The GP1's are I suppose the classic Ergon shape. I decided to get these as I wanted ultra comfort. The more rounded edges of the GP1 appealed to me.
I have placed the old GS1grips on my Original Orange Brompton and are happier with the feel of them on the M type handlebar.
Having been on quite a few rides recently, some of them a fair distance, I have to say they are lovely on the hands. There are lots of different grip positions and I cannot fathom why it has taken nearly three years to walk away from the original Brompton foam grips?
Fitting is really easy and once in the correct position for your hand they are great. If you are suffering with the original Brompton grips you could do worse than have a look at these. They really will make life easier. Having large hands I opted for the 'L' large version but there is also an 'S' version for those with smaller hands.