Any tall guys/gals using 172 cranks?

[thomas]

Since marginal gains seem to be the name of the game, I'm thinking about trying out 172.5 cranks, even though at 6'2", accepted wisdom says they're too short for me. Benefits touted seem to be less angle at the hips, allowing for lower bar height and better aerodynamics, and maybe better ergonomics and power. Not sure how these will work on hills, though. I've got a set that I'm throwing on the bike and will give it a try, with a test on a hilly 15 min +/- TT course I use.

Any other 6+footers using shorter cranks?

I've tried longer cranks in the past, 177.5 and 180's. While they felt nice at first, I eventually came to think they slowed my cadence and had a noticeable dead spot. My knees said No finally.

[DOOFUS]

I'm 1m85 and I've been using 172.5 cranks since '98. 84-97 I used 175s. For me, 172.5s = higher cadence, fewer knee issues.

I'm a TT guy, and the 2.5mm shorter crank never bothered me in a TT. watts is watts. if you have to turn 3rpm higher, learn how to do it.

I've raced against a lot of cat 1-2 crit studs who use 172.5s for more leg speed, all of them six foot or taller.

[guido]

I'm 6'1" and I use 165mm crank arms. I used to do triathlon where they helped me get down despite a large rib cage. They also help my knees a lot. I do have shortish Femurs...

[11.4]

They may or may not be too short for you. When your leg rotates, the length in your calf is a constant in the adjustment of saddle height/crank length. It's the length of your femur that determines how much your feet really raise or fall in a pedal revolution, and thus how much crank arm length you want to consider.

But then you have to consider body build, hip rotation, and whether you can manage the greater rise and drop of a longer crank -- if they push your thighs up into your diaphragm and limit your breathing or delivery of power, you either have to sit more upright or go to shorter cranks. The former isn't all that ideal, so crank arm length is critical.

Another issue when you have longer calves and shorter femurs is that you don't want your knee angle to vary so dramatically through a pedal stroke -- I'm not supporting the KOPS argument, but if you use too long a crank, your knee ends up farther behind the pedal at one point and farther in front of the pedal at the other. Greater range of movement can cause more knee problems in some people.

Last, you have to consider what your personal power output is like at different knee angles. If you can't put out power at all at the top of your stroke -- or at the bottom -- then longer cranks aren't for you. You don't necessarily want to go short and simply limit your range of motion, but the trend is usually to go too long and bring about both overuse injuries and loss of effective power output. I can't say that most fitters really understand these points.

The genetics of a successful pro rider tends to favor longer cranks. For most of us

[Lionel]

6'5", 172.5

[Hindmost]

I've tried longer cranks in the past, 177.5 and 180's. While they felt nice at first, I eventually came to think they slowed my cadence and had a noticeable dead spot. My knees said No finally.

Interesting! I have been riding similar crank lengths and coming to this same conclusion in the last few weeks for some of the reasons you mention. I have been somewhere between 6'2" and 6'1' over a bunch of years. I have ridden 170's on the track, 172's in criteriums and 175, 177, 180's in various races and riding. I have thought that the longer cranks got me up hills better but recent knee issues have caused me to move back to 175 and add some lower gears. I like having my spin back.

[Saab2000]

For a number of years I was using 175s and I've recently switched back to 172.5. I'm 6'00" tall. I've toyed with the idea of a 170 just for fun. I'd probably put it on my test mule - the Hampsten single-speed.

This all came about after riding a borrowed bike last year which had 172.5s and my old Serotta Colorado Legend CRL and one specific ride where I just felt 'in the groove' with my spin. On a whim I swapped my Hampsten to a 172.5 and immediately liked it, especially in a group situation where the speed was 23-26 mph. The spin was just more natural and made me wonder what a 170 would be like. That's next. I doubt I'd switch all my road bikes to 170s, but stranger things have happened.

The switch back to shorter cranks has been a net positive. I'm not faster but I think it's more natural. The 170s may be another increment. I started cycling on 170s, so there is precedent. In any case, I think I'm done with 175s.

I've never had knee issues, but the spin feels more natural with the shorter cranks.

[chasea]

Visit a competent bike fitter, not the internet.

[christian]

I've visited a competent bike fitter, and based on that experience, I'd trust Lane and DOOFUS about 500% more.

[blasdelf]

They may or may not be too short for you. When your leg rotates, the length in your calf is a constant in the adjustment of saddle height/crank length. It's the length of your femur that determines how much your feet really raise or fall in a pedal revolution, and thus how much crank arm length you want to consider.

Nailed it!

But then you have to consider body build, hip rotation, and whether you can manage the greater rise and drop of a longer crank -- if they push your thighs up into your diaphragm and limit your breathing or delivery of power, you either have to sit more upright or go to shorter cranks. The former isn't all that ideal, so crank arm length is critical.

You can't really do that without also considering how crank length affects saddle position — for me having cranks 5mm longer means my saddle can be almost a cm further forward

My knees are lower with shorter cranks, but with they push my ass further back too, so the tighter hip angle means my chest has moved down as well

[11.4]

You can't really do that without also considering how crank length affects saddle position — for me having cranks 5mm longer means my saddle can be almost a cm further forward

My knees are lower with shorter cranks, but with they push my ass further back too, so the tighter hip angle means my chest has moved down as well

The problem with that analysis is that if you are able to move your saddle forward to track the maximal forward position of your pedals, you also have to consider that you are sending the pedal farther back as well. At that point your knee and hip are both subject to enough flexion that you are most likely delivering less power there. May feel ok, but won't be as fast. We went to that place repeatedly with a couple very tall riders and lots of analysis.

Further, the same kind of issue applies to your comment about how your glutes are pushed farther back. What you may be doing is de-rotating your hips, which is costing you power as well even if it's giving you comfort. There's no free lunch with long cranks (or with short ones, for that matter).

[thomas]

The problem with that analysis is that if you are able to move your saddle forward to track the maximal forward position of your pedals, you also have to consider that you are sending the pedal farther back as well. At that point your knee and hip are both subject to enough flexion that you are most likely delivering less power there. May feel ok, but won't be as fast. We went to that place repeatedly with a couple very tall riders and lots of analysis.

Further, the same kind of issue applies to your comment about how your glutes are pushed farther back. What you may be doing is de-rotating your hips, which is costing you power as well even if it's giving you comfort. There's no free lunch with long cranks (or with short ones, for that matter).

Have to agree that the comment about moving the saddle forward with a longer crank did not make sense to me, or moving it back for a shorter crank. Doesn't seem to jive with other fitting concepts.

[DOOFUS]

you don't change setback or height when you change cranks (unless you were at maximum extension with the shorter crank...in which case I would wonder why you went longer).

[thomas]

I raised my seat after switching to shorter 172.5 cranks. Kept my leg and knee at same extension at bottom of stroke, and lessened knee angle at top of stroke. Didn't feel right leaving it same height for the 175 cranks.

[guido]

Seat height definitely comes up when changing to shorter crank length.

[Saab2000]

Seat height definitely comes up when changing to shorter crank length.

Why? I've wondered about this in the past but when I recently changed to shorter cranks I left the the seat height alone.

The center of the rotation of the crank remains the same.

[DOOFUS]

I meant going longer

going shorter, yeah, seat goes up - if your knees are sensitive to saddle height

[lumpy]

Why? I've wondered about this in the past but when I recently changed to shorter cranks I left the the seat height alone.

The center of the rotation of the crank remains the same.

The distance from the saddle to the pedal at max extension gets shorter.

[blasdelf]

The problem with that analysis is that if you are able to move your saddle forward to track the maximal forward position of your pedals, you also have to consider that you are sending the pedal farther back as well. At that point your knee and hip are both subject to enough flexion that you are most likely delivering less power there. May feel ok, but won't be as fast. We went to that place repeatedly with a couple very tall riders and lots of analysis.

With 175s I find myself sliding back on the saddle, which really sucks on a Brooks since it's got that sharp ass-scraper of a cantle plate (and the rails are so short it's already slammed back)

180mm cranks situate me further forward and avoid that, so I have them on most of my bikes, helps make my position more normal despite my 37" inseam

It's really obvious when you see a stumpy-legged dude on 175s with their saddle slammed way forward, swap to 165s and their position normalizes


My hardtail has 200mm cranks, and I just built up a road bike with 190s, feels good man

It's a lot harder to get a feel for when you're pussyfooting around with 2.5mm increments