You guys have any opinions on crank length? I've recently started riding a different bike and I'm finding myself experiencing a lot of hip discomfort and don't feel as efficient. Just noticed it has 175mm cranks whereas my other bike had 170mm cranks. Could that be the problem? What length do you run normally?
1. Yes, that difference in crank length could certainly account for your discomfort, especially if you have shorter legs.
2. Ideal crank length depends mostly on leg length and rider preference - using longer cranks gives a slight advantage in producing torque, shorter cranks will encourage efficient spinning.
3. If you want a data point to compare to, I have a 33" inseam and find 172.5 to be optimal
>>895605
Mostly what I've read suggests crank length problems usually cause knee discomfort, which is kinda why I was confused. Not actually sure what my inseam is, but based on my height it's probably around 31", and that would make a lot of sense based on your preference because I like the feel of 170.
I'm 5'6" so crank length is important to me. Unfortunately most manufacturers only make 170-175cm cranks, and sometimes 172.5cm ones, just to cut costs.
The only ones doing a really large variety of sizes with reasonable prices and availability are Touring crank manufacturers like Sugino and Stronglight, but those are all old designs with square taper BBs and the like. Not so good for modern road bikes.
I race track primarily and have been toying with the idea of putting 165s on my road bike. My crit bike for next season will have 165s. I've never noticed a difference in crank length, I've got 175 on my road bike (had 172.5), 167.5 on my touring rig, 170 on my gravel bike, 165 on my track bike.
You sure your saddle is positioned properly? Do you need a seatpost with/without setback? These all play a large role in your hip angle also.
>>895657
Listen to this anon and also KOPS (knee over pedal spindle). If you increased your crank length 5mm and didn't move your saddle forward 5mm then you aren't far enough forward.
>>895657
>>895659
I've been troubleshooting saddle position for awhile, like I said it's a different bike. Made some improvements but they haven't helped much. Did another adjustment today and put on some toe straps to make sure it's not a posture issue, will report the results
175mm cranks on a 56cm frame doesn't make much sense to me. Anyone know why they would do this?
>>895646
>cm
r u a giant
>>895595
that is not a significant enough distance. Ensure the saddle and bars are fit to you properly first.
>>895595
I'm 6' and I like 170s. Never really cared to learn exactly why that is, they just feel the best for me.
>>895659
>KOPS
Zero scientific basis.
>>895832
shut up
>>895839
Use the SI precisely as prescribed in the current edition of the SI Brochure.
im like 6'1/6'2 and ive got 170s on my bike right now but ive been considering going 175 because i like the leverage/torque a bit more than the spinning
i just returned from my bike shop, changed 175 with 170 just because i couldnt find cheap 175 cranks chainset and my bik is cheap (old trek 6000). im short as hell ( 5 5) so this should be ok.. but who knows i was used to the 175's, ill post my feelings soon as soon as i ride some more . that will be in a hwile, cheers.
The curve for crank lengths looks something like this.
That is, you want the longest crank possible that you can use without it negatively affecting your performance.
Longer length means a long lever and most muscle activation, however it also puts the joints at more extreme angles, which is bad for bio mechanical efficiency and joint health, as well as limiting breathing by compressing the diaphragm.
This leads to a gradual gain in performance the longer the crank is, a plateau at the top, but a sharp decrease in performance when the crank gets too long.
Shorter cranks are always safer. Someone whose optimal crank length is 175 will not suffer as much using 165, compared to someone who should be using 165 using 175 instead because of the asymmetry of the curve. Still, most people would go for their optimal crank length, because it's still better.
2.5mm differences are usually not noticeable, which sum up to a 5mm difference in diameter. 5mm differences, which sum up to 10mm can be noticeable, and a 10mm difference summing to a 20mm difference in diameter can be quite noticeable.
The reason why 172.5 exists is because it works as a "medium" size for people that would either be optimized for 170 or 175, with almost no negative drawback for either because of the small change.
Short people with short legs should always try to get short cranks because of the rapid fall off in performance. Tall people with long legs should always get long cranks because long cranks are still on the short side for tall riders because there is much more variance in height that crank length so even a 175 will be shorter than optimal. Average height riders should generally go for 170, or 172.5 if north of average. If there is any doubt at all about possibly having short legs, go for 165 because the potential drawbacks are not anywhere near as bad as potential gains, or it may end up making no difference.
>>895970
Also, rider position can have an effect on crank length because of the breathing issue. Even a tall rider may prefer short cranks if they find a long crank interferes with breathing.
>>895970
…and this is based on what?
>>895973
It's based on truth, you're free to ignore it if you don't want to. You will see a very small performance decrease if a crank is to short, but a considerably greater performance decrease if a crank is the same length too long.
>>895987
It's not based on any particular source. Its an opinion based on personal experience as well as multiple articles and studies which all point to the same thing. Too long is bad. Too short is not that bad. Variance in crank lengths manufactured is not as great as variance in people's heights/leg lengths.
Tall people should always get 175mm, and short people should always get 165mm, unless you are out of proportion (like Nairo Quintana who uses 172.5mm) which is supported by pretty much every crank length formula assuming proportional leg length.
>>895828
people say KOPS is a myth but 9 times out of ten its a good rule to start with when dialing in a fit. It does work for the vast majority of people.
Big cranks, saddle really forward, cleats slammed as far back to the heel as possible: max power.
This is what most pros are trending toward.
>>895973
he's an expert at reading cycling forums
>>895992
Big cranks like Zinns are only trending for people with long legs. It's not that everyone is moving towards longer cranks, it's that people are acknowledging 175mm is not long enough for long legged people, and the increasing availability of specialized equipment for them.
>>895994
Better than the opinion "I use 170s and they're fine for me so they'll be fine for you"
>>895996
not true
longer cranks give more leverage
thats beneficial to short and tall, more beneficial for smaller riders, if they can get away with it with out pain some are opting for shit like 180mm
pantani was 5'7" and used 180mms
they're crap for accelerating but great for climbing and TTing.
peloton mag just had an article with adam hansen about all this shit
how longer legs interfering with breathing is complete crap too
>>895972
you have to move your seat way forward and higher with crank length, (just like a TT bike, which is why they make sense, that position is so much better for competitive riding) you can roll your shoulders back and open up your chest and that gives you a lot more lung room than your legs coming up toward your stomach.
>>896079
>Mixing unit systems
>Abusing SI prefixes and unit symbols
Please re-read the SI Brochure.
Lower gears give more leverage too.
>>896079
>longer cranks
>higher seat
What are you even.
Pantani liked long cranks because his favorite thing to do was stand.
>>896079
Adam Hansen is 6 feet tall. Long cranks literally killed Pantani, not to mention he was fucking weird anyways because one of his legs was 2 inches shorter than the other.
>>896079
Longer cranks give more torque. The amount of leverage provided is a function of your body type. If you are too short to power a longer crank then you will have poor leverage.
>>896082
Americans mix units because we use both US Customary, and SI. If it bothers you, learn to convert, or skip the post.
>>896089
This. The legs and the cranks make up a system of levers. You can't go around with 500mm cranks just because it gives you more leverage, and just because the lever is longer doesn't mean it necessarily allows more work to be done.
>>896091
Feel free to use the most arcane units of your choosing when communicating within the confines of your own backwater. On a website intended for an international audience however, common courtesy, sound logic and the pursuit of the precise transmission of ideas demand that you use internationally standardised and understood units, exactly as described in the SI Brochure (please re-read it).
Those Americans who find expressing their opinions in a readily understandable way bothersome should skip making their post.
>>896098
Just add inches and feet to your board filter senpai desu
>>895951
its me again, did a short ride to test my new transmission.
at the beginning i barely noticed but a few minutes into pedaling and whats described on the pic happened.... i felt like instead of pedaling in circles as i always do i was saliding my both feet forward and back, like in a a 35º position, see pic, it was just like that... i liked the feeling, dont know if its better to pedal like this or how i used to... but i just dont feel the pedals going in circles.. by the way i dont use any foot retenstionsystem to keep my feet to the pedals (in other words i just use snekers).
any input is welcomed.. i felt i could go faster, but that also may be that i have a new lower gear now (42/11 old,. 48/12 new).
>>896099
That is an unsatisfactory solution for a number of reasons. Firstly, there is the potential for false positives when 'feet' or 'inch' is used with a meaning other than the non-SI units not approved for use with the SI. Secondly, any hidden posts which are replies and have replies would represent an irritating interruption of the conversation. Thirdly, not addressing the non-compliant aspects of such posts would undoubtedly lead to a decreasing respect for the need to conform precisely to the proper use of SI units, prefixes and non-SI units approved for use with the SI as prescribed within the SI Brochure.
unless you are doing only crits or track racing, you should be on the longest cranks your knees can handle
most knee pain is from an inflexible posterior chain, mostly tight glutes and hamstrings
usually, if you are flexible enough that you can touch your head to your knees, your saddle/cleat position can be pretty much anywhere and you won't experience knee pain
>>896198
dude, you're stealing the autism thunder from the trainfags. chill bro.
>>896234
You are retarded, yes?
>>896098
4chan is US based and US founded. you can fuck off to a euro chan where nobody will rustle your jimmies over units.
>>898665
Due to the pervasive nature of nation-states, it is nigh on impossible to do anything entirely independent of them all. On that basis, the mere accident of the location of a website's founding or hosting is a poor rationale for deducing whom it is intended for. If 4chan was intended for a US audience exclusively or even primarily, moot would have chosen to host it in the .us TLD.
>>898734
hey, man, my car gets 40 rods to the hogshead, and that's the way it'll always be! USA! USA! USA!
>>898756
I'm glad you realise that your choice of arcane units singles you out as something of a decrepit stick-in-the-mud.
>>896089
>>898665
>Doesn't know about the sad "SI-brochure" troll
I for one hail the Americas slow but sure creep towards SI units. Not that SI was that much better but it has, quite clearly, become a world standard.
I'm sure though that American cars, when they finally get metric dashboards, will still measure fuel economy in "km/l", which infact is retarded.
>>899039
What would you measure it with and why?
>>899039
>Not that SI was that much better
>>899478
I would like to think that it partially got adopted due it's superioirity, but mainly because the whole world had their own idea of what pound and feet exactly meant.
In those circumstances, French, Portuguese, German, Belgian and Spanish colonialism probably helped a lot, that effectively made half of the world metric.
I looked it up and for some reason only the Spanish and Portuguese colonies officially switched inits with their mother countries in 1850s, the African colonies only hundred years later. I wonder why, did these countries really use imperial units colonial trade, was the British influence so strong?
>>899457
liters / 100 km.
That concretely tells how much you are spending for a given distance (100km). instead of how far you can go with some amount of fuel (gallon).
>inb4 "europoor needs to count how far he can afford, I just want to know how far before I fill 'er up again!"
Which is true, you global misdeeds affect our fuel prices way more.
>>899555
That's a unit of fuel consumption though.
>Not even 'muripleb
