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What is the difference between road(long cage) and mtb rear(3 posts)

What is the difference between road(long cage) and mtb rearberstarr
Oct 18, 2002 2:42 PM
derailleurs? I am going to make a 13-32 rear cassette by removing the first two cogs on a 12-27; then adding a 13 tooth first position cog and a 32 at the end. Shimano lists its mtb rear derailleurs as having a maximum of 34 teeth. The long cage Ultegra rear is listed as having a 27 tooth capacity. I am using a double crank on a road bike.
Can anyone offer some insight, on the difference between an Ultegra long cage (triple) and a Deore XT rear derailleur.
re: You need a MTB rearzmarke
Oct 18, 2002 3:28 PM
I just got off the phone with Shimano Tech support the other day about a similar issue.

A road "triple" rear (long GS type) still only has a max capacity of 27, it is just supposed to be used with a front triple crank to help with chain tension.

A mountain "triple" rear (long SGS type) has a max capacity of 34 and assists in chain tension.

A MTB rear will work with any current road sti lever of the same speed and a double or triple road crank, it is the MTB and Road fronts that are not interchangable.

They recommend this setup and state that many people use this setup when they already have a double crank since it is usually less expensive alternative than changing to a triple crank since you will have to replace you rear anyway.
it works great for meColorado Ron
Oct 18, 2002 7:54 PM
I'm using a 12-34 XTR cassette and a XTR long cage derailluer with ultegra double cranks and dura ace sti shifters.