Check this out: https://www.nettally.com/palmk/crankset.html

Although that link tends to confirm my choice of shorter cranks, it still doesn't address the issue of someone with bad knees. There's just more factors involved than a one size fits all formula!

Physical condition- General health/fitness AND "defective" joints.
Age- One would expect that a younger rider could spin faster than someone 40-50 years older.

As I stated, for ME, the shorter cranks have increased my speed slightly, but have increased my ENDURANCE significantly. OTOH, on my "short errands", where I don't have to "save myself for the long ride", I can ride noticeably faster. I can sweat and gasp after I get home!

Several of my girlfriends have complained about my crank being too long...oh, wait...never mind, wrong forum.

I guess, at 68, my cadence is about 80-100, generally. I don't think age has much to do with cadence. Other factors may - i.e., knees, but age as an independent variable seems to me to be non-significant.

5mm makes a big difference on recumbents where the leg length is locked in. On a regular bike, the body can compensate for slight differences by moving back and forth on the saddle which a recumbent rider can't do. I run 165s on my bents and can tell quite a bit of difference if I put on 170s, mainly because I'm shorter than average (5'7"). With 170s, my knees come back too far causing an over-contraction and I get sore thighs. FWIW, I've got a line on a set of 155 mm carbon cranks and might give them a try.

It seems we all have such different experiences with crank lengths. I have a Madone WSD and changed the 170 cranks to 175 as I felt like I was constantly spinning out on the shorter cranks. I tried them for 500 miles and was happy when I made the switch.

I would think you'd have the opposite effect?
With the 175's, 65 RPM was all I could maintain and it took a conscious effort. 68 RPM and my feet were coming off the pedals.
With the 170's, I'm aware that I'm spinning faster, but I don't feel like I'm "spinning out". I kind of expect to increase my cadence somewhat, through "repetition".
I messed up my back though, so I'll be off the bike for a few more days. The 165's should be in the shop tomorrow. I guess they'll be there a few more days!

Good article..

https://www.velonews.com/tech/rev/crank.html

"I pretty much want the fastest speed that I can comfortably maintain. I'm NOT fast, so going from 10 MPH to 11 MPH is a 10% increase! The shorter cranks HAVE helped my speed slightly, but they have REALLY helped my endurance. At this early time, it appears I can ride about 60-70% further with the same level of fatigue. On my shorter errands (1-2 miles), I can "crank it up" an extra 2-3 MPH."

...I agree that short cranks give you more endurance. My speed on flat roads averages 14 mph, but seniors like me can keep it up "forever".

I'm 5'9" with a 35" inseam and I find 175mm cranks much more comfortable than anything shorter. I would like to try longer cranks, but they are hard to find.

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.
https://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"!
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.