7 speed shifters

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sparrow101

Active Member
Location
south east wales
i have a peugoet with 7 speed sti's but the left hand one no longer works, due to the lack of availabilty of 7 speed shifters i'm considering fitting 9 speed shifters but would these work ok with the existing chainset or would i have to change to a 9 speed one?

my other bike is 9 speed but i have fitted a 10 speed chainset and chain which works fine
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
You should get away with 8 speed STI's - the spacing is 0.1mm difference. I use 8 speed spacers on my 7 speed bikes......
 

RedBike

New Member
Location
Beside the road
Its rare but you can occationally find just the left (front) shifter for sale. In which case it wouldn't matter if the shifter is 7,8 or 9 speed.

Or you could just buy a pair and only fit the left hand one?
 
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sparrow101

Active Member
Location
south east wales
i decided to get 9speed sora shifters as they were cheaper than 8speed shifters and the chainset and bottom bracket was worn out, so i replaced these with a tiagra compact and the bottom bracket that i had recently taken off the other bike.
i'm still using the 7speed 105 derailers
 

RecordAceFromNew

Swinging Member
Location
West London
i decided to get 9speed sora shifters as they were cheaper than 8speed shifters

I would expect problematic indexing if your plan is to use a 9 speed sti with a 7 speed cassette/freewheel. The difference in sprocket pitch between 7 and 9 speed is significant (while as Fossyant and gbb said above the difference between 7 and 8 speed is usually manageable).

The problem of using a 9 speed sti is compounded by the fact that one usually can't simply replace the 7 speed cassette (if it was indeed a cassette and not a freewheel) with a 9 speed one because of their freehubs' difference in width, and the knock-on effect on dish if one does replace the freehub and respace the hub.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
6-7-8 speed chains, spacers, mechs etc etc..... are interchangeable (excluding DA 7400 mechs....) ................. 9 plus isn't (ish).............. - The chain on 9 speed is narrower.

PS 9 speed chains work really well on 8s systems................. less chain rub too on the front mech........
 
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sparrow101

Active Member
Location
south east wales
I would expect problematic indexing if your plan is to use a 9 speed sti with a 7 speed cassette/freewheel. The difference in sprocket pitch between 7 and 9 speed is significant (while as Fossyant and gbb said above the difference between 7 and 8 speed is usually manageable).

The problem of using a 9 speed sti is compounded by the fact that one usually can't simply replace the 7 speed cassette (if it was indeed a cassette and not a freewheel) with a 9 speed one because of their freehubs' difference in width, and the knock-on effect on dish if one does replace the freehub and respace the hub.


i'm going to use my fulcrum 7 wheels which have a 9 speed cassette already fitted.
i'll be fitting a 9 speed cassette to the old wheels (minus 1 cog so it fits) and using this for the turbo
 
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