Crank length, two different formulas

I’m not going to argue if cranks should be different lengths depending on how big or small you are, it’s obvious to me that someone taller should use a longer crank and the opposite if you’re short.  I’m beyond debating that point. But what I’m not clear about is who’s formula is most accurate. Keep in mind no formula is exact because I’m sure leg ratio, the type of riding you’re doing, your preferred cadence etc. all will effect these numbers a little bit.

Formula #1 by Lennard Zinn

multiplying your inseam (in millimeters) by 0.21 or 0.216 = length of crank in mm

http://www.zinncycles.com/cranks.php

Formula #2 by Kirby Palm

L(mm) = 5.48 x I(in)

http://www.polaris.net/palmk/Crankset.html

http://www.polaris.net/palmk/resume.html

I’m currently leaning towards Zinn’s formula and my tests I’ve done so far seem to prove it right, at least to me. Also keep in mind one of these formula’s was made by a bike builder, avid cyclist and former racer, where Palm well, I think he’s a smart guy, but I don’t know where he comes up with his numbers for his formula and I his about page does not paint the picture of someone who practices what they preach. I see Palm not having any history as an elite cyclist or bike builder and avid cyclist, but that of recreational cyclist that happens to be an engineer.

Let me know what you think?

Have you ever tried different length cranks, what was your experience?

Crank length tests

I’ve been experimenting with crank length the last few months, I’m currently riding 190mm, as much as I like them the verdict is still out if I’m going to stay with them though. I’m going to ride them for the next couple months continously while I work on my cycling position as well, then throw my 175mm back on for a month or so and then make up my mind. I might even just go to something inbetween like 180′s as a comprimise.

I rode the 190′s the end of last season for about a month, after the end of the month they really grew on me and I felt that I was onto something as I was faster and more comfortable, but I’m not sure if that was just because I finally got a needed break from all the group riding I had been doing all summer.

Also my riding position was bad, and I’m sure was aggravated by the longer cranks, as the longer cranks made my KNOPS out even further backwards, when my knee needed to move foward, actually my knees and whole body needed to move forward. But even with the bad position I still experienced about a 2.5MPH average speed increase on my 1 hour TT loop I do at least once a week.

I’ve very curious to see what happens with my new improved position and the 190′s and then having a couple months of saddle time in on them, I think it will work out good, but we’ll see. And I’m even more curious to see what will happens when I go back to the 175′s.

What makes this testing difficult is that my body is changing and getting stronger and faster, and that it can take several weeks for your legs to adjust and get smooth and powerful on the new length of crank.

I think what I should do is shorten the time I spend on one length and go back to the other, because if I spend too much time on one length by the time I go back I’ll be 2 months stronger and it will be hard to take my results seriously when I switch cranks.

So I think what I’m going to do, is ride a bunch of easy and moderate rides for 2 weeks, and when it feels like I’m pretty much adapted and use to the new length I’ll switch to the other for two weeks and then at then end of those 4 weeks I should know which I want to say with.

Cycling position changes 2/13/09

I have been working on my cycling position lately after discovering I had major fit problems, currently I’m fine tuning and experimenting and trying to get closer to my perfect fit. I had an expert fitting the other day, but, I think fit is such a personal thing that they can only get you close, in the end you’ll have to know for yourself if a small change is helping.

So I spent some time yesterday marking and measuring where the fitting had me, so that I could come back to that position and reset my fit position if my position experiments don’t work. I know that I need to give each position a couple weeks to get used to and judge, but some of the things I could tell right away needed to be adjusted because it was obvious after a short one hour ride.

So these are my latest changes

  1. Switched from my WTB saddle to my San Marco saddle that originally came with the bike.
  2. Moved my fore-aft position forward about 3/4″
  3. I assume my KNOPS is moving forward by moving my saddle forward, but when I measure with a plum string it doesn’t seem to be moving forward, but I know that it must be? I think I need to find a way to measure KNOPS better. I need to be on a trainer or someone holding me straight while I get a real plumb string not just a string with a tool hanging on the end.
  4. Moved the saddle up 1/4″

These changes are based on the feeling of not engaging all of my leg muscles fully, I think my KNOPS was still too far back.

Also I don’t think I like wear the fitting put my cleat further back, it feels like it’s to far back now,  I think the ball of my foot is now actually slightly forward of the pedal axle where I like to be either right on it or slightly behind.

I was careful to make sure that I didn’t make the mistake of putting my saddle too high like I had it before, it was giving me a dead spot in my pedal stroke the fitter said, I think he was right. I like the saddle on the high side, but you have to know what the limit is.

I still need to move my brake levers closer though I think, the fitter suggested that but I haven’t had time yet.

The scourge of the moderate cyclist

If you want to get faster on the bike, it’s not going to happen by riding around mile after mile at a moderate pace when training. It’s not going to happen by going out and trying to hammer on every training ride. It’s not going to happen if you double your millage or your weekly training time. Yes, saddle time is very important, tempo rides are important, but to move up to new levels of speed and power requires careful control of training intensity.

Go slow to go fast

To get faster, you have to train faster, but also slower too, let me explain. To ride and train really hard so that you break through new barriers, you need to prepare yourself for these breakthrough training rides by letting your body fully recover from the last hard breakthrough ride.  You actually get slower when you’ve trained hard, it’s on your recovery days or easy days that you heal and recover from your last hard training session and get just a tiny bit faster. It’s very easy to screw up the rhythm of your training and mess up this tiny improvement they call “super compensation”. If you’re not fully recovered and try to go out and do another hard session you won’t be able to do it at 110% effort, maybe 90% and it will take even longer now to recover let a alone reach a state of super compensation.

It’s much easier said then done though. It’s very tempting to “test” ourselves on every ride, to start hammering with reckless abandon, to get competitive on “easy” group ride days. To want to win so bad that you find it impossible to ride slow on easy days. But have faith, those easy days are probably more critical for getting fast then your fast days, if you can hold yourself back and let yourself recover fully and listen to your body, and only go all out when you’re 100% you’ll see much better results, be less tired, less likely to get injured, less frustrated, less likely to just quite cycling all together out of frustration when you’re not improving. Be patient, let the training process work, you have to believe in it.

Recovery day rides are not meant to test you or challenge you, they are meant to speed up recovery. It’s very easy to push to hard and re-stress your body when it shouldn’t be. Here are some tips I use to make sure my recovery days are just that

  1. Don’t do group rides on your “easy” days as it’s too easy to get caught up in friendly competition of if the ride leader is  feeling good that day they might take you on some killer hill climbs etc. that you should not be doing on your easy day.
  2. Use a heart rate monitor with it range alarm function to “yell” at you when you start to push to hard. Most monitors allow you set a maximum BPM you want it to go to, when you go higher the alarm goes off to tell you to ease up.
  3. Ride on roads with little traffic that are scenic, there’s something about cars flying by you on the road that forces you to ride faster, sometimes there are legitimate safety reasons for not riding slow on certain roads or sections of roads.
  4. You could also cross train on your easy days, go for hike, go for jog, swimming, even a fast walk will work
  5. Just as bad as training hard before you’re fully recovered, not doing anything and sitting around on stiff sore legs can be just as bad and delay recovery.
  6. If all else fails and you are a hammer and find it impossible to ride slow, then take off on your easiest days, but try to at least go for a walk etc. if you can.

Train faster to get faster

As obvious as it sounds, you’d be surprised at the number of cyclists that just keep doing moderate training rides, thinking slowly but surely they’ll get faster some how. They ride miles and miles and miles day after day, always pushing to go faster, but wondering why they’re not improving or improving very slowly. They only ride slow when they’re forced too because they’re exhausted from the volume of moderately hard rides and lack of recovery, or injury, some even get so discouraged they quit.

The “secret” to riding faster is that you’re going to have to make sure you’re fully recovered before a hard day, and then on that hard day, you want to give it 110%.  Hard break through sessions don’t need to be long, and probably shouldn’t be as you only need a taste of intensity to stimulate your body to get a little stronger, you don’t’ want to rip yourself to shreds by doing high intensity and high volume at the same time, you’ll only dig yourself a deep hole from which you need to recover from then. So hard training days should be shorter in general. You get faster not by volume but by increasing intensity, so be very careful with the volume of high intensity riding you do, it’s very easy to push yourself over the edge and actually get slower not faster.

The tricky part of getting this training rhythm right is knowing when your body is ready to train at 110% again.  Just because you have a hard day planned doesn’t mean you should be going hard that day. There are signs and signals your body will give you to let you know you need back off for another day or two or longer. Like

  1. Increased resting heart rate at waking
  2. A sudden drop or gain in weight, you may be dehydrated, or be holding water in your muscles because they’re swollen, or both.
  3. Darker urine, you’re probably dehydrated
  4. You may feel moody or cranky
  5. Lack of motivation to train
  6. You may feel weak or jittery
  7. Have a headache
  8. Difficult to get out of bed
  9. Legs feel heavy
  10. Difficulty sleeping
  11. Lack of appetite
  12. Inability to concentrate
  13. If you train, your heart rate will be higher then normal
  14. The amount of watts you can produce at a given heart rate is lower then normal, or heart rate is higher then normal
  15. Lowered Libido
  16. Inability to raise your heart rate to it’s max if you’re doing max efforts that normally would push your heart rate there.
  17. Leg muscles that feel weak when riding
  18. Leg muscles that fail and burn much faster then normal
  19. Difficulty spinning at higher RPMs

And most importantly, sometimes you just don’t know that you need to rest more, you may have no symptoms or signs, this is why it’s critical to have planned in recovery weeks in your training cycles through the year, and also to have a transition period at the end of the season where you let your body recover from the entire season in general. I’ve started training in phases and at then end of each phase I have a full easy week, where I let myself recover, even if I feel a 100% and want to go hammer I make sure to take it easy this week, they’ll plenty of chances to hammer in the next 4-5 week training phase. They call this week an “unloading” week. you ramp up your efforts over 3-4 weeks then have an unloading week to make sure you’re fully recovered. You are ramping up and recovering during your weekly training cycle too, with unloading days, and ramp up days.  Being too enthusastic and not letting yourself recovery fully is probably the most common training mistake, and also not riding hard enough on your “hard” days.

Everyone’s  training rhythm is different, so you may be able to do two or three really hard days a week, where someone else can only handle one really hard day a week, and need to take it easy the rest of the weak. In general smaller fitter riders seem to recover faster, then larger more unfit riders, also genetics plays a role too.

Don’t let this season be mediocre for you, have it be a breakthrough season!