Swapping chainrings
#1
Thread Starter
Cries on hills
Joined: Jun 2007
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From: Central NH
Bikes: 2007 Trek Pilot 1.2, 1969 Raleigh Sprite 5
Swapping chainrings
Ramping up my riding this year, after some time off, and realized I had a stretched chain. Have a replacement chain and cassette, but the chainrings look a bit worn, so, I'd like to fix that also--I think I've gone through 3 or so chains on this bike, so there is some wear. Right now the bike is a 9 speed, 12-23, with 30/42/52; crank is a Bontrager Select. 74/130BCD. Shimano STI's. Question: can I just buy some Suigino rings? I understand I'll lose the ramps and pins, so shifting performance might suffer. I was not planning on spending that much; I don't feel any play in the bottom bracket so I'm not sure I need to replace it.
While the 30 and 42 is decent the 52 is useless to me. I'm tempted to try 28/39/46, something of that sort.
While the 30 and 42 is decent the 52 is useless to me. I'm tempted to try 28/39/46, something of that sort.
#2
Senior Member
Joined: Feb 2007
Posts: 1,414
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From: Central CA
Bikes: A little of everything
I wouldn't go changing the tooth count on the front much (or at all) or you may cause yourself some headache with front derailer compatibility. Check shimano's tech docs on your particular derailer (I believe the model number, 'FD-xxxx' will be on the back side of the derailer, viewable from the non-drive side. Bring a magnifying glass and look for text within a rectangular shape).
Are you sure your chainrings are really worn? If you never used your 52 then it might just have cosmetic wear. Though a worn middle, and sometimes low, gear on a triple is pretty common. Even if you don't use your 52, if you ever go to sell the bike the missing gear might be a turn-off. Or you might want it there once you start putting on the miles and get stronger.
If you wanted to emphasize your lower gears, I would have suggested a lower-geared cassette, like a 12-25/27. Or even a junior cassette, like a 14-25. Don't forget to check those tech docs on your rear derailer regarding chain length/tooth capacity
If you're still serious about rings, just keep your eyes open and hunt around for a good deal- triple road rings, and even entire triple road cranks, are pretty cheap. They get dumped because a large majority of people are buying doubles and 1x drivetrains now. If you don't think Suginos will be an improvement over your current hardware, then don't buy them (or feel free to link us to what you're looking at).
Are you sure your chainrings are really worn? If you never used your 52 then it might just have cosmetic wear. Though a worn middle, and sometimes low, gear on a triple is pretty common. Even if you don't use your 52, if you ever go to sell the bike the missing gear might be a turn-off. Or you might want it there once you start putting on the miles and get stronger.
If you wanted to emphasize your lower gears, I would have suggested a lower-geared cassette, like a 12-25/27. Or even a junior cassette, like a 14-25. Don't forget to check those tech docs on your rear derailer regarding chain length/tooth capacity
If you're still serious about rings, just keep your eyes open and hunt around for a good deal- triple road rings, and even entire triple road cranks, are pretty cheap. They get dumped because a large majority of people are buying doubles and 1x drivetrains now. If you don't think Suginos will be an improvement over your current hardware, then don't buy them (or feel free to link us to what you're looking at).
Last edited by Raiden; 06-01-16 at 07:37 PM.
#3
Senior Member
Joined: May 2011
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From: Upstate NY
Bikes: Bianchi San Mateo and a few others
You might find that straying too far from the stock chainring sizes degrades shifting a bit, too, since modern derailleurs are sculpted with specific chainring combinations in mind to aid indexed shifting systems.
#4
Senior Member

Joined: Jul 2005
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From: Boulder County, CO
Bikes: '80 Masi Gran Criterium, '12 Trek Madone, early '60s Frejus track
I wouldn't go changing the tooth count on the front much (or at all) or you may cause yourself some headache with front derailer compatibility. Check shimano's tech docs on your particular derailer (I believe the model number, 'FD-xxxx' will be on the back side of the derailer, viewable from the non-drive side. Bring a magnifying glass and look for text within a rectangular shape).
#5
Mostly harmless ™
Joined: Nov 2010
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From: Novi Sad
Bikes: Heavy, with friction shifters
He's decreasing the gap with a smaller big ring. It could work just fine. Though I'd go for a 48 tooth big ring. 42-46 is too small a difference to bother shifting up front.
Also, 48 will be closer in size to the original.
Also, 48 will be closer in size to the original.
#6
Thread Starter
Cries on hills
Joined: Jun 2007
Posts: 1,088
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From: Central NH
Bikes: 2007 Trek Pilot 1.2, 1969 Raleigh Sprite 5
I was told by a friend that my big ring looked a big chewed up (it's an alloy gear, the other two are steel), and the middle ring looked worn. I can feel some sharp edges. So I wanted to look into changing them, and if I'm changing, ergo, can I optimize?
A few years ago I changed the cassette from 12-25 to 12-23 so as to intentionally get the 16T (again it's a 9spd cassette). I was very happy to receive that as it filled a gap in the gearing. Honestly, I do think the 42T chainring is pretty good--if I were to have a 1x9 setup I might very well run 42 x 12-23. When in shape I rarely went above 42x14 or 42x13 on the flats. [I found myself frustrated on flat ground, going from 42x17 to 42x15, it came up on a few roads, that gearing gap.] The only time my 52 comes into play is if I can hit a downslope and get my speed above 20mph.
I'm out of shape and am finding it easier to spin in 30x19 instead of mashing 42x19 on our hills; I'm not sure how wise it is to use either end of the cassette when in the middle ring so I only use 42x21 when sitting and spinning and tired. I did notice the change from 25T to 23T when I hit dirt (I'm not afraid to take some fire roads and even some technical stuff on occasion). The 52T chainring is strictly a downhill gear for me. Ergo, the desire to fool around with 28/39/46--pull my two primary chainrings down a bit, and maybe find a spot where the big ring might be usable on the flats for me. If I hadn't already bought a 12-23 I'd give thought to a different cassette, but I'd again want some nice close gears that would mimic the 42x19/17/16/15/14/13 ratios I already have (since I "know" those are my primary gears).
Sounds like though I might not like the change in shifting, and I might not actually have worn out the rings. In which case I'd probably be happier to just leave well enough alone. Maybe I'll just do that instead.
Thanks!
A few years ago I changed the cassette from 12-25 to 12-23 so as to intentionally get the 16T (again it's a 9spd cassette). I was very happy to receive that as it filled a gap in the gearing. Honestly, I do think the 42T chainring is pretty good--if I were to have a 1x9 setup I might very well run 42 x 12-23. When in shape I rarely went above 42x14 or 42x13 on the flats. [I found myself frustrated on flat ground, going from 42x17 to 42x15, it came up on a few roads, that gearing gap.] The only time my 52 comes into play is if I can hit a downslope and get my speed above 20mph.
I'm out of shape and am finding it easier to spin in 30x19 instead of mashing 42x19 on our hills; I'm not sure how wise it is to use either end of the cassette when in the middle ring so I only use 42x21 when sitting and spinning and tired. I did notice the change from 25T to 23T when I hit dirt (I'm not afraid to take some fire roads and even some technical stuff on occasion). The 52T chainring is strictly a downhill gear for me. Ergo, the desire to fool around with 28/39/46--pull my two primary chainrings down a bit, and maybe find a spot where the big ring might be usable on the flats for me. If I hadn't already bought a 12-23 I'd give thought to a different cassette, but I'd again want some nice close gears that would mimic the 42x19/17/16/15/14/13 ratios I already have (since I "know" those are my primary gears).
Sounds like though I might not like the change in shifting, and I might not actually have worn out the rings. In which case I'd probably be happier to just leave well enough alone. Maybe I'll just do that instead.
Thanks!





