Originally Posted by HillRider

As to details if you go ahead here are my recommendations:

1. Front Derailleur: I'm not certain what style front derailleur you need but I expect the frame has a braze-on mounting tab so get a braze-on front derailleur. Specialized's web site doesn't say so check with a bike shop or knowledgable friend first to confirm this. You can always get an adapter clamp if you need a clamp-on type.

2. Rear Derailleur: Specify the GS long cage rear derailleur. The bike has a compact (50/34) crank and with a wide range cassette you need the wrap capacity the GS cage provides.

3.Cassette: Specify the 11x28 since you already know that works on another bike.

Excel Sports is not know for being the low cost supplier of anything so search around to see if you can do better.

Originally Posted by alcjphil

When Shimano went to 11 speed, they had to lengthen the cassette body. This means that an 11 speed cassette will not fit on a cassette body designed for 8,9, or 10 speed cassettes. However, the fact that your bike is a 2014 model may mean that your wheels can accept an 11 speed cassette. That said, Shimano really improved shifting with their 11 speed groups, there were a lot of complaints about the shifting precision with the last generation of 10 speed shifters. I built up a bike for a friend last year using an Ultegra 6800 group, and he tells me that the shifting is far superior to the shifting on his other, otherwise almost identical bike that has a Dura Ace 7900 10 speed group, so now he rides his Ultegra bike almost all the time. However, one of the reasons why shifting is so much better with the newer 11 speed setups is lower friction shift and brake cables, so in theory you could upgrade your bike quite a bit by installing the newer cables on your current setup