I am a 50+ Clydesdale and have been riding for many years. I have always used a 175 crank arm length. (6'1", 34 inseam).

But I have been chasing lower back problems for a long time. I have done several things that help, but I still get searing back pain on long rides. I have done the bike fit and got a endurance bike. I am wondering about slightly shorter cranks. I very rarely get pain during spin class. The spin bikes have shorter cranks.

Has any older riders gone with a shorter crank set up as you have gotten older?

Thoughts?

I can't answer you, but I would like to see your responses. I'm short legged and have wondered if a 170 crank would fit me better. It may not make that much difference but most bikes come with 175 and that's what giants use, so it seems to me that a shorter person would need shorter cranks.

If the crank length is causing you pain, I suspect your real problem is (a lack of) flexibility. Time to join a yoga class, or at least pull out Bob Anderson's "Stretching"?

I think mashing and high force, slow cadence may be associated with back pain.

Some people spin faster with shorter cranks, but you may try dropping a few gears, and see how it goes.

I am with CliffordK about the benefit of using lower gears.

I would leave the crank alone and invest instead in some lower gearing. I recently put an 11-36T SRAM 11-speed cassette on my Di2 Shimano-equipped bike rated for 11-32T. This only required B-screw adjustment; ratings tend to be very conservative.

Maybe try a hard foam roller for your hamstrings, or a massage. I'd be surprised if your crank length was a problem. As others mentioned, try spinning easier gears.

A lot of older recumbent riders use shorter cranks to save their knees. I've only tried it once on a Greenspeed GTO recumbent trike. Went from the stock 170mm to 155mm and really didn't notice a difference. Perhaps I just used a higher gear to compensate for the shortened cranks.

I broke my femur around 5 years ago. After it healed I still didn't have the range of motion that I had previously. I experimented with cranks as short as 148 mm. I can manage 170 mm cranks today but the sweet spot for me seems to be 165 mm.

Did you notice any change in your cadence?

I didn't notice any change in anything other than my leg angle and how my hip felt. I'm thinking that I probably compensated by using slightly easier gears but who keeps track of stuff like that?

Way back in the day I overtrained and got hip bursitis. This time I'm picking it up more slowly. Did the shorter cranks help your hip? My condition caused me to stop racing that year and I was leading the clydesdale class. I've already put pedal spacers on my bike and that seems to fit my anatomy better. I wouldn't wish hip bursitis on anyone, it took years to get rid of.

No pains for me, but when I hopped on a borrowed bicycle with 170MM cranks I instantly found out why my bicycles didn't quite fit correctly, and why I always felt I was 'over-rotating' (is that a correct term?). I changed my own bicycles to 170mm cranks from 175mm and I've been happy ever since.

Also - if the pain is in your lower back look into handlebar height as a possible issue. It might be time to raise the bars a little to get a more upright riding position if your bicycle allows it. Amazing what 10-20mm of extra bar height can do for an aging back.

If the short crank is better, use two on your bike. I wonder if all the spinning bikes are the same; everybody around me spins faster than I do.
Until yesterday . . . . when I fondly thought things were looking up. Maybe I just got my hands on a short cranked spinner!

I have three bikes, each with a different version of the three most common crank lengths: 170 on the medium size compact frame comfort hybrid; 172.5 on the 22.5" horizontal top tube road bike; 175 on the 58cm hybrid (with 60cm horizontal top tube). Usually I'm most comfortable with the taller bike with longer cranks. (FWIW, I'm 5'11", 33" inseam, size 11 shoe, so my leg stroke is relatively long for my height if I pedal on the balls of my feet.)

Yeah, each feels different. But it's not something I can attribute to the crank length. That bit is minor compared with other factors: overall riding position; saddle design, height, etc.

I've had the road bike only three weeks and about a week ago began experiencing some minor pain in the front inner knee (anterior medial). Very rare for me to experience knee pain as I'm usually very careful. But I doubt crank length is a factor. More than likely it's a lack of adequate hill climbing gears for me -- it bottoms out at 42T front/24 rear, while I'm accustomed to a 30/40/50 triple and 13-28 rear on my other bike. And I tried a saddle position that was too far forward for a couple of days.

I'm feeling less knee strain since sliding the saddle back and adjusting the seat post height to suit, taking more time to warm up (I need as long as an hour nowadays just to warm up) and spinning without forcing anything, while avoiding any serious hills climbs over 2-3% gradual grades.

"Has any older riders gone with a shorter crank set up as you have gotten older? "

I have my favorite bikes , step thru like , small wheel folding bikes with lower BB.

they also happen to have 170 cranks.. hit 70 in October..

I like the ease of getting on and off & lower BB at stoplights..





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My understanding is that crank length is an aspect of proper bike fit. If you're uncomfortable on the bike, might be worth getting a fit at a local shop before investing money in new parts. You might find your current crank is correct, but you need to adjust seat height or bar drop or stem length.

Shorter crank arms do encourage spinning. I have a 170 mm crank on one bike and 165 mm on the other. I'm short, though, and fall between the two lengths being optimal for my fit. Bonus, shorter cranks give you more clearance to pedal through corners.

I have a 180, several 175 & several 170's not into high cadence performance, so its all good

length of leg un changed, so length of pedal to saddle top is consistent.


note bike count..




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I am 64 yo and haven't changed my 175s. I do however take time every morning to stretch my Achilles and hamstrings. I used to focus exclusively on my hamstrings and usually only when I knew I'd be riding but I partially tore my Achilles several years ago. I now stretch each Achilles with my heel on the floor, ball on a 2 1/4" high block, knee forward for about a minute and about 20 seconds each leg of leaning forward to get the lower hams. (I grind coffee every morning by hand on a Japanese grinder to near espresso grind. 350 turns. My legs love it. I get to drink great coffee.)

I've heard it said that aging isn't for sissies. I think there is some truth there.

Ben

One thing, I mentioned back and mashing. And I do think there is a connection.

However, I also believe in the adage, "If you don't use it, you lose it".

So, while a lot of stress may be bad, a little stress is good, and may make you stronger. So, personally, I choose the cadence that feels right at the time, and do pedal a bit slower than average.

I have been sleeping lazy-boy chair recently as my back feels better in the mornings than what I get from many beds.

My preference has always been for 170mm AND still is. Feels great to me at 64. I've got a herniated disc (L4-L5 & sciatica) but still feel great riding on my fixed gear & a couple of thousand miles touring per year.

Think about adding some other exercise to your cycling. Some deadlifts and squats will add strength to your back in a way that it's not getting right now.

You should typically use a lower gear and higher cadence with shorter cranks. Foot speed stays the same due to smaller pedal circles. The advantage is less knee flex.

As usual, BP is correct. At 5'7", I've always used 165mm cranks even as a Cat2 back in the '80s. The reason is as mentioned, less knee flex.

Disclaimer: I'm a natural spinner. Even at 66, my average cadence as per Strava is 90-100 for every ride.

I don't think crank length will have much influence on back pain. Shorter cranks allow the knee to flex less, so if you have range of motion restrictions in your knees, shorter crank arms can help. I'd look to other aspects of bike fit to address back pain: e.g. stem length and height, seat set-back, etc.