Is there a list of Shimano groupies and their relativity to each other?
I have Sora shifters with my bike. I find it hard to shift using the thumb levers in any position other than resting on the shifters. Hoping an upgrade may help.
I just changed my Sora 3400 shifters (with the thumb switch) for Sora 3500 shifters which have the split lever/paddle shifter, they were £85. I was going to move to Tiagra but didn't want to have to switch the entire drive train to 10 spd (chain, front dérailleur etc).
Going with the latest Sora meant I could get paddle shift easily without having to look out for used Tiagra 5500 which are still pretty pricey second hand. Have a look at the German bike websites for cheap shifters like Rosebikes.co.uk and bike-discount.de
I will say though that Sora 3500 despite looking almost identical to Tiagra 5500 is more clunky and less refined in operation, I am still happy with it though :-)