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Can I swap a triple crankset for a 1x crankset without any changes to the groupset?

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Can I swap a triple crankset for a 1x crankset without any changes to the groupset?

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Old 05-05-18, 11:12 PM
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RMoudatir
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Can I swap a triple crankset for a 1x crankset without any changes to the groupset?

I was thinking if I can swap the triple crankset for a 1x crankset and remove the front derailleur and front shifter. Will that work, perhaps just some adjustments in the rear?

Last edited by RMoudatir; 05-05-18 at 11:13 PM. Reason: Editing errors
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Old 05-06-18, 01:31 AM
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No, you do not need to change your groupset. You don’t even need a new crank. Just remove the big ring and small ring. You can replace the big ring with a bashgurd. If not, you will need shorter chainring bolts.

You should shorten the chain, as your new single ring will now be the “big” ring.

The real issue is chain retention (not dropping the chain in the front). Solutions depend somewhat on what setup this is. What rear drivetrain are you running? How many speeds and is it SRAM os Shimano? Is the rear deraileur a “clutch” type?

Last edited by Kapusta; 05-06-18 at 07:26 AM.
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Old 05-06-18, 09:19 AM
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Short answer yes... But it will be kind of half baked
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Old 05-06-18, 10:16 AM
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Originally Posted by Kapusta
No, you do not need to change your groupset. You don’t even need a new crank. Just remove the big ring and small ring. You can replace the big ring with a bashgurd. If not, you will need shorter chainring bolts.

You should shorten the chain, as your new single ring will now be the “big” ring.

The real issue is chain retention (not dropping the chain in the front). Solutions depend somewhat on what setup this is. What rear drivetrain are you running? How many speeds and is it SRAM os Shimano? Is the rear deraileur a “clutch” type?
I don't have a mountain bike as of now but I am looking to buy my first one and I wanted a drive train that has large cassette rings around 40t or more for very steep climbs I have in the mountains I live by; avg 7-8% and sections with 15-25%. I only need one small chainring as I am not going fast on it downhill or racing. The mountain bikes I wanted to get in the price range of 500-600$ only had triple cranksets so that is why I wondered if I can remove the triple and if that would give me a wider range for the big cassette.
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Old 05-06-18, 02:39 PM
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Originally Posted by RMoudatir
I don't have a mountain bike as of now but I am looking to buy my first one and I wanted a drive train that has large cassette rings around 40t or more for very steep climbs I have in the mountains I live by; avg 7-8% and sections with 15-25%. I only need one small chainring as I am not going fast on it downhill or racing. The mountain bikes I wanted to get in the price range of 500-600$ only had triple cranksets so that is why I wondered if I can remove the triple and if that would give me a wider range for the big cassette.
i am not sure I follow you..

Just going to a single ring up front does not make the cassette any different in its range.

For example if the bike has a triple crank and a 11-32t cassette, and you change the front to a single ring, you are still going to have an 11-32t cassette.

Are you talking about going with a single ring AND swapping the cassette to a wide range one?

if you goal is to get low gearing, the triple crank already gives you that with the small ring in front. The reason for the super wide range cassettes is to make up for the range lost when going from a triple ring crank to a double or a double to a single.

So, it is very unlikely that you would achieve lower gearing going to a single ring. If anything you will LOSE some low end.

Also, unless you are looking at 11 speed stuff, you are not going to find a rear deraileur the will work off the shelf. You will need to look into a Goat Link or similar to use with the RD.

if the bike you are looking at are triples, the small ring is probably 22 (maybe 24) if they are 9 speed bikes, the biggest cog on the cassette is probably 34. 22:34 is a pretty darn low gear. Even 24:34 is.
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Old 05-06-18, 02:57 PM
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Originally Posted by Kapusta


i am not sure I follow you..

Just going to a single ring up front does not make the cassette any different in its range.

For example if the bike has a triple crank and a 11-32t cassette, and you change the front to a single ring, you are still going to have an 11-32t cassette.

Are you talking about going with a single ring AND swapping the cassette to a wide range one?

if you goal is to get low gearing, the triple crank already gives you that with the small ring in front. The reason for the super wide range cassettes is to make up for the range lost when going from a triple ring crank to a double or a double to a single.

So, it is very unlikely that you would achieve lower gearing going to a single ring. If anything you will LOSE some low end.

Also, unless you are looking at 11 speed stuff, you are not going to find a rear deraileur the will work off the shelf. You will need to look into a Goat Link or similar to use with the RD.

if the bike you are looking at are triples, the small ring is probably 22 (maybe 24) if they are 9 speed bikes, the biggest cog on the cassette is probably 34. 22:34 is a pretty darn low gear. Even 24:34 is.
What I meant was to have a bigger cassette in the rear, since most bikes with triple cranks I saw had up to a 32t or 34t cassette in the rear but I wanted a much larger one like a 40t or bigger which is why I questioned if it would affect the set up since the biggest chainring of a triple will be much larger than a 1x chainring, I was not sure if a triple crankset would limit the range of a cassette making it not able to go 40t or above.
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Old 05-06-18, 05:13 PM
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Originally Posted by RMoudatir
What I meant was to have a bigger cassette in the rear, since most bikes with triple cranks I saw had up to a 32t or 34t cassette in the rear but I wanted a much larger one like a 40t or bigger which is why I questioned if it would affect the set up since the biggest chainring of a triple will be much larger than a 1x chainring, I was not sure if a triple crankset would limit the range of a cassette making it not able to go 40t or above.
OK, I get what you are asking. I think you are going to find this is a lot of work and expense that yields no improvement over the stock triple in terms of low end range. I will break this down to specifics.

Will a triple limit how wide a range cassette you can use? Yes, it probably will. The reason is that the rear derailleur (RD) pulleys can only take up so much slack, which is called its "chain wrap capacity", or often just "capacity". Going from a 32-34t big cog to a 40t will mean you need another 6-8t of capacity. Unfortunately, most triple setups are probably close to the max capacity of the RDs. Ultimately you will need to check the capacity of your RD to check. The "capacity" needed is calculated by adding the difference of the biggest and smallest cog, and biggest and smallest ring. So if you have a 22-32-44 triple crank and a 11-34t cassette, the capacity needed is (34-11)+(44-22) = 45t. Change that to a 11-40 cassette and that becomes (40-11)+(44-22) = 51t. While most capacity rating are conservative, I doubt most RDs will deal with 51t, but I could be wrong.

OK, so will going with a single ring help with this? Yes, it will. Since there is only one ring, there is no capacity needed for the front, because now the big and small ring are the same thing. For example, if you used a 32t ring, the math would be (40-11)+(32-32) = 29t.

So the CHAIN WRAP capacity is going to be OK. Unfortunately, that is not the only "capacity" you need to consider. The other issue is the "max cog size" capacity of the RD. In other words, what is the largest cog the RD can accommodate. I am not aware of any RDs 9 speed or under that will do this off the shelf. You will need to buy a special adapter (a Wolf Tooth "Goat Link" or similar) to make your RD accommodate this. Some 10 speed RDs will work off the shelf, others not.

OK, so let's say you get your max cog size capacity worked out. If your goal was to get lower gearing than the 22:34 (ring:cog) combo that the triple gave you with the stock cassette, you are going to need a 26 tooth ring or smaller (such as the 22t ring on your triple). Now you have another problem: The only place you are going to be able to fit a ring that small is on the small ring position of the crank, and that is going to bugger up the chainline as you move to the higher gears on the cassette, which you will need to do often as you have such a small chainring.

You could try to go with the middle chainring position for a better chainline, but the smallest standard ring that will fit that is 32t. There are special rings that will work as small as (I think 28t) but they are not cheap.... and will still leave you with a less low gear than the stock triple setup.

I think you will find it a struggle to find a crankset that takes something as small as 22-24t ring and has the chain line you want. Maybe a trials crankset? This is definitely not a typical application for this and I can think of numerous potential issues.

Long of the short, If you want super low gearing, I would not go 1x unless you are willing to go with all new 11 speed stuff so you can get a 11-50t cassette and an RD made to work with it. And even with that, you are going to need a ring smaller than 32t to get lower than what you have with most 9 speed triples. There are plenty of cranks that will take 28t rings and work for you, but that means buying a new crank.

One option you may consider is going 2x. Drop the big ring, and keep the middle and small. Dropping the big ring will reduce the needed chain wrap capacity enough to make room for the 11-40 cassette, and the chainline issue will be resolved because you can use the middle ring. Now all you have to deal with is the max cog size issue.

Or, get a cassette with a 36t cog. That will most likely work with the system as is and not need a goat link.

All that said: Are you really sure that a 22t ring and 34t cog is not low enough? Much lower than that and it is hard to stay upright you are moving so slow.

Last edited by Kapusta; 05-06-18 at 05:20 PM.
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Old 05-07-18, 05:51 PM
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I'll throw on wrench in Kapusta's very fine and detailed explanation: There ARE offset inner rings that are 28t. They use the granny bosses but put the chainline in/near middle-ring position.
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Old 05-07-18, 07:12 PM
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Originally Posted by dminor
I'll throw on wrench in Kapusta's very fine and detailed explanation: There ARE offset inner rings that are 28t. They use the granny bosses but put the chainline in/near middle-ring position.
Interesting. Could be handy.

But 28t is too big to get him what he wants.
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Old 05-07-18, 10:39 PM
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Originally Posted by Kapusta
OK, I get what you are asking. I think you are going to find this is a lot of work and expense that yields no improvement over the stock triple in terms of low end range. I will break this down to specifics.

Will a triple limit how wide a range cassette you can use? Yes, it probably will. The reason is that the rear derailleur (RD) pulleys can only take up so much slack, which is called its "chain wrap capacity", or often just "capacity". Going from a 32-34t big cog to a 40t will mean you need another 6-8t of capacity. Unfortunately, most triple setups are probably close to the max capacity of the RDs. Ultimately you will need to check the capacity of your RD to check. The "capacity" needed is calculated by adding the difference of the biggest and smallest cog, and biggest and smallest ring. So if you have a 22-32-44 triple crank and a 11-34t cassette, the capacity needed is (34-11)+(44-22) = 45t. Change that to a 11-40 cassette and that becomes (40-11)+(44-22) = 51t. While most capacity rating are conservative, I doubt most RDs will deal with 51t, but I could be wrong.

OK, so will going with a single ring help with this? Yes, it will. Since there is only one ring, there is no capacity needed for the front, because now the big and small ring are the same thing. For example, if you used a 32t ring, the math would be (40-11)+(32-32) = 29t.

So the CHAIN WRAP capacity is going to be OK. Unfortunately, that is not the only "capacity" you need to consider. The other issue is the "max cog size" capacity of the RD. In other words, what is the largest cog the RD can accommodate. I am not aware of any RDs 9 speed or under that will do this off the shelf. You will need to buy a special adapter (a Wolf Tooth "Goat Link" or similar) to make your RD accommodate this. Some 10 speed RDs will work off the shelf, others not.

OK, so let's say you get your max cog size capacity worked out. If your goal was to get lower gearing than the 22:34 (ring:cog) combo that the triple gave you with the stock cassette, you are going to need a 26 tooth ring or smaller (such as the 22t ring on your triple). Now you have another problem: The only place you are going to be able to fit a ring that small is on the small ring position of the crank, and that is going to bugger up the chainline as you move to the higher gears on the cassette, which you will need to do often as you have such a small chainring.

You could try to go with the middle chainring position for a better chainline, but the smallest standard ring that will fit that is 32t. There are special rings that will work as small as (I think 28t) but they are not cheap.... and will still leave you with a less low gear than the stock triple setup.

I think you will find it a struggle to find a crankset that takes something as small as 22-24t ring and has the chain line you want. Maybe a trials crankset? This is definitely not a typical application for this and I can think of numerous potential issues.

Long of the short, If you want super low gearing, I would not go 1x unless you are willing to go with all new 11 speed stuff so you can get a 11-50t cassette and an RD made to work with it. And even with that, you are going to need a ring smaller than 32t to get lower than what you have with most 9 speed triples. There are plenty of cranks that will take 28t rings and work for you, but that means buying a new crank.

One option you may consider is going 2x. Drop the big ring, and keep the middle and small. Dropping the big ring will reduce the needed chain wrap capacity enough to make room for the 11-40 cassette, and the chainline issue will be resolved because you can use the middle ring. Now all you have to deal with is the max cog size issue.

Or, get a cassette with a 36t cog. That will most likely work with the system as is and not need a goat link.

All that said: Are you really sure that a 22t ring and 34t cog is not low enough? Much lower than that and it is hard to stay upright you are moving so slow.
Ohhhh I just realized that the small chainring on the triple chainsets use a 22t chainring... this whole time I was thinking it was 30t which is why I thought those 1x groupsets had a bigger advantage being able to use a larger cassette.
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Old 05-08-18, 12:19 PM
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Originally Posted by Kapusta
But 28t is too big to get him what he wants.
Guess I didn't read everything thru as well as I could have. Thought the OP wanted a compromise between granny and middle-ring gearing. Holy cow, if he wants that low and still be able to pedal anywhere, maybe he should stick to a 2x setup.
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Old 05-08-18, 12:26 PM
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Originally Posted by RMoudatir
Ohhhh I just realized that the small chainring on the triple chainsets use a 22t chainring... this whole time I was thinking it was 30t which is why I thought those 1x groupsets had a bigger advantage being able to use a larger cassette.
Glad that got cleared up.
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