what size business-type suit do you usually wear? i must be getting lucky or something cause i just take the number from my suits (42) and buy that and it seems to work out. keeping in mind US42 = euro 52 (ie, dainese suits are typically sized with euro sizing, but most show both numbers) tight is better, but dont judge your crotch tightness by when your standing up straight... it should feel like a good fit when you're in the tucked position. if you're looking for a more relaxed suit, there are super moto suits and 2pc suits. finally, if you post your weight, height, and whether you have abnormally proportioned monkey arms or midget legs, and your build (fatty, skinny, athletic, etc) people can offer you feedback based on their experience.