Alright, I am considering switching to a 180mm crankset. I am 6’7" with a 36" inseam, so I think it makes sense from that standpoint. However, I have been doing some research and I have seen mixed reviews about making a switch from 175mm to 180mm, especially when it comes to spinning and hills.
I was just wondering if anyone made this switch and if so what you thought of the transition.
the evidence we have, which is little, is that crank lengths
don’t matter very much
if they do matter, the ideal is usually shorter than what people have historically thought.
at 6’7" you are super tall, which would make a 175 crank a bit shorter than normal for you, which might make it perfect.
I still don’t know what spinning is, and why anyone would care about enhancing it. what do you h ope to accomplish with longer cranks? its not going to affect hill climbing differently than anything else. your bike has gears, whatever leverage you want, you get by picking the right gear. its merely a question of what crank lets you make the most power.
and like I said, what little evidence we have suggests it doesn’t really matter, and shorter is usually better
so, i wouldn’t bother switching =)
you absolutely should try it. because a 180mm crank is still ridiculously short for you, like a guy of average height riding around with 140mm cranks.
take a look at this and then this. measure your legs, punch in some numbers see what you get. you will be surprised.
your bike has gears, whatever leverage you want, you get by picking the right gear.
uh, not exactly.
put on some 140mm cranks, find a good climb, and then “pick the right gears” as you ride, and report back. i think you will discover that gears can only do so much when you cranks are ridiculously short (or ridiculously long).
so get a ridiculous chainring to go with em
your bike has gears, whatever leverage you want, you get by picking the right gear.
uh, not exactly.
put on some 140mm cranks, find a good climb, and then “pick the right gears” as you ride, and report back. i think you will discover that gears can only do so much when you cranks are ridiculously short.
So, do you think I can find 197mm crankset? That is what the calculation recommends. I do appreciate the articles, they seem to support what I was thinking. I feel like I could really capture some more power with longer cranks
of of course both of those articles uses guessing and thought experiment as their reasoning, not experiment.
and the one that does refer to experiment suggests that those results (which contradict his thought experiment) are hogwash…maybe they are, but I’d love to see him demonstrate it rather that just declare it =)
you absolutely should try it. because a 180mm crank is still ridiculously short for you, like a guy of average height riding around with 140mm cranks.
take a look at this and then this. measure your legs, punch in some numbers see what you get. you will be surprised.
yes, you can find a 195mm or 200mm cranksets. there are a few companies that make them.
you do realize that i am not saying that i am absolutely sure that you need exactly 197mm cranks, only that common sense and logical thinking seems to indicate that you should be riding proportional cranks, so riding cranks a lot longer than what you are on now. so trying 180s are a no brainer.
but if i was your height and wanted to ride better and faster, i would definitely venture into the 195mm+ plus range. you have very little to lose, and likely a lot to gain.
I know, I was just being sarcastic. I would think it would be pretty hard to track down a crank that size.
to date, afaik, there are no studies that have studied the effects of changes of cranks lengths (over a wide range of cranks) on riders’ submaximal cycling performance.
none.
For road or tri? For road, ride whatever you like. For tri, you’d be happier on shorter cranks, I think. The links GregX posted don’t account for hip angle at TDC with a TT/Tri position. Nor do they account for muscle-contraction speed, which is most definitely a factor when you consider the arc length you are moving through.
I’m 6’3", but with an actually longer inseam than you (37"). I ride 172.5. I like them much better than 175. And MUCH better than 180s. I’ve ridden all of the above, in both road and tri positions.
I’ve been riding longer crankarms for some time now; about four years. I have a 34 1/2 inch inseam. I spent a lot of money on the idea that longer cranks will make me go faster, but now I have to admit, it is more of a personal preference issue than anything. I prefer the 190s on my road bike with climbing gears since I love to go looking for steep/long hills. The nice, open hip angle doesn’t make them any sort of liability and they are very nice at lower rpm riding or out of the saddle. A couple of limited tests showed that I could produce more power on steep climbs than compared to a set of 175s. However, as Rappstar has mentioned, riding in the tri position requires a tighter hip angle and this becomes even more of an issue with very long crankarms. I went back down to a set of 180s and then pulled out a set of really old cranks to try 170s. I ride a pseudo-superman postion and the extra space created by the shorter arms helped. I spin really fast on them and climbing is not really an issue as long as you don’t mind spinning 110 rpm uphill and have a 36/28 gear that will allow you to do that.
Oh, High Sierra Cycle Center sells lengths from 140 to 220 for about $350 the last time I checked.
Chad
The links GregX posted don’t account for hip angle at TDC with a TT/Tri position.
actually they do. you don’t recall similar triangles in geometry? if you are riding in a tri position and are very tall and use proportionally the right length cranks for your hip angle at TDC, you will have the same hip angle at TDC as a shorter person using proportionally the right length cranks.
For road or tri? For road, ride whatever you like. For tri, you’d be happier on shorter cranks, I think.
I agree with Jordan.
What some people are finding is that in the standard tri/TT postion with “normal” crank lengths, they are finding that at 12:00, if they have tight hips, things can get jammed up as you come across the top of the pedal stroke. I know this was an issue with my wife. We have tried all kinds of different solutions with this and she has been seen by some of the best fit people in the business. A light went on for me some time ago when I was reading one of the threads about crank length and I though, what if we go shorter - really shorter. Studies had shown that power is the same across a wide range of crank lengths. Jordan had reported back that the same after going shorter and racing earlier this year. So we picked up a set of 165 Ultegra cranks( dropping down from 170) and put them on her Cervelo P3. The jamming sensation at 12:00 went away almost right away and a niggling low back pain that she got after riding for 4 - 5 hours went away as well. Mission accomplished.
How do you measure your inseam for cycling purposes? I’m just shy of 6’4, and 175lbs, so I’m pretty long and lean like yourself. I measured my femur from the greater troch to the later epicodyle, it was 47cm. I ride 180’s on my 2008 B2, size 60. I originally got the 180’s put on my road bike which I had a modified tri set-up during the race season. The longer crank length allowed me to keep my seat post lower. When I got the Felt I used the same rational when putting a 180 crank on it. Currently the seatpost on my B2 is at the “2” position, i can move it up about one more cm before maxing out the seat post. My saddle is in the forward position in the seat post and the tip is about 1cm infront of the BB. My saddle/arm rest drop is about 6 inches.
I’m wondering if: 1) Would the shorter crank arm allow me to get lower in the front? 2) If I switched to the shorter crank, I’d have to raise my seatpost, would this be safe given that it’s just about maxed out? 3) Or do I just have the wrong frame/crank all together… in which case my wife will make me give up the sport because she’ll be pissed if Icome home and tell her I’ve got the wrong bike?
Sorry to high-jack the thread.
So we picked up a set of 165 Ultegra cranks( dropping down from 170) and put them on her Cervelo P3.
uh, steve, i hate to break this to you, but recalling the photos of your wife and her bike that you posted, unless she’s grown since then, 165mm is not likely a “short” crank for her. probably it’s actually a* proportional* crank. you want to try short? put your wife on some 130mm cranks and then have her tell us how that worked for her. it will really open up her hip angle, but my guess is that they won’t work so well for actually going fast.
this whole conversation reminds me of the funny folks that ask what PSI should they race or train at. a very goofy question without a critical piece of info: what is the weight of the rider/bike? optimal PSI also is proportional to the size of the rider. for some reason that is hard to understand for a lot of people.
Wow - just wow.
I need to run an EMG/NCV on you, just for fun, and then on a 3-5" midget to see if the motor latency is any different … Human biomechanics are MORE than just the simple “physics” you are making it out to be (i.e. a riders inseam/height vs. crank proportion). We are all aware of your stance ;0 on the matter. Thanks.
uh, steve, i hate to break this to you, but recalling the photos of your wife and her bike that you posted, unless she’s grown since then, 165mm is not likely a “short” crank for her. probably it’s actually a* proportional* crank. you want to try short? put your wife on some 130mm cranks and then have her tell us how that worked for her. it will really open up her hip angle, but my guess is that they won’t work so well for actually going fast
Greg,
Agreed.
All we really cared about was that she’s WAY more comfortable pedaling. She can keep her knees in more( more on top of the pedal) and the back pain is gone. All that happened when going from 170 - 165. I realize that the math and the physics may not work out, but it seemed to solve our problems.** **That’s all that mattered.
I can’t get to the articles – at work…
I think the best place to follow up on this is at Leonard Zinn’s site. www.zinncycles.com
He’s about 6’7", too and produces longer cranks. He’s done some testing on different lengths, but I can’t remember the outcomes.
I think Rappstar’s Q about road or tri is pertinent.
I need to run an EMG/NCV on you, just for fun, and then on a 3-5" midget to see if the motor latency is any different.
no, what you need to do is run an EMG/NCV on me (I am 5’10") and then run one on a male that is 5’7" and one on a male that is 6’1", and then see if the motor latency is any different.
that is a far more appropriate test that would correspond to the point i am making.