Anyone using a Cateye?

[FlandersZA]

When I bought my bike in late August last year, I wasn't even aware of Garmins or any of the other fancy gadgets cycling had on offer. I wanted a basic speedometer/odometer and so opted for a Cateye Velo wireless.

 

In the instructions, there is a list of wheel sizes to make calibration possible, unfortunately my exact tyre size was not there for whatever reason (my bike is a MTB 29er with Rocket Rons) so I had to input the outer circumference manually. The number I came up with after measuring was 232cm. It seemed correct since one of the other listed sizes in 29er was 233cm - 1cm difference.

 

Anyway, I soon noticed that the cateye was not calibrated that accurately since I started Strava-ing my rides with a handheld Garmin e-trex 10 I keep in my pack. The cateye over-read by about 1km per 25km. I didn't bother with re-calibrating it until now, after it was somehow reset this past weekend. I now have it dialled in very accurately after some painstaking measurements using GPS tracks.

 

On a ride of exactly 32.5km, the cateye now reads 32.52km - good enough for me. The weird thing is the measurement I used to get it there...222cm. According to the instruction manual in the box, if 222cm is used as a manual input, it would mean my wheel is: 42-622 28 x 1.60 (700 x 42C)

 

whereas in actual fact, it's: 57-622 29 x 2.25

 

I know it's accurate now. Speeds and avg. speed etc. as well as distance are spot on. How they get their numbers however, totally eludes me.

[mrbaker]

You lost me at ..."In the instructions..."

Edited May 29, 2014 by mrbaker

[PeterF]

Tyre pressure will have an impact on the wheel size. I measure mine by sitting on the bike on rolling it through 3 wheel revolutions, then dividing by 3. This gets it pretty acurate. My 29er with Maxxis Icons measures 2246mm.

[FlandersZA]

Tyre pressure will have an impact on the wheel size. I measure mine by sitting on the bike on rolling it through 3 wheel revolutions, then dividing by 3. This gets it pretty acurate. My 29er with Maxxis Icons measures 2246mm.

 

Ah ok, so my 222cm is in the neighbourhood after all. Pity I can't input mm - it's limited to cm. Thanks

[PeterF]

I have the Cateye V3 wireless with hrm and the wheel size is in mm so you can set it pretty accurately.

[FlandersZA]

That's a bonus! Mine is the Velo Wireless Plus.

[MAK]

Go and google "bicycle computer settings", it'll comeup with Sheldon Brown's page, with settings for every cycle computer and tire sizes. Then print it and keep it handy. Different makes have quite a variation for the same tire size.