Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Struggling get my 8 speed brake/shifters to index correctly.. HELP!

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Struggling get my 8 speed brake/shifters to index correctly.. HELP!

Old 03-09-13, 08:13 PM
  #1  
bill meyer
Member
Thread Starter
 
Join Date: Jan 2013
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Struggling get my 8 speed brake/shifters to index correctly.. HELP!

I'm having some serious difficulty with my Ultegra 8sp brifters combined with my DuraAce 7402 8sp rear derailleur. It's shift throws are just a tad long, so if I adjust properly on 1st, by the time it's down to the 5th or 6th cog it's getting noisy, then will skip 7th entirely and jump down to 8th. This all worked perfect with my 8sp downtube shifters, so I know the rest of the system is fine.

Thinking my Ultegra units were bad, I purchased some cheap Shimano sora 8sp brifters, and this gave the same result.

I'm confused why this 8sp dura ace derailleur would be incompatible??

Thanks for any suggestions!

Bill
bill meyer is offline  
Old 03-09-13, 09:14 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 14,939

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2927 Post(s)
Liked 1,209 Times in 849 Posts
IIRC the 8 speed DA used a different cable spec then the rest of the Shimano line. The cable was a 1.6mm diameter, just about all other Index systems use a 1.2mm (well 1.1 also) cable diameter. So mixing the shifters and or the cable will upset the amount of cable that is pulled and in turn the amount of dérailleur movement. This difference will be noticed as you shift through more gears, just one shift is not enough build up to show the miss match yet. What i don't remember is if the actuation ratio is also different (how far the dérailleur moves for a unit of cable movement.) If you were to change out the DA 7402 to a 9 speed one and use the new shifters with a 1.2 cable all will play nice. Andy.
Andrew R Stewart is offline  
Old 03-09-13, 10:10 PM
  #3  
Gonzo Bob
cycles per second
 
Gonzo Bob's Avatar
 
Join Date: Oct 2003
Location: Minnesota
Posts: 1,790

Bikes: Vitus Aluminum, DiamondBack Apex, Softride Powerwing 700, "Generic" Ishiwata 022, Trek OCLV 110

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The cable pull of the Dura-Ace 7400 series is different than all other Shimano. You need either Dura-Ace 8-speed shifters or any Shimano 9-speed shifters to shift the Dura-Ace 7402 RD for Shimano 8-speed spacing. See this table https://sheldonbrown.com/dura-ace.html#indexing .

Or as Andrew says, get a new rear derailer - any Shimano except Dura-Ace 7400 series.

Your 8-speed downtube shifters must have been Dura-Ace.

Last edited by Gonzo Bob; 03-09-13 at 10:15 PM.
Gonzo Bob is offline  
Old 03-10-13, 08:58 AM
  #4  
bill meyer
Member
Thread Starter
 
Join Date: Jan 2013
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Ok, that makes sense, of course Dura Ace would be different.. I did have Dura ace downtube shifters, so that answers that.

Thanks!
bill meyer is offline  
Old 03-10-13, 05:01 PM
  #5  
bobotech
Senior Member
 
Join Date: Jan 2012
Location: Spokane, WA
Posts: 2,255

Bikes: Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I just realized something. I was fixing up a K2 road bike frame and put some 8 speed brifters on it and set it up. The rest of the components are RX100. I was having a devil of a time getting the 8 speed brifters to index with the rear cassette. I looked at the brifters and they are Dura Ace. Do the Dura Ace 8 speed brifters use that same odd pull that is only usable with the Dura Ace rear derailleurs?
bobotech is offline  
Old 03-10-13, 05:58 PM
  #6  
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Wisconsin
Posts: 7,865
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 151 Post(s)
Liked 53 Times in 44 Posts
+1 to above. You either need different shifters, or more sensibly, a different RD.

Originally Posted by bobotech View Post
I just realized something. I was fixing up a K2 road bike frame and put some 8 speed brifters on it and set it up. The rest of the components are RX100. I was having a devil of a time getting the 8 speed brifters to index with the rear cassette. I looked at the brifters and they are Dura Ace. Do the Dura Ace 8 speed brifters use that same odd pull that is only usable with the Dura Ace rear derailleurs?
Yes. Dura Ace 8-speed shifters actually pull the same amount of cable as all Shimano 9-speed, but with one less click of course. See Gonzo Bob's link above.

Now the real question - why were you putting DA STI on an RX-100 bike???
FastJake is offline  
Old 03-10-13, 07:43 PM
  #7  
bobotech
Senior Member
 
Join Date: Jan 2012
Location: Spokane, WA
Posts: 2,255

Bikes: Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by FastJake View Post
+1 to above. You either need different shifters, or more sensibly, a different RD.



Yes. Dura Ace 8-speed shifters actually pull the same amount of cable as all Shimano 9-speed, but with one less click of course. See Gonzo Bob's link above.

Now the real question - why were you putting DA STI on an RX-100 bike???
I have them? I don't know what to do with them. I honestly don't like doubles all that much because I'm so big (350+) so I like to have the option of a bail out granny gear. The bike was built up with the RX100 stuff a while back using a double crankset but I used a 9 speed cassette and a pair of 3x9 Ultegra shifters. Worked fine but I robbed the 3x9 shifters and cassette for another bike I just finished (an old Rockhopper drop bar conversion). I had the Dura Ace 2x8 shifters in my junk bin so I threw them on it but now they don't shift well until it dawned on me that well they are one of the odd ball models.

So I'm kind of back to square one now.
bobotech is offline  
Old 03-10-13, 08:18 PM
  #8  
onespeedbiker
Retro Grouch
 
onespeedbiker's Avatar
 
Join Date: Oct 2007
Location: Santa Cruz
Posts: 2,210

Bikes: Yes

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by FastJake View Post
+1 to above. You either need different shifters, or more sensibly, a different RD.

Yes. Dura Ace 8-speed shifters actually pull the same amount of cable as all Shimano 9-speed, but with one less click of course. See Gonzo Bob's link above.
I have the a set of the Shimano SL-BS77 Dura Ace Double/Triple Bar End Shifters (9-Speed). One of the confusing aspects was a sentence in the service instructions that warn, "This shifting lever can not be used with any rear derailleur other than Dura Ace". Apparently this was some hold over from the proprietary DA days, as starting with 9 speed, DA derailleurs and shifters became cross compatible with the rest of the Shimano line. As mentioned, the combination of the new 9 speed shifters (all, not just DA) and the old 8 speed DA derailleur, shifts the same as an 8 speed DA shifter and DA derailleur; the 8th index click is just adjusted out. Further as a 9 speed index shifter it will work with the whole of the Shimano line (Yes, I'm sure there are some limitations here, but the cable pull length/ derailleur movement will be the same).
Your 8-speed downtube shifters must have been Dura-Ace
It is also possible the OP had one of these 8/9 speed bar end shifters.

What I find amusing is there are still a lot of LBS wrenches and posters that will tell you that the SL-BS77 will only work with Dura Ace because of that warning, even though it's only validity is with the 8 speed index mode.
onespeedbiker is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
sballent
Bicycle Mechanics
2
04-30-15 08:47 AM
Jexbrah
Bicycle Mechanics
3
07-31-14 09:13 AM
spunkyj
Bicycle Mechanics
12
11-07-11 05:01 PM
djhep
Bicycle Mechanics
7
05-21-11 11:04 PM
rgoldfinger
Bicycle Mechanics
6
04-06-10 08:46 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.