GP2-S to GP4-S bar-ends: interchangeable?
 

Given that the bar ends are essentially the only difference, are they interchangeable?

In summary, would GP2/GP3/GP4 -S take the same bar-ends so I wouldn't need to remove the entire grip to put in a new one?

Thanks in advance.

Why ask why ask twice?

I had Ergon GP2 'bar ends (the ones with the short stub end) but changed them for GC3s (the touring model). Unfortunately, my GC3 grips were designed for use with twist-grip gear changes and were short. That was not a problem for the right hand grip as I do have a twist-grip for the rear gears, but the left grip was a bit short for comfort. My original GP2 left hand grip was full length so I decide to fit the touring 'bar end to it. The two models do have a slightly different locking system to them but I just needed to cut a small piece of rubber from the left hand grip to allow the 'bar end to fit correctly. It was very easy to do with a sharp knife and the 'bar end covers the part where the rubber was removed.

My original Ergons were bought several years ago so the fittings may have been changed since then. However, the current set up works well.

Hope this helps.