road STI and MTB derailers—Compatable?
09-05-07 | 01:53 PM
#1
Thread Starter
RED STEEL
Joined: Aug 2007
Posts: 26
Likes: 0
From: DSM, IA
Bikes: '93 Simoncini Europa SLX Ultegra STI
road STI and MTB derailers—Compatable?
I am helping a friend adding STI 8 speed to his old bike. I can get 8 speed RSX STI and wondered what derailers I can mate it to. I looked at the prices of rear and front derailers and noticed mtb. equipment prices are much lower. Could I mate the shifters to a deore 8/9 speed rear derailer sold on Nashbar https://www.nashbar.com/profile.cfm?c...t%3A%20Rear%20
What about the front? Anyone have an idea. He is not looking for the cutting edge or super high performance. I have a chain casette and rear wheel for 8 speed he can use.
What about the front? Anyone have an idea. He is not looking for the cutting edge or super high performance. I have a chain casette and rear wheel for 8 speed he can use.
09-05-07 | 02:03 PM
#2
Boomer
Joined: Nov 2003
Posts: 7,214
Likes: 1,458
Bikes: Diamondback Clarity II frame homebuilt.
Rear derailleurs will work fine but the front MTB derailleur does not operate at the same cable pull ratio as the Road STI shifter. Try picking up a SORA front 8 speed derailleur, they are inexpensive and will do the job.
09-05-07 | 02:05 PM
#3
Gone, but not forgotten
Joined: Jul 2002
Posts: 2,301
Likes: 12
From: Newtonville, Massachusetts
Bikes: See: https://sheldonbrown.org/bicycles
I am helping a friend adding STI 8 speed to his old bike. I can get 8 speed RSX STI and wondered what derailers I can mate it to. I looked at the prices of rear and front derailers and noticed mtb. equipment prices are much lower. Could I mate the shifters to a deore 8/9 speed rear derailer sold on Nashbar https://www.nashbar.com/profile.cfm?c...t%3A%20Rear%20
What about the front? Anyone have an idea. He is not looking for the cutting edge or super high performance. I have a chain casette and rear wheel for 8 speed he can use.
What about the front? Anyone have an idea. He is not looking for the cutting edge or super high performance. I have a chain casette and rear wheel for 8 speed he can use.
If you have a triple in front, that turns into a can of worms.
See: https://sheldonbrown.com/front-derailers
Sheldon "Doubles Are Easy" Brown
11-17-07 | 07:36 PM
#7
Senior Member
Joined: Feb 2005
Posts: 9,438
Likes: 10
From: Oklahoma
Bikes: Trek 5500, Colnago C-50
And the shifters must match the number of cassette cogs.
Al
11-17-07 | 07:41 PM
#8
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!
An MTB crank will work ok with a road fd even though the cage curvature isn't ideal. In the past Trek equipped some of their road bikes with 7-speed RSX which came with 46/36 double or 46/36/26 triple cranks and they also used RX-100 road fd's intended for 53/39 or 52/42/30 chainrings. They shifted just fine.
11-17-07 | 08:17 PM
#9
Senior Member
Joined: Oct 2007
Posts: 3,054
Likes: 10
From: CT
maybe mine is a mish mash of things someone put together.. it's 50/44/28 hopefully things will work.. or i just make it work mostly for the middle and big gear and call it good enough for now. got the bike cheap and am not really looking to put much $ into it.. so we'll see how it goes
