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8 spd cassette on 7 spd hub

633 views 5 replies 4 participants last post by  foz 
#1 ·
Can any of you remember if a 8 spd cassette fits on 7 spd hub on shimano?

Regards Anders
 
#2 ·
it will, but you'll have to change the freehub body for an 8 speed one, take a spacer from the axle on the non-drive side to keep the same OLN dimension (either 126 or 130mm, depending on the age of the frame and wheel) and then re-dish the wheel. it'll make the wheel slightly weaker (from the extra dish), but if you're not over heavy (either yourself or on your wheels) and it's done properly then it'll cause no problems.

foz
 
#4 ·
If you have a 126mm hub, you can run a "8 of 9 on 7" on it. Useful for frames that can't be spread, such as glued aluminum. Search for Sheldon Brown's excellent writeup on how to do it. If you are lucky you will have a freehub that's both uniglide and hyperglide compatable and the 9sp stuff will slide right on.
 
#5 ·
foz said:
it will, but you'll have to change the freehub body for an 8 speed one, take a spacer from the axle on the non-drive side to keep the same OLN dimension (either 126 or 130mm, depending on the age of the frame and wheel) and then re-dish the wheel. it'll make the wheel slightly weaker (from the extra dish), but if you're not over heavy (either yourself or on your wheels) and it's done properly then it'll cause no problems.

foz
I'm with you on the 130mm hub, but have you actually tried this with a 126mm hub?

I have the impression that130mm hubs are dished about as far as is possible. I've never tried it but my impression has been reinforced by the number of broken spoke threads. Is it possible to get aa reasonably durable wheel after installing an 8/9/10 speed freehub body on a 126mm hub?
 
#6 ·
Spoke Wrench said:
I'm with you on the 130mm hub, but have you actually tried this with a 126mm hub?

I have the impression that130mm hubs are dished about as far as is possible. I've never tried it but my impression has been reinforced by the number of broken spoke threads. Is it possible to get aa reasonably durable wheel after installing an 8/9/10 speed freehub body on a 126mm hub?
yes, i've done it and it worked (and still works!) fine. old 7 speed 105 hub, 126mm. took the freehub off and installed an 8 speed duraace one with the 8 speed duraace cassette (this was back in the day when 8 speed duraace was the latest and greatest, about 15 years ago!). the 8s freehub is a bit wider than the 7s one, so to reduce the axle length again and leave it as close to 126mm as possible you have to take out a spacer from the non-drive side of the axle. redish the wheel because changing spacers etc will leave the rim off to the non-drive side with respect to the outer lock nuts. once done, the actual dimension is somewhere between 126 and 130mm (i can't remember if it's exactly 128mm, but it's thereabouts). you need to separate the dropouts slightly on your 126mm frame and the wheel works no problems. mine worked fine for at least 30,000 miles, and still works fine, although it only gets used a couple if times per year.

foz
 
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