Gear Ratio
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Gear Ratio
I am rebuilding an old road bike (new to me) and am about to put on a new chain. I was doing the calculation to see the length of chain needed and got to thinking maybe the current gear ratio is not right for me and I should address that before cutting down the chain. The chain rings are 52/42T and the 6-speed freewheel is 13-24T.
This is my first bike since I was a kid and got the bike to ride for recreation at a pretty leisurely pace. I'd like to use the bike in somewhat hilly (and scenic!) areas, am in my mid-twenties, and would consider myself to be in average shape. Is a 42:24 gear ratio low enough for any climb I'll ever face or should I opt for a different freewheel? Again, I'm not looking to power my way up any hills -- just want to make sure I'll be able to climb hills period.
This is my first bike since I was a kid and got the bike to ride for recreation at a pretty leisurely pace. I'd like to use the bike in somewhat hilly (and scenic!) areas, am in my mid-twenties, and would consider myself to be in average shape. Is a 42:24 gear ratio low enough for any climb I'll ever face or should I opt for a different freewheel? Again, I'm not looking to power my way up any hills -- just want to make sure I'll be able to climb hills period.
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I have a 52/42 on my '85 trek 460. I have ridden it with a 14-23 and a 12-28 7 speed cassette out back (newer wheels & hubs). The 12-28 is much better.
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Did you have any trouble with the 12-28T freewheel and the rear derailleur or was there adequate clearance? What group set did you replace the freewheel on? Thanks!
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You might consider this https://store.velo-orange.com/index.p...et-34x48t.html
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
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When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
Last edited by Barrettscv; 01-21-14 at 03:17 PM.
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I'm going to move this to the Mechanics Forum where it will find a larger pool of mechanical experts.
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When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
#6
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You might consider this https://store.velo-orange.com/index.p...et-34x48t.html
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
https://www.amazon.com/Shimano-MF-TZ2.../dp/B003EQ71QI
Sarcasm off.
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42/24 isn't going to cut it in hills for any but seriously strong riders. Buy yourself a wider range freewheel for starters, but even that may not be enough.
BTW- there's never a problem with a chain cut to Maximum length. Loop the 42/24 combination through the derailleur and take up slack until the idler cage moves off the dead stop. That's the longest chain length that will work in all gears, and will leave room for a larger freewheel later.
BTW- there's never a problem with a chain cut to Maximum length. Loop the 42/24 combination through the derailleur and take up slack until the idler cage moves off the dead stop. That's the longest chain length that will work in all gears, and will leave room for a larger freewheel later.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
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You can probably replace the 42 inner chainring with a 39 or 39 (assuming a 130 BCD), and also replace the freewheel with a 12-28 or similar. See sheldonbrown.com for how to measure BCD.
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Much better to spend $100 for a crank set (and maybe more for a new BB) than $15 for a freewheel!
https://www.amazon.com/Shimano-MF-TZ2.../dp/B003EQ71QI
Sarcasm off.
https://www.amazon.com/Shimano-MF-TZ2.../dp/B003EQ71QI
Sarcasm off.
The owner needs to know his options.
__________________
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
Last edited by Barrettscv; 01-21-14 at 03:55 PM.
#10
Mechanic/Tourist
The 28 tooth low is the minimum I would suggest you consider. There's no way to tell if that's sufficient, as "average shape" means little when it comes to cycling. The problem is that we don't know if your derailleur will handle the 28 tooth cog. It's not "clearance" but rather "capacity" that is the issue. You need to find out what model of derailleur you have, or at least take a picture (from the side, at the level of the derailleur). If the bike is friction shift then changing both derailleur and freewheel is still not that expensive, and you can go larger than 28 teeth. But even a 42/34 may not be low enough for "any hill" you may encounter.
I would not recommend any chainwheel upgrades without knowing more about the bike, as you may end up putting in much more money than is advisable.
I would not recommend any chainwheel upgrades without knowing more about the bike, as you may end up putting in much more money than is advisable.
Last edited by cny-bikeman; 01-21-14 at 04:28 PM.
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Suntour Cyclone II derailleurs. No issues. It will be better than what you have and a 14-28 costs about $15. A good place to start.
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42/24 isn't going to cut it in hills for any but seriously strong riders. Buy yourself a wider range freewheel for starters, but even that may not be enough.
BTW- there's never a problem with a chain cut to Maximum length. Loop the 42/24 combination through the derailleur and take up slack until the idler cage moves off the dead stop. That's the longest chain length that will work in all gears, and will leave room for a larger freewheel later.
BTW- there's never a problem with a chain cut to Maximum length. Loop the 42/24 combination through the derailleur and take up slack until the idler cage moves off the dead stop. That's the longest chain length that will work in all gears, and will leave room for a larger freewheel later.
The 28 tooth low is the minimum I would suggest you consider. There's no way to tell if that's sufficient, as "average shape" means little when it comes to cycling. The problem is that we don't know if your derailleur will handle the 28 tooth cog. It's not "clearance" but rather "capacity" that is the issue. You need to find out what model of derailleur you have, or at least take a picture (from the side, at the level of the derailleur). If the bike is friction shift then changing both derailleur and freewheel is still not that expensive, and you can go larger than 28 teeth. But even a 42/34 may not be low enough for "any hill" you may encounter.
I would not recommend any chainwheel upgrades without knowing more about the bike, as you may end up putting in much more money than is advisable.
I would not recommend any chainwheel upgrades without knowing more about the bike, as you may end up putting in much more money than is advisable.
You might consider this https://store.velo-orange.com/index.p...et-34x48t.html
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
The smaller 34t inner chainring will provide a much greater improvement in climbing range (about 20%) than changing from a 24 to a 28 large cog on the freewheel (a 14% change). You existing derailleurs will work fine with this crankset.
Much better to spend $100 for a crank set (and maybe more for a new BB) than $15 for a freewheel!
https://www.amazon.com/Shimano-MF-TZ2.../dp/B003EQ71QI
Sarcasm off.
https://www.amazon.com/Shimano-MF-TZ2.../dp/B003EQ71QI
Sarcasm off.
EDIT: I forgot to add that I have "Biopace" chain rings that are not perfectly circular. Would it be okay to keep the 52T Biopace chain ring and use a perfectly circular 39T (or other) chain ring?
Last edited by laserspeed; 01-21-14 at 06:00 PM.
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