Bicycle Mechanics - MTB 8 spd shifter campatible with 7 spd cassete?

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My vintage Miyata Elevation 8000 has a shifter that is going bad. Will an 8 speed shifter index the 7 speed cassete or must I now begin the search for a good used or NOS set of 7 lx to xt level rapid fire shifters.
It will work fine, you will just have one less gear available. The cassette spacing on an 8 speed cassette is near identical to a 7 speed cassette. The 8 speed cassette is about 4 mm wider. I use an 8 speed shimano bar end shifter on my 7 speed shimano hyperglide cassette, and it indexes perfect.
Jeff Wills
06-19-09, 10:30 PM
My vintage Miyata Elevation 8000 has a shifter that is going bad. Will an 8 speed shifter index the 7 speed cassete or must I now begin the search for a good used or NOS set of 7 lx to xt level rapid fire shifters.
Maybe yes, maybe no. The indexing on a 8-speed shifter is different from a 7-speed shifter- it might work OK if the tolerances stack up right. I tried it (once, a long time ago) and I couldn't get it to index properly.
What's going on with the shifter? Many times a good spritz of spray lube into the shifter restores it to usefulness.
If it does really need replacement, you can still get 7-speed RapidFire shifters... just not XT or LX:
http://www.bikepartsusa.com/bikeparts/item/01-129865/
I've done it to two different bikes and it worked fine both times. Once with Shimano and once with Grip Shift.
Grand Bois
06-20-09, 12:38 AM
I tried it and couldn't get it to do anything but work perfectly.
Ultegra 8 speed bar end shifters converted to thumb shifters, a 7 speed cassette and Shimano 600 derailers.
http://inlinethumb52.webshots.com/11763/2414855690068014369S600x600Q85.jpg (http://rides.webshots.com/photo/2414855690068014369CRiJPB)
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