eay

I'm trying to understand gearing and cadence and so on in an effort to not mess up my knees and to gradually improve my aerobic conditioning. Oh yeah, and then there's weight loss ...

This is what I have figured out so far:

I finally got around to putting my bike specs into the rpm calculator on sheldon brown's website. (I don't have a cadence meter but I have gotten pretty good and squinting at my tiny printout and eyeballing my gears to figure out what my cadence is.)

Assuming a fairly constant speed and level terrain (hurrah for canal-side paths!) I can poke along at 70rpm for miles, can sort of maintain 80 if I think about it, and can inch up to 100 for a short while (I have plain old pedals). Then I start huffing and puffing like an out of shape middleaged woman. Uh, wait ...

So I know that I want to increase my aerobic capacity and get a higher rpm.

If I want to go, say, around 16 or 17mph between 80 and 100rpm, then I have several choices of gear combos

(Uh - the bike - 2007 trek 7.2 w/ 48/38/28 + 8 speed 11-32)

80rmp: 28+11 or 48+18 or 38+14
90rpm: 48+21 or 28+12 38+16
100rpm: 28+14 or 38+18

I'm trying to understand how the different combinations of gearing yield a different feel to the pedaling - some combos are easier then others and I don't think it is just the different RPMs. (remember, speed and terrain are fairly constant) I have, so far, tended to stick to the 28 or maybe 38 and rarely venture onto the 48. It seems to me that 90rpm in 48+21 is tougher then 28+12.

Anyone care to explain this to me? Or am I nuts? Or overthinking (again)?

Hope the no-doubt non-standard nomenclature is not too confusing.

Mr. Beanz

More than likley overthinking. It takes practice to acquire a high cadence. Keep trying th high cadence, go ahead, huff and puff, you will adapt as you increase your fitness level.

Some gears are repeats on today's cogs and chainrings. I have a chart that names the gear inches for each combo. Just an example, the 39/19 might be the same as the 30/14. I go with what is comfy for my style. On a flat trail, I hold about 20 mph inthe 39/14 combo rather easily.

One thing that helped was doing high cadence drills on a trainer. DO intervals, trying to hold 100+ for a minute at a time. I di one rainy season (rare in Cali) but when I returned to the outdoors, I was shocked by my cadence and new style.

One gets to know when the cadence is correct. After that, it doesn't matter what combo I use, I pay more attention to the effort and feel. I used a cadence function on my computer at one time. After a month, I figured it to be a waste. I wasn't aiming for a number, I was using what felt right for my legs.

Some might watch the screen and aim for 90+. Just seems like overthinking. I use my 39 ring very often. My friend has a cadence monitor but always points out that my cadence is higher than his 95. I just don't need a monitor to tell me I'm spinning.

djnzlab1

HI,
I found that we tend to be to hard on ourselves when we do less than expected and I tend to over train, I also forget that I am we bit older than I used to be , if I have a great day thats good If its windy and I stand on the pedals to do 15 MPH going home , thats a good work out too.
I ve noticed that heart rate can tell if your too tired on a ride, so if it races I slow down a bit. and let it recover I feel better too.
for me my target is 120 to 140, my catchup resting recovery is around 118.
If I am tired I hit 120 very quickly if I am having a really good day I can push 20 mph and barely make 120 so I pay attention to how I feel, I can sort of guess without even looking at the monitor based on my breathing and how I feel. If your legs are burning and your puffing a bit your pushing your limits..
I may leave the heart thing at home in the future, if you breathing to hard your working to hard.
If you can talk you probably in the green zone. If your building ,do intervals till your out of breath and then recover for a mile or two. each ride you'll find you can go farther faster if your getting enough rest.
doug

PS I too have done the Spinner on OFF days and find it help build that speed motor.
IF you spinning a bit on the bike I feel like its less effort to go fast than mashing pedals to go fast.
and you recover faster when your used to spinning versus mashing..

deraltekluge

Sounds reasonable to me.

Why? What are you trying to accomplish? What is your ultimate goal? RPM is not really a goal, though it might be a means to a goal.

StephenH

Sounds like overthinking to me. I'd say use whatever gear seems easiest to maintain a given speed. If you want more of a workout, go faster. I can't see a point to intentionally spinning faster at a lower speed just to get more of a workout.

Bill Kapaun

Some combinations shouldn't be used such as 28-11,12 & 14.
That's called cross chaining. Your chain operates at a very severe angle from the smallest ring to the smallest cog. Also from the largest ring to the largest cog.
This accelerates wear and can also be noisy.

80rpm: 28+11 or 48+18 or 38+14
equals L-8 or H-4 or M-6
M-6 is the straightest chainline.

90rpm: 48+21 or 28+12 38+16
equals H-3 or L-7 or M-5
M-5 is the straightest chainline. (near perfect)

100rpm: 28+14 or 38+18
equals L-6 or M-4
M-4 is the straightest chainline. (near perfect)
L low
M middle
H high

When on the middle ring, your chain theoretically lines up perfectly between cogs 4 & 5 on an 8 speed.

Bill Kapaun

And now another post on the less mechanical things-
IF you can "nearly" maintain 80, try to maintain 75ish for a week or so.
Building up cadence doesn't happen overnight. It's something that requires practice.

Another factor that affects cadence is crank length. If your cranks are longer than "ideal" for you, you simply can't reach as high of a cadence.
I have a "bad" R knee and was using 175MM cranks. Simply switching the 170's I had from another bike increased my cadence from about 62 to 75 immediately!
The 175's simply exceeded the range of motion for that knee. The 5MM difference actually works out to 10MM, since you raise the seat 5MM.
Which reminds me- IS your seat the correct height? IF it's too low, you have to bend the knee more, which will also slow you down and tend to put more strain on the knee .

eay

my cranks are 170 - I like them! Which is a good thing 'cause I'd have to change the whole chainring out to change the cranks.

Yep - my seat is the right height - I experimented quite a bit to find the right height - I notice that it is too low at the usual height if I wear shoes with thicker soles.

eay

a fount of info! thanks - this answers some questions I've had in the past

eay

One of my ultimate goals is better aerobic fitness, which I have seen improve over time through bicycling - in general, I'll get winded now before I run out of 'leg'. Used to be the opposite!

And I have noticed that, as my average mph has increased, it takes more effort to run out of breathing capacity. And I have been noticing how lovely it is to not mash my way up hills. And focussing on using a generally higher cadence has led to these results.

youcoming

First thing I would say is this. If you are concerned with your cadence then totally forget about your speed, that's right don't worry about speed, also don't over think your gearing. If you want to increaes your aerobic level do intervals it's all get the HR up then quickness to recovery. Cadence is a great thing for saving the knees and will definatly increase HR. If you can cruise along at 15mp with a cadence of 75 drop two gears, yes you'll be slower but your cadence should increase with less resistance on pedals. It will increase with time, as also stated a trainer can be a great thing. That's why it's called a trainer not a rider. I use to think anything over 115 was out of the question I now routinly see 190 on th ecadence monitor, can't keep it there for long but am working to 200, I can maintain 150 for awhile and quite comfortable at 110-115 for long periods. Keep at it and it will be of great benifit, especially when you move up to a roadbike and start spinning the hills.

youcoming

If you train at a lower speed with a higher cadence you will actually train your fast twitch muscles. This helps for as you get stronger your muscles will be accustomed to the high cadence. Plus spinning is not as hard on the knees as mashing gears to get more speed. I was coached on this by an old racer and it has paid huge benifit at least to me. Also read somewhere but can't remember that spinning fast in a low gear also trians your fast twitch muscles which will help in sprints or just catching the pack if required. Not a concern if you don't race such as myself but can help if you fall back from group and want to catch up.

Bill Kapaun

eay-
Is your riding mostly flat?
IF so, you might want to try more of a "road" cassette, It dispenses with the largest couple cogs and gives you more closely spaced "middle" cogs.
Here's some examples, although there are many more.-
https://aebike.com/page.cfm?PageID=30...id=3337&type=T

I've made up a 13-24.
13-14-15-16-17-19-21-24
I love it for my flat land riding. If the wind changes a little bit, I can shift up or down 1 tooth and keep my cadence "zeroed in". My 38/24 is low enough for a decent "take off" gear.
IF I were to run into hills, I've still got the small ring in reserve.

dygituljunky

I've found that it's easiest for me to forget about speed and just keep a do-able cadence and amount of pressure on the pedals. Even more, I find it good to just forget about the numbers altogether and just drive the bike (except for making sure I don't use the gear combos that make the chain not straight). (EDIT) I don't even bother counting my leg revolutions to monitor cadence, I just spin at a comfortable rate and pedal pressure.(/EDIT) I may not be moving very fast but I do keep moving.

Rather than thinking in terms of speed or the gear combination needed to get to a certain speed, I think in terms of just going as fast as I can with the power available (I'm in no danger of breaking the speed limit). My engine only has so much torque but I have a good bit of stamina.

In regards to the gear combination, just gear down to the gear necessary to go up that hill and gear up to the point that you're putting pressure on the pedals but not burning out your legs. Think about it this way: you supply the juice to the gears, the gears convert it to either high-speed/low-torque output for the downhills, low-speed/high-torque for the uphills, or something in between for flatter terrain.

I've become well accustomed to knee pain and any mashing of the pedals makes it worse. I've been quite pleasantly surprised to find out that spinning not only didn't make the knee pain worse, my knee pain is almost gone after the last intense-riding week. That's right, spinning out as many miles over the last four days as I used to mash in a month has made my knees nearly stop hurting.

Hope that helps.

Mr. Beanz

HUNH?!


You guy smust be some sensitve riders. I have 172's and 175's on different bikes and I can't tell a dern difference.....Bike geo yeah, but crank length?Pffft!

Bill Kapaun

I really believe that YOU can't tell the difference!

Other people can!

deraltekluge

Three millimeters is about an eighth of an inch. I wonder how many people could tell the difference in a double-blind test.

youcoming

Drop your seat 3mm and see how that feels, I can feel that.

deraltekluge

Can you feel a pea through 20 mattresses and 20 feather beds, too?

eay

Well, first I was going to say - no. But actually I can have flat if I want, but hills are the norm around here (foothills of the Sierra Nevadas in northern CA).
To get out of my neighborhood I have a choice of a simply awful hill or a only kind of awful hill. Demoralizing first thing when not warmed up!

When I was thinking so hard about cadence, I went down to a canal-side path a few towns away so I could have nearly flat terrain and no intersections or anything to slow me down

So I guess I have a choice, depending on where I want to ride.

I have thought about swapping out various parts of my bike but I want to find the limits of the bike, instead of the limits of me, before I starting getting crazy with the wrench.

Bill Kapaun

It depends on how "in tune" you are with your equipment!

One thing you are missing is that changing the crank length gives twice the difference as one would think.
%MM shorter crank means you raise the seat 5MM. The seat is now 10MM higher than the "up" pedal.

As I mentioned- SOME people can't tell. Others can! Just because YOU can't.....

https://www.bikeforums.net/fifty-plus-50/361045-your-cranks-too-long.html

Mr. Beanz

Hmmm, when I set my seat height, I measure from the pedal at the bottom (6'oclock). So if my crank arms were 172 or 175, I'd still set from the bottom, how would that compare to dropping the saddle after it's set?

Ranger63

I'll go with B: Overthinking
What's worked for years for me is to get out on the road and find what works for you.
There's a certain combination-and it's probably unique to each cyclist-that simply feels right to the legs and the body and ..the lungs.
Once you find that sweet spot you'll be able to inch up in speed as you condition yourself.
I'm willing to bet you'll be able to look at the cassette on your bike after a while and know what gears work just by the ones you see dirty.
If you give yourself a few miles warm up before the 'fast ride' you'll find you have a lot more left in the tank thruout the ride.

DieselDan

Here is plan C: Invest in clipless pedals and cycling shoes. Get double sided Shimano SPD or a similar knockoff version.

youcoming

Just putting it in a different way. I've only ever used 175mmcranks but I was having issues at the begining of last year and got otu the measuring stick and my fit papers and the only thing that had changed was my seat had came down 3mm. Pumped it back up and issue went away, maybe I'm just sensitve...lol