For every millimeter you shorten your cranks, you are opening up your thigh-torso angle by 2 mm. The millimeter at the top of the revolution is obvious, but you also gain a millimeter at the bottom because you raise your seat by the same amount as the decrease in crank length.

I tend to ride with a pretty agressive position and switched from 175 mm cranks a couple of years ago to 165's. This gains me about 20 mm of clearance and I'll never go back to long cranks. FWIW, I'm about 6' tall with about a 33" inseam.

By the way, I just got a new custom bike that is eerily similar to Dan's new ride - 81 degree seat angle and 10 cm headtube. In my case, I opted for a conventional head tube angle but the bike is still very stable due to a long top tube and 8 cm BB drop.

I guess I'm really confused about crank arm size now. I just assumed longer was better (to a point) in any time trial effort. But I'm sure Slowman knows what he's doing.

I got a new water bottle to take to Shreveport and thought that was going overboad.

Dan may I ask what kind of bike time and over all time you're looking for in Shreveport?

This is what I thought too- longer cranks meant "faster" because you were gaining torque/power ( I guess? I am no physics expert). My origioanl question also stemmed from a problem I have with my hip flexor and ham. The right flexor is hurting on the bike, along w/ my right ham. Maybe shorter cranks would help by opening up the hip angle? I have a twisted SI joint which contributes the seeming leg length discrepency, but I was wondering if lowering my seatpost or shortening my crank length (which apparently is too long anyway beause I am barely 5'6" and have short legs and am using 172.5s)would help. I have a pretty even cadence regarding quad to ham usage and left to right leg usage while spinning (49-51% on Computrainer.

But now it looks as though (at least for time trial situations) shorter is better?

well my lil bike with it's 175 mm crank arms is sitting in Shreveport waiting for me. So if shorter is now suddenly better than longer I'm out of luck. When did they pass that law in physics anyway?

"Dan may I ask what kind of bike time and over all time you're looking for in Shreveport?"

i don't know. i guess i feel ready to go fairly fast on the flats, but i'm best using the rythm method. i don't like u-turns and corners to break up my concentration. no wind, no turns, no bike traffic to ride through, flat course, i'd like to ride close to an hour. but i don't know. we'll see.

overall time? i don't know what's good on that course. i guess i'd like to run 37s or 38s if it's not too hot, but i have no idea what i'm going to do a no-wetsuit 1.5k swim in. plus, i don't know how long the transitions are. hey, i just want to be in the top 16 in the AG, which'll get me to portugal.

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Dan Empfield
aka Slowman

"This is what I thought too- longer cranks meant "faster" because you were gaining torque/power."

singles hitters don't use 40 oz bats. i need bat speed. i'm not a power guy. i've got to turn the cranks at 95rpm, maybe even over 100rpm for a lot of it. that's especially true on a flat course, where i'll fry my thighs if i try to mash gears for 25 flat miles.

plus, i've got a VERY low front end on this bike, so i need to open up my hip angle. shorter cranks mean my femur won't have to rise as far at the top of the pedal stroke.

if i was muscling up a 22% grade while seated then i'd have 180s on my bike. just depends on what you want to do.

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Dan Empfield
aka Slowman

Some of the fastest times on bikes have been done on the track with 165 -167.5 cranks. That is of course over a short distance and no run to follow.
On the road conventional wisdom has been that longer cranks give more leverage thus a bigger gear and more speed in a TT effort. Now some folks are thinking that a smaller length of crank with a lower gear with a higher tempo may take less energy and may leave you fresher on the run.
Ah the grand experience of life. My advice is to run what ya brung and do not change cranks a week before the Nationals . What are you guys thinking?
And we will see, If Dan sucks at Nats I guess we will all stay on the long old cranks. However if the Slowman is a hero at Nats, we will all have to put that in the things that make you go Hmmmmm? file. Aloha G

Dang, that's a lot of pressure for Dan. The entire future of crankarm length in triathlons is on his shoulders.

  Slowman can handle, He almost singlehandedly invented the tribike, made the firstest best'es wetsuit, made the first company based on tribikes, and has invented the triforum. Hell, turning 130rpms in a 92 inch gear for 52 min is like a walk in the park for him.
I have paid a couple of ringers however to get in front of him and do sprints every time he tries to pass. This will test out his, new theory on blocking and passing violations . Good luck to all at the mudhole triathlon. Aloha G