I bought the Evotech one, and if you have a Gen1/2/3 you don't need to sweat the clutch side because they don't make one. Why did I buy Evotech? tbh, I was buying some other stuff from them anyway and I just could be arsed thinking about it any more. That means I paid ?100. I know others are cheaper, but some of them only seem to suit dedicated track bikes - mine does road too. I am not sure how other manufacturers do it, but what I'd say about the Evotech is that it means that the inner screw, normally deeply recessed in the handle is now sitting flush with the edge of the bar end. It occurred to me that this means it's more exposed in a fall, which may be a minor irritation compared to other potential damage... just something to consider maybe.
One thing I'm not sure about is whether to leave it fitted to the bike, or only put it for trackdays. I believe you're meant to put them on with thread lock (?), which means it's a PITA to keep un/fitting it? Leaving on was roundly ridiculed by 44 Teeth in their weekly news last week (in amongst many other things). I had planned to leave it on, and I'm not taking it off just cos Al doesn't like it, but thought I'd ask... even tho' it looks like yours is a track bike Mark?
