SRAM Rival-lowere gear

[Oldwheels]

This my first thread and hope it is in the right section.I have a compact chainset with a 12-25T rear cassette. I need a lower gear for climbing hills(plus age is against me) and would like to know if a 11-13/28 cassette will fit? The rear mechanism is a short arm. The bike is a Boardman Team Carbon.
Thanks for any comments.

[Joe_W]

Hm. The SRAM homepage is a bit... difficult. Makes you appreciate the Shimano one for their Techdocs and the specs...
The only information I could find was that the medium cage (SRAM Apex) is compatible with 32 T cassettes. I guess you could try a 28T cassette with the short cage. Take a look at the current setup to try and judge if 3 more teeth might be a problem - after all, it is about a 12% increase in diameter. You might need a longer chain, too.