longer crank
 

So, I'm thinking about one of the comfort/endurance bikes around now. I'm early 60's with some neck/spine issues. My road ride now is a 56 cm Madone that I had to have fit with a riser. I test rode a 58 cm Domane last week and its too long for me, at least off the rack. I'm 6' with longish arms and legs so I'm a trapped between 56 and 58's. 56 looses stem height, 58 is stretched for me. Trying to figure out how to shorten my reach on either size. I've experimented with moving forward on the saddle while riding on my current bike, with thoughts that I could actually move the seat forward if needed. I've found that different muscles come into play which could make me stronger (don't know). Its easy to slide forward an inch or more, which is a lot. I've thought that maybe a longer crank would help with this and keep my knees in a better position.

Question is, would a longer crank help me . Seems the differences are small, maybe 5 mm. But, if it means that I could move my seat forward more, and maybe move it down a bit, then possibly I could make it without one of those fredly risers . I know that stem lengths and angles are first things to check, but don't think thats enough for me.

Thanks so much.......

I dont Know if it will help you , or not.. or how the low posture that is what a Road Bike is all about, will help the back issues, except perhaps you support More weight with your arms.

I have several bikes with 170,175 and 180 arms . I stuck the M730 180 arms on My trekking bike to give the Illusion the seat post angle was lower than it was ,

though the weight balance was unchanged , until I Bought a seatpost with More Setback. other than that, I switch back & forth with out much difference.

I'm 67 & no carbon fiber bikes. maybe your youthful self image is like that of a sports car, but your body is no longer comfortable in that racer's posture . :50:

Don't choose your crank length by saddle position. Choose your saddle position by weight distribution (the hands off test) and work everything else from there. Choose your crank length by inseam length. Choose your reach by back angle and the 90° upper arm test.

OP, You said, "early 60's with some neck/spine issues",,,,,

You can adjust all you want, making things better by degree's,, Just look at the DF riding position from a distance, get the big picture.. Really ? Are you racing ? Do you really need the 'Tuck' ? all that pain, that neck position ,,,,. Or you could go ahead and buy yourself a Cadillac and enjoy the ride,

When I need a break, when I'm maxed out and need to throttle back I can rest on the bike, relax sitting In the saddle..

http://bikeforums.net/attachment.php...hmentid=449830http://bikeforums.net/attachment.php...hmentid=449831http://bikeforums.net/attachment.php...hmentid=449832


Look at that seat,, the 3 inches of supportive foam padding, the coolback seat back,,Yeah It's that comfortable..
I get my power from pushing back into the seat back...
My View is fantastic, my neck Is In a normal position, I can look all around me..
I can keep up with most roadies my age just fine.. It ain't the bike It's the Engine remember ?

Of course you can keep adjusting your current bike,,,

Or you could fit your self on a bike like this, Fit Is so hard to get right, so complex. I got mine spot on the first try..

First you set the seat, Lower back tight against the back of the seat, heel on pedal at max pedal to seat back distance, Knee slightly bent......

Seat back angle how ever you like it,,, Elbows bent some,,,

Your done...

Thanks for the replies. I'm certainly not a racer but I do enjoy riding hard. I also like carbon bikes. I've got a steel ride that I enjoy when its called for. My neck has sort of autofused and does not have much mobility, my back is following the same path. But I have gotten stronger over the years and work on my core a bit. I just can't look up as easily as most. Its not painful but I just can't do it. I'm in decent shape otherwise. Sorry, but just can't do the recumbent thing (not that there's anything wrong with it.)

So, after reading some fit articles, it occurred to me that maybe I could move myself a bit forward to bring the bars closer. Probably makes no sense, but thought I'd ask. The thought being that I could slide my seat forward and , by extending the crank arms, keep my foot over pedal position roughly the same. Whats the deal with crank arm length? I've never altered a bikes cranks so I'm curious. I'm thinking a longer crank would position the pedals lower on the bottom stroke, a bit more forward at horizontal, and higher at the top. Whats the ramifications of all of that? My apologies if this is just a stupid line of thought.

I agree with CFB...forget the crank thing vis a vis reach. Position your seat to put yourself over the BB as you prefer, and use stem and bars to adjust for reach.

If you'r looking at new bikes, I'm sure you can find one with a tall enough head tube that with the right stem, you could put the bars where you need them.

Definitely go with a 56, though. There's a lot more room to stretch fit than shrink it, and more advantages to riding a smaller bike than larger.

Thanks again. I might just stick with what I have, but getting the itch and I'm nearing getting my retirement bike so I'm asking questions. Good advice about getting a smaller bike when between sizes.

I've spent a lot of time trying to figure out optimal crank arm length, reading Zinn and Burrows and other theoreticians, and trying a variety of lengths for extended periods of time.

I started with the assumption that there was something important there and that the bicycle industry was making a fundamental mistake by not offering a full range of crank arm lengths for people of all sizes. But after years of experimentation I came to the conclusion that it really doesn't matter much. I firmly believe that most road cyclists use cranks that are longer than they need, and that we'd all be better off with shorter crank arms and lower bottom brackets, but the cost of retooling the whole industry would far outweigh the advantages, which would be slim indeed.

Longer crank arms may help your weight distribution on the bike, but only a tiny bit. They may also do permanent damage to your knees, which are not really replaceable. I'd advise against it.

I'm with Carbonfiberboy in that your first priority is to be in balance and not have to hold yourself up with your arms.

In re-reading your post I get the impression that it is not really a crankarm/saddle issue but in reality a steering tube issue. The biggest issue with an off-the-rack bike is that you are stuck with a cut steering tube and then left trying to cope with some severe stem angle. Have you thought of getting a new fork for your current bike, at least to play around with, and then making the reach/height adjustments with spacers and stems? You can run spacers on top of the stem until you get the best fit for you neck/spine.

My advice is to get your current bike as comfortable as you can before you spend bucks on your retirement bike. That way you can just transfer your fit to your new bike instead of starting from scratch. And I agree that it is a lot easier to fit from a slightly small frame than one that is a little too big.

John

Thanks John,

I was just daydreaming about the crank length thing. Lots of good responses here cleared up the issue for me. I don't overly rely on my arms to hold me up. My core is ok, could be better but I try to lower my shoulders and keep my elbows bent. I've ridden a few bikes over the last month and all of the fitters said without hesitation that I should be on a 58. Yesterday I rode a Specialized and its setup felt great. Funny, I've always had this bias about that brand but I its the one that fits me the best. I'm finding it hard to pull the trigger though.