Finally got some shorter cranks, so I decided to update my results.
I thought I had a line on some 165's last Winter, but that fell through. Budget matters!
I saw this mentioned on the Mechanics Forum (I think) and couldn't resist the price, even if they didn't work out.
http://www.nashbar.com/profile.cfm?sku=20985
$7.49 + S&H! I couldn't resist, so I bought 2! After S&H, that averages $10.37 per set!
Obviously, these are cheap cranks and only fit sq. taper BB's. Also, they are ONLY 160MM long.
Now some things are a bit different this year, than when I switched to the 170's from 175's.
Because of the WINDY weather and some illness, I haven't been riding as much. In fact, I hadn't gone over 5 miles in a day for a couple months.
I decided to do a 10 mile test, on basically flat, paved terrain. About 50-50 city-rural.
In "cruising mode", my cadence was about 83, or 10 RPM higher than with the 170's. That's 20+ higher than the 175's.
My average for the entire trip was 12.6 MPH. That's probably 2.5 MPH faster than my average with the 175's.
I was facing an estimated 5-10 MPH headwind during about 2/3 of the "cruising" stage, so that probably slowed me down 1 MPH?, since I have to sit VERY upright because of my back.
About 1/3 of the way in, I realized something wasn't quite right. I wasn't extending my leg far enough. I than realized that I forgot to raise the seat an additional .4"!:rolleyes:
At least I was "in tune" enough to notice, so that made me feel better:)
I didn't notice any adverse effects except I could use bigger cogs in back or smaller rings in front. The smaller rings isn't going to happen, since these are the riveted kind.
Right now, I'm using a 13-14-15-16-17-19-21-24 cassette and stayed on the middle ring the entire time. I didn't go above the 15T cog except for a slight down hill at the start of my ride.
I wish I had a 14T top cog, so I could throw in an 18T for the "stiffer" head winds. I've found I'm most efficient in a very narrow cadence range and there were a couple times where neither the 17 or 19 were quite "right".
Maybe if my conditioning was a little better, it wouldn't matter though.

Anyway, overall I give a thumbs up, considering the price.
It would be an excellent chance to experiment with 160's, if you have a sq. taper BB.
Just keep in mind that your cassette WILL feel like it has smaller cogs.
These cranks also may be usful for "kids" riding adult bikes.

Hey, I purchased the same $7.49 crankset this past winter, just in case I wanted to try it on my hybrid. It is still in the packaging.

When I purchased my Fuji flat bar bike, it had 175mm on my frame size. I got them to swap it with the 170mm cranks on the next smaller size frame for free. That is working okay.

I picked up an old 1980s Panasonic bike that has 165's on it. I like those a lot.

And I swapped out my 170's on my recumbent for 155's. Many people find that they like shorter cranks on bents. My cadence is up about 15 and my speed close to 2 mph. The bent is now a much more pleasant ride.

I'm toying with the idea of trying to find a high'ish quality MTB crankset with 165 arms to put on the Fuji. I think a good 44/34/24 w/165 would be nearly perfect on that bike.

I think we need to recognize not to generalize too much. I've had experience similar to Beverly's, that I am faster on the road, more comfortable, and find it easier to go my distances (35-45 miles when I have enough time) after having switched 2 bikes from 170 to 172.5. One may argue I'm not fast, but I can argue I'm faster than last year. Speed is about power, and added torque implies added power (it's just physics). Longer arms imply greater torque for a given pedal force. Where the piper must be paid is in the body systems that stoke the boiler - more power requires more energy processing by the body, and there might be a challenge to the body to provide this added power. I'm in an acclimation period.

Climbing speed is also about power.

My cadence is often slower, but normally I don't get my regular cadence up into the 90s until around this time of year - no discernible difference as yet. I have taken some spins into the mid 90s. Last year I did some in August in the low 100s.

For me the key question was, do my hips "like" the increased closure angle? I've been relieved to find they are adapting well, if anything less pain and discomfort this year.

Having read Beverly's posts for over a year now, I think she has considerable distance capability, and has done much bigger rides than I have. If a longer crank is right for your body, it's right as a distance rider.

I'm 6'3", with a 37" inseam. According to Lennard Zinn (framebuilder, exponent of proportional crank arm sizing, and all around tall guy), I should be riding 195 mm cranks. Yes, one NINETY fives. On my upright bikes, I ride 175s because they're readily available and work well for me. Tried 180s a few times over the years and had nothing but trouble, mostly sore knees all the time. It may have to do with the fact that I've always cultivated a smooth, fast (100+ rpm) spin, but whatever. The moral of the story being you shouldn't blindly accept what you're given, be it advice or equipment. Experiment, and find out what works best for YOU.

BTW, Bill, you'd probably be well served by working to increase your pedal speed. 65rpm is AWFUL slow. A higher cadence is easier on the legs and knees, and gives you a better cardio workout.

Scott P
Bend, OR

Well Scott, apparently you missed the part from yesterdays post-
"In "cruising mode", my cadence was about 83, or 10 RPM higher than with the 170's. That's 20+ higher than the 175's."

OR, from my original post about bad knees and WHY I had trouble spinning faster than 60's with 175MM cranks!
BTW, I would have posted this in the 60+ forum IF they had one!

It's a personal thing, related to your flexibility, strength, leg length and a number of other factors. I have been using 180s for more than 30 years. I ordered a new bike in 2002 and special-ordered 180 Dura-Ace cranks for it. For most people, those cranks are too long. I came from a time-trialling tradition and longer cranks enabled me to turn bigger gears. I don't like the feel of shorter cranks. If I were more of a "spinner", I would definitely want shorter cranks. In fact, my circa-1970 track bike had shorter cranks. They were advantageous for sprinting and fast turnover.
If you feel you have to step over a hill at the high point of a pedal stroke, you definitely want to go with shorter cranks. I've coached senior athletes in several other sports. I always advise the athlete to listen to his or her body. Do what works for you, regardless of other people's experiences.
Van

Can the chain rings be replaced on those C051 cranks from Nashbar? If the cranks could be swapped to a more expensive crankset, it would be worth it to buy.

Nope They are the riveted type.
I didn't realize Shimano made a cheaper set than the similar Bio pace I was using in the interim. Then I found these!
For $7.49, I guess you can't expect too much!
I would have preferred 165's (I think), but for the price, it was certainly worth the experiment. I had them swapped before my coffee got cold and didn't even have to adjust the FDER!

Thanks. The reason I asked was because I've already got a 26 little ring on the front. I'd be looking at going to a 24 or 22 if I went to shorter cranks, my engine is a bit under-powered.

With that leg length, traditional fitting philosophy would put you on 170s or 172.5s. After wide adoption of Cyrille Guimard's "long crank" fitting in the 1980s, cranks got longer. Greg LeMond, at 5'10" and with similar leg length, used 175s.

My inseam is a bit over 35". I started on 170s, as everybody else did back then. When longer cranks became widely available I switched to 175s and found my climbing improved, at the expense of my sprint.

"Traditional fitting philosophy" assumes your knees work properly.
Mine don't! My R knee was injured many years ago and doesn't flex as much as the L one.
The L one doesn't flex as much as it used to, since I'm 60.
I would have preferred to try 165's, but money is tight for me, so I tried these since I could afford them.
They are working better than the 170's, which worked MUCH better than the 175's. Facts trump "philos0phy" every time!

You're right, whatever works for you is what's best. I cite "philosophy" only because it can put some issues in perspective. Many riders ended up using longer cranks than they might have preferred because of fitting "philosophies" or fashions.

I just learned that Jacques Anquetil, at 5'9", preferred 175s, which never interfered with his suppleness and snap.

I disagree - I say it's your inseam (Leg length).

I have a 28" inseam

I was 'used' to 170s cause that's what came on 90 percent of bikes out there. I picked up a small mid-80s Trek with 165s and immediately got used to that with no issues at all. I later found an old 1960s Rudge "colt" 3-spd for young teens - short top tube, but standard 26" wheels. It had 140mm cranks. sure, it was not the zippiest ride uphill, but again, the comfort was there for me right away. No adjustment time needed.

I finally went back to my old bike with 170s after several months and it SUCKED! It was like my knees were being violently jerked around.

I agree whatever works is great - but what was Anquetil's inseam? Height doesn't mean much for crank length. My wife is four-five inches shorter than me, but has an inch longer inseam.

No, it's more like being in a higher gear. You have to apply more force to the pedal to get the same torque and the same force in the chain.

http://www.hscycle.com/ I'm 6'8" with a 39 inch inseam, I'm using 190mm cranks, not quite long enough, but the 230mm cranks were just to long for corners, etc. however on a straightaway the longer cranks allowed me to average 23mph, when using the 185mm cranks the average was 18mph. The above link is for custom cranks.:)

DnvrFox

It should be stamped on the inside of the crank arm close to the pedal. Otherwise just measure center to center.

Just changed cranks on my Wahoo from 170 to 175. I think it makes a big difference in climbing power. I like them.

Here is a great device for experimenting with multiple crank lengths, for example from 150mm to 190mm. Unfortunately, for some reason, the price is $650! It sure doesn't look like it should cost anywhere near that amount.

http://www.hscycle.com/Pages/adjustablecrankset.html

Check this link for another example of crank length adjusters.

http://www.tandemseast.com/parts/cranks.html

Check this out:

175mm= 6.8 inches
172mm= 6.7 inches
170mm= 6.6 inches

We are only talking a little less than an 1/8 of inch difference between
the lengths. I'm really not sure if one will notice a big difference performance
wise unless they go into the 180 mm something or 160mm something if the
were using something like 172 mm crank. I could be wrong in all this since
I have never ventured from my 175 mm cranks, but on a positive note there
must be some benefit between the lengths even though it is only an 1/8' of
an inch otherwise the manufacturers would not bother to make them.

But I will say this, everyone I ride with that has shorter cranks than my 175mm
will get dropped by me on the hills and the rollers. This is why I never considered
changing them to something else.

The formula of: crank length= (1.25 x inseam in cm) + 65 = 170 mm for me.
But I have no intentions on changing to it.

Is this because it is impossible for any of them to maintain a higher cadence than you?

Apparently, you didn't read the very first post of this thread?
Some ONE did!

Are you 50+?

Don't you contradict yourself within your own post? Apparently there IS a difference in performance...

NO, I didn't contradict myself, I said in my opinion I do not feel going from 172mm to 175mm or 170mm to 172mm, even from 170 to 175mm is going to make a big difference in performance. It may help with a "Fit" issue, but it's not going to make a person faster. I also said that the guys I ride with have shorter cranks and I drop them on the hills and rollers. My point in that was, I drop them because I spin faster with my 175 mm cranks than they do with their so called "shorter cranks". Whereas I have read in replies here that going from a 175 mm crank to a 172 mm or 170 mm crank would allow you to spin faster. Well you will not spin any faster just by reducing your crank length 1/8" or 3/16”. You want to spin faster work on the engine….:thumb:

If you think less than a 1/8" or 3/16" of crank length will make you a lance Armstrong or enhance your performance and add 2-3 mph on your average speed, you are mistaken. :D

The primary reason to move to a smaller crank arm is comfort. If you use too long of a crank arm and adjust your seat height so as for the angle of your knee to be optimal at the bottom of the stroke, then the angle at the top of the stroke will be more severe. For many people this can result in more pain in their knees over extended usage.

It can also affect performance by making it difficult for the cyclist to maintain their optimal spinning motion. Obviously this would vary from person to person.

This seems to be even more of an issue for recumbent riders, where one's leg position is fixed relative to the pedals.

I use 170mm cranks on my upright bikes and those have worked well. However on my recumbent, 170 was too long. I was either losing some contact with the pedal on the downstroke, or it was coming up too high for comfort on the upstroke. I switched to 155's and my cadence went up by 10 and my speed by 1 mph immediately ... because I was then able to apply power throughout the stroke. And just cruising along is now so much easier than it was with the 170's.

Hmmmm.... aren't facts dependent on your particular view of reality? Remember the story of the man who wanted facts about what the inside of an orange looked like. He had two oranges and he cut one top to bottom and the other horizontal. He was quite confused, because they looked nothing alike. So, that fact was that it depends.

Glad you found a crank length that works for you and your knees.

I may have missed it, but I didn't see any discussion of physical build beyond leg length and height. Yet, my reality is that my thighs and calf muscles are much larger than most folks (even seasoned cyclists) for someone my height. Hence, the longer cranks allow me to use some of that muscle mass in ways that a shorter crank won't.

I'm not certain this is a significant factor for selecting your optimal crank arm length. Having more muscle might not really help if one is using too long of a crank arm, as it would prevent you from using that muscle as efficiently as you might on a shorter crank.

Granted, it might enable to you to shove a longer crank where someone else might struggle. But that doesn't mean you would be able to hit your maximum power output on the longer one. We are looking for maximum mechanical efficiency here.

FACTS are what actually has HAPPENED! I can't explain it much simpler to you than that!

Why would you ASSume, I remember some story about an ORANGE, when I NEVER heard it?

I guess that's your version of "facts".

Until you have experimented with different length cranks AND the subtle gear changes appropriate to those different length cranks, you are simply guessing about what the best length is!
I've made up a custom cassette from 2 different cassettes. Thus I have the ability to fine tune my gear ratios VS crank length. I've probably made 4-5 minor changes to get the cassette dialed in for MY riding. That will probably change in the Winter, when it's colder & windier.
So far, I've used 175, 170 & 160MM cranks.
The 175's are definitely too long for my bad knee, as explain in the original post.
I'm slightly faster on the 160's than the 170's, but they seem to feel a bit too short. I hoping some 165's get left on my doorstep by the crank fairy. Then I can wonder if 162.5 or 167.5 is better:)
Budget constraints prevent me from buying some. (My 160's were $7.50 +S&H)