What use is a cadence sensor?

Donkeywings

Having spent a lot of money on a new Madone 3.1 and a Garmin 800, what little money I have left is burning a hole in my pocket. For £30 I can get a cadence sensor for the Garmin. What use could I make of this data?
cheers! :-)

cougie

Well it tells you how many rpm you pedal at.
It's not vital. Can you count ? Just count how many revs you do in 20 seconds and multiply by 3.

thegreatdivide

The sensor takes two readings - cadence from the non drive side crank and speed from the rear wheel. A standalone Garmin will give you speed calculated from GPS but I've found that the sensor combinded with the GPS data gives you a much more accurate reading. If you're riding under lots of trees the speed on a standalone unit can go a bit haywire too.

daviesee

It is of use if you are concerned with your cadence. Obviously

For example, I used to have really bad technique. I just got the bike into top gear as quick as possible and kept it there for as long as possible. The result being that I was mashing a big gear going quickly but would burn out before 50 miles.
Without the cadence sensor I kept reverting to mashing. Now I can keep track of my cadence, ride a smaller gear, higher rpm, same speed but can last over 100 miles.
Counting works but I'd rather just take a quick glance and enjoy the ride.

jordan_217

I use mine on the turbo trainer and that's it. Mainly becuase doing x mins at x rpm intervals stops me from putting my head inside my rotataing rear wheel out of boredom.

lambpie

There'll be 50% of people who say its a waste of time, why do you even need a computer, and the other half who love all the data and swear by it.
If you've gone to the expense of buying an 800 then you might as well use all the functionality and data - get the cadence sensor and a HRM strap and then do some reading on how to use them. When i bought mine (only a 500) i realised that i needed to up my cadence - now i'm targeting over 90 rpm when riding and selecting the gear to maintain my heart rate in the right sort of zone for the ride i'm doing. The results? I reckon by doing this i've added 1-2 mph to my speed overall by being more efficient with pedalling and managing my energy.... others might easily say i'm talking boll..ks but....

meesterbond

For what it's worth, I've use my 800 over two road bikes and I've only got one cadence sensor (at the moment). I've always had a tendancy to push bigger gears than I probably should, so having that number in front of me encourages me to spin. I do miss not having it on the other bike, so will be getting another at some point.

rolf_f

cougie wrote:

Well it tells you how many rpm you pedal at.
It's not vital. Can you count ? Just count how many revs you do in 20 seconds and multiply by 3.

Actually, this is exactly what I thought until I got a cadence sensor! If you think you'd benefit from increasing your cadence, counting is no substitute for a sensor. Even just having current cadence doesn't quite do the job. What I've found has really made the difference is having my computer display both current and average cadence. That has quickly increased my average from around 79 to 91-92 on my commutes.

Whether you think that is a useful achievement or not is something else but for me only the combination of those two parameters stops me from quickly drifting back to a grind.

Bar Shaker

I think it is the single most important piece of info a computer can give you.

lef

Bar Shaker wrote:

I think it is the single most important piece of info a computer can give you.

...if I had to choose I would want my computer to tell me heart rate and / or power over cadence. Cadence contains no info about effort, fatigue possibly.

MarkAshton

I find cadence useful if changing positions, but only for a little while

i.e. I recently started riding a TT bike. Was useful to see how my cadence varied between my road bikes.

Donkeywings

Thanks for all the replies guys - I ordered one.

northpole

Donkeywings, I hope you'll find it useful - I find it one of the best indicators, especially on a long ride, when I need to change gear. It really saps it out of you slogging away in a slightly too high gear on the flat or gentle slope. Cadence falling away is one of the quickest ways of spotting this - my mind can play tricks on me when tiredness sets in.

Peter

ReesA

One thing I really found interesting recently when trying to change my running style to a forefoot strike and use a barefoot running style was that this is also based on a cadence of 90 strikes per minute. Same as spinning in cycling.

rolf_f

lef wrote:

Bar Shaker wrote:

I think it is the single most important piece of info a computer can give you.

...if I had to choose I would want my computer to tell me heart rate and / or power over cadence. Cadence contains no info about effort, fatigue possibly.

Depends on how you look at it. I think an HRM is more useful when you are specifically training but when you are just riding a bike, cadence is more useful.

Donkeywings

Thanks to Amazon Prime it came next day, and is now installed. A few minutes of panic when I thought all it was doing was *recording* the cadence and not *displaying* it ... but you have to add the field to your screen. Sorted :-)

Now... please stop raining - this is supposed to be August :-(