Help me understand RD Specs

For discussions about bikes and equipment.
Post Reply
User avatar
bikes4two
Posts: 1306
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

Help me understand RD Specs

Post by bikes4two »

I am looking for a replacement RD but am confused by some of the specs given. For instance CRC list the following spec for the Shimano SLX M675 Shadow


1. Shifting Action: Top-Normal
2. Mount Type: Direct Attachment
3. Maximum Sprocket: 36T/11T
4. Minimum Sprocket: 32T/11T
5. Front Difference: 22T
6. Total Capacity: 35T

> Line (1) - what does shifting action: top normal mean?
> Line (4) - Minimum Sprocket - I've not come across this term before - is it saying the cassette's range must be at least 32T/11T? If so, then that's (32 minus 11) 21T of the total capacity taken up, leaving just (35 minus 21) 14T for the front i.e. something like 32T/46T

All advice gladly received.
Without my stoker, every trip would only be half a journey
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Help me understand RD Specs

Post by Brucey »

1) defaults to top gear when the cable is slack
4) you should have a big sprocket of between 32 and 36T ideally, and 11T top regardless.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
beardy
Posts: 3382
Joined: 23 Feb 2010, 4:10pm

Re: Help me understand RD Specs

Post by beardy »

The specifications given by CRC are very unreliable if they give them at all!

That 35 tooth total capacity will probably be for the GS medium cage version and the long cage SGS version will be something more like 45 tooth capacity.
I dont suppose that the other figures vary between the two versions but I wouldnt buy anything based on CRC's specifications without checking them with another source.
tim-b
Posts: 2091
Joined: 10 Oct 2009, 8:20am

Re: Help me understand RD Specs

Post by tim-b »

Hi
Full spec here...p30
Regards
tim-b
~~~~¯\(ツ)/¯~~~~
Post Reply