>>1308011an ideal length of bar end is around 120 to 130 mm
the longer 150 mm+ or curved versions may obstruct or delay access to the brake levers
the older round type of bar end is 25.4 mm diameter and 70 mm circumference and can be used to good effect with foam grips
newer types are profiled to a particular hand shape so you would need to shop around for one that fits you
or you could go to something like cane creek ergo control bar ends - they are set further back so will not stick out too far
