As far as the Brompton is concerned I'm going to have to cutdown the grip. I've ordered a hacksaw but not sure if I'm going to cut the grip. I really think you should use ESI grips that can easily be cut off to fit with your hands. I tried the thumb grips on my mountain bike this weekend and found them to be too far away for them to work well. I put them on my Micro Kickboard and they feel good. I'm still deciding whether to cut down my Ergon grips on the Brompton from 115mm to 110mm to get the thumb grips to fit. The Micro Kickboard has 110mm grips and that seems to be the size for me to get the best use of the thumb grips. Now this will be different for everyone depending on the size of their hands . I can see if you want to stay away from bar ends these thumb grips do help but they are no replacement for a good pair of bar ends.