chain sizing, whats the best method?
07-23-12, 09:39 AM
#1
Senior Member
Thread Starter
Join Date: Apr 2012
Posts: 415
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
chain sizing, whats the best method?
park tool site has two methods that will work for me.
1.) going big ring to big ring and and adding an inch
2.) using a mathematical equation to figure out the overall length
I cannot use the old chain as I have swapped out the cassette and crank for a different size.
So which of these methods (or post others) is the standard by which chains are sized properly?
1.) going big ring to big ring and and adding an inch
2.) using a mathematical equation to figure out the overall length
I cannot use the old chain as I have swapped out the cassette and crank for a different size.
So which of these methods (or post others) is the standard by which chains are sized properly?
07-23-12, 09:53 AM
#2
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,725
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5791 Post(s)
Liked 2,581 Times
in
1,431 Posts
The second is to predict how much chain you'll need, but you always confirm by direct measurement when fitting.
Note that the big/big plus 1" measurement is the minimum length. Campagnolo uses a different method, small/small with all slack out and the RD cage under minimum tension, which yields the longest chain possible. OTOH, Shimano uses a third method based on cage angle which yields a mid length chain. Note that if the gear combination uses the full take-up capacity of the RD, the minimum, maximum, and mid-length will all be the same.
If I have the option of a longer than minimum length chain (excess RD take up capacity) I prefer fitting a longer chain, so that down the road, I may remove a damaged link without replacing the chain.
Note that the big/big plus 1" measurement is the minimum length. Campagnolo uses a different method, small/small with all slack out and the RD cage under minimum tension, which yields the longest chain possible. OTOH, Shimano uses a third method based on cage angle which yields a mid length chain. Note that if the gear combination uses the full take-up capacity of the RD, the minimum, maximum, and mid-length will all be the same.
If I have the option of a longer than minimum length chain (excess RD take up capacity) I prefer fitting a longer chain, so that down the road, I may remove a damaged link without replacing the chain.
__________________
FB
Chain-L site
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.
FB
Chain-L site
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.
07-23-12, 09:58 AM
#3
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
^^^ This. As FB noted the second method just gives you a good approximation but the first method assures the chain will shift into big-big without damage.
Campy's small-small with no slack works fine if you stay within the rear derailleur's "wrap" limits. If you exceed them, as I often do, you can make the chain too short to allow the absolutely necessary ability to shift into big-big.
Campy's small-small with no slack works fine if you stay within the rear derailleur's "wrap" limits. If you exceed them, as I often do, you can make the chain too short to allow the absolutely necessary ability to shift into big-big.
07-23-12, 11:12 AM
#4
Senior Member
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 643 Times
in
364 Posts
I'm a big/big fan but not so much that I argue with folks who use one of the other methods.
07-23-12, 11:15 AM
#5
Senior Member
Join Date: Jul 2002
Location: Sacramento, California, USA
Posts: 40,865
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 2952 Post(s)
Liked 3,106 Times
in
1,417 Posts
07-23-12, 12:36 PM
#6
Zip tie Karen
Join Date: Aug 2009
Location: Fair Oaks Ranch, TX
Posts: 7,004
Bikes: '13 Motobecane Fantom29 HT, '16 Motobecane Turino Pro Disc, '18 Velobuild VB-R-022, '21 Tsunami SNM-100
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 1465 Post(s)
Liked 1,542 Times
in
806 Posts
I'm a big/big + 1 full link fan, but recently used the small/small derailleur slack method to set the length for a derailleur swap. The new one had a shorter cage and different dimensions. I wound up going 1 link shorter than the big/big method would've dictated. It permitted the new derailleur to work best.
I definitely must avoid cross chain extremes with this setup, though.
I definitely must avoid cross chain extremes with this setup, though.
07-23-12, 03:43 PM
#7
Senior Member
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 643 Times
in
364 Posts
I'm a big/big + 1 full link fan, but recently used the small/small derailleur slack method to set the length for a derailleur swap. The new one had a shorter cage and different dimensions. I wound up going 1 link shorter than the big/big method would've dictated. It permitted the new derailleur to work best.
I definitely must avoid cross chain extremes with this setup, though.
I definitely must avoid cross chain extremes with this setup, though.
The beauty of the big/big method is it produces the shortest chain that will safely cover the big/big combination. That's important. If your chain is shorter than that, and you ever accidentally shift into the big/big, you can do serious damage to your bike in less time than it took me to type this sentence.
07-23-12, 04:08 PM
#8
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,725
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5791 Post(s)
Liked 2,581 Times
in
1,431 Posts
Now I am going to argue.
The beauty of the big/big method is it produces the shortest chain that will safely cover the big/big combination. That's important. If your chain is shorter than that, and you ever accidentally shift into the big/big, you can do serious damage to your bike in less time than it took me to type this sentence.
The beauty of the big/big method is it produces the shortest chain that will safely cover the big/big combination. That's important. If your chain is shorter than that, and you ever accidentally shift into the big/big, you can do serious damage to your bike in less time than it took me to type this sentence.
The big/big +1" produces the MINIMUM chain length. If you're running a derailleur with excess wrap capacity, you can always go longer (as I do), but you can never go shorter. Over the years I've known too many knowledgeable riders who run derailleurs over capacity, and opted to pinch at the short end. Famous last words for drivetrains and rear hubs are "I never cross chain anyway".
If you run a derailleur over capacity pinch at the long end. The worst that can happen is you shift to small/small and the chain hangs down like a pregnant possum's belly. But nothing will break.
__________________
FB
Chain-L site
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.
FB
Chain-L site
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.
07-23-12, 06:45 PM
#9
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
+1
The big/big +1" produces the MINIMUM chain length. If you're running a derailleur with excess wrap capacity, you can always go longer (as I do), but you can never go shorter. Over the years I've known too many knowledgeable riders who run derailleurs over capacity, and opted to pinch at the short end. Famous last words for drivetrains and rear hubs are "I never cross chain anyway".
If you run a derailleur over capacity pinch at the long end. The worst that can happen is you shift to small/small and the chain hangs down like a pregnant possum's belly. But nothing will break.
The big/big +1" produces the MINIMUM chain length. If you're running a derailleur with excess wrap capacity, you can always go longer (as I do), but you can never go shorter. Over the years I've known too many knowledgeable riders who run derailleurs over capacity, and opted to pinch at the short end. Famous last words for drivetrains and rear hubs are "I never cross chain anyway".
If you run a derailleur over capacity pinch at the long end. The worst that can happen is you shift to small/small and the chain hangs down like a pregnant possum's belly. But nothing will break.
Thread
Thread Starter
Forum
Replies
Last Post
bikecommuter13
Bicycle Mechanics
13
06-12-16 03:54 AM
