have to disagree here. I switched my bike from a triple with 8 speed rear to a compact double with a 10 speed rear. With the triple I found myself hunting for gears, and that 30 tooth gear was too small for a lit of stuff especially as my power improved. Not only that but once you peak the hill and head for the downhill it was more gear hunting, or 2 big shifts to get to the large ring. With the compact I find I have every combo I need and its far faster and easier to get to them. I will never buy a bike with a triple again except maybe a mountain bike.

Sometimes a lot of choices is way too many.
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Old 09-07-09, 11:00 AM   #10
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You can't beat the Backcountry price for the crank. There are micro spacers for chainrings if you need them, as this whole 9 speed 10 speed stuff is confusing.
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Old 09-07-09, 01:16 PM   #11
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If you're going to switch, at least switch to a regular double for gods sake. If you can. Compacts shift even worse than triples. Avoidi anything that says "sram", "truvativ", or "fsa" and "campy" if you're going compact. Go buy shimano everything.
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