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Should I change my triple down to double?

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Should I change my triple down to double?

Old 02-24-16, 02:18 PM
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DVCB
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Should I change my triple down to double?

I recently purchased a 2010 Cannondale Synapse Carbon 105. The original owner was in Colorado and so the FSA cranks were a triple. I will never use that third ring in my riding - is there any benefit to having that reduced down to a double? Also, the cassette is the Shimano 105 10-speed. How long do those typically last? If I get a new one, should I go ahead and get the 11-speed? Thanks for any input.
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Old 02-24-16, 02:36 PM
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Have you actually ridden the bike much yet? I would suggest that you do and then make up your mind as to what gear range you want then do that mod within the 10speed spec. Saves a lot of $ and retains the possibility of going back to a triple should your future change. BTW running a triple shifter as a double can have it's aspects to be aware of. The cable pull from the small to middle might not be the same as from middle to large. Also some have reported that the shifter can over move and jam up if the small to middle is what is used as the double function.

As to how long a 10speed cassette lasts- less long then a 9 speed but longer then an 11 speed all things being equal. Frequent chain replacement and, in between that, cleaning greatly influences the real results. Andy.
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Old 02-24-16, 02:44 PM
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Thanks for the response! Yes. I have put about 400 miles on the bike and I find myself shifting a little more than I did with my old CAAD8. I figure that is because of the different gearing on the triple/10 vs. the double/10. I thought 11-speed might help a little. I do clean the bike/cassette/chain quite often but I have not yet gotten a new chain. I will take it in to my LBS and get that done.
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Old 02-24-16, 02:56 PM
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Originally Posted by DVCB View Post
I do clean the bike/cassette/chain quite often but I have not yet gotten a new chain. I will take it in to my LBS and get that done.
There's no point in changing the chain unless its worn. The way to determine if its worn is to measure it, as explained at the bottom of this page: Chain Maintenance . Also, changing a chain is a simple affair, not requiring an LBS. Simply shorten the new chain to match your old chain using the chain breaker on your multitool then use the master link that comes with the chain to join the ends together.
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Old 02-24-16, 03:09 PM
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11 speed will require new shifters.
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Old 02-24-16, 03:32 PM
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Leave the Middle on the triple crank Put a cyclocross bash guard on instead if the Big ring,

and there You go a double from a triple a single ring and a Bail Out Gear.


Braze on FD wont move down Much , just get the bash guard as Big as the outer chainring is now,

But toothless , and It will look fine ..

You figure out if you should or Not.

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Old 02-24-16, 03:49 PM
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Originally Posted by DVCB View Post
I recently purchased a 2010 Cannondale Synapse Carbon 105. The original owner was in Colorado and so the FSA cranks were a triple. I will never use that third ring in my riding - is there any benefit to having that reduced down to a double?
When you can spin 39x21-25 (depending on starting cog) up the majority of your climbs and enjoy the rest a double works great because you can't over-shift past the 39 ring.

Those are the lowest gears you can have with a double where you have one tooth jumps to the 19 cog and front-shifting doesn't become too frequent -

11-12-13-14-15-16-17-18-19-21 10 cogs
12-13-14-15-16-17-18-19-21-23 10 cogs
13-14-15-16-17-18-19-21-23-25 10 cogs (or 13-26 for Campagnolo riders)
11-12-13-14-15-16-17-18-19-21-23 11 cogs
12-13-14-15-16-17-18-19-21-23-25 11 cogs

Otherwise a triple with a smaller cassette gets that spacing with at least as much range as a compact double (a 26 inner ring still shifts well, and 26x25 is like 34x34).

Also, the cassette is the Shimano 105 10-speed. How long do those typically last?
Four+ chains when you change them approaching 1/16" of elongation. 6,000 - 20,000+ miles.

If I get a new one, should I go ahead and get the 11-speed? Thanks for any input.
Only if you want to buy new shifters and a new rear derailleur.
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Old 02-24-16, 09:03 PM
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Originally Posted by dedhed View Post
11 speed will require new shifters.
11 speed will require a heck of a lot more than new shifters. It will require new shifters, new derailleurs, new chain, new cassette, and unless the rear wheel is compatible with an 11 speed cassette(unlikely) a new rear wheel
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Old 02-25-16, 03:57 AM
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Removing an unused gear saves an insignificant amount of weight as seen to bike + rider. particularly considering the work required.
There's some benefit if it means going from a double to a single, as front shifts aren't as fast as rear shifts.

But for a triple-to-double rework, it's a fair amount of effort only to lose a ring and possibly to reduce q-factor a little.

I'd only consider it if state of wear on cranks already prompted a replacement for that reason. Sometimes, cranksets can be had for less than new rings.
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Old 02-25-16, 12:53 PM
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You can do whatever you want, but realize there is very little to gain here. The only benefits are a tiny decrease in weight and a slight decrease in q-factor, which may or may not be any benefit to you.

If you were building the bike up from scratch you might decide to use a double instead of a triple. But since it's already setup triple you'll have to do some work for very little reward.

I wouldn't bother.
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Old 02-25-16, 01:18 PM
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What is the current rear cassette? If the prior owner was a mountain climber probably 12-27 or 11-28 or such

If you are a flatlander just swap the cassette for an 11-23 or 12-23. Your shifting will be MUCH tighter, and you may find yourself actually using the small ring for whatever hills you do have.

Save the climber cassette for your vacation to CO so SoCal
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Old 02-25-16, 03:14 PM
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How do I know what size the cassette is?

Originally Posted by bikebreak View Post
What is the current rear cassette? If the prior owner was a mountain climber probably 12-27 or 11-28 or such

If you are a flatlander just swap the cassette for an 11-23 or 12-23. Your shifting will be MUCH tighter, and you may find yourself actually using the small ring for whatever hills you do have.

Save the climber cassette for your vacation to CO so SoCal
Here is a picture of the numbers on my cranks - but I can't find anything on the cassette? Where do I look?

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Old 02-25-16, 03:15 PM
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Count teeth one at a time.
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Old 02-25-16, 03:17 PM
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How do I know what size the cassette is? I can't find it on there anywhere. I did find numbers on the cranks (see below) but looked and didn't see any on the cassette.
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Old 02-25-16, 03:58 PM
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Originally Posted by DVCB View Post
How do I know what size the cassette is? I can't find it on there anywhere. I did find numbers on the cranks (see below) but looked and didn't see any on the cassette.
usually it's very hard to see the numbers on the cassette when mounted, so just count the teeth on the smallest and biggest cogs and you know your range, eg 11-28 means smallest is 11 teeth and 28 on biggest cog
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Old 02-25-16, 03:58 PM
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Originally Posted by fietsbob View Post
Count teeth one at a time.
count cassette teeth each one with your finger clean the cassette off so you dont get your finger dirty.
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Old 02-25-16, 04:28 PM
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It's a 12-25 cassette.

Last edited by DVCB; 02-25-16 at 04:35 PM.
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Old 02-25-16, 05:49 PM
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Originally Posted by DVCB View Post
It's a 12-25 cassette.
An 11-speed 12-25 cassette would add an 18T cog between the 17 and the 19. Otherwise, the gearing is identical. If you really wanted that 18T gear, you could get a 10-speed 12-23 cassette. Personally, I'm happy with a 12-30 10-speed, but that's a personal preference thing.

As others have said, going from a 52-39-30 triple to a 52-39 double wouldn't really gain you anything that you don't already get by just not shifting down to the small ring. I'm a big fan of triples. You should think of a triple as a double with a bailout ring. You won't use the small ring 99% of the time (maybe more), but when you're heading up a steep incline or a really long climb it's very nice to have. The common alternative these days is a compact double (usually 50-34), but I think that's the worst of all options because you can't practically use the 50T ring 99% of the time so you end up spending something like 25% of your time using what should be your bailout gear and the bailout gear doesn't bail you out as much as the 30T on a triple.
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Old 02-25-16, 10:00 PM
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Originally Posted by Andy_K View Post
An 11-speed 12-25 cassette would add an 18T cog between the 17 and the 19. Otherwise, the gearing is identical. If you really wanted that 18T gear, you could get a 10-speed 12-23 cassette. Personally, I'm happy with a 12-30 10-speed, but that's a personal preference thing.
.....
Yes, or swapping to 10 speed 12-23 gets the 18t.
The benefit of having the triple crank in a flat area is you can run tight spaced cassettes like 12-23 or even 12-21 and get very tight shifting. 12-25 is already pretty good compared to the 11-28 cassettes. Enjoy!
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Old 02-26-16, 09:39 AM
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Originally Posted by Andy_K View Post
An 11-speed 12-25 cassette would add an 18T cog between the 17 and the 19. Otherwise, the gearing is identical. If you really wanted that 18T gear, you could get a 10-speed 12-23 cassette. Personally, I'm happy with a 12-30 10-speed, but that's a personal preference thing.

As others have said, going from a 52-39-30 triple to a 52-39 double wouldn't really gain you anything that you don't already get by just not shifting down to the small ring. I'm a big fan of triples. You should think of a triple as a double with a bailout ring. You won't use the small ring 99% of the time (maybe more), but when you're heading up a steep incline or a really long climb it's very nice to have. The common alternative these days is a compact double (usually 50-34), but I think that's the worst of all options because you can't practically use the 50T ring 99% of the time so you end up spending something like 25% of your time using what should be your bailout gear and the bailout gear doesn't bail you out as much as the 30T on a triple.
I agree 100%.
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Old 02-26-16, 11:30 AM
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Originally Posted by Andy_K View Post
The common alternative these days is a compact double (usually 50-34), but I think that's the worst of all options because you can't practically use the 50T ring 99% of the time so you end up spending something like 25% of your time using what should be your bailout gear and the bailout gear doesn't bail you out as much as the 30T on a triple.
If you can't use a 50t ring 99% of the time, when are you ever going to use is a 52t? Basically, what you want is a ~30/42t double, which is a standard mountain crankset. 30/25 is roughly the same ratio as 34/28. Granted the spacing is tighter with a triple.

I happen to like the compact, but on most of my flat riding I'm in the 50t and in the middle of a 11-28 cassette. I do find that into very strong headwinds or long shallow grades (~2% for 2-3 mi) I'm near the edges of the cassette.
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Old 02-26-16, 12:42 PM
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Originally Posted by gsa103 View Post
If you can't use a 50t ring 99% of the time, when are you ever going to use is a 52t? Basically, what you want is a ~30/42t double, which is a standard mountain crankset. 30/25 is roughly the same ratio as 34/28. Granted the spacing is tighter with a triple.
Personally, I never need a 52T ring. In fact, I just installed Shimano RS685 brakes on my commuter and so was forced to go to 11-speed and a double. What I chose to do was to replace my 50T ring with a bashguard and set it up as a 39-30 double. I would rather have 42-30, but the small chainring on my Tiagra 4603 crank bolts directly to the middle ring so I'm stuck with 39-30. The problem with a mountain double is that it pushes the chainline out way too far in light of the fact that I'll commonly be using the "big" ring with the low gear end of my cassette. Otherwise, I'd happily use one.

But to address your question more directly, I could use the 50T ring 99% of the time, but I'd be mashing pretty much any time I was going much under about 15 mph. With a 50-34 cassette, accelerating from a stop while maintaining a reasonable cadence looks something like this -> start out in the 34T ring, pedal through four or five cogs, downshift twice in the rear while upshifting once in the front (still a big jump), cruise in the 50T ring. This isn't a terrible problem if I'm riding on open roads and will be cruising at good speeds most of the time, but it completely sucks for riding through the suburbs where I have to deal with stop signs and traffic lights. And even on the open road, it's not as good as having a triple because the triple has a lower low gear or tighter spacing for the same low gear (however you prefer to look at it).

Still, I'm not going to argue with anyone who wants a 50-34 double. I'm actually planning a build myself right now that will use one.
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Old 02-26-16, 01:05 PM
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Originally Posted by DVCB View Post
Thanks for the response! Yes. I have put about 400 miles on the bike and I find myself shifting a little more than I did with my old CAAD8. I figure that is because of the different gearing on the triple/10 vs. the double/10. I thought 11-speed might help a little. I do clean the bike/cassette/chain quite often but I have not yet gotten a new chain. I will take it in to my LBS and get that done.
I found this online gearing calculator really useful for picking the right cassette and chain wheels. I think you can find the right combination without going through the hassle and expense of converting to an 11 speed and compact double.

Sheldon Brown's Bicycle Gear Calculator

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Old 02-26-16, 01:24 PM
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yup, ride as is.
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Old 02-26-16, 02:05 PM
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Originally Posted by Andy_K View Post
With a 50-34 cassette, accelerating from a stop while maintaining a reasonable cadence looks something like this -> start out in the 34T ring, pedal through four or five cogs, downshift twice in the rear while upshifting once in the front (still a big jump), cruise in the 50T ring. This isn't a terrible problem if I'm riding on open roads and will be cruising at good speeds most of the time, but it completely sucks for riding through the suburbs where I have to deal with stop signs and traffic lights.
Make sense. I get around the start/stop issue by using the 11-28, and just cross-chaining to the 50/28 for starting, with a narrow range cassette that's obviously much less viable.

I did a similar conversion to my MTB, currently its setup as a 22/32/bash, and I really wish it was closer to a 36t top, but it's hard to justify the extra $$ for a new crank (bought the bike used with XTR).

With 10/11 speeds in back and wide ranges, I don't think anyone really needs a triple anymore, but finding the correct double crankset is frequently challenging. I feel like a 30/44t crankset would be ideal for many people, but that's not really a standard option, so instead those bikes ship with a triple.
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