Fitting a Shimano HG70 11T-28T (7) cassette to a Shimano DX FH-M650 HUB (7)

I'm not sure but I have a hunch that your said derailleur predates 11T cogs.
If so, Shimano isn't/wasn't going to change all their instructions sheets to state that it works after releasing it.

Others will know better than me as I was really just starting out back in the early 90's.
Ahhh good point @synchronicity i didn't think about that.
 
The DX rear mech is classed as not compatible with 11T because it came before 11T and when 11T was released at that level, DX was phased out.

It works, just like M900 mechs work with 11T and they never had an 11T cassette to go with them.

If you hub is 7 speed and you want to put a 7 speed cassette on it, that is fine. As you want to fit a compact 11T one on you'll need a thin spacer at the back to allow the cassette to be clamped up correctly. If you have the old cassette, you take it apart (a few long bolts or crack the rivet out) and pinch the funny shaped thin one.

That usually does it.
Thanks for replying @FluffyChicken and for the insight 🙌🏻 great to know this will work 🎉 yes that was the next bit i was confused about, i couldn't figure out where this spacer needed to go. Please see attached cassette i just bought. I don't have the original cassette sadly.
Is the spacer you mention the silver washer looking ring on the left in the first image?
Do you know where the 2x dark grey washer / spacer rings would fit in the middle image?
And it looks like the rivets on the back can be unscrewed with an adjustable spanner maybe.

Thanks so much for the help.
 

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No problem with older derailleurs and 11T. That's what the B-tension screw is for, adjusting the drop between cassette and top jockey.
Essentially Shimano didn't change the geometry of the design between 1988 and 2005 or so.

As an aside, Shimano have huge margins for error built into their compatibility. If they say it will work, it's pretty much guaranteed. However you can usually stretch things a fair bit. I bet the reason they put 12T min was because 11T didn't yet exist and at that time 13 or 14T was the norm for top gears from the time of freewheels. Freehubs were still a pretty new idea in 1989.
Thanks so much @hamster you truly are a wizard, please let me know what i need to do to transfer you the money for free body and axle etc (also dumb question i know, just wanted to check it would be a hollow axle i don't need the screwers as i'm going to be using those pitlock security skewers) but just wanted to double check.
 
The dark grey 1mm spacer fits between the two smallest cogs. Essentially insert in the stack until all the spacings are equal. The silver one looks liek a 3mm spacer needed to fit the 7s cassette on an 8/9/10 hub, which has a longer bit for the extra gears.
 
The dark grey 1mm spacer fits between the two smallest cogs. Essentially insert in the stack until all the spacings are equal. The silver one looks liek a 3mm spacer needed to fit the 7s cassette on an 8/9/10 hub, which has a longer bit for the extra gears.
Incredible thanks @hamster thanks for help with 1mm washers, so your STX hub i'm guessing is 8/9/10? so i have everything i need if i use the 3mm spacer at the back? according to sheldon he also says, i need to buy a Hyperglide C lock ring as well, do you think that's necessary? (sorry for more questions)

Note, if you install an 11-tooth sprocket on an existing cassette that had a larger top gear, you must also replace the Hyperglide lockring with a Hyperglide-C lockring. The lockrings made to work with 11-tooth sprockets have a smaller outside diameter. If you use a larger lockring, the side plates of the chain will hit the edge of the lockring, and the chain will not run properly on the 11-tooth sprocket. (Hyperglide-C lockrings are compatible with 12-tooth sprockets though not always with larger ones.)
 
Incredible thanks @hamster thanks for help with 1mm washers, so your STX hub i'm guessing is 8/9/10? so i have everything i need if i use the 3mm spacer at the back? according to sheldon he also says, i need to buy a Hyperglide C lock ring as well, do you think that's necessary? (sorry for more questions)

Note, if you install an 11-tooth sprocket on an existing cassette that had a larger top gear, you must also replace the Hyperglide lockring with a Hyperglide-C lockring. The lockrings made to work with 11-tooth sprockets have a smaller outside diameter. If you use a larger lockring, the side plates of the chain will hit the edge of the lockring, and the chain will not run properly on the 11-tooth sprocket. (Hyperglide-C lockrings are compatible with 12-tooth sprockets though not always with larger ones.)
If you move to a newer freehub, and it is 8 speed and not 7, then you'll need that 3mm spacer.
If you just wish to fit that 11-28T to you current free hub you need to find another of the thin 1mm funny spacers and put one at the back.

If you try to fit a different freehub it is not a simple unbolt and bolt on. (if the above 1mm thin spacer does not work)
You need to take the axle out (so thin spanners needed)
You need to unscrew the freehub body (so long handled 8mm Allen key needed (same Allen key as used for crank bolts into bottom bracket)
You'll need some nice grease, you'll need the learn how to setup cup/cone hubs. A good skill to learn, can be fiddly and you'll want to learn how to do it properly (leaving a tiny amount of play).
 
Generally it's a 10mm Allen not 8mm.
That's true.
I wonder what crank bolts I did with a 10mm Allen key.
Or I'm going mad, which is more likely.

(not relevant to above hubs - - I know the past 15 years or so they moved to a 12mm Allen key, has that changed again yet with the 11/12speed stuff?)
 
according to sheldon he also says, i need to buy a Hyperglide C lock ring as well, do you think that's necessary?

Any 11T [shimano] lockring should work. These have a smaller flange diameter than 12T lockrings. They're not called hyperglide-C lockrings anymore.
 
Its really is as simple as @FluffyChicken said in his first utterance! All you need to complete the task is a spacer, put on the freehub first.....then put on the cassette.

Unless you want 8 speed or more, there us little point changing the roughly 30mm 7 speed freehub out for a 35mm longer one for 8 + speed......as you will just need more spacers to mount your cassette.

If you ask in the wanted section, im sure somebody will have a 1mm washer....

The reason there is a problem, which may help you understand the solution, comes from the way the 11 vs the 12 bottom cogs are cut where they interface. 12s goes right onto the freehub splines, but an 11 does not.....it has a rim on it.....hence needing the washer to make up the lost space so you can clamp the stack down.

Also , more "modern" hubs have a slight cut away on the edge of the splines which allows 11 speed to engage further onto the freehub.
 

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