Is it that simple?
03-24-24, 09:49 AM
#1
Midlifecyclist
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Is it that simple?
3x9 to 1x8 conversion on vintage Italian
originally a 115mm ita BB.
Should I be moving the chain line 5mm inboard by using a 105mm cartridge square taper ITA BB?
Is the axle protrusion equidistant? I don’t really know how else to say it without sounding like a dick.
originally a 115mm ita BB.
Should I be moving the chain line 5mm inboard by using a 105mm cartridge square taper ITA BB?
Is the axle protrusion equidistant? I don’t really know how else to say it without sounding like a dick.
03-24-24, 10:08 AM
#2
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The stack of gears on the rear axle determine where your chain line should be. So if you want good shifting to them all with equal chain angles to the high and low sprocket, then shoot for a chain line that hits the middle within a few mm. If you know you ride more on one half of the cassette, then lean your chain line a little more toward that if shifting is satisfactory enough all the way to the other extreme.
It's more a try it and see thing than a absolute, IMO. If you are shifting well enough without and wear is okay, then how much more perfection do you need?
It's more a try it and see thing than a absolute, IMO. If you are shifting well enough without and wear is okay, then how much more perfection do you need?
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03-24-24, 11:48 AM
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The stack of gears on the rear axle determine where your chain line should be. So if you want good shifting to them all with equal chain angles to the high and low sprocket, then shoot for a chain line that hits the middle within a few mm. If you know you ride more on one half of the cassette, then lean your chain line a little more toward that if shifting is satisfactory enough all the way to the other extreme.
It's more a try it and see thing than a absolute, IMO. If you are shifting well enough without and wear is okay, then how much more perfection do you need?
It's more a try it and see thing than a absolute, IMO. If you are shifting well enough without and wear is okay, then how much more perfection do you need?
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03-24-24, 01:55 PM
#4
Really Old Senior Member
Why not 1X9 instead of 1X8?
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03-24-24, 04:14 PM
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Clark W. Griswold
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03-24-24, 05:32 PM
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Are you using your existing triple crank?
If so, which chainring position?
John
If so, which chainring position?
John
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03-25-24, 12:23 PM
#7
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03-25-24, 12:23 PM
#8
Midlifecyclist
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03-25-24, 12:40 PM
#9
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Why not just simplify everything and leave the FD on it and just keep it in the big ring? Obviously there is enough leeway in chain lines to let bikes use the big/big and small/small combo's. Though sometimes the manufacturer will caution against running the small/smalls.
But if you want the bestest more perfect <grin> chain line, then do what you can to move that ring where the center ring is now on that 3x crank. I think some 3x spiders, the outer ring can be put in the center position. Others you might can adjust spacers on the crank spindle or in other ways. Or just get a 1x crank with the correct chain line.
If the 3x crank is original to the bike, then the measurement of the center ring to the center plane of the seat tube should be the correct chain line. Or at least as correct as it needs to be.
But if you want the bestest more perfect <grin> chain line, then do what you can to move that ring where the center ring is now on that 3x crank. I think some 3x spiders, the outer ring can be put in the center position. Others you might can adjust spacers on the crank spindle or in other ways. Or just get a 1x crank with the correct chain line.
If the 3x crank is original to the bike, then the measurement of the center ring to the center plane of the seat tube should be the correct chain line. Or at least as correct as it needs to be.
03-25-24, 01:36 PM
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Then going from 115mm to 105mm will essentially put the outer ring in the middle ring chainline with the 115mm BB.
Only word of caution would be going from an asymmetrical 115mm to symmetrical 105mm spindle. But if they are both symmetrical, you should be fine.
John
Only word of caution would be going from an asymmetrical 115mm to symmetrical 105mm spindle. But if they are both symmetrical, you should be fine.
John
03-25-24, 02:15 PM
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Why not just put the ring in the triple middle position? Then, if the chainline was right before, it will still be good. And as someone else said, why go to an eight speed cassette when your current setup is nine speed? If you're changing shifters, wouldn't it be better to go ten speed?
I stuck with 2x7 and 3x7 for a decade or two, 8 or 9 speed didn't really offer sufficient advantage to switch, but a couple of years ago I supplemented the collection with a 1x10 and the simplicity of use, and range that it provides are appreciable, even without using a huge bottom gear.
I stuck with 2x7 and 3x7 for a decade or two, 8 or 9 speed didn't really offer sufficient advantage to switch, but a couple of years ago I supplemented the collection with a 1x10 and the simplicity of use, and range that it provides are appreciable, even without using a huge bottom gear.
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03-26-24, 07:07 PM
#12
Clark W. Griswold
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Claris would likely be a downgrade it is rare Claris would be an upgrade and when it is it is usually coming from Tourney which is basically as low as you can go maybe a light upgrade to some Altus stuff which is basically Tourney in some cases or a minor notch above it. If you have 9 speed keep that all you don't need to change anything aside from deleting the front shifter and derailleur or locking the front derailleur so it stays in one place and doesn't move so it turns into a chain guide.
