big ring to big ring lockup
07-18-16 | 06:20 AM
#1
Thread Starter
Senior Member
Joined: Jul 2015
Posts: 171
Likes: 0
big ring to big ring lockup
need some assistance because I've tried everything I can think of.
I don't pedal in the big ring to big ring because of cross chaining but on the work stand I like to be able to shift in to that combo. When I do it locks completely up.
The RD is a Shimano medium cage and the cassette was a 11-28 that I changed to a 12-25 and have the same issue.
Thoughts?
I don't pedal in the big ring to big ring because of cross chaining but on the work stand I like to be able to shift in to that combo. When I do it locks completely up.
The RD is a Shimano medium cage and the cassette was a 11-28 that I changed to a 12-25 and have the same issue.
Thoughts?
07-18-16 | 06:40 AM
#3
Senior Member
Joined: Aug 2005
Posts: 33,657
Likes: 1,119
From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
07-18-16 | 06:51 AM
#4
Mechanic/Tourist
Joined: Apr 2007
Posts: 7,522
Likes: 12
From: Syracuse, NY
Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.
It may also be possible the B screw is way too far out.
07-18-16 | 08:15 AM
#5
Senior Member
Joined: Sep 2010
Posts: 8,327
Likes: 1,112
From: Roswell, GA
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
You need to be able to shift into that combo without straining anything because you will inevitably forget and try to engage it while riding; if the chain is too short to allow this you will do a lot of damage before you know what has happened. So always check, gently, to be sure whenever you make any change which could affect the needed chain length.
07-18-16 | 10:20 AM
#6
Keepin it Wheel
Joined: Aug 2011
Posts: 10,969
Likes: 5,247
From: San Diego
Bikes: Surly CrossCheck, Krampus
As already said, chain is too short. Buy a new chain, new chains are (almost always) a handful of links too long, and big/big will work. Remove links if the big/big doesn't stretch out the RD to near-horizontal.
Hopefully your tests of locking up your drivetrain didn't bend your derailleur or chainring or pull your dropout or frame out of alignment
Hopefully your tests of locking up your drivetrain didn't bend your derailleur or chainring or pull your dropout or frame out of alignment
07-18-16 | 10:39 AM
#9
Senior Member
Joined: Aug 2005
Posts: 33,657
Likes: 1,119
From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
The same gearing only means something if the chainstays are the same length. If the problem bike has longer chainstays it will need a longer chain.
07-18-16 | 10:59 AM
#10
Senior Member
Joined: Sep 2010
Posts: 8,327
Likes: 1,112
From: Roswell, GA
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
If you forget and you (or another rider) shifts into that combo you will be very sorry, and the damage will have already been done. I would strongly suggest you get a chain which is long enough.
