Flip the chain wheel so that it sits on the inside of the crank arm bolts
#1
Flip the chain wheel so that it sits on the inside of the crank arm bolts
Hi,
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike, it is opposite, so the chain is warped and under unnecessary torque). When you flip it, the chain will sit perfectly straight."
Can any explain way the reviewer means by this? Maybe explain it in different words
Cheers
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike, it is opposite, so the chain is warped and under unnecessary torque). When you flip it, the chain will sit perfectly straight."
Can any explain way the reviewer means by this? Maybe explain it in different words
Cheers
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#2
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Here ya go: https://www.sheldonbrown.com/chainline.html
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#3
Thanks but I think there are too many gaps in my knowledge to understand the information from that link.
What I hoping someone can tell me is something like you need to use tool 'x' to remove part 'y' then do 'xyz'
Once I get a bit hands on I think the sheldon brown info would make sense
What I hoping someone can tell me is something like you need to use tool 'x' to remove part 'y' then do 'xyz'
Once I get a bit hands on I think the sheldon brown info would make sense
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#5
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I think what you're asking is how to optimize the chainline when using a road-type double crank for a single front ring. It is often enough to mount whatever ring you intend to use on the inner plateau of the crank arm rather than the outer plateau.
First, does your crank actually have a removable outer ring? Some low-end cranks have the outer ring permanently swaged onto the arm. If that's the case, game over. Run the chain on the inner ring and ignore the outer ring and live with what you have, or buy a different crank.
If the ring is removable, you'll need tools to fit the mounting bolts. Usually a 5mm Allen key for the front of the bolt and a special spanner to hold the back.
Remove the mounting bolts, then remove the rings from the crank arm. Mount the ring you intend to use on the inner plateau and secure with mounting bolts. You may need to use shorter mounting bolts or spacers.
#6
I would need to find a video showing someone 'Installing a chain wheel so it sits on the inside of the crank arm bolts' as opposed to my current setup which guess is a chain wheel on the outside of the crank arm bolts
Last edited by b1983; 11-20-21 at 07:46 AM.
#9
Undo the bolts using your tool and a 5 mm allen key, remove the ring, thread it back over the spider (fiver-armed thing) such that the indentations around the five holes sit on the inside (towards the frame), put the bolts back in the original orientation.
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#10
I just gave it a go but could not get the bolts loose.. However I now totally understand what I'm trying to do.
I will try again
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#11
Sr Member on Sr bikes
Dan
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#12
It's a shame it's not setup properly stock, because it doesn't look as nice with the chainring on the inside, but it also looks like he can't go any narrower with the bottom bracket... Oh well, happy riding!
#13
Senior Member
If the current chainring comes within 1mm to 3mm or so of the chainstay, you can't move it in any further. Ignore all the above.
It is possible to dimple the chainstay for more clearance without harming structural integrity, but that is another project.
If the chainline is a problem, I'd look back at the rearend.
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#14
Senior Member
Good point. What cannot be seen from the photos the OP sent is how close the chainring is to the chainstay. If the gap is too small, installing the chainring on the inside of the crank spider will result in the chainring rubbing the frame, not a good result
#15
Senior Member
Another tradeoff is chainring size and rear sprocket size.
So if your current chainring is too close to the chainstay, you could get a smaller chainring, and move the sprocket in closer by either choosing a narrower bottom bracket, or moving the chainring to the inside of the crank spider.
If you can adjust both the chainring size and rear sprocket size, you may not impact gearing very much.
So if your current chainring is too close to the chainstay, you could get a smaller chainring, and move the sprocket in closer by either choosing a narrower bottom bracket, or moving the chainring to the inside of the crank spider.
If you can adjust both the chainring size and rear sprocket size, you may not impact gearing very much.
#16
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Hi,
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike…
Cheers
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike…
Cheers
Can the rear cog be moved in or out to improve the chainline?
If you can add/remove a spacer, that is the way to go.
Sorry, but I don’t have any experience with a fixie.
John
#17
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Dan
#18
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If the “new” bike is a fixed gear, the first thing to do is to eyeball the chain to the rear hub to see if it is perpendicular. If it is close, just ride it.
Can the rear cog be moved in or out to improve the chainline?
If you can add/remove a spacer, that is the way to go.
Sorry, but I don’t have any experience with a fixie.
John
Can the rear cog be moved in or out to improve the chainline?
If you can add/remove a spacer, that is the way to go.
Sorry, but I don’t have any experience with a fixie.
John
So, OP, stand behind your bike (elevated on a stand or kneel on the floor) and line your eye up with the chain. Does it run straight from the cog to the chainring or does it have to jog over because the chainring doesn't line up? (3mm or less is as good as dead on straight.)
Until you do this with your bike, not an "identical" bike you saw on a U-tube, you have no idea whether you are better off with the chainring inside or outside.
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#19
Junior Member
Finally someone asking the real question. I was wondering this morning when I saw this thread but I didn't have time to reply.
So, OP, stand behind your bike (elevated on a stand or kneel on the floor) and line your eye up with the chain. Does it run straight from the cog to the chainring or does it have to jog over because the chainring doesn't line up? (3mm or less is as good as dead on straight.)
Until you do this with your bike, not an "identical" bike you saw on a U-tube, you have no idea whether you are better off with the chainring inside or outside.
So, OP, stand behind your bike (elevated on a stand or kneel on the floor) and line your eye up with the chain. Does it run straight from the cog to the chainring or does it have to jog over because the chainring doesn't line up? (3mm or less is as good as dead on straight.)
Until you do this with your bike, not an "identical" bike you saw on a U-tube, you have no idea whether you are better off with the chainring inside or outside.
#20
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Hi,
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike, it is opposite, so the chain is warped and under unnecessary torque). When you flip it, the chain will sit perfectly straight."
Can any explain way the reviewer means by this? Maybe explain it in different words
Cheers
I wondering if someone can explain what something means.
The backstory is I bought a fixed gear bike about 6 months ago and recently looked at the reviews for it from the site it was bought.
One of the reviewers said the below should be done to the stock bike...
"Flip the chain wheel so that it sits on the inside of the crank arm bolts (on the stock bike, it is opposite, so the chain is warped and under unnecessary torque). When you flip it, the chain will sit perfectly straight."
Can any explain way the reviewer means by this? Maybe explain it in different words
Cheers
Bear in mind also that using a single chainring on a double crank will likely require new chainring screws/nuts - the original nuts are long enough to accommodate two rings and the crank arm, but will likely be too long for only a single ring and the crank arm. You can get a set of shorter "single stack" chainring screws/nuts from most bike shops
Last edited by Litespud; 11-21-21 at 12:02 AM.
#21
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With reference to the above photo, the chain ring is mounted in front of, i.e., closer to the viewer than, the spider.
Another option is to mount the chain ring behind, i.e., further from the viewer than, the spider.
#22
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#23
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To sum up the advice…
First check the chain angle from the chainring to the cog to see how straight it is running.
If it is not exactly how you want it, measure the distance from the current chainring to the chainstay at its closest point. Moving the chainring from the outer position to inner moves it 5mm closer to the chainstay. I would think you would want to have at least 8mm from your current ring setup to the chainstay so you end up with 3mm after moving the ring.
John
First check the chain angle from the chainring to the cog to see how straight it is running.
If it is not exactly how you want it, measure the distance from the current chainring to the chainstay at its closest point. Moving the chainring from the outer position to inner moves it 5mm closer to the chainstay. I would think you would want to have at least 8mm from your current ring setup to the chainstay so you end up with 3mm after moving the ring.
John
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#24
Oops! I deleted my post by accident while trying to edit it, and now you're quoting a non-existent post. Anyway, it's true that the solid ring has a narrower inner circle than a typical 38T chainring, but yeah, the triangles being deeper than the stepped extensions of the arm that the ring bolts to mean that the ring must pass! ;-)
#25
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Also, Race Face sells chainring tab shims to fill in the shoulder where the outer ring mounts. I haven’t used them, but I made my own tabs from a worn ring.
It does look better with them than without. But if you have 1x bolts with a double crank, you’ll need longer ones.
John
It does look better with them than without. But if you have 1x bolts with a double crank, you’ll need longer ones.
John
Last edited by 70sSanO; 11-21-21 at 01:23 AM.