Question For Experienced Bike Mechanics!!!

[winjim]

Yes, your current RD (the 400) and the RD in that set are both 'direct mount'. No idea what a 'B' link is. You get three kinds of way that an RD attaches. You want this one and an allen key (5mm I think). For nomenclature confusion see: https://www.cyclechat.net/threads/tyres-on-the-wrong-way-for-over-two-years.219604/ (and definitely not a spanner). Does a 'wrench' 'wren' anything, I wonder? Maybe it does: (Old English wrencan "to twist")
How do you know Jesus didn't actually have 10 disciples and a couple have been added along the way, for reputational reasons?

I've nothing much to add regarding the mech, but I'd just like to point out that a metric system using base-12 would be far superior to the one we currently have.

A spanner spans, but does a hammer ham?

 

[Ajax Bay]

I'd just like to point out that a metric system using base-12 would be far superior to the one we currently have.

I blame the Chinese who first thought up the decimal (base-10) system.

 

[winjim]

I blame the Chinese who first thought up the decimal (base-10) system.

I believe that base-12 is used in the county of Norfolk.

 

[Cannondale101]

Dude...if you are going to type something funny...please don't do it when I have a mouth full of Pepsi lest it get sprayed all over my keyboard!!!

Most grateful and I will order that kit and report back.