Anyone know of a cylclocomputer with cadence only? All I really need is a little readout for current cadence.

I guess I could build one, but that seems like a pain.

can't you just get one that has cadence and not hook up the speed sensor?

I've considered some of the general speed+cadence computers. But why get an expensive complicated widget, when there's a better simpler solution.

Whats wrong with having the speed?

I propose this...If you're having trouble finding it then there probably isn't a better simpler simpler solution. Perhaps you are stuck with the more complicated widget.

I thought about putting a comp on my fixie but I realized that there are no cables to run the wires on. This is one area where a wireless comp would make sense.

Something just seems wrong about putting a computer on a fixed gear bicycle. I went to put one on for a couple of days so I'd know exactly what distances I was doing and I couldn't do it. But that's me.

Tie a stick to your seat tube.

Count the number of times it smacks you in the shin per minute.

That's your cadence

i laughed so hard when i read that, it deserves some kind of award

Kevan wins the intarweb. I'm writing this one down.

Funniest thing for days.

You can get a cheapo speedometer, and you can calculate your speed for any given cadence since you're only running one gear. You can also figure out your cadence/speed factor and do a little math when you look at the computer (or make a little chart and tape it to your bars, until you memorize it or something).

Eitherway, you could get a pretty good idea of your cadence with just your basic speedometer

Or you could be really awesome and do some crazy math (well, not that crazy) and hope that the wheel circumference number goes high enough that using what you know about your gearing and your actual wheel circumference to set a speed-only computer to display your cadence. You'll amaze your friends with max speeds of 230 mph too.

That's a really great idea. My pre-coffee fuzzy brain seems to think that it may just be a matter of taking your actual wheel circumference and muliplying it by the number of revolutions your crankarm makes per wheel revolution. But then that would be a *smaller* number than the wheel circumference... to Sheldon!

Calculate your gear inches. That's your virtual wheel diameter and will give you cadence if you plug it into your computer

I knew it had to be simple.

Nah, that can't be right. If you multiply gear inches (unit: distance) by frequency of rotation (unit: inverse time), you still get a linear unit of speed of distance per unit time. I'm actually having too much trouble figuring this out myself for some reason. Perhaps I should use some paper and a calculator. If I get anything, I'll report back. Either way, I doubt any computer will allow a wheel circumference of 5742 mm (72 gear inches).

Actually... I think most cyclocomputers have a provision for 4 digits, given that a 700x23 wheel/tire combo is around 2000 mm in circumference. The only thing I don't know is how large the thousands digit would go... I don't see why they wouldn't make it 0-9...

Cant you just use a watch?

Pick a time on the watch to count easily up to 10 seconds.
Count your pedal strokes like every time the left foot is down full up to the 10 seconds
Then multiply that number by 6 to get the revs per minute.

Here's a way to do it assuming you computer will handle this.

Go to Sheldon Brown's Gear Calculator, put in your wheel size and gear ratio and find your speed at 100 rpms. Now divide 100 by your speed to get the ratio of mph:rpm. Call this number R.

Now either calculate your wheel circumference (I have 700c x 25 tires, so C = 3.14(622+25+25) = 2110.08mm) or look it up on a chart.

Instead of entering your circumference into the computer enter your circumference * R.
For me, this number would be 2110.08 * 4.1667 = 8792.

If you computer will accept that massive number, this should work.

Yes, but for each unit distance, your crank turns once. For a fixed gear you can calculate cadence based on velocity as it's a fixed relationship. What we're doing here is putting in your gear inches so that relationship is 1:1. (By the way, conversely if you start counting cadence you can calculate that speed thath you're so worried about knowing... Look out!

Well that's the real kicker. If you can't, you could do something simple like divide your circumference by 10. Then you'd get readings like 7,8,9 that would correspond to 70,80,90 rpm. Simple enough.

The Vetta V100 has separate wireless sensors for speed & cadence - don't want speed then don't put the sensor on. I have the V100 on my track bike and like knowing my cadence & speed, fashion faux pas and all.

I have a dorkier method:

I sort of have 60bpm (or rpm in this case) programmed into my head, so assume quarter note = 60 rpm, 90 rpm is just a compound time signature (3 against 4). 120 rpm is just an eighth note. My system doesn't work well for other cadences, though.

I'm just thinking about how ridiculously many miles you would log if you managed to set a speed-only computer up to read cadence. Then you could really show those roadies...

What's the point of having cadence on a fixie anyway? Once you know exactly how fast you're pedaling, what are you going to do if it's not ideal?

Edit: Ooh! I just had the least complicated idea yet. Since speed is frequency * circumference, just make your circumference somehow read one mile (you know...160934.4 cm...), and put your magnet on the crank and sensor on the chainstay just like a regular cadence computer. Again, you'll need some sort of ridiculous computer to take careo f that six digit number for you...

Gear down/up.