Well I can shift the Ergo lever from the drops but my hands may be different than yours....the position of the thumb shifter is much different than the Sora thumb shifter position.
There is no difference between 05 and 06 Centaur...for 07 they changed a lot and IMO not in a good way. Sure they added CF to the Ergo levers and the RD but the escape mechanism is just a step back from where the components were. The good news is that you don't have to worry about that though since you are looking at the older model...which works just like Record and Chorus. The thumb shifter will allow you to go from the biggest cog to the smallest with one big push...while you will never go that far, ,going 2-4 at a time can be useful when changing rings or working on your bike.
I run Record on my Roubaix and am building an older Eddy Merckx up with 2005 Centaur...I don't expect to be able to feel any difference in the performance of the group...only the finish level is different...and a bit more weight because of the use of different materials.
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