tattman23

What's the fastest path to fitting an 8-speed cassette on a bike that currently sports a 7-speed cassette on a hub that's labeled Shimano FH-M290? Could it be as simple as a new cassette and freehub body? Early results are discouraging, as they make it seem that in order to upgrade the gearing to 8-speed for smaller transitions in the mid-gears, would take a whole different wheel - one that doesn't say FH-M290 on the hub.


The bike left the factory an 8x3, that's the funny part. By the time I acquired it, the lovely 11-32 SRAM stuff it probably was built with, had been replaced (unbeknownst to me til I got home with it) with the Shimano wheelset including 7x cassette.


This is all speculation/guesswork of course. I just have my doubts that an 8-speed freehub body would "just fit".

Advice & counsel kindly sought,
Tattman23

bikeman715

yes you need to change out the freehub to a 8/9/10 . maybe redish the wheel if needed . going from 8 to 7 was a step backward .

HillRider

AFAIK, that hub will accept almost any other Shimano freehub body as it is bolted to the hub shell with the standard 10 mm hollow bolt so you can easily upgrade it to an 8/9/10-speed body. What you may also need is different cones and dust seals to match the replacement body.

The FH-M290 was an Accera level hub with a 7-speed freehub body but spaced 135 mm OLD. Updating it to 8-speed+ will require revising the spacer configuration and probably redishing the rim.

Bill Kapaun

You have to be aware that not all FH bodies are interchangeable. Some of the newer low end ones (like the RM-30) use a totally different spline interface.

What shifters does it currently have? IF 7 speed, just go to 9 speed shifters, chain & cassette.
9 speed cassettes come in a much wider array of combinations than 8 speed.
Price between 8 & 9 speed cassettes/shifters isn't that much different.
You would need a 9 speed chain.

I went from 7 to 8 to 9 speed and simply wish I hadn't bothered with 8.

tattman23

Thanks all replies for the sage advice. The shifters are 8-speed. I had my fingers crossed that a well meaning bike fixer simply tossed the current 7-speed cassette on, adding spacers as needed, to the original wheel (either due to the factory components being trashed, or maybe they found a use for the stuff on a different bike <shrug>).


Maybe I'm wrong but - An additional rear wheel, with an 8-speed cassette mounted, would be preferable to re-dishing. Or, change shifters and a couple more drivetrain parts and jump to 9-speed per Bill K.

Bill Kapaun

To use the current hub, you would need the 8/9 speed body.
That body is something like 3-4mm longer, thus you would have to remove an equal amount of spacing on the NDS.
That means the wheel gets shifted to the NDS by that amount.
The RIM has to be dished back to the DS 1/2 that to recenter.
Due to spoke/hub geometry, most of that will be accomplished by loosening the NDS spokes noticeably more and a bit of tightening on the DS spokes.
That's not a problem for someone that builds wheels and has a spacer kit. (I do)
Now if this is an old wheel, with frozen nipples, it gets to be a total pain.

Jukebox

I had the same question. I used a "FH-M525A Freewheel Body Unit" from Shimano (UPC: 689228017450). I had to redo the hub spacing, so an axle spacer kit is necessary (if I remember correctly, I moved the biggest NDS spacer to the DS under the freehub and put a 3 or 4mm spacer on the NDS, just make sure there is about 5mm of exposed axle on each side to fit in the dropouts). The wheel did need a slight re-dish, but it wasn't too bad with proper hub spacing, just add lubricant to all the spoke nipples before starting. I am currently running SRAM GX 10 speed and it works great.

Duragrouch

Okay. If it was originally 8 speed freehub and they used the same freehub to mount 7 speeds, they added a small spacer behind the cassette to do so. Remove the cassette and spacer, put on 8 speed cassette, change shifter to 8. Done.

If the freehub was changed from 8 to 7, or is originally a 7 hub, you need an 8 freehub, it's a touch longer. Not by much, may fit; Check online and measure clearance between hyperglide lockring and inside of right dropout.

If the freehub is 7 and you want to mount 8 with minimal changes, there are tricks on sheldonbrown.com for cheating this, by using thinner spacers and/or cogs, and changing shifters accordingly. Go look.

Bill Kapaun

This thread is 7-1/2 years old-

Duragrouch

GAH! I really need to look at the dates. It just shows up as recent in the subforum, and then I jump in and read, and of course the last response is recent.

I think this may be the result of a) the search function kicking back a thread in response, or b) the system listing a related or similar question in a list at the end of a thread ("Related Topics"), with no consideration of thread age. Would be good if the mods noticed that, perhaps added "last response date" along with the thread listing.

Bill Kapaun

It's called Google

Duragrouch

You might be right. I did a search of the thread title (not on google, but on DuckDuckGo, came up). If I was bike forums, I would try to figure this out, not just for this but general solutions; contact the recent poster and ask exactly how they got pointed to the thread, whether it was a google search, or suggestion from BF itself. Second, it would be easy programming to implement as a response to trying to post on a zombie thread, "The last reply to this thread was X years ago. Are you sure you want to reply?" Easy peasy. They already have it automated to go to the first unread post in a subscribed thread. This is easier, just a couple of If-Thens based on thread age versus a decided parameter, perhaps one or two years.

Bill Kapaun

Ignore List-
You just can't seem to stop with trivial crap.