The timeless appeal of 7-speed gearing

[bigjim]

And I redeem myself with the thought that I have curated these great old freewheels for future generations!

Of course there is the thing, where it all gets chucked in a skip on your demise.

[MtbTourer]

The wheel dish is the most important thing IMHO. Starting with a 7s/135mm hub you can have a virtually dishless rear wheel. It is also easy enough to fit 8 sprockets from a 9s cassette to a 7s freehub body. This means you get to chuck a (useless, dish-causing) 11T or 12T sprocket in the bin.

cheers

Hi Brucey,

Brilliant idea, thanks for this.

I have some 7-speed hubs.

And I have an 11-34 Deore XT 9-speed Cassette.

However, the 11-34 is not a good option for 8-speed because the 13t cog does not have indents for the Lockring. Also the mid-range of this cassette is not as good as the 11-32 with the jump of 3 teeth between the No. 5 (20t) and No. 6 (17t) cogs whereas the 11-32 has a 2 tooth jump from 21t to 19t.

When I remove the 11t cog and place the cassette on the 7-speed Freehub body, the 13t cog has about a 1mm overhang over the end of the Freehub body. I imagine it would be the same for the 12t cog of the 11-32 cassette.

What is the minimum Overhang required to ensure proper engagement of the lockring with the serrations of the last cog?

Thanks!

[Brucey]

if you re-use a 'second smallest' sprocket as a 'smallest sprocket' often (but not always) you will find that there is a small counterbore in the middle of the sprocket so that a smaller (11T) sprocket with an integral spacer is strong enough to work OK. This counterbore often allows you to use a small diameter lockring, which is handy if it looks like there won't be enough threads engaged otherwise.

Lockrings vary in diameter and in length too. If you don't have a stash of old ones , try the LBS; they may have a drawer (or a scrap bin) full of them.

If you want to take the wheel dish to an absolute minimum with a 7s freehub body, the shoulder on the left of the body can be reduced in width (8/9/10s bodies have this smaller shoulder already, but most 7s bodies don't). Or you can use a dished #1 sprocket, or you can relieve the carrier on a cassette like an XT one. IME if you move everything more than 1.5mm leftwards then you will usually need a spacer between the lockring and the smallest sprocket when using an 8-from-9 setup.

If the lockring has no working serrations (eg if it bears against a smooth surface) then I would advise using a little threadlock on the lockring; it can make a bit of a mess otherwise, should it come loose.

There are many, many subtle variations in cassettes which may help or hinder you from making an adaptation of this sort.

Note that the required engagement of the smallest sprocket will vary depending on which type of 7s freehub body you are using. Assuming you are using an HG cassette it can be one of three types

- HG-C with relieved (shorter) splines (this is the most common type)
- UG/HG compatible (full length splines, with threads cut into the end of the splines)
- original HG (with full length splines)

You can only normally only use a HG-C body if you have a top gear sprocket with a built-in splined spacer. With an original HG body you can often use a flat sprocket provided you have got your cassette length perfect.

cheers

[MtbTourer]

Note that the required engagement of the smallest sprocket will vary depending on which type of 7s freehub body you are using. Assuming you are using an HG cassette it can be one of three types

- HG-C with relieved (shorter) splines (this is the most common type)
- UG/HG compatible (full length splines, with threads cut into the end of the splines)
- original HG (with full length splines)

You can only normally only use a HG-C body if you have a top gear sprocket with a built-in splined spacer. With an original HG body you can often use a flat sprocket provided you have got your cassette length perfect.

cheers

I have a Deore DX FH-M650 7s hub and a Deore LX FH-M560 7s hub.

They have the "full length splines, with threads cut into the end of the splines" which makes them the UG/HG compatible type.

So, instead of a 12t lockring, it looks like I can use the original 11t lockring supplied with the cassette.

The following link shows a 12t 2nd smallest cog.

https://www.cdnclouds.net/p/a0b7664def6 ... %2012T.JPG

Thanks!

[landsurfer]

7 speed .... Luxury !!

5 speed .. 13 straight .. single chainring 52 .... aaah the good old days .... Young and fit TT'er ...
Now ?? ... 26 or 34 single chainset ... 11-40 9 speed cassette ....

But still in love with the bike ...