Single Chain Ring

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
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Do I really need 3 chain rings, I only use the large one, I was thinking of reducing to 1 ring on my Carrera Vengeance, has anybody done this, Cheers.
 

anotherkiwi

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Jan 26, 2015
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You might need 2, what motor does it have?
 

Fordulike

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Feb 26, 2010
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Do I really need 3 chain rings, I only use the large one, I was thinking of reducing to 1 ring on my Carrera Vengeance, has anybody done this, Cheers.
Is there a reason why you want to reduce it to only one chain ring
i.e. aesthetics and/or less clutter on the handlebars?
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
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Elgin Moray
Is there a reason why you want to reduce it to only one chain ring
i.e. aesthetics and/or less clutter on the handlebars?
Main reason is, even before I fitted the motor, I seldom used the small ring, and since I fitted the motor I only ever use the large one, the 3 rings are all one, so when the last one wore out I had to fit the whole chain ring, and I also remember the guy from Halfords saying that I could fit a 3 ring crank and pay a bit more for for one that you could fit whatever ring was slipping.
 

anotherkiwi

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Jan 26, 2015
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anotherkiwi

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Our posts crossed: to relieve strain on the chain you should really change down to the second cog when you need to use bottom gear.
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
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OK I am guessing Shimano Acera then. The advantage of keeping the front derailleur is that it stops the chain from jumping off.

I think you should be able to remove the small cog from this one and as you can see the big one is removable on a 104 BCD spider so you would just swap it when it wears.



https://www.bike-discount.de/en/buy/shimano-acera-9-speed-crank-fc-m391-44-32-22-170mm-612668/wg_id-8794
OK I am guessing Shimano Acera then. The advantage of keeping the front derailleur is that it stops the chain from jumping off.

I think you should be able to remove the small cog from this one and as you can see the big one is removable on a 104 BCD spider so you would just swap it when it wears.

https://www.bike-discount.de/en/buy/shimano-acera-9-speed-crank-fc-m391-44-32-22-170mm-612668/wg_id-8794
Cheers for that, I'll have a look at them, so just run it with 2 rings and the 8x spd cassette.
 

awol

Esteemed Pedelecer
Sep 4, 2013
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On my Carrera I too would like to find a single front cog with changable gear for when it's worn, any ideas ?
I have changed my front to only have the large cog just like you are after.
I dremmelled the rivets out of the cog assembly to remove the smallest cog then I think the screws go through the large ring into the middle ring so moved the large cog to the inside side of the pedal bar part where the middle one was and put those screws back in with the middle cog on the inside to screw to and to stiffen the large cog. Then cut a disc out of some mdf for the chain-guard and sprayed it all black.
At first the chain kept coming off on the higher or lower gears, so I put the front deraileur back on as a guide to stop it. It seems to work ok on the stand in the garage but I can't say it has worked perfect yet as I've only been up the road on it since last summer when I did it.

IMG_20170119_200600.jpg IMG_20170119_200644.jpg
 
D

Deleted member 4366

Guest
If you use a single ring, the chances are that it'll catch on the chainstay, so you'd need a spacer and a longer BB spindle. If you're going to change your chainset, it's worth upgrading to a hollowtech one. I always change to this one on every bike I get unless it already has a better one. The 48T is particularly useful if you want to pedal above 20 mph:

http://www.woollyhatshop.com/shimano-deore-fcm590-9-speed-chainset-48t-170mm-in-silver-efcm590c866xs?gclid=Cj0KEQiA5IHEBRCLr_PZvq2_6qcBEiQAL4cQ0xlu_ImfDvRfpb-ArC-ouNq98Au6kQ7iFFtFUcyV150aAhcs8P8HAQ

I did a thread somewhere on how to fit the PAS - basically open up the hole in the middle to 25mm and turn the holding bracket around.
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
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Elgin Moray
If you use a single ring, the chances are that it'll catch on the chainstay, so you'd need a spacer and a longer BB spindle. If you're going to change your chainset, it's worth upgrading to a hollowtech one. I always change to this one on every bike I get unless it already has a better one. The 48T is particularly useful if you want to pedal above 20 mph:

http://www.woollyhatshop.com/shimano-deore-fcm590-9-speed-chainset-48t-170mm-in-silver-efcm590c866xs?gclid=Cj0KEQiA5IHEBRCLr_PZvq2_6qcBEiQAL4cQ0xlu_ImfDvRfpb-ArC-ouNq98Au6kQ7iFFtFUcyV150aAhcs8P8HAQ

I did a thread somewhere on how to fit the PAS - basically open up the hole in the middle to 25mm and turn the holding bracket around.
Cheers for that, max reading on the cyclotricity speedo is 18.5MPh, and the large chainring keeps up ok on the flat. Chainstay??? is that the part of the frame between the rear dropout and the BB that is usually coated with clear plastic to protect it.
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
128
36
72
Elgin Moray
Our posts crossed: to relieve strain on the chain you should really change down to the second cog when you need to use bottom gear.
I had a look at the gears with the bike on the stand tonight to see what was going on, when on the large chainring, the chain looks happiest on the 3 smaller cogs on the cassette, I this may be because I fitted the PAS on the crank side of the BB which extends the crank slightly, but maybe it was like this before. If I`m on the large chainring and on any of the smallest rear cogs, then change to larger rear cogs to make pedaling easier, and then swop to the middle chainring, it makes pedaling so easy that you have to change to smaller cogs at the rear, kinda defeats the purpose, any automatic bike gearboxes on ebay. I thinks I`ll study this a bit more before any mods.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
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What size is your large cog? With a motor you can add 4 teeth to it in most cases. That makes it interesting to keep two chainwheels on the front with a smaller one for really steep hills.

I would say for a 26" wheel bike a 48-38 or 48-36 on the front is a good choice for a strong rider and 46-32 for a normal rider. 27.5 and above 46-32 or 44-32. I run a 42-32 now on my 28" bike because I have slowed the pace down a little because of various riding style changes.

Gearing is very important even on a pedelec but there are many personal factors that make it hard to say one size fits all.
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
128
36
72
Elgin Moray
What size is your large cog? With a motor you can add 4 teeth to it in most cases. That makes it interesting to keep two chainwheels on the front with a smaller one for really steep hills.

I would say for a 26" wheel bike a 48-38 or 48-36 on the front is a good choice for a strong rider and 46-32 for a normal rider. 27.5 and above 46-32 or 44-32. I run a 42-32 now on my 28" bike because I have slowed the pace down a little because of various riding style changes.

Gearing is very important even on a pedelec but there are many personal factors that make it hard to say one size fits all.
Cheers for that, I`ll count the teeth tomorow and let you know.
 

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
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West Wales
I have a converted Carrera Crossfire. This came with 3 rings, I removed the smallest to fit the pas ring, leaving me 48-36. No chainline problems and big ring is good for 32-35mph, small ring good for west wales hills.
The Vengence must have a different chainset as I seem to remember mine just unbolted. I know it has a smaller large ring as this is what caused me to reject it as a conversion candidate.DSCF2959.JPG
 

JohnnyGM7LSI

Pedelecer
Dec 5, 2016
128
36
72
Elgin Moray
I have a converted Carrera Crossfire. This came with 3 rings, I removed the smallest to fit the pas ring, leaving me 48-36. No chainline problems and big ring is good for 32-35mph, small ring good for west wales hills.
The Vengence must have a different chainset as I seem to remember mine just unbolted. I know it has a smaller large ring as this is what caused me to reject it as a conversion candidate.View attachment 17341
Cheers Ben, yup, cheaper bike, cheaper chainset, when this one gives up the ghost, I`ll probably go for something like that, just sussing out the options just now so I can get one in advance.
 

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