If so, how do you like them? Worth it? What do you use them for, how fast do you usually spin, and how tall are you?
I’m considering getting a pair of 200mm cranks. I’m pretty tall…
and into time trialing. I currently ride 180 cranks for TT and road. Anyone out there experiment with longer than 180 cranks?
proportionally speaking, i think 200mm cranks would still be very short for you.
Here’s a description of getting a custom bike built with 210mm cranks by a 6’ 7" tall guy …
several long rides later he reckons the longer cranks are absolutely fantastic and a performance improvement
http://www.roadcycling.co.nz/GearTalk/project-big-a-custom-zinn-experience.html
If so, how do you like them? Worth it? What do you use them for, how fast do you usually spin, and how tall are you?
I’m considering getting a pair of 200mm cranks. I’m pretty tall…
and into time trialing. I currently ride 180 cranks for TT and road. Anyone out there experiment with longer than 180 cranks?
What fit issues do you have that are causing you to contemplate modifying your crankarm length?
I currently don’t have any fit issues… I guess it’s just out of curiosity for more power.
Online crank arm length reccomendation algorithms put my appropriate crank arm length at anywhere from 205 to 215mm. Of course, most of those algorithms are linear, like L = x(inseam) + y, and not based on a logarithmic scale. Since I’m a but of an outlier anyway, I wonder about the accuracy of such predictions on the extreme ends of the distribution.
Tom, you’re pretty knowledgeable about time trialing and time trialists… Do you know what crank length some of the taller TT specialists use? I.e. David Millar, Bradley Wiggins and Gustav Larsson? Larsson has almost identical measurements to me if I remember correctly.
How tall are you? Inseam? I am curious to see where this thread goes as I am 6’ 6.5" with a just short of 38" inseam.
lol. Getting all personal now.
I’m 6’5" with a 39" inseam. Short torso and lanky.
lol. Getting all personal now. I’m 6’5" with a 39" inseam. Short torso and lanky.
What size is that Felt? Looks like you are huge on that thing. I know how you feel though.
its a 60cm Felt B16. I had to special order an extra-long seatpost from Felt. It flexes more than I’d like, but what can you do with a big bike, eh? Ironically, I was able to get it because some guy bought it and it was too big for him and couldn’t sell it and dropped the price a lot.
I am 6’8" and ride a 65cm Cannondale with 180mm cranks… definitely an improvement over standard 175s, but I am not sure if anything longer would really help any more…
I am 6’8" and ride a 65cm Cannondale with 180mm cranks… definitely an improvement over standard 175s, but I am not sure if anything longer would really help any more…
I’m 6’4" with a 38" inseam and ride 177.5 cranks on both my road and tri bike. I believe that the jump to 177.5s did help. (It also allowed me to justify a Campy Record crank to the wife.) I didn’t go longer because I was concerned that my cadence would slow down.
The road bike is a custom Ti frame but the tri bike is a 61 cm P2C. The main reason for the custom route was to stiffen up the rear triangle. As you know the tall frames tend to get a bit flexy.
-- Scott
I’m no expert on bike fit.
I will say that in that picture, your right knee looks pretty close to your handlebars.
A longer crank arm woudl get it even closer.
I’m 6’4 with a 39" inseam. I rode a 60cm B2 and just switched to a 61cm p2c. I’m really happy I made that move. The seat post on the Felt drove me crazy, I had it maxed out (and I still needed more height) and it flexed a lot too. The p2c has a much sturdier seatpost and is a bigger bike, feels much more sturdy over all. I ride 180’s and I don’t think I’d switch them out. My hip angle is perfect at tdc is just about perfect. Any longer and I’d have to raise the front too.
I am 6’5" and have ridden 200mm cranks, both std on my tri bike, and powercranks on my trainer bike, for years. Love them. You never go back to midget crank arms. :o)
Dave
I’m 6’4 with a 39" inseam. I rode a 60cm B2 and just switched to a 61cm p2c. I’m really happy I made that move. The seat post on the Felt drove me crazy, I had it maxed out (and I still needed more height) and it flexed a lot too. The p2c has a much sturdier seatpost and is a bigger bike, feels much more sturdy over all. I ride 180’s and I don’t think I’d switch them out. My hip angle is perfect at tdc is just about perfect. Any longer and I’d have to raise the front too.
Curious, did you use the standard seatpost on the B2, or did you find a longer one?
Also, I don’t spend enough time on sloqtwitch to know that “hip angle at tdc” is?
I used the standard seat post. I didn’t know there was a longer one, but it was just so small, filmsy and so much of it sticking out of the frame it swayed laterally too much for my comfort. I don’t put out enough power to break it… it just gave me an uneasy feeling. TDC: Top Dead Center of the pedal stroke. I’m probably running as much drop (about 16 cm) as i can with 180 cranks. If I went up in crank length I’d have to raise the front so my hips don’t get too tight when at the top of the pedal stroke.
FWIW with the 61 P2C and 16cm of drop from the saddle to armrests… I only have 3cm (spacers and top cap) under my stem. The P2C is just a much bigger bike frame. I have the exact same fit coordinates… the frame just takes up more space now: i have less seat post, and my stem is clamped closer to the actual frame.
Any pics of you on the 61? or the felt for comparision? What is your stack and reach for the P2C, TT and ST lengths? Thanks!
I used the standard seat post. I didn’t know there was a longer one, but it was just so small, filmsy and so much of it sticking out of the frame it swayed laterally too much for my comfort. I don’t put out enough power to break it… it just gave me an uneasy feeling. TDC: Top Dead Center of the pedal stroke. I’m probably running as much drop (about 16 cm) as i can with 180 cranks. If I went up in crank length I’d have to raise the front so my hips don’t get too tight when at the top of the pedal stroke.
FWIW with the 61 P2C and 16cm of drop from the saddle to armrests… I only have 3cm (spacers and top cap) under my stem. The P2C is just a much bigger bike frame. I have the exact same fit coordinates… the frame just takes up more space now: i have less seat post, and my stem is clamped closer to the actual frame.
I currently don’t have any fit issues… I guess it’s just out of curiosity for more power.
Online crank arm length reccomendation algorithms put my appropriate crank arm length at anywhere from 205 to 215mm. Of course, most of those algorithms are linear, like L = x(inseam) + y, and not based on a logarithmic scale. Since I’m a but of an outlier anyway, I wonder about the accuracy of such predictions on the extreme ends of the distribution.
Tom, you’re pretty knowledgeable about time trialing and time trialists… Do you know what crank length some of the taller TT specialists use? I.e. David Millar, Bradley Wiggins and Gustav Larsson? Larsson has almost identical measurements to me if I remember correctly.
Well…this guy isn’t exactly a “TT specialist” (unless you consider the bike leg of an IM to be an extra-long TT) but IIRC he’s about 6’3" (4"?) with fairly long legs and he just went DOWN to 172.5s and is thinking about trying even SHORTER cranks 
Here’s my take on the whole thing, and I’m sure I’ll get blasted by the “proportionality” folks…but there have been plenty of discussion here on ST about crank lengths and power production and the fact is that most folks can accommodate a VERY wide range of crank lengths without any appreciable effect on their power output.
Most people get caught up in the fact that the crank arm is a lever…yet lose sight of the fact that it is only ONE lever (well, 2 actually…one on each side) that is a part of basically a series of “continuous levers” (i.e. the gears) that make up the total “gain” between the force/pedal speed at the foot to the force/speed at the tire/ground interface.
I look at it this way…your legs “want” to apply force in a fairly linear direction…that’s just how they’re “designed”. The crankset is a fairly efficient mechanism for converting this fairly linear force application to a circular motion. As such, the “power stroke” of the pedal cycle only accounts for ~1/4 to 1/3 of the total pedal circle, while the rest of it is really just a way to get the foot back into the “start” position for pushing down again. Now, when one varies crank lengths, IMHO it’s VERY important to ALSO move ones saddle so that the orientation of ones leg relative to the pedal is the same. In other words, if you move from a 170mm crank to a 175mm crank, for example, you should move your seat AND your bars forward by 5mm as well.
Here’s another way of looking at it. Draw out circles that would be inscribed by crankarms of, let’s say, 170mm, 175mm, 180mm, and 200mm. Now, instead of making them concentric, make it so that they are tangent to each other along the horizontal direction. Now, look at the portion of each circle that’s +/- 1/6 of the circles, centered on that tangent point. There’s not a very large difference in the paths, is there? That’s where the power is being produced.
So…to sum up for now…if you don’t have any “fit” issues that could be alleviated by going to longer cranks (I actually can’t think of any), then I don’t see the point. If it’s “leverage” you’re looking for…well, as I said above, that’s only one part of the total gain of the system, and it’s probably better for you to just use different gearing…it does the same thing. One thing you alluded to above that you need to be concerned with is that going to longer cranks will necessarily speed up your tangential foot velocity at the same cadence (since your feet would be following a larger circle in the same time)…so, going to larger cranks would tend to slow your cadence…which again might require gearing changes. If you don’t feel your cadence is too high as it is, then again, what’s the point?
One last thing you might want to consider is what effects going to longer cranks would have on your position if you happen to need to comply with UCI requirements for some events. Being as tall as you are, you’re already going to be constrained with your bar reach. If you put on longer cranks, in order to keep the orientation of your leg to the pedal in the “power stroke” the same, this will mean moving your entire body forward relative to the BB. That could end up putting beyond the UCI bar end limit and/or make your front end REALLY “cramped”. In fact, that right there is an argument for experimenting with SHORTER cranks for taller riders Not to mention the fact that shorter cranks tend to allow folks to ride with their torso more “horizontal” without excessively tightening up the thigh/torso angle at the top of the stroke. Longer cranks will do the opposite and you may need to raise your front end to prevent being “cramped” at the top of the stroke.
Anyway…just my 2 centavos…flame away 
I used the standard seat post. I didn’t know there was a longer one, but it was just so small, filmsy and so much of it sticking out of the frame it swayed laterally too much for my comfort. I don’t put out enough power to break it… it just gave me an uneasy feeling. TDC: Top Dead Center of the pedal stroke. I’m probably running as much drop (about 16 cm) as i can with 180 cranks. If I went up in crank length I’d have to raise the front so my hips don’t get too tight when at the top of the pedal stroke.
FWIW with the 61 P2C and 16cm of drop from the saddle to armrests… I only have 3cm (spacers and top cap) under my stem. The P2C is just a much bigger bike frame. I have the exact same fit coordinates… the frame just takes up more space now: i have less seat post, and my stem is clamped closer to the actual frame.
txdillard, I was able to special order a 350mm seatpost from Felt (as opposed to their stock 301mm) It makes a bit of a difference, but the seatpost only comes down to the bottom of the top tube-seat tube juncture, and the bike still flexes a bit.
The side to side sway of the seat is noticibly more than my previous TT bike: a 63cm Leader 720TT with a cylindrical seat tube. It bugs me a bit and I can’t spin as easily when approaching 100 cadence. But, I’ve discovered that around 90-92 cadence the flex might actually help a bit. It’s antecdotal, but in a practice TT (as per the photo above) my time splits were 9:10, 9:04 and 8:46 for laps 1,2,3 around Fiesta Island. Each lap is almost exactly 4.1miles.
For the last lap I adopted a bigger gear and dropped my cadence down to about the 90ish range. My avg speed for the third lap was 28.1mph. The previous two were 27.0mph. Not sure if I just have to try to figure out the bike, or if I am legitimately losing power, or perhaps sway is just to be expected for large TT bikes with aero profiled seat tubes?
Is there still noticeable sway on the 61cm P2C? I’d be curious to see your photos and your thoughts about the P2C vs. the B2.
For comparison, I have 23.5cm drop from seat to elbow rests in that photo I posted.
What Tom said, plus my experience: My inseam is 82cm and I went from (my life long MTB habit of) 175mm cranks on my TT bike to 165mm and experienced NO power loss at all at my normal TT distances (25-42min). It took me less than a week to adapt. It did open up the option to bend over more and get even more aero. I’m faster now.