Crank length?

[Nos131]

I have a question regarding crank length.
I ride on a Sram Red 53/39 172.5mm crank set with an 11-28 cassette.
Looking forward to ToB I was considering buying a compact crank set as I don't climb particularly well, but I do want to sprint on them and not run out of gears. So what I would like to know is should I go for shorter cranks, longer cranks or the same size? And what is the benefits or losses of one over the other.
Or finally should I just harden up and race on the 53/39
Thanks

[Andrew]

Harden up.

I've been told 172.5 is perfect for my height, so it should be the same for you?

[SimonD]

The only thing more controversial than compacts is crank length! Do Hanslip will give you a 2 hour lecture on deciding crank length then conclude with it's "just whatever works for the individual".

[Nos131]

The only thing more controversial than compacts is crank length! Do Hanslip will give you a 2 hour lecture on deciding crank length then conclude with it's "just whatever works for the individual".

Well I'm glad I didn't ask him today in our descending course.:)

[SueP]

I've made it up Hotham in a 34/25 and in a 39/27, so you can easily get up there in a 39/28! If you can't , you will be out the back of womens C grade with me :potstir:

[bosworth*]

you are the sprinter, so the only hill you need to get over is rosewhite, which is like stromlo, but shorter.

3 of the sprints are almost dead flat, 1 of the sprints is 1% - 2% downhill.

[Nos131]

Thanks Boz I think I'll just keep the set up I've got then

[Driver]

AND you can do the sprints in Bright with a compact.

AND anyone here who tells me this cannot be done can suck my jerseys

[Simonsky]

AND you can do the sprints in Bright with a compact.

AND anyone here who tells me this cannot be done can suck my jerseys

Ah, that's why they had to pull the C grade bunch over to let us pass a few years back. :D

[SSSimon]

Actually to get back to the original question, you may want to get a set of 175mm cranks for the ITT stage. Generally in ITTs, as the max cadence is lower - cause there's no sprint - you can gain an efficiency with a longer crank length. These days with easy crank changes, assuming you're going to be using just the one bike for all the TdB stages and are looking to hold or improve your GC place in the ITT, you could use a set of 175's for the 2nd stage. You'd also need to chase a set of clip on ITT bars, skin suit, aero boot covers, aero helmet and deep section wheels - probably running an 11-23 cassette as the ITT stage is comparatively flat.

[SueP]

Then there is the opposite argument Simon... good evidence to suggest that a SHORTER cranklength may be a benefit, particular to time trialists.
http://www.powercranks.com/cld.html

This clip is quite interesting.....
http://www.powercranks.com/assets/movies/a-CLD240.mov