going from 50/34 to 53/39 crank
#1
Junior Member
Thread Starter
Join Date: May 2009
Location: Hampton, VA
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
going from 50/34 to 53/39 crank
Other than moving the front derailleur, do I need to lengthen the chain or anything else?
#2
Senior Member
Join Date: May 2007
Location: SW Idaho
Posts: 643
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Very possibly the chain... Check the big/big combination and note whether the rear derailleur pulley has enough clearance.
#3
Senior Member
I just did this in reverse swapping an Ultegra 53/39 for a 50/34. Adjusted the FD and took a couple of links out of the chain.
More than likely you'll have to add a couple.
More than likely you'll have to add a couple.
#4
Low car diet
Join Date: Aug 2007
Location: Corvallis, OR, USA
Posts: 2,407
Bikes: 2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 4 Times
in
4 Posts
Possibly need to lengthen the chain. If the chain was previously sized to be as short as possible with the 50T ring, then it will be too short for 53T. See here: https://sheldonbrown.com/derailer-adjustment.html#chain
Before adding links, think about this:
1) Does the chain require a special connecting pin (Shimano) or quick-link? The design of newer chains allows the chains to be stronger, but removing and re-connecting the same pin can damage the outer plate, creating a significant weak spot.
2) How old is the chain? If it's stretched enough, it may be best to just replace the whole chain.
Before adding links, think about this:
1) Does the chain require a special connecting pin (Shimano) or quick-link? The design of newer chains allows the chains to be stronger, but removing and re-connecting the same pin can damage the outer plate, creating a significant weak spot.
2) How old is the chain? If it's stretched enough, it may be best to just replace the whole chain.
#5
Low car diet
Join Date: Aug 2007
Location: Corvallis, OR, USA
Posts: 2,407
Bikes: 2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 4 Times
in
4 Posts
Also, going to a new crank may require a new bottom bracket if the crank/bottom bracket interface is different (square-taper vs. ISIS vs. External, etc.) or a different spindle length is required.
#6
Determined Survivor
Join Date: Dec 2008
Location: Ontario, Canada
Posts: 169
Bikes: Cervelo R3, Specialized Transition, Kona Paddy Wagon, Giant TCX. Lots of bikes in the Garage.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Don't bother changing the botom bracket or even the crank arms.
Chances are your 50/34 is a 110 not a 130mm.
I made the same move as you.
I just ordered a 52/38 set of chain rings.
The theory is that the change only cost about $150 and if I am planning on a big hard hilly Century the chain rings can go back to 50/34 in a couple of minutes.
My problem with the 50/34 was that I didn't like the big gear spread. If you are just looking for speed it is not rally going to gain you very much. Why not install a 23-11 or a 25-11 cog? or If you really believe that you have power to burn try a 21-11 cog.
Much easier to change sprockets than chain rings.
Chances are your 50/34 is a 110 not a 130mm.
I made the same move as you.
I just ordered a 52/38 set of chain rings.
The theory is that the change only cost about $150 and if I am planning on a big hard hilly Century the chain rings can go back to 50/34 in a couple of minutes.
My problem with the 50/34 was that I didn't like the big gear spread. If you are just looking for speed it is not rally going to gain you very much. Why not install a 23-11 or a 25-11 cog? or If you really believe that you have power to burn try a 21-11 cog.
Much easier to change sprockets than chain rings.
#8
Senior Member
Join Date: Feb 2005
Location: Oklahoma
Posts: 9,438
Bikes: Trek 5500, Colnago C-50
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 7 Times
in
6 Posts
If the problem is the big ratio jump between the 50 and 34 another option would be replacing the 34 with a 36.
Al
Al
#9
Junior Member
Thread Starter
Join Date: May 2009
Location: Hampton, VA
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks for all of the input. I'm in the process of acquiring parts so I can build up a second bike. I would put the 53/39 on my main bike and put the compact on a second bike. Some good CL deals on cranks now. I'll get some advice from the LBS as far as chains go too.