Crankset Upgrade Issues
#1
Junior Member
Thread Starter
Join Date: Aug 2020
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Crankset Upgrade Issues
This is my first build, and I've run into a couple problems,
I am building my road bike from a 1981 Fuji Sports-12 frame. I upgraded from the original crankset to a Shimano SORA R3000, but when I re-assembled the bike, the chain has tons of slack when its on both of the smallest rings. It didn't have this problem on the old crankset, so I'm wondering if the smaller front ring on the new set is just smaller in diameter, causing more slack? The Rear wheel is actually set further back in the dropouts now, so I don't think that is the issue. I want to be sure this is the issue before I take out some of the chain links.
I'm also having an issue with the friction shifters... They shift just fine when I turn them, but are immediately pulled back to their original position and the bike shifts back. Should I be setting the cables when the shifters are already pulled all the way down?
I appreciate any help. Thank you
p.s. I would upload photos but apparently I need to post 10 times before it allows me to.
I am building my road bike from a 1981 Fuji Sports-12 frame. I upgraded from the original crankset to a Shimano SORA R3000, but when I re-assembled the bike, the chain has tons of slack when its on both of the smallest rings. It didn't have this problem on the old crankset, so I'm wondering if the smaller front ring on the new set is just smaller in diameter, causing more slack? The Rear wheel is actually set further back in the dropouts now, so I don't think that is the issue. I want to be sure this is the issue before I take out some of the chain links.
I'm also having an issue with the friction shifters... They shift just fine when I turn them, but are immediately pulled back to their original position and the bike shifts back. Should I be setting the cables when the shifters are already pulled all the way down?
I appreciate any help. Thank you
p.s. I would upload photos but apparently I need to post 10 times before it allows me to.
#2
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
Do not shorten you chain unless you are certain that it will be long enough to go onto the big front/big rear combination. If you have a small ring with fewer teeth than the old one you will have more slack with the same length chain, but don't shorten it without checking big/big; you may need a derailleur with a higher takeup capacity.
https://www.sheldonbrown.com/deraile...ent.html#chain
https://www.sheldonbrown.com/deraile...ent.html#chain
#4
mosquito rancher
I'm also having an issue with the friction shifters... They shift just fine when I turn them, but are immediately pulled back to their original position and the bike shifts back. Should I be setting the cables when the shifters are already pulled all the way down?
__________________
Adam Rice
Adam Rice
#5
Really Old Senior Member
Put your chain on BIG ring & cog.
See how much slack you have with my quick method.
You want a minimum of 1" slack to be safe.
Excess can be removed.
See how much slack you have with my quick method.
You want a minimum of 1" slack to be safe.
Excess can be removed.