180mm cranks

Anyone use em? It's been suggested it would be a good idea for me as I'm super-tall.
Somewhat worried about long cranks/fixed gear/banked turns though. Or am I just being stupid?

can you not just get a longer seat post and headset?

What?

longer cranks allow someone with longer legs to use more of their effective leg stroke as I understand it.

and I'm asking if it would not be the same if you're just sitting further up, ie longer seatpost.

I don't think that's the way it works. Anyone?

Imagine it this way: If two people, one with long and one with short legs bend their legs to the same position (angles angles at knee and hip) the longer legd person's foot would be further off the floor. Meaning to use the full stroke of my longer legs, I should have longer cranks. I think.

think that a longer seat post would do the same job mate.

http://www.polaris.net/palmk/crankset.html

Well yeah it would be better for a long-legged person like yourself but on a fixie....not so much you would have to deal with pedal strike and toe strike(wheel when turned hitting off the protruding foot)
The only solution would be to get a very high bottom bracket(ed) frame, but this would only sort out the pedal strike. For the toe strike a very stretched out frame would be the only option(ie lots of clearance between wheel and the down tube)
Hope this helps.

Well yeah it would be better for a long-legged person like yourself but on a fixie....not so much you would have to deal with pedal strike and toe strike(wheel when turned hitting off the protruding foot)
The only solution would be to get a very high bottom bracket(ed) frame, but this would only sort out the pedal strike. For the toe strike a very stretched out frame would be the only option(ie lots of clearance between wheel and the down tube)
Hope this helps.

It does indeed. Thanks! I'll see if I can try a few out and see what the "strike" positions are.

Well when your toe is fully forward in the pedal stroke it will hit off your wheel( eg left foot facing forward turning right.) plus the other is pedal strike off the ground when your turning(banking) since your running a fixed wheel the pedal will be forced to finish its rotation and will lift your back wheel off the ground causing boo boo's haha.

i run a 180mm on my ss mtb, but 170 on the fixie as to not bash me pedals on the road and die.

i am 6'1" with a 36" inside leg...

180mm far to long for fixed riding. I'm 6'6" run 170mm on fixed and 175mm on other bikes. The toe overlap and pedal strike is just to much of an issue when running fixed, and it is easier to keep up high RPM with shorter pedal arms. So unless you have some freak frame and want to ride really big gears stay away form such long cranks on the fixed.

more to the point the lever arm on 180's feels horrible and pathetic when the rolling resistance is so low. keep 180's for mtb going up a 1 in 3 mud hill, 170 for the road, and 165 for the track. and then i'll be happy

Indeed, the longer the crank arm the more leverage you have (No it isn't just about saddle height), but on the track pushing a huge gear generally isn't the chosen thing. And fixed on the road is likely to require a lower gear still. The issues then change from one's ability to gain leverage to one's ability to spin. The longer arm hampers this. Some tall roadies (Boonen - 6'4" for example) run 177.5 or 180, but on the track few riders of any size will run more than 172.5, and neither pedal strike nor toe overlap are problems when riding at speed on steep tracks like Manchester. On the road these can be issues, toe overlap at low speeds, pedal strike on corners at high. Toe overlap is a particular issue because track frames generally come with shorter top tubes and tighter angles than equivalently seat tube sized road bikes.
Basically I think you will find 170 to be perfectly adequate. I think campy do a 172.5 as may DA if you must but most, me included, would feel little if any improvement around town. Any longer than that anyway and you are in custom territory, although 180 road cranks are fairly easy to buy OTP.
Oh and if pedal strike is a major concern, say on a low BBed conversion as opposed to a track bike then small/single sided pedals can make quite a difference IMHO.

Thanks for all the tips chaps.
I'll keep em short then!

Like everyone has said, you need shorter cranks on fixed for road use (prevent pedal strike and overlap) and on the track (to allow you to spin at high revs). I'm 6'4" with a 37" inside leg and use 170s.

1 hr world record on track 49.7 km/h was done on 190mm cranks ;)

long guy

ondrej sosenko, just got done for doping :(

1 hr world record on track 49.7 km/h was done on 190mm cranks ;)

No need to accelerate because you're on your own => no need to spin => 190mm cranks if you're as tall as him.

He also had a rear wheel that weighed 3kg or so because the rim was packed with lead, but I doubt many people will copy that bit of equipment choice. Mind you half the HHSBs seem to use the same saddle to bar drop so maybe I'm speaking too soon.

Aye, dogsballs is right, but for around town...

his bike was custom made with high BB, but with the monster top tube, you'd never get toe overlap.

Hell, he's only an inch or so taller than me, I reckon I could put that saddle down a bit. I'll take it. If it feels a bit too aggressive I can always put some BMX bars on it. That wouldn't look sh1t, no, no it's a great idea.

I ride fixed on 177.5mm Campagnolo track cranks, for my extra long femurs, anyone want to come on one of my 2-3-4 hour road training rides around Richmond Park? Those slick looking Velocity V's of yours are just a dead weight up hills, but they look really coooooool, cruising for chicks at 5mph :)

Perhaps you're worried you'll get your white/yellow tyres dirty?

Jacques Anquetil 175mm
Lance Armstrong 175mm
Magnus Backstedt 177.5mm
Ivan Basso 172.5mm
Paulo Bettini 170mm
Chris Boardman 170mm
Tom Boonen 177.5mm
Santiago Botero 172.5mm
Fabian Cancellara 177.5mm
Angel Casero 175mm
Mark Cavendish 170mm
Mario Cipollini 172.5mm
Alberto Contador 172.5mm
Nicole Cooke 170mm
Fausto Coppi 171mm
Danilo Di Luca 172.5mm
Malcolm Elliott 172.5mm
Cadel Evans 172.5mm
Stefano Garzelli 172.5mm
Tyler Hamilton 172.5mm
Bernard Hinault 172.5mm
Thor Hushovd 175mm
Miguel Indurian 180mm (190mm for second Hour record!)
Laurent Jalabert 172.5mm
Sean Kelly 172.5mm
Kim Kirchen 172.5mm
Levi Leipheimer 172.5mm
Greg Lemond 175mm
Brad McGee 175mm
Robbie McEwen 170mm
Eddy Merckx 175mm
David Millar 175mm
Francesco Moser 175mm
Marty Northstein 167.5mm in Keirin (170mm in kilo)
Scott Nydam 175mm
Graham Obree 175mm
Marco Pantani 170mm (180mm in mountains)
Alessandro Petacchi 175mm
Yaroslav Popovych 172.5mm
David Rebellin 172.5mm
Roger Riviere 175mm
Jean Robic 170mm
Tony Rominger 172.5mm (175mm for Hour record)
Carlos Sastre 170mm
Oscar Sevilla 175mm
Andy Schleck 172.5mm
Frank Schleck 172.5mm
Ondrej Sosenka 190mm
Jan Ullrich 177.5mm
Christian Vande Velde 175mm
Rik Verbrugghe 175mm
Jens Voigt 177.5mm
Bradley Wiggins 175mm
Erik Zabel 172.5mm
David Zabriskie 175mm
Alex Zulle 175mm (180mm in mountains)