A Misreading Cateye Bike Computer

Ged has a Cat eye bike computer which is giving him all the wrong readings and he wants to know what to do about it. He has a couple of options that he can take, so we go through them here

Question:

Hi
I have a Cat eye Strada computer that reads 3% too high. The distance has been checked on two maps and by a ciclspeed computer.

The wheel size is actually set to less than it should be so the situation is even worse.

I know that front lights can interfere but in the morning it is not on so it isn’t that.

Any ideas?

Thanks
Ged.

Hi Ged,

Yes, you are correct front light can sometimes make the Speedo miss read, but it sounds like you have discounted that one.

Option 1. Have you measured the wheel accurately? With the tire at the correct pressure roll the wheel out one revolution, the valve being the best place to start. The chart that comes with the computer can be a little out with its calculations.

Option 2. If the measurement is good then you need to set the wheel as slightly larger to compensate for the miss reading. Try to ride with a friend who has an accurate bike computer and compare speeds. You need to adjust your wheel size setting until you are both at the same speed.

Option 3. Throw the old Speedo away and spend some money on a new bike computer that works properly, there are lots to choose from, you could go for one with a pulse monitor so you can improve your fitness at the same time. You could also get a Speedo that works from GPS, this is the most modern and effective way to record speed, distance and all the other important details you need.

7 Responses to “A Misreading Cateye Bike Computer”

Rich McCarthy August 17, 2009

Sam is right on the money with the “settings via the instruction booklet often need tweaking”I went thru 5 re-dos on my sigma before getting it dialed in correctly. And the setting I wound up using wasn’t one listed in the booklet.

Ernie August 17, 2009

My method for measuring the distance of 1 wheel revolution is to cut three pieces of masking tape so there is a point at one end. I tape one piece to the garage floor, tape one piece to the tire sidewall, and align the two points to meet exactly. I lay a straight stick on the floor and while sitting on the bike, roll forward until the wheel has gone through one revolution and the tape is again pointing straight down. I get off the bike and put the third piece of tape on the garage floor to point at the tape on the tire sidewall. Measuring between the 1st and 3rd tape points, I then set the cyclometer. I’ve set two cyclometers this way, resetting if I change tire sizes. My two cyclometers are close to dead-on accurate.

Wayne August 17, 2009

Wireless or non- wireless ? Check battery in censor on fork. My wireless computer goes wild when the front light is on , even madder when on flashing mode.Check that the censor is close to the wheel but not too close to be dangerous !!!One computer I had will not cancel after having been subjected to 3 hours of my light in flash mode

Robert August 17, 2009

I have to say the absolute best cyclo-computer is the Garmin Edge. The benefits over an old style cyclocomputer are exponential. Spend a little more money for tons more benefits and features!!

jez August 17, 2009

If you go for a new cyclo-computer, in my experience I’ve had a lot of problems with wireless units whereby readings have clearly been “interfered” with due to a temporarily dodgie signal. This happens from time to time with a Polar CS100 I have on one bike (this comes, by the way with user “unfriendly” instructions and such small print that mega eyesight is required). I’ve also had experience of the SIGMA wireless units which also I wouldn’t recommend as they seem to have a very finite life span of between 9 – 12 months and then caput. GPS would seem to be your best option although currently a bit expensive. However, if you have a DECATHLON near you, they do a GPS unit which does speed, distance, average speed, max speed etc for around 90,00 GBP. I have one and it seems to work quite well and you can download your data to your computer also. It comes with user friendly instructions also.

Clinton Slayton August 17, 2009

I have tried several and have settled on wireless VETTAs.PROS: VETTA has a good spare parts catalog online, a major plus. Buttons are fairly easy to manipulate while wearing full gloves.CON: finicky about restarting (does not awake from “sleep” when the tires roll again) and use Euro cable ties, thinner than the standard ties that are generally available. See below. Measuring the mounted tire is the only way to get accuracy. I have had more problems with cold weather affecting the (two types) of batteries than with anything else.

h August 17, 2009

for other readers, try changing the batteries in your front lights. I had no interference for a long time then it would read double if the light was on. Replacing the light batteries fixed this.