Direct Mount rear derailleur

top_bhoy

Apologies if this seems a bit of a bog-standard question; I'm a MTB noob and cannot fully confirm my question using the search function.

I currently use a medium cage conventional rear derailleur on my commuting hybrid. This medium cage is only available at the moment as a Direct Mount version.

Can the conventional version be replaced by the direct mount rear derailleur; if so, are there any pitfalls to be wary of?

Or, should I just wait until I can source the conventional version?

Thanks

whyamihere

Pretty much all new Shimano rear derailleurs are direct mount, they just come with an adaptor plate which allows them to be fitted to a conventional hanger. Do you have a link to the derailleur you want to buy?

If it is being sold as direct mount only, then it can't be fitted to a conventional hanger. The options if you did want that one would be to get the adaptor plate (many people probably have them hanging around after fitting a direct mount derailleur) or to see if a direct mount hanger is available for your frame.

dgmoose

Top_Bhoy wrote:

Apologies if this seems a bit of a bog-standard question; I'm a MTB noob and cannot fully confirm my question using the search function.

I currently use a medium cage conventional rear derailleur on my commuting hybrid. This medium cage is only available at the moment as a Direct Mount version.

Can the conventional version be replaced by the direct mount rear derailleur; if so, are there any pitfalls to be wary of?

Or, should I just wait until I can source the conventional version?

Thanks

This line of thinking is narrowing your choices.

There is usually a medium cage further up or lower down, which are not direct mount, in Shimano's heirachy of rear derailleurs that will be compatible.

Also, you should specify your exact RD model number.

The Shimano installation doc regarding direct mount derailleurs specifies a list of non-DM RDs that could be fitted to a DM frame if you remove the RD bracket that normally attaches to a hanger. So, if your current RD is on that list then you could fit a DM RD using the bracket from your current RD - that is, only if Shimano has not changed this design concept.

Note that the term "medium cage" or "GS" designation is not created equal across Shimano's range of RDs. For example, the long cage (SGS designation) shadow version of a RD vs non-shadow SGS is slightly shorter by comparison. That is, the centre-to-centre measurement between the two pulley wheels is slightly shorter on a shadow SGS. This is reflected in the max capacity of the RD. It is the same for the GS RDs.

top_bhoy

Apologies for the delay in getting back to you for your input. I've been bogged down a bit with life.

I searched out the installation guide and it appears that for a conventional frame mount I can use any one from M986/M981/M820/M781/M786/M670/M675 providing it is the bracket type. One other thing I learnt is that I may need the long cage if I use a a 38/24 at the front and a rear cassette larger than a 11-32.

Thanks again.