# Cateve Odometer

#### losse

##### New Member
Hi guys
Do you find your odometer/computer gives innacurate readings? I did a distance with my bike and then I did it with my car and my car gave a reading of 17.8 km and my bike gave a reading of 18.3 k. That's a difference of 500 meters or 2%... That could really add up if you go longer distance...

Is that an error that has to be accepted with all cateyes or do I have the settings wrong?

My wheel is 26inches and I set up the cateye with 26inches as well...

Thanks

#### eric_the_red

##### New Member
losse said:
Hi guys
Do you find your odometer/computer gives innacurate readings? I did a distance with my bike and then I did it with my car and my car gave a reading of 17.8 km and my bike gave a reading of 18.3 k. That's a difference of 500 meters or 2%... That could really add up if you go longer distance...

Is that an error that has to be accepted with all cateyes or do I have the settings wrong?

My wheel is 26inches and I set up the cateye with 26inches as well...

Thanks
More likely your car is wrong. But if you realy want to set the Cateye exactly measure the circumference of you bike wheel and input that number, instead of using the number from the instructions.

#### bernmart

##### New Member
eric_the_red said:
More likely your car is wrong. But if you realy want to set the Cateye exactly measure the circumference of you bike wheel and input that number, instead of using the number from the instructions.

I checked my Cateye against my car odometer, and they agree with a difference of .5%. But the point's well taken; the entry codes are nominal for tire size, and only careful measurement of the circumference will give exact results.

#### losse

##### New Member
But doesn't it also matter where on your spoke you put the sensor? For example, wouldn't the speed/distance be different is your set the computer for, say, 26" tires but you put the sensor 10 inches from the hub versus putting the sensor 5 inches from the hub?

#### 531Aussie

##### Well-Known Member
the only good way to get accuracy is to do a long roll-out while on the bike.

I do mine on the local velodrome for at least one lap, or (usually) 1km

A running track would also work, or any track that has the distance clearly marked.

I set my Catey Mity 2 at 208 for my 700cc wheels

##### New Member
They're both right. The difference is when you're going round corners and so on. Your car needs a bit more room than your bike, longer turning circles and other scientific stuff.

#### losse

##### New Member
I think what I'll do is keep changing the settings until I come as close to my car odometer as possible. I take it that the folks at Toyota did a lot more research into their odometers as the people at Cateye.

#### eric_the_red

##### New Member
losse said:
But doesn't it also matter where on your spoke you put the sensor? For example, wouldn't the speed/distance be different is your set the computer for, say, 26" tires but you put the sensor 10 inches from the hub versus putting the sensor 5 inches from the hub?

Distance from the hub doesn't matter, the sensor just records the number of times the wheel goes round in a fixed time period. The circumference of the wheel is always the same therefore the distance travelled in x revolutions is the same.

#### eric_the_red

##### New Member
losse said:
I think what I'll do is keep changing the settings until I come as close to my car odometer as possible. I take it that the folks at Toyota did a lot more research into their odometers as the people at Cateye.

Yes Toyota probably did a lot of research but there's a lot of variables involved. If you tires are a bit below recommended pressure, or if you've replaced the tires, then the speedometer could be inaccurate. I've checked both our vehicles, a Toyota and a Mazda, with my GPS and one speedometer is 3% slow and the other is 1% fast.

I still say I can get more accurate results with my Cateye, mostly because it can be adjusted to suit each individual bike.

#### str8shooter

##### New Member
I'm using a Cat Eye Astrale 8 on my bike. Riding one of the measured local bike paths here marked at 5.2 miles I zeroed the trip odometer at the start. When I reached the end of the path my odometer read 5.201. Mine seems to be real accurate basing it on that ride.

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