I have a pair of Ergon grips without the extensions. I was thinking about using them on a trekking bar set-up but they are too long.
Has anyone had any experience cutting/shortening the length?
Thanks!

I have hack-sawed some other brand ergo type ones, as they were too long for the riser bars with more angle I put on a bike a few years ago. It worked out fine because when I put my hands on the grips, I could see that my hands were basically resting on only a certain amount anyway, so cutting some off the inner area wasnt a problem. My hands are not big, so this may not work for your grips.
I suggest really looking at your hand position on the grips and seeing where they really rest in a natural riding position, and then go from there.

I can take a photo sometime if you want. Let me know.
cheers

I sawed off the ends of Ergon grips to fit on my short handlebars. The hacksaw cut through them fine. However, now a couple of years later the grip surface is peeling a bit and looks ratty. I am not sure but it might be from the fact that I sawed off the ends. They do sell shorter Ergon grips made for grip shifters. When I have to replace mine that is what I am going to get.