VDO C3 computer problems



cyclespeugeot

New Member
Aug 29, 2007
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Anyone using one of these? I bought one with my new bike and it's driving me crazy. It cost a lot of money (well, AUS$140), and I thought I was buying the best quality I could. Instead I have a cycle computer that works when it feels like it. It is a remote head wireless type, I have checked the sensor gap -seems all within spec, the computer body has a small cylindrical shape extruded in the back of the casing, that may be the sensor reading point (I don't know because the instructions are useless) and that can be obscured by the STI shifter cable at the handle bar. I tried tilting the body forward slightly so this point would have a clear view of the sensor and that worked for a while. But now it is back to its intermittant ways, regardless of position. Very frustrating, as I bought this computer with my new bike in the hope it would be a like an odometer. So far it's recorded about 85 percent of my rides...Great.

It never reads a change in speed without a 2 or 3 sec delay no matter what - maybe that's normal (not with my other cycle computers), but then when it's playing up it goes to zero, or sometimes it reads 199km/h. Often it doesn't like going over 20km/h, and decides it's too fast and stops working. Other times it'll stop mid ride, and just won't start working again. I have tried adjusting every which way, resetting the computer etc. It might work for a while, then suddenly doesn't. It seems to happen more often when the front wheel has been off, but then other times it's unrelated. Happens 10km into a ride.

Now I am no tech head, but I bought a wired BC-1 computer at Kmart, fitted it to a bike, got a Giant wireless for $90, fitted to another bike. Both recorded every turn of the wheel without fail. This VDO was fitted by the bike shop, but I can't see that they've done anything wrong with the install.

Aside from throwing the VDO in the bin and installing the Giant computer from my other bike, does anyone have any suggestions? VDO is well known in the auto industry, so are they just incompetant making cycle computers? I will take it back to the bike shop, but if it recovers itself and works, then the bike shop isn't really going to be able to do anything, are they?
 
I've been using a VDO C4DS for more than a year now and there's been no problem. The key with these wireless is to make sure they don't have a somewhat flat battery. All the strange behaviours I've encountered with my unit have all been attributable to the battery. A set lasts me around 4 months.

Otherwise, take it back to the shop and get them to check it out. It's under warranty, right?
 
I bought it 6 weeks ago so it should be under warranty. I am taking it back to the bike shop, but I wanted to see if there was something I was missing.

That's a thought re: the battery, but geez 4 months doesn't sound very long to last - I thought 12 months minimum? Anyway, a battery fault could explain its erratic ways.

Does your C4DS take a few seconds to register a change in speed or is it pretty instantaneous?
 
cyclespeugeot said:
That's a thought re: the battery, but geez 4 months doesn't sound very long to last - I thought 12 months minimum? Anyway, a battery fault could explain its erratic ways.

Does your C4DS take a few seconds to register a change in speed or is it pretty instantaneous?
Not sure if it's instantaneous or not, but definitely not excessively delayed. Bear in mind, the digital read out is in 0.5km step, so you are not going to get x.2, x.4 kind of jumps and may fully or partly explain your perception of delay.

As for battery. Well, given it's a wireless unit that requires signal transmission, I'd be surprised any unit out there would give you a year's worth of riding unless a much bigger battery is used. A single CR2032 battery lasting 3-4 months isn't too bad.
 
cyclespeugeot said:
I bought it 6 weeks ago so it should be under warranty. I am taking it back to the bike shop, but I wanted to see if there was something I was missing.

That's a thought re: the battery, but geez 4 months doesn't sound very long to last - I thought 12 months minimum? Anyway, a battery fault could explain its erratic ways.

Does your C4DS take a few seconds to register a change in speed or is it pretty instantaneous?

Before you do anything, replace the battery. It's not uncommon for a battery to be dead right out of the package. There's no telling how long that battery has been in the package or in line to be put in a package.

I don't know if anyone but Duracell is putting sell by dates on their packages, but it is a good idea. I'm not pushing Duracell, but you do get a better idea, via the date, what kind of state the battery might be in.
 
sogood said:
Not sure if it's instantaneous or not, but definitely not excessively delayed. Bear in mind, the digital read out is in 0.5km step, so you are not going to get x.2, x.4 kind of jumps and may fully or partly explain your perception of delay.

As for battery. Well, given it's a wireless unit that requires signal transmission, I'd be surprised any unit out there would give you a year's worth of riding unless a much bigger battery is used. A single CR2032 battery lasting 3-4 months isn't too bad.
Well, I'm often doing 3.5km/h or 5km/h after I've stopped at some lights, with a foot out of the pedal and on the road and then looking at the speedo, so yeah, it's definitely not on the programme, so to speak. Works the other way too, when I'm flying down a hill but still only doing 25km/h, then I've 'suddenly' accelerated to 40km/h!

Anyway, most likely the batteries, so I'll get a couple fresh ones and let you know how I go....
 
cyclespeugeot said:
...when I'm flying down a hill but still only doing 25km/h, then I've 'suddenly' accelerated to 40km/h!
I can relate to that and certainly is within the realm of symptoms a flat battery can give. Good luck!