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-   -   Simplest Cyclometer possible, Only want my RPMs need as basic as it gets (http://www.bikeforums.net/electronics-lighting-gadgets/696333-simplest-cyclometer-possible-only-want-my-rpms-need-basic-gets.html)

GoUSF 11-19-10 06:07 PM

Simplest Cyclometer possible, Only want my RPMs need as basic as it gets
 
Anyone got any ideas, I dont need any other information as I have a GPS that will tell me all my heart rate speed distance what not, I just need a way to track my RPM's.

anyone got any insight?

BarracksSi 11-19-10 06:46 PM

http://www.cateye.com/en/product_detail/407

Cateye Strada Cadence. That's what I'd get now if I wanted another computer. Wired so there's no interference (which was a problem with a wireless Strada and some headlights) and longer battery life (which is what annoyed me about a Blackburn Neuro).

I'm probably going to keep my Shimano Flight Deck, though, because it calculates cadence even while coasting, which is handy (even if unnecessary) when I'm on a downhill and want to start pedaling again.

GoUSF 11-19-10 11:02 PM

Ok dumb question, what on there is the RPM? Cadence? Speed? Im confused I just want something up on my bars to say if im in the 70 RPM range or not

CaptainCool 11-20-10 02:17 AM

Pedal RPM is cadence.

If you can't find a basic bike computer that does cadence, you can buy one that doesn't, mount the sensor and magnet at the crank, and use a calibration number that will return RPM in place of speed. http://www.63xc.com/martink/cadence.htm

kevrider 02-27-11 09:56 PM

^^ only gonna work with a fixie/ss.

ItsJustMe 02-28-11 07:10 AM

No, that should work regardless. He wants cadence. If he puts the magnet and sensor on the crank, it'll read a variation on cadence regardless of how fast the bike is going.

Assuming it's set to KPH. The wheel diameter setting is in millimeters on every computer I've seen. He wants a per minute reading. The comp is trying to deliver a per hour reading. So what you want is a setting that returns 70 kph when he's turning 70 RPM.

To make it think you're going 70 KPH at 70 RPM, obviously you have to make it think that it's attached to a tire that will go 70 KM when it turns over 70 * 60=4200 times. That means a wheel that's 16.667 meters in circumference. OK, that's not going to work, no bike comp can take 16,667 as a circumference.

So divide by 10, put in 1667 as the wheel circumference (this is very close to a 20" tire). It'll say 7.0 KPH when you're going 70 RPM.

This is actually a very clever thought by CaptainCool. It means you can pick up the crappiest $8 computer at Wal*Mart and use it as a cadence readout.

Leisesturm 03-04-11 02:49 PM

Shall file this under bikeforums comes through yet again. :thumb:

Looigi 03-04-11 03:07 PM

Get a Garmin Edge 800 with GSC10 and set the display to read only cadence. No information superfluous to your purposes will be displayed.


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