smontanaro 

What are peoples' experience with changing crank length and/or saddle height as you age? I have to believe some adaptation is required, but I'm not entirely sure what the key factor would be, perhaps maximum knee flexion?

beng1

As with all parameters of how a bike fits, it is a subjective individual thing, and as long as the bike does not bother you on long rides and you are having fun it does not matter what size it is. One thing most people do not realize unless they have done it, is that when you fit a longer crank you have to lower your seat to reach the pedal when it is at the bottom of the stroke. I am tall, just under 6'3", and am in my 60s, and I still like as long a crank as I can find on my bike. If I had chronic knee problems, no matter what age I was, and a lot of people do early in life, then I would use short cranks of course. But aside from any physical problems, an avid regular cyclist should be in good shape and have better flexibility than the average citizen. Every parameter of cycle size changes with different sized individuals, so it makes sense that crank-length should change with the size of the individual too. I would like to see scientific research on using different length pedal cranks with different sized cyclists, as I do not think it has ever been done. The only testing has been done using one-size of cyclist with different length cranks, not with one size of cranks and different length cyclists. !!!

My own testing shows I have more power the longer my cranks are, which makes sense as I buy my blue-jeans in a 35 inch length. So proportionately, a 180mm crank to me is no different to me than a short person with 30 inch long jeans using a 165mm or 170mm crank. I would not mind trying a 190mm crank.

smontanaro 

Thanks for the response, beng1. I was thinking that as you age, generating power at the top of the stroke (maximal flexion) gets to be harder on your (creaky) knees. It seems that as long as your hips aren't seesawing with each stroke (going to maximal extension) you've got a bit of wiggle room at that end of the stroke.

I asked though for two reasons. One, my new bike will have 175 cranks while I've generally used 170s (I'm 6'1", 34-inch inseam, FWIW). Two, I've had some mild knee issues the past couple years and would like to avoid exacerbating any latent problems. If I left the saddle-to-pedal distance at its typical length, my pedal would be 5mm higher (and thus have slightly more knee flex) at the top of the stroke. Isn't that were power generation is lowest

My attempts to figure things out are probably not helped by having multiple bikes, each with slightly different geometry. Nothing like changing multiple variables at once to make it difficult to "analyze the data."

easyupbug 

[QUOTE=smontanaro;22806041...My attempts to figure things out are probably not helped by having multiple bikes...[/QUOTE]
I finally realized this in my 70s and the result was with a focus experimentation. A 172.5 and 175 crank are gathering dust and I have two 165s with more to come and I am gonna try a 160mm. Arthritis has been with me for decades but now my biking issues with it are mostly hands and back, knees much improved. When in AZ I ride routes in a well maintained community with frequently swept streets and my times over 40 years have held up well. In the summer in the WY foothills with my routes ever changing I could be slower but clearly knees are much happier. Wish I had made the moves years ago.
I have held saddle to pedal constant even though at my annual physicals I am shocked at my loss of height so have been thinking I need work in this area.

Carbonfiberboy 

I'm 77. Haven't changed anything in 25 years. I don't have any musculoskeletal problems.

staehpj1

I don't see why I'd change anything with either at my age (71) or any time in the forseeable future.

My dad passed at 79. I am pretty sure he was still using pretty much the exact same setup as he did when younger other than a bit lower gears.

GhostRider62

I had to lower my saddle a touch and move it forward a touch to accommodate underside muscle on my left leg that attaches in the backside at I believe the trochanter. A touch is maybe 5 mm or 6

RB1-luvr

at 58, I'm still riding the same height as I have since my 20s, but my urologist asked me recently to switch to seats with the center cutout, so I've been converting all my bikes to that.

Iride01 

I wouldn't think either will change much due to just aging. However if you are having some particular issue due to aging or injuries that don't heal as well when old, then you might get some relief trying something different.

Possibly you might get some relief going to a shorter crank if your range of motion is getting less for your knees. But then again, riding more often and for longer might keep ones knees from losing their range of motion.

PeteHski

Two very experienced fitters I've spoken to, suggest that shorter cranks are the way to go if you have any sort of joint mobility issues. Theory and experiments suggest that shorter cranks won't significantly affect your power output, although any change will likely require some adaptation.

Carbonfiberboy 

Or going to the gym twice a week and working up to doing full-depth squats.
Of course one can do that latter at home just fine without the barbell and that's where to start. I doubt that more riding will increase range of motion - only increasing range of motion will do that IME. It's a slow process though. Patience.

Iride01 

I agree.

I just said that more frequent riding might keep one from losing range of motion. If one only rides occasionally for short periods of time or for random long rides, then their body might never get use to riding and they'll always have this or that bothering them.

big john

Don't forget that longer crank arms will have the pedal further away from the saddle at the bottom. It's generally suggested to lower the saddle when installing longer cranks.
I've used 175mm cranks on everything for 40ish years and I can't think of any reason to change the crank length or saddle height. The only thing I've changed over the years is saddle to bar drop. I can't get as low as I did years ago.
You might want to see a fitter about the knee thing, or maybe a PT.

terrymorse 

I haven't changed my crank length, saddle height, saddle-to-bar reach, or bar drop since I picked up road biking again around year 2000.

No aches or pains that would suggest I should, either. Age: 65.

79pmooney

70 very soon here. I have changed very little other than a lot more attention to my hand positions. (I'm long and skinny, Not a good upwind combo. Being able to comfortably ride with a near flat back is as important now as it was racing decades ago. So weight on my hands is a given.)

No changed in seat height or crank length. 175s for all my bikes including fix gears. And yes, I've shortened more than an inch, but it is all in my spine. Hips to floor not very different than my teen years. (I'd look better in swim trunks if some of that shrinkage was evened out. My torso hasn't gotten smaller, it's just becoming a slightly collapsed dumpling.)

Calsun

The trend is toward shorter cranks as the leverage gain is minimal with multi-speed bikes and shorter cranks can be spun more readily for improved cadence. Shorter cranks also increase the clearance between the rider's toes and the front wheel and from the pedal to the ground when turning.

freeranger

72, and still using the same 175 cranks I've used for decades. Never liked being too "stretched out" (guess since I rode off-road long before owning a road bike), so stem length the same. I have made some saddle adjustments the last few years, though. Lower and maybe a very small amt more forward. DAMN--just realized I used "for decades". Guess it goes with the territory!

staehpj1

For all practical purposes that means keeping the saddle height the same. I always measure and set saddle height based on where the pedal is at the bottom of the rotation. Tiny differences in bar height are less important, but bar height is based off saddle height so that would change as well. At least that is the way I'd look at it if changing crank length on my bike. Truth be told I may not noticce 5 or 10 mm in bar height all that much or maybe at all, but I definitely would in seat height.

big john

Huh?

Iride01 

I think they are using your post as a segway to expounding in more detail. And not replying to you or criticizing.

I have the same feeling of "huh?" quite often when I see such. Although I've probably done the same, I wish people wouldn't quote other's when they say essentially the same. And if they do, then make it readily apparent that they are just building on the quoted message and not taking issue with it.


This by itself without the quote will stand very well.

big john

The confusion was the two apparently contradictory lines.

Iride01 

Oh... I didn't see that as contradictory since the saddle height they were describing is measured from the pedal and not the BB or crank center.

I also measure my saddle height from the pedal furthest away from the saddle.

big john

Me too. Therefore, longer crankarm=lower saddle. Or am I losing it?

Iride01 

It's not lower when compared to the pedal position. It is lower when compared to the ground or the BB center. So it's just a frame of reference issue.

You do have to change the saddle position. And I guess the three of us agree on that. But the saddle height only changes when the reference is to something other than the pedal.

big john

So when he said "keeping the saddle height the same" he meant in relation to the pedal. I guess that's why you get paid the big bucks.