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-   -   Dura Ace 7400 dt shifter question (https://www.bikeforums.net/classic-vintage/931489-dura-ace-7400-dt-shifter-question.html)

poke em 01-26-14 12:24 AM

Dura Ace 7400 dt shifter question
 
So it seems that 9 speed 7700 shifters are a match with 8 speed 7400 drivetrains. Does that mean that 7/8 speed 7400 dt shifters would index properly with a 9 speed 105/ultegra/DA drivetrain? The dark gray shifters would look great with a tricolor group and a 9 speed cassette.

lasauge 01-26-14 12:46 AM

Shimano 9-speed shifters only index an 8-sp cassette if you're using a 7400 derailer. Going the other way (indexing a 9-sp cassette minus one cog with 8-sp shifters an a 9-sp compatible derailer) works as long as you use "hubbub" routing. Here's the best page I know of for explaining how drivetrain mashups can be done: http://www.ctc.org.uk/cyclists-libra...gears/shimergo

poke em 01-26-14 01:01 AM


Originally Posted by lasauge (Post 16441182)
Shimano 9-speed shifters only index an 8-sp cassette if you're using a 7400 derailer. Going the other way (indexing a 9-sp cassette minus one cog with 8-sp shifters an a 9-sp compatible derailer) works as long as you use "hubbub" routing. Here's the best page I know of for explaining how drivetrain mashups can be done: http://www.ctc.org.uk/cyclists-libra...gears/shimergo

Would you have to "hubbub" if you were using a 7400 dura ace shifter rather than regular 8 speed (ultegra/105)? I have read that the cable pull for 7400 shifters is the same as 9 speed shimano (all) or would it be plug and play?

Fred Smedley 01-26-14 06:02 AM


Originally Posted by poke em (Post 16441194)
Would you have to "hubbub" if you were using a 7400 dura ace shifter rather than regular 8 speed (ultegra/105)? I have read that the cable pull for 7400 shifters is the same as 9 speed shimano (all) or would it be plug and play?

The cable pull is identical , for 9 speed cassette with non 7400 rd it should work right minus one click . not sure if they had a "ghost"click like some of the 7's so you are most likely going to loose a gear on one end.

Gonzo Bob 01-26-14 07:50 AM


Originally Posted by poke em (Post 16441148)
So it seems that 9 speed 7700 shifters are a match with 8 speed 7400 drivetrains. Does that mean that 7/8 speed 7400 dt shifters would index properly with a 9 speed 105/ultegra/DA drivetrain? The dark gray shifters would look great with a tricolor group and a 9 speed cassette.

7400 8-speed shifter (DT or brifter) would shift 9-speed 105/Ultegra/DA (RD-7700) at 9-speed spacing but there would be clicks for only 8 cogs. Not sure you could get the 9th cog.

dddd 01-26-14 12:27 PM

The "hubbub" cable attachment mentioned by lasauge works just the opposite of how one would want if they were using 8s Dura-Ace shifters, i.e. the derailer's travel is further reduced using the hubbub cable attachment.
The Hubbub attachment is most useful for adapting Shimano derailers to work with Campagnolo Ergo shifters (allowing one to use 9s cassette spacing with 10s Ergoshifters, instead of having to use 8s cassette spacing).

But for using non-Dura-Ace 8s shifters with non-Dura-Ace derailers (having any # of speeds), the Hubbub attachment will change the cog spacing requirement from 8s to 9s (i.e. reduced movement of the derailer).
It would similarly change the cog spacing requirement from 9s to 10 when using 9s shifters with perhaps a 10s cassette with one cog removed.

There is also the traditional "alternate" cable routing, more or less to the opposite side of the pinch bolt, which will increase the derailer's travel so as to allow a pre-9s Dura-Ace shifter to index the same # of speeds using any non-Dura-Ace rear derailer.

I've done all of these mods and more, and most work as described. There is a difference between 7s and 8s cog spacing that I find useful to keep in mind when switching between those spacings, as one often does when having to use a freewheel with 7 speeds on an older wheel. In other words, one can be fussy about these details of they want their shifting to be equivalent to an unmolested, brand-new bike.

The people riding all these modern bikes must think that I'm seriously warped for actually preferring to use friction shifters, but I find that with modern chains, cables and careful selection and setup of the components, that downtube or stem friction shifting can work far better than it ever did back in the day.
Not that I don't appreciate what modern bikes have to offer, I do enjoy the feeling of confidence when attacking a serpentine, 15-minute climb amidst fast company on the stock, 2004 Orbea Orca that I bought myself in December.

jeirvine 01-26-14 01:32 PM


Originally Posted by dddd (Post 16441984)
...with modern chains, cables and careful selection and setup of the components, that downtube or stem friction shifting can work far better than it ever did back in the day.

I'm coming around to this view as well. Haven't tried it beyond 8 speed.

dddd 01-26-14 03:45 PM


Originally Posted by jeirvine (Post 16442119)
I'm coming around to this view as well. Haven't tried it beyond 8 speed.


Having the internet today means that one can also tap into every detail, and every detail's proponents and experts.

So anyone should be able to get a really slick-shifting friction setup up and running.

But if there is one thing about friction shifting it is that it seems better matched to slightly wider-spaced gearing, using fewer cogs.

I've gone as far as 7 in back, and really didn't want to have to shift closer ratios any more often.

52/42 with a 7s 13/28, or 54/44 with a 7s 13-30, or 52/36 with a 5-speed 13-24t, I don't need tight 13-14-15t cog spacing and wouldn't really want it using friction shifters.

Using retrofriction shifters with a 52/42 and 7s, 12-25t, UG freewheel is my ultimate go-fast friction setup on my '79 PX10E using a Suntour Sprint derailer and 7.1mm-width chain.


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