what speedo/odometer/computer thingy?

[2seas]

Can those in the know please recommend me a accurate, reliable and reasonably priced bicycle computer thingy?

It should be able to tell me riding time, distance and be waterproof. How accurate are these things?

cheers

[itsnotarace]

I use a Cateye Micro Wireless

It's pretty accurate, although the distance and top speed recorded does vary by a bit compared to my iphone cyclemeter GPS app (Cateye over-reads). I suspect it may be due to the distance down the spokes that I have the sensor mounted

The only thing is that I have bought a turbo trainer and mounted the sensor to the back wheel and the distance is too far to keep the unit mounted on the stem as it was, I need to think of a solution - or buy a new computer lol

[2seas]

interesting - my search through amazon reviews seems to pick out this as the best buy:

http://cgi.ebay.co.uk/CAT-EYE-STRADA-WIRELESS-CC-R...

which i think is what you're talking about..

[itsnotarace]

Mine is this one

http://www.wiggle.co.uk/p/cycle/7/Cateye_Micro_Wir...

[Raven Flyer]

itsnotarace said:

I use a Cateye Micro Wireless

It's pretty accurate, although the distance and top speed recorded does vary by a bit compared to my iphone cyclemeter GPS app (Cateye over-reads). I suspect it may be due to the distance down the spokes that I have the sensor mounted

The only thing is that I have bought a turbo trainer and mounted the sensor to the back wheel and the distance is too far to keep the unit mounted on the stem as it was, I need to think of a solution - or buy a new computer lol

Cateye Strada is an excellent unit.

Er... does putting the sensor further down the spoke induce wheel spin? If not, its position along the spoke cannot make the wheel turn faster than the ground. That said, Cyclemeter is the single most useless app I have on my iPhone. Rubbish use of the GPS chip, rubbish maps and wildly inaccurate and speed, to 100ths of a mph... updated every 2-3 seconds!!

If you have set the wheel size correctly on your Cateye, I would believe that over Cyclemeter.

I bought Cyclemeter because of the reviews on here and BR. This is a screen shot from my one and only ride with Cyclemeter. I could have bought a nice pint of beer with that £2.99.




I will be sticking to the vastly superior Motion X in future.

[bikemonster]

itsnotarace said:

I use a Cateye Micro Wireless

It's pretty accurate, although the distance and top speed recorded does vary by a bit compared to my iphone cyclemeter GPS app (Cateye over-reads). I suspect it may be due to the distance down the spokes that I have the sensor mounted

That might be true...if different parts of the spokes went past the sensor a different number of times for every revolution of the wheel.

Somewhere in the Cateye's brain is a number, which is the number of mm that you cover for every revolution of the wheel. If you're over-reading, reduce the value of this number to get it right.

[itsnotarace]

No but if the sensor is mounted further towards the hub it will be rotating fractionally faster, won't it. My wheel type is set correctly.

GPS is not 100% reliable - trees / buildings can all interfere with the signal so you do get the odd erranous reading. I find that uploading the Cyclemeter GPX output into Ridewithgps.com - the latter allows you to update the elevations and at the same time it smooths out any unexpected blips from the speed

[neilski]

itsnotarace said:

No but if the sensor is mounted further towards the hub it will be rotating fractionally faster, won't it. My wheel type is set correctly.

No. The magnet on the spoke it will only pass the sensor on the fork once for each revolution of the wheel regardless of whe whether it's placed by the hub, rim or anywhere in between.

[bikemonster]

itsnotarace said:

No but if the sensor is mounted further towards the hub it will be rotating fractionally faster, won't it. My wheel type is set correctly.

No - closer to the hub means the magnet is moving slower as it has less distance to cover every revolution. Closer to the rim means the magnet is moving faster, although obviously still once past the sensor for every revolution. For this reason, closer to the hub is better.

Your wheel type may be set correctly, but I have always found that the number given is a rough approximation. Different manufacturers' 700x23C tyres will have slightly different rolling diameters.

[itsnotarace]

If the sensor was mounted close to the hub, the distance the sensor travels to complete one full revolution will be less. If it was mounted right by the rim, the distance the sensor travels to complete one full revolution will be further.

No?

[angusc43]

itsnotarace said:

If the sensor was mounted close to the hub, the distance the sensor travels to complete one full revolution will be less. If it was mounted right by the rim, the distance the sensor travels to complete one full revolution will be further.

No?

Yeah but it works by counting the number of revolutions and multiplying that by the circumference of the wheel/tyre combo.

There's a series of set-up options where you enter your wheel size and tyre width - this calculates (or estimates anyway) the circumference.

[neilski]

itsnotarace said:

If the sensor was mounted close to the hub, the distance the sensor travels to complete one full revolution will be less. If it was mounted right by the rim, the distance the sensor travels to complete one full revolution will be further.

No?

While that's true, it's completely irrelevant as it doesn't calculate speed by how fast the magnet passes the sensor, it calculates it by counting the number of times it passes per second which is the same regardless of whether the sensor is by the hub or the rim.

ETA: To explain a bit better, imagine a straight blade fork. The whole of the spoke passes the fork at the same time so it doesn't matter whether the magnet & sensor are both at the top of the fork or near the hub, the time taken between readings will be the same for each complete revolution of the wheel.

Edited by neilski on Friday 1st October 15:08

[john_p]

PistonHeads...angular velocity matters!

[Mr Will]

neilski said:

itsnotarace said:

If the sensor was mounted close to the hub, the distance the sensor travels to complete one full revolution will be less. If it was mounted right by the rim, the distance the sensor travels to complete one full revolution will be further.

No?

While that's true, it's completely irrelevant as it doesn't calculate speed by how fast the magnet passes the sensor, it calculates it by counting the number of times it passes per second which is the same regardless of whether the sensor is by the hub or the rim.

ETA: To explain a bit better, imagine a straight blade fork. The whole of the spoke passes the fork at the same time so it doesn't matter whether the magnet & sensor are both at the top of the fork or near the hub, the time taken between readings will be the same for each complete revolution of the wheel.

And just to confuse things a bit further, the magnet's speed will vary between 0mph and twice the speed that the bike is travelling at through-out each wheel rotation

It also never moves backwards, only up, down and forward at varying speeds.

[2seas]

so 1 vote for the cateye then...

Edited by 2seas on Friday 1st October 15:42

[Mr Will]

2seas said:

so 1 vote for the cateye then...

Edited by 2seas on Friday 1st October 15:42

I have the same cateye as itsnotarace and I'm happy with it. I am finding myself regretting not getting one that does cadence as well though.

[walm]

I have the strada too and it works great. Slightly smaller than I was expecting - mounted on my road bike stem and is thinner than that.
The only thing is that it doesn't have a light (as far as I could find).
That micro one does have a light.

Now I am annoyed I have the strada. Damn.

[Rich_W]

Mr Will said:

2seas said:

so 1 vote for the cateye then...

Edited by 2seas on Friday 1st October 15:42

I have the same cateye as itsnotarace and I'm happy with it. I am finding myself regretting not getting one that does cadence as well though.

I have the Cadence one (Double wireless) and tbh, after one ride, it's a wasted gimick. It doesn't give average cadence over a ride. Just "real time" and all it proved was that I spin somewhere between 75 and 110ish on the handful of times I can spare to look down at it. Having a PHd in Hindsight I'd say go for the basic one. I will add that the Cateye's are not the easiest thing to set up as the instructions aren't great.