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Can an 8 speed shifter be made to work with a 7 speed cassette?

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Can an 8 speed shifter be made to work with a 7 speed cassette?

Old 05-11-20, 03:34 PM
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jc907
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Can an 8 speed shifter be made to work with a 7 speed cassette?

Howdy folks,


Please have patience with this newbie to the forum if my question seems like a "Duh!" one. I've been out of the saddle a looong time (mountain bikes were a new novelty when I started riding) and I've found the tech's changed dramatically since those days when I virtually lived on 2 wheels.


I've taken my 1995 GT Tequesta out of mothball and had to 86 the original Shimano STX rear/right hand shifter. I tried rehabing it by completely dismantling & degreasing out the tar/sand/crude that was not letting the cam engage. I cleaned it thoroughly with trichlorethylbadstuff, but found after rebuilding the unit and applying a light silicone lubricant to the metal parts, I could only get 6 shifts out of it and not the 7 that it used to do, hence, my decision to deep 6 it altogether.


Obviously the STX line's long discontinued & 7 speed units that are Shimano derailleur compatible are not easy to find as most units are now 8, 9, 10 or higher speeds. I'd like to avoid replacing the rear derailleur and/or cassette as both are still in good working order showing minimal wear and tear.


I've been told I can use an 8 speed shifter as long as it's Shimano derailleur compatible and simply limit the derailleur travel using the derailleurs limiting screws.


Is that true and/or are there other things I need to take into consideration?


Thanks in advance for reading and I look forward to hearing from anyone out there.
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Old 05-11-20, 04:06 PM
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If it's a 7-speed shifter, it will have 6 clicks. If you don't believe me, count them on your fingers: 1 to 2 is 1, 2 to 3 is 2...
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Old 05-11-20, 05:49 PM
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As KenCarlson stated you have the right number of shifts for a 7-speed shifter, but Amazon has many trigger, twist and brifter styles of shifters to choose from.
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Old 05-11-20, 06:36 PM
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If, after heeding the advice given above, and if it turns you get 6 gears and 5 clicks, then the answer to your 8 speed shifter question is yes.

I started mountain bike riding late in life and when an LX 7 speed shifter was giving me problems, I went to look for a replacement. I found older 7 speed shifters so overpriced, and new ones were not very good, and I could get a better 8 speed shifter for less.

I took my 7 speed cassette apart. Sanded the plastic spacers from 3.15mm to 3.0mm. Put it together and ran 7 gears with 8 speed shifters and never looked back.

John
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Old 05-11-20, 09:07 PM
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You can use 8 speed shifter with a 7 speed cassette. Be sure to set the limit screws correctly on the RD. Obviously you will have 1 click in your shifter that will be blocked by the limit screw (you can pick high or low).
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Old 05-12-20, 02:17 AM
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Understood, but the indicator only goes to "6" now. I haven't reinstalled the unit and attached the cable to it so could that have something to do with it only indicating 6? going
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Old 05-12-20, 02:18 AM
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Solid copy. Thx
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Old 05-12-20, 11:27 AM
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You can also you 7 cogs of an 8-speed cassette. That will get you exactly the right shifting. Or measure the thickness of the 8-speed spacers, and use them with your 7-speed cassette. The differences between 7/8 are very minor and sometimes you can get away with mismatching, but not always.
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Old 05-12-20, 11:31 AM
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Originally Posted by FastJake View Post
You can also you 7 cogs of an 8-speed cassette. That will get you exactly the right shifting. Or measure the thickness of the 8-speed spacers, and use them with your 7-speed cassette. The differences between 7/8 are very minor and sometimes you can get away with mismatching, but not always.
Thx. Appreciate it greatly!
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Old 05-12-20, 11:40 AM
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Thanks

Originally Posted by dsbrantjr View Post
As KenCarlson stated you have the right number of shifts for a 7-speed shifter, but Amazon has many trigger, twist and brifter styles of shifters to choose from.
Originally Posted by 70sSanO View Post
If, after heeding the advice given above, and if it turns you get 6 gears and 5 clicks, then the answer to your 8 speed shifter question is yes.

I started mountain bike riding late in life and when an LX 7 speed shifter was giving me problems, I went to look for a replacement. I found older 7 speed shifters so overpriced, and new ones were not very good, and I could get a better 8 speed shifter for less.

I took my 7 speed cassette apart. Sanded the plastic spacers from 3.15mm to 3.0mm. Put it together and ran 7 gears with 8 speed shifters and never looked back.

John
Originally Posted by tFUnK View Post
You can use 8 speed shifter with a 7 speed cassette. Be sure to set the limit screws correctly on the RD. Obviously you will have 1 click in your shifter that will be blocked by the limit screw (you can pick high or low).
Originally Posted by jc907 View Post
Understood, but the indicator only goes to "6" now. I haven't reinstalled the unit and attached the cable to it so could that have something to do with it only indicating 6? going
Originally Posted by FastJake View Post
You can also you 7 cogs of an 8-speed cassette. That will get you exactly the right shifting. Or measure the thickness of the 8-speed spacers, and use them with your 7-speed cassette. The differences between 7/8 are very minor and sometimes you can get away with mismatching, but not always.
Thank you all greatly for your incisive and timely responses.

Update: I've tried it one last time and it seems the gear shift gods have decided to smile upon me: The shifter now is running through all shifts except the last two on the return. I'm suspecting that it will work properly once the new cable is installed and there's tension on the return.

Thx to all again
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Old 05-12-20, 04:38 PM
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If you do end up needing a new shifter, it looks like you can get a set of Microshift ones for pretty cheap: https://www.amazon.com/MicroShift-Th...322857&sr=8-23

I haven't tried their 7 speed stuff, but I know from experience their 11 mountain bike shifter is solid.
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Old 05-13-20, 04:20 PM
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Originally Posted by 70sSanO View Post
If, after heeding the advice given above, and if it turns you get 6 gears and 5 clicks, then the answer to your 8 speed shifter question is yes.


I took my 7 speed cassette apart. Sanded the plastic spacers from 3.15mm to 3.0mm. Put it together and ran 7 gears with 8 speed shifters and never looked back.

John
Wow...you da man.
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