What does a 5mm crank difference do?
 

So i have steel 170mm road cranks on my bike. It's a converted but has a high bottom bracket which has never pedal striked:
Attachment 28619
So what i want to know is if i get 165s what will be the diff other than having a better % of not having pedal strike? If i do get alum crank will the weight diff be slight or noticable compared to having steel? Also are alu better durable for street than steel or should i stick with the steel( btw it is a very good crank from the 80's not sure what kind tho).

The differences will be very slight, but in addition to a greater lean angle, you will have a slightly smoother spin since your foot will travel a smaller distance each time it goes around, but you will also have slightly less power for each stroke.

steel cranks weigh a ton, you will probably notice the difference in weight.

^sivat, your bareknuckle is the best!!!

gyeswho, dont fret about that 5mm. those 170mm cranks you are running should be good enough. altough one could potentially spin better on smaller cranks, one shouldnt rely on parts for a lack of technique (if smooth spinning ever becomes an issue). enjoy what you have and ride it.

thanks i will boross. naw spinning is not an issue i spin well and since like having power to my spin i dont think i would like to loose any of it. i must say you are one of the few caring people on this site who isn't arrogant. God bless you and all that you do. thanks again. what you put really means alot.

If you don't want em, send them this way.

Thanks!

You'll be able to go slightly faster down hills with shorter cranks...and you'll have a slightly harder time going up the hills. Thats about it.