[Yak] Cordless computer problems and Bike Fridays

[Brian Zupke]

Briar and Neil Whitehead wrote:

> Greetings yakkers!
> 
> Anyone had any problems with cordless computers on BF's? I'm having 

The only time I've had trouble with the wireless on my BF is when I've 
been near power lines - the readings sometimes went wacko.

> went perfectly for a month, then began playing up. Went to the LBS and 
> piece by piece we changed all the components - the transmitter, the 
> computer (first of all the batteries in both), trialling each time we 
> made a change. The problem continued with every configuration. The only 
> difference was it reset earlier - at 14kph. The guys at the LBS are 
> shrugging their shoulders and concluding that the BF's small wheels are 
> the problem. ie the magnet on the spokes whizzes by the 
> detector/transmitter so fast that there is no time for the computer to 
> register the data before it receives the next lot. 

If you think about this, I don't think it makes much sense.  Most bikes 
have the sensor fairly high up on the forks, towards the rim of the 
wheel.  At a given speed, the rim of the wheel is going to travel by a 
fixed point at the same rate of speed.  So a magnet near the rim is 
going to be passing the sensor at the same or similar rate.

Overload in other
> words. On that basis we shifted the detector/transmitter down the fork 
> of the front wheel as close as we could get it to the hub where the 
> spokes move past slower. The only difference that made was to raise the 
> resetting speed to 29kph. Otherwise it's behaving the same... Seems to 
> indicate a wheel size problem?

The problem might be with the distance between the transmitter and the 
computer.  Because of the smaller wheels, the transmitter is further 
away from the computer since the handle bars are going to be positioned 
as if the bike was a full-size frame with a bigger wheel.  I've had this 
problem on my Birdy folding bike - I had to mount the computer on the 
cables - while I wasn't able to easily monitor my current speed, I was 
able to keep track of my distance ridden.  Have you tried setting the 
computer closer to the transmitter and see if this has any impact to its 
behavior?  Try holding the computer just above the wheel and move the 
magnet and sensor closer to the rim.  If you find that the computer 
behaves properly at all speeds, then the problem is likely that the 
signal is too weak with the computer being mounted on the handlebars.

> I asked, How come it went perfectly for a month? (Nothing changed on the 
> bike before the trouble started, except I lowered the angle of the seat 
> by one click) They say it was probably because the battery was highly 
> charged at that point.

This supports the weak signal theory.

> The cordless is sensitive to temperature but we've been using it well 
> inside specification range.
> We wondered about changing to the non-remote but aren't sure that's 
> going to work any better if the wheel size is the main problem.

The only problem you may encounter with going with a wired computer is 
something happening to the wire when you fold or pack your bike.  It 
will work fine with the smaller wheels (providing you get a long enough 
wire to reach the handlebars).

> We are touring on these bikes in 2 weeks for 3  months - and we want 
> this thing to work.
> 
> Any ideas guys?

If it turns out to be the distance, you have four possible solutions:

1. Some wireless sensors have a switch to boost the signal (at the 
expense of increased battery drain)
2. Mount the computer closer to the wheel.
3. Get a different wireless computer that supports a longer distance 
between the sensor and the computer
4. Get a wired computer with a longer wire

Hope this helps.

-Brian

> 
> Thanks
> 
> Briar
> 
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