Hellooo, I just got great bike, '91 520 in dark purple. the only problem is that the stem is just too long for me and it hurts by back. i'm going to buy a nitto technomic to fix this problem but am not sure what diameter to get. does anyone know what size this would be?
There are two sizes you need to check: the steerer tube diameter (probably 1" or 1 1/8") and the handlebar diameter. If you have calipers, these are pretty easy to measure; otherwise, go to your LBS and they will be able to measure for you.