crank length for new bike

[emily_in_nc]

OTOH, I ride a small framed bike (46 cm) and use 170 mm cranks, and like them fine (no knee pain). 165s will help with faster spinning, but 170s give a bit more leverage. I have 170s on all my bikes (road and mountain). It's really a personal decision and depends on the particular person's biomechanics as to which would be optimal. If she has longer legs for her height, the 170s might be more appropriate and vice versa, but there are exceptions to every rule! I am 5'2", by the way.

Emily

[Zen]

You sure about that height, Emily ?

I'm 5'2" (I think)
47 cm frame
size 39 Sidi's
170 cranks
no problems

[emily_in_nc]

You sure about that height, Emily ?

I'm 5'2" (I think)
47 cm frame
size 39 Sidi's
170 cranks
no problems

Good one, zen - you read my "I'm Shrinking" thread! That's why I said 5'2", when I usually say 5'2-1/2". I guess I'll drop the 1/2", but I'm not quite ready to compromise on the 5'2"!

I also wear 39 Sidis just like you!

Emily

[KnottedYet]

I prefer 175's, so don't nobody ask me!

[DirtDiva]

Yeah, but you're taller than everyone else in this thread except perhaps the fella who started it.

[boy in a kilt]

At worst, she may get a tad bit of toe overlap. As long as she isn't prone to doing lots of track stands, she'll probably be ok. A quick way to check is measure from the center of the crank spindle out about 210mm (I'm guessing on the spindle to end of toe-box measurement). If you haven't gotten to the tire yet, she'll be ok.

The main difference she'll notice is the extra bit of torque she'll get when she pedals. The extra 5mm of lever arm may not seem like much, but it does make a bit of difference.

[VeloVT]

I'll share my experience, for what it's worth (maybe not very much, since I'm not the same size, and it doesn't address toe overlap issues at all). I'm 5'6". I have a 52 cm cx frame and a 54 cm road frame, both still with stock cranks. The 54 cm frame has 172.5mm cranks, and the 52 cm frame has 170mm cranks.

I notice the difference. Really. I wouldn't have believed I'd feel a 2.5mm difference but I do. I definitely prefer the 172.5 mm cranks. I feel I get considerably more power, especially on hills. Since I'm also thinking of switching the cx bikes triple for a compact double with slightly higher gearing, I'm considering getting longer cranks at the same time.

FWIW.

Oh, I'm also a size 39 shoe.