rem002

Hi all, for some reason my bike computer doesn't work when I first start out in the morning. It reads 0 mph the entire, short ride to work. Once I get there and stop, it starts working. Is there something weird going on with the unit? Or is it some crazy electromagnetic force in my garage? Any thoughts are appreciated.

Thanks

alcjphil

What sort of bike computer are you asking about? Is it wired? Wireless? Does it use GPS? Not knowing what sort of sensor it uses to determine speed makes any answer a guessing game

Barry2 

"Thoughts"...
I think you should tell us the brand and model of the bike computer!

Iride01 

If its a very old GPS type cyclometer, and you are turning it on as soon as you start riding, then maybe it's not getting a satellite lock until you get to work. My first GPS cyclometer, I turned on about 5 to 10 minutes before starting my ride while I was going about doing other stuff, like airing up tires, filling my bottles and etc.

Though soon after my first GPS, they started getting better and faster at obtaining a lock on the satellites. However one of my old handhelds will take a very long time to get a lock if I'm moving. If I can be still for five or ten minutes and let it get a lock, It's then one of my most accurate for my track.

But like others ask.... what do you have?

alcjphil

This is a pretty good guess. My older Garmin Edge 500 computer takes a lot longer to get a satellite lock than my newer Edge 820

rem002

WOW!!! You all are amazing and yeah...I guess makes and models are important. Sorry. As a rookie, they won't let me show a pic but it is a standard bicycle speedometer, waterproof and wireless bike computer from amazon. It's on the kastewil.com site. Cost about $20. I like that idea of the satellite issue and will try that out tomorrow. Thanks so much

Iride01 

This thing?


https://www.amazon.com/Speedometer-W...3373623&sr=8-3

I don't think that has a gps. But I didn't read the full description. Probably just a poorly adjusted wheel sensor or just the life expectancy exceeded considering the cost of it.

rem002

Yes, that's the one. Yeah, I thought it was the sensor etc but without touching anything, it works after I get to work. Only a 15 min ride.

Iride01 

It's really a question for the Electronics, Lighting, & Gadgets sub-forum IMO, but probably most of those that view that sub-forum also view this sub-forum. Though some are more active in it than here.

Is there a magnet located on one of the wheels and a sensor on the fork or stay that the magent passes by. A non-gps device will have to have one. Many are wired. Perhaps that needs a battery or aligned better with the magnet.

I don't know if this would use a wireless sensor or not. It does say wireless in the title, but wireless what? I don't like to read the descriptions on such things from sellers on Amazon as there are more meaningless words than helpful words. Most is just for fluff.

So maybe someone else will care to do that or actually knows.

pdlamb

Weird. I'd start by cleaning the contacts on the head unit.

alcjphil

It is a wireless computer. There are no external contacts on the head unit

Bob Ross

fwiw I owned a couple of different relatively simple CatEye wireless cyclometers 10-15 years ago, and they were all susceptible to interference from high tension power lines, such that they would completely stop working for several miles when I rode near those towers. Just in case OP's commute happens to take him near such a scenario, there's a plausible explanation.

ClydeClydeson

Wheel-sensor based computers are sensitive to the amount of clearance between the magnet mounted on the wheel and the sensor mounted on the fork. The magnet needs to get very close but not touch the sensor when it comes around.

Wireless computers are also sensitive to the relative position of the sensor/transmitter on the fork, and the head unit. You may have to adjust the angle of the transmitter or the position of the transmitter or head unit to get reliable function, but you also need to keep the clearance between the sensor/transmitter and the magnet very close.

These two set-up based details are commonly the cause of unreliable bike odometers. There are also batteries in the head unit and in the sensor/transmitter that might require replacement. Sometimes these units will sit in a warehouse for years before being sold, so the battery might be going flat.

Crankycrank

Also check for corrosion where the batteries in the computer and sensor are. It won't necessarily be obvious so just wipe off the battery and contacts and as mentioned could be a bad battery. This can cause it to work erratically.

rem002

Thanks for the responses. I really appreciate it. Today, I reset and prepped for my ride 15 mins early, just to try and get the computer working and it read my speed and distance perfectly. I guess it just needs some time to wake up. Totally stupid but I guess I can live with it. This is the second computer that this has happened to so I don't think it is so much the product as it is to the aura of my house. haha. thanks again for your help.

vane171

I bought XOSS wireless bike computer and in the manual it says that it takes several minutes to lock on GPS. I didn't measure the time it takes, probably also depends if you start moving the bike before it locks.

But I get speed reading from a sensor, only elevation comes from GPS and that is something one might look at only after the ride. It probably also does some route tracking but that probably would require offloading the data to desktop computer and normally I use my phone for that. I slip the phone into my pocket when I go out on bike and after ride I can see the route and all those other data.
Just do as advised above, switch it on five minutes before you start the ride. Or get a job much farther away so the time for your device to lock on GPS becomes progressively more negligible the longer the distance you have to ride...

Crankycrank

It just dawned on me that OP may be running a headlight along with the computer which can fecker up the function of some less expensive computers especially if the light is in a blinking mode. If no headlight ignore and.....carry on.