Well, my problems seems a bit common as I started to read on the internet about it, as my lever is able to cope with 2 and 3 wheelchain, there is always a change to force it to the 3rd one without having actually it, like in my case. I now that the only way out will be replacement of the lever, but I don't want to get the same lever and end up with the same problem in the future, so I'm considering upgrade to a better lever for the left side, or even replace both as seems a bit difficult to buy them separated. Also seems the ST-4501 is designed only for 2 wheelchain, so this problem could be avoided but who knows if it is going to work exactly as it says? Could you guys advise me on a good upgrade? I've found a single st-4501 left side lever for about £70-80, but I'm really considering to upgrade to something better, but I just don't want to waste money on something I don't need. The bicycle is used for diary commuting (18 miles) and occasional weekend usage. I was thinking about ultegra, do you guys recon its a good idea to use a better left lever on my set up? Thank you very much for your help!!!