Like several of you, I get numb and tingly from longer rodes. I have tried different grips, bar risers, grip puppies, gel gloves, etc etc..... I wanted to slide some grips over my existing grips but did not want to make my grips too large (like grip puppies). I came across these "Alloy Art TRR-01" and fitted them today. Took the bike for a blast and they seemed to do the trick. They were a bit of a pain to fit but after reading the WD-40 trick on another forum then cleaning the grips with window cleaner then alcohol to make them tacky I have found the perfect grip for me. They retail under $20 and I got mine on ebay for about $18
got to position this one better... but you get the idea!