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My 2 year old bike has a (damaged) Nexus 7 IGH, it started running heavy and I can't find out why.

Rather than getting it fixed I'm considering replacing it with a Nexus 8 hub, as they supposedly of higher quality (apart from the obvious extra gear).

Obviously I need a new 8-speed shifter to do this, but it looks to me that I can use the old roller brake assembly and the chain (very little obvious wear).

Can anyone confirm this?

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  • Be aware that it may be more cost effective to replace the entire rear wheel rather than replace the hub alone. Spokes generally cannot be re-used and having a wheel re-built with a replacement hub is relatively expensive.
    – Argenti Apparatus
    Commented Sep 12, 2018 at 12:29
  • @ArgentiApparatus: That was exactly my plan, a complete wheel is only a little more expensive and a lot less work.
    – Pelle
    Commented Sep 12, 2018 at 12:33
  • Did you ever give the hub an oil change ? Could be you're pushing around coal instead of oil inside there.
    – Criggie ♦
    Commented Sep 12, 2018 at 12:40
  • I tried oiling the hub earlier this week, but when I put it back in the wheel I could feel the resistance when turning it. I intend to get it to work eventually as a spare, but in the mean time I need a working bike to commute.
    – Pelle
    Commented Sep 12, 2018 at 12:50
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    BTW, chains can be worn out but not look worn. Buy a chain wear gauge (they are not expensive) or have a bike shop check it .
    – Argenti Apparatus
    Commented Sep 12, 2018 at 12:52

1 Answer 1

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Depends what roller brake model you have.

Looking at the Shimano 2015-1026 component line up document you can see what components work together. (Very useful current line up web pages here, with links to PDF docs for previous years.)

You presumably have a Nexus SG-C3000-7R hub. That should be paired with the BR-IM81-R, BR-C6000-R, BR-C3010-R or BR-C3000-R roller brakes.

The Nexus 8 is the SG-C6000-8R or SG-C6010-8R hub which works with the BR-IM81-R or BR-C6000-R brakes only.

The PDF doc is very long, but you can search for the product numbers to find the Nexus 7 and 8 sections.

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  • That looks like a fun puzzle to solve, I'll have a look at my parts and what I can buy as an upgrade
    – Pelle
    Commented Sep 12, 2018 at 14:17
  • Yes, it is a SG-C3000-7R, and unfortunately paired with the BR-C3000-R. I may try to use the brake anyway, as the more expensive sets fit both hubs, so the mounting should be compatible (I think). I can always upgrade both brakes to a better series later.
    – Pelle
    Commented Sep 12, 2018 at 19:36
  • @Pelle, yeah, definitely worth a try
    – Argenti Apparatus
    Commented Sep 12, 2018 at 19:42
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    I have just completed the replacement by a SG-6001-8R, the roller brake fit just fine. Now to find out if it is the improvement I hope it would be.
    – Pelle
    Commented Sep 23, 2018 at 18:17

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