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Old 11-22-09, 07:45 PM   #1
adlai
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From a Compact Double to a Triple

Curious: anything I have to look out for?
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Old 11-22-09, 07:54 PM   #2
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Are upgrading components of any existing bike or planning on moving to a whole new ride?
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Old 11-22-09, 07:58 PM   #3
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Look out for more comfortable gear ratios...A triple makes the front derailleur capable of so much more help to the legs.
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Old 11-22-09, 08:03 PM   #4
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New bike. The compact double is a lot less convenient than I'd imagined. I end up cross-chaining a TON.

I figure when the time comes to replace the front crank, which should come in two years time, I'll do it then.
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Old 11-22-09, 08:07 PM   #5
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If upgrading, you'll need a longer cage RD and either an FD for a triple and/or the need to raise the FD
a tad higher on seat tube. Your left shifter/brifter will need to be swapped out for one that can shift thru
3 chainrings; may need new shifter cable.
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Old 11-22-09, 08:11 PM   #6
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Some triple crank owners I know like to have those chain guide catchers on their seat tube.
I ride a 50/34 compact crank w/12-27 cassette. Previous bike was a triple.
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Old 11-22-09, 08:35 PM   #7
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Quote:
Originally Posted by adlai View Post
Curious: anything I have to look out for?
Yeah, include even less information in your post so we can't help you.
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Old 11-22-09, 08:45 PM   #8
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Yeah, include even less information in your post so we can't help you.

ha.

bikesdirect fantom cx
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Old 11-22-09, 10:46 PM   #9
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Also, I cross-chain like crazy...

My problem could be alleviated to a large extent I suspect by a rear cassette which overall had larger cogs.
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Old 11-22-09, 11:26 PM   #10
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I looked up the specs of my bike and apparently I have a 12-26 Sram 950 for the rear cassette.

Suggestions for something with slightly lower gearing? Is it possible to fit a mtb cassette like the hg50 onto it?
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Old 11-23-09, 12:15 AM   #11
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On my triple, a 53/39/30, I have a 12-27 cassette. I RARELY get off the 39 ring, in fact wore it out after 15000 miles! Even moderate hills were no problem with 39/27 combo. When I go to the real hill counrty I do use the 30 for up, and the 53 for down hills. I think the 12-26 will be fine for even fairly steep hills. If not you can always get a Shimano 12/27, or the new 11/28. I also have a 50/34 compact on my other bike with a 12-27 cassette, and rarely get out of the 50, so I also crosschain A LOT.

Last edited by Halfast; 11-23-09 at 12:19 AM.
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Old 11-23-09, 02:22 AM   #12
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I looked up the specs of my bike and apparently I have a 12-26 Sram 950 for the rear cassette.

Suggestions for something with slightly lower gearing? Is it possible to fit a mtb cassette like the hg50 onto it?
... Seriously you need to start giving us more information. Start by listing the complete specs for your bike.
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Old 11-23-09, 08:29 AM   #13
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... Seriously you need to start giving us more information. Start by listing the complete specs for your bike.
Bikesdirect fantom cx.

relevant specs are

50/34 compact crank

12-26 Sram rear cassette.

I think that the long length of the chainstay might help a little in cross-chaining. I'll often go as high as like gear 6-7 on the 50t
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Old 11-23-09, 08:42 AM   #14
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Quote:
Originally Posted by adlai View Post
I looked up the specs of my bike and apparently I have a 12-26 Sram 950 for the rear cassette.

Suggestions for something with slightly lower gearing? Is it possible to fit a mtb cassette like the hg50 onto it?
Depening on what you consider to be "slightly lower," you may not need to go to an MTB cassette. I run an Ultegra 11-28 cassette with a compact crankset on my road bike, and I have all the low end I need for my New England hills. That was an upgrade from the stock 12-27 that came on the bike, works fine w/o changing the RD.

When I was buying that bike, I used Sheldon Brown's gear ratio calculator to compare a compact vs. triple (assuming the same cassette), and I really only gave up a couple of lower gear ratios by going with the compact. IMHO, worth it to have a simpler FD to maintain...I hate having to adjust the FD on my hybrid (which has a triple).
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Old 11-23-09, 09:31 PM   #15
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Depening on what you consider to be "slightly lower," you may not need to go to an MTB cassette. I run an Ultegra 11-28 cassette with a compact crankset on my road bike, and I have all the low end I need for my New England hills. That was an upgrade from the stock 12-27 that came on the bike, works fine w/o changing the RD.

When I was buying that bike, I used Sheldon Brown's gear ratio calculator to compare a compact vs. triple (assuming the same cassette), and I really only gave up a couple of lower gear ratios by going with the compact. IMHO, worth it to have a simpler FD to maintain...I hate having to adjust the FD on my hybrid (which has a triple).
...and yet another question.

Thoughts on replacing the 9 speed with say, an 8 or 7 speed? I don't get the purpose of the 9speed, honestly. I usually end up shifting two gears at a time, and it seems that the only difference between the 9 and the 8 is that the 9 has a 12-13-15 while the 8 has 12-15

heck, this 6 speed may beall i need

http://www.amazon.com/Sunrace-Freewh...9033297&sr=8-9
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Old 11-23-09, 10:43 PM   #16
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...and yet another question.

Thoughts on replacing the 9 speed with say, an 8 or 7 speed? I don't get the purpose of the 9speed, honestly. I usually end up shifting two gears at a time, and it seems that the only difference between the 9 and the 8 is that the 9 has a 12-13-15 while the 8 has 12-15

heck, this 6 speed may beall i need

http://www.amazon.com/Sunrace-Freewh...9033297&sr=8-9
With indexed shifting the shifters, cassette, and chain must be compatible.
Multiple cog close ratio cassettes help the rider maintain a higher effeciency cadence. This is especially important on flatter rides when drafting or when fighting a strong headwind.
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Old 11-23-09, 11:27 PM   #17
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Quote:
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...and yet another question.

Thoughts on replacing the 9 speed with say, an 8 or 7 speed? I don't get the purpose of the 9speed, honestly. I usually end up shifting two gears at a time, and it seems that the only difference between the 9 and the 8 is that the 9 has a 12-13-15 while the 8 has 12-15

heck, this 6 speed may beall i need

http://www.amazon.com/Sunrace-Freewh...9033297&sr=8-9
Well, if you don't get much benefit out of close gear spacing, you might also think about a wide range double. An MTB 11-32 or 11-34 cassette and MTB derailleur in back leaving your compact up front, would be another way to eliminate your cross chaining issues and would remain compatible with your current shifters.
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Old 11-24-09, 04:18 AM   #18
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Well, if you don't get much benefit out of close gear spacing, you might also think about a wide range double. An MTB 11-32 or 11-34 cassette and MTB derailleur in back leaving your compact up front, would be another way to eliminate your cross chaining issues and would remain compatible with your current shifters.
Oh, I'd need a new derailleur though? I couldn't just drop in an HG50 mtb cassette in with the tiagra road derailleur?
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Old 11-24-09, 06:52 AM   #19
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I changed my Fantom CX to a triple with a 11-34 cassette for some touring and winter riding (needed high cadence in cold weather due to knee and back issues).

IIRC, I needed to switch the rear derailleur to a long cage model. I used a deore rd. I also changed the fd to a triple and bought a new chain.

Last edited by rogerstg; 11-24-09 at 08:35 AM. Reason: clarify
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Old 11-24-09, 07:01 AM   #20
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Quote:
Originally Posted by Steve in MA View Post
When I was buying that bike, I used Sheldon Brown's gear ratio calculator to compare a compact vs. triple (assuming the same cassette), and I really only gave up a couple of lower gear ratios by going with the compact. IMHO, worth it to have a simpler FD to maintain...I hate having to adjust the FD on my hybrid (which has a triple).
The downside to a compact is that for some people neither chainring is ideal for the majority of their terrain. When I considered a compact for one of my builds, I quickly crossed it off the list when I realized that I'd be constantly shifting chainrings. With my triple, I do most of my riding in the middle ring (42 tooth) and split the rest between the little and big rings.

FWIW, if I lived out west and climbed a lot of mountains, a compact would probably work out great. With the constant up and down where I live, it would be a hassle. A compact will also never offer the range or tight gear spacing that you can get with a triple.
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Old 11-24-09, 12:30 PM   #21
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Oh, I'd need a new derailleur though? I couldn't just drop in an HG50 mtb cassette in with the tiagra road derailleur?
12-25 and 11-32 cassettes both work with my mid-cage Tiagra derailleur. 36t and 48t chainrings up front.

If you make the switch, you might need to tighten the B-screw (or screw it in from the back) to get more clearance between the biggest cog and the jockey pulley. It's counterintuitive, but when switching to a larger cog you can sometimes use a shorter chain to pull the jockey further away from the cog. If your chain is currently longer than necessary, you could shorten it.

That being said, going to a bigger cassette might not help that much with cross-chaining when you are on the smaller chainring. Tooth counts at the high end of the cassette are typically the same across road and MTB cassettes (11 or 12 teeth). The change will mostly be at the bigger-toothed cogs on the cassette, which will make the middle cogs more usable with the bigger chainring. That's not so helpful if you're riding in a city, with frequent starts and stops. Perhaps another solution is to use a small chainring with more teeth (say, 38t if you're currently using a 36t).

FWIW, I explored the same options when I started riding my Surly Cross Check. I didn't yet appreciate the close 12-25 cog spacing and uphills were killing me (a probable case of swine flu didn't help). I emailed Surly to ask about changing to a triple, but they very politely suggested that I HTFU instead. They were right, and now I'm very much enjoying the stock setup. So maybe you should try things out for a while before buying a ton of replacements.
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Old 11-24-09, 01:49 PM   #22
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So in conclusion, the answer is no, since I'm not keen on replacing derailleurs.

Weirdly, I also haven't been able to find many 48t/36t front cranks.
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Old 11-24-09, 02:50 PM   #23
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Your instinct to change to a triple is the right one. When you need wide gearing, it is the nature of a compact to cross-chain. There's just no way around it.

Unfortunately the conversion is not an easy one. You'll need the crankset, probably a FD, possibly a right shifter, and possibly a RD. (You still haven't told us enough about your components to be able to say for sure.)

Changing RDs isn't a big issue, btw.
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