Tandem Computer how do ya'll do it?
 

I have a few computers laying around and at first I was thinking of just having a computer in the stoker position because there are already wires in place.(Cadence also)

But I would like to have the info as well.

Here's my thought....

I'm planning to put a Vetta C20 in the captains position, and wiring a C10 or C15 in the stokers. The wifey doesn't care about cadence...

I will splice the speed sensor wires together, and only I will have a cadence reading, anybody else done something like this or have any ideas?

Will this at all affect battery life or harm the computers in any way?

Thanks.

Wires? What are wires?

I run Garmin Edge up front and I have a wired computer for my stoker. I wouldn't assume one sensor battery would be able to drive two computers.

I didn't know whether the signal of a wireless computer would reach the stoker handlebars from either wheel. The instructions for most of them say that the two parts should be less than 18 inches apart.

I did have to splice an extra length of wire so the stoker computer would reach the rear wheel. I soldered it and used heat-shrink wrapped sleeves to weather proof it.

Just put a Bontrager Node 1 wireless on for Stoker. Uses a digital signal that will reach to the captains bars. Have not installed a cadence sensor at this time, just speed so far. Looks like I can setup one sensor and use the pairing function to link both captains and stokers computers.

I too have a Garmin Edge, and after doing some reasearch found that the only non-Garmin computer that will read from the Garmin ANT+ cadence/speed sensor is Bontrager's $75 Node 1 and $140 full-featured Node 2, reviewed here

I purchased a Node 2 at my LBS for $129. In addition to the Node 1's usual speed/cadence function, it has an altimeter, heart rate monitor, and most importantly, Grade%. Essentially it has everything a Garmin has, save GPS (with the addition of temperature, which is handy).

A team starting wireless from scratch, that wanted to keep their Garmin options open, could get two Node's operating off the same sensor, and when they eventually get a Garmin simply substitute for one of the Nodes.

No wires:

http://farm5.static.flickr.com/4133/...bbeacfb546.jpg
Detail

http://farm5.static.flickr.com/4147/...99965bcf9e.jpg
Stoker's view

http://farm5.static.flickr.com/4085/...456f7df9_m.jpg http://farm5.static.flickr.com/4088/...463f7c06_m.jpg
Garmin ANT+ Cadence/Speed Sensor.........Side view

I think I remember having some in the past, but it must have been a long time ago. I use a Garmin Edge 705 up front and stoker has an eTrek Legend.

Look at the bikes in my sig line.... I got to have my wires....


I'm really only worried the two computers won't run off one speed sensor.

I need to lengthen the wires on the stoker set anyway so it won't hurt to splice it again if it doesn't work.

We have been running the etrex up front. With our recent switch to a Sigma ROX 9.0 the GPS may be installed on the frame water bottle mount and used for emergency know where you are and GPS calculated (non barometric) amount of climbing.

Our navigation skills from route sheets has been less than awesome. A lot has to do with mileage differences from the master computer (car) or internet maps. We have always struggled with no easy way to do rapid resets for point to point distance on a route sheet, or had any luck with going off total mileage on the sheet compared to the bikes computer.

After a bunch of looking around, I could not find a bicycle computer that was easy to read without glasses and had the ability to do a single button reset.

Going back to my off-road moto fun, I convinced myself we needed an ICO checkmate enduro computer. Yes it's big and heavy compared to a cycling computer. But along with a whole bunch of racer data info, and having a large display, you can do single button resets and it will also autocalibrate itself to the route sheet totals during a ride very easily. Until she learns more about all the unit can do, she can currently see speed, total distance and distance from last reset, and time from last reset, plus time of day.

LMAO...If she figures out it's other functions she can program our start row, and keep us on our minute for checkpoints.

Sebring rally is this coming weekend, we'll probably be 100 miles in on a 60 mile route by the time we finish.

PK

Garmin 800 up front 705 in back, problem solved!

You have given me the idea to run our garmin GPS60CSx at our stoker position, thanks.:thumb:

We had a pair of wireless for about a year. This was good because on a coupled bike it's one less thing to undo and redo. But I finally got fed up with the flakiness of the wireless systems. You get to have batteries both in the transmitter and the head, and if you lose signal is it because the sensor got bumped - and is no longer close enough to the magnet? or is it because the transmitter battery is getting a little weak? or perhaps the receiver battery is just weak enough that it's not picking up, even though it can drive the display. So I put a wired on the front, and we still have the original wireless on the back. Keep in mind that we ride year round (had to fix a broken chain yesterday at -10C), and batteries have less ability to produce power for a given charge level as the temperature drops.

Yes you can get cadence transmitted wirelessly to the stoker bars. In fact, the wheel magnet is further away, and it reaches. There is a smaller selection out there that will transmit with enough range to give cadence to the captain. Stoker says she no longer needs cadence.

Garmin 705 up front, 305 in back. At some point I'll move the 705 and get an 800 up front. The battery life on the 305 really doesn't permit running the backlight during the day. I use the backlight on the 705 almost full time to improve readability.

Cateye V2C wireless for captain and stoker. I have used this for a year with no problems - one sensor for speed and cadence on the chainstay works with both computers. The only issue is that it goes to sleep in about five minutes, so you have to be sure to wake it up after a stop.

I vote for a cyclometer on the stoker 'bars only. The stoker can thus contribute a bit more to the riding experience, and the team will have something else to talk about on every ride. Added bonus: You might actually find it liberating to ride without a cyclometer staring you in the face. I know I do!

Let take a shot at asking the question you actually asked...

Yes, I've spliced two computer heads into a single speed sensor wire. It worked, but was problematic since you create a single point failure for both computer heads, i.e., if your pick-up sensor or the wheel magnet get knocked out of alignment you loose both computers. You must also make sure the splices are sealed up so that no moisture can get in to the splices, so shrink wrap is a must. The computers don't know that they're running off the same signal wire, so no issues there. I believe the computers I spliced together were Trek and Sigma Sports models, with descent wire that could be soldered. Not all computer wires like to be spliced, so you'd need to Google on "slicing Vetta Computer wires" or something like that to be sure.

Ultimately, I ended up running pick-up wires for each computer off the front fork: ganged together on one fork so that one magnet would trip both of them. The stoker's wires ran down her boom, around my seat post and along the underside of my top tube, pretty much the same route that you'd use for a splice. On some tandems that don't have super-long stoker compartments you can usually run a rear-wheel sensor wire to the seat stay / brake block area along the underside of the stoker's top tube. I did an article with pictures on this technique about 11 years ago: http://www.thetandemlink.com/articles/bc1200.html

As others have noted, wireless is quickly becoming the range where cost is not a big consideration, noting several folks will have dual Garmin units, etc.. (ourselves included). However, wired-computers still dominate the landscape on many tandems, moreso that the small sampling here might suggest.

I have an old C20 that I have mounted up front. I mounted the speedo sensor on the front fork and the cadence on the bottom tube with a long cable tie. You could splice in another head without corrupting the signal, but I would just mount another harness on the rear and run the wire to the stoker bar in the conventional way-like on a single. This way, you have redundant systems and the old C20's (with their longer rear mount harness) can be found cheaply on ebay. I've had this old Vetta unit for 20 years and it just keeps on ticking!

You could buy these two units:

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

I think a couple well placed wires look a lot better than those ugly sending units with multiple batteries, I have old Vettas on all my bikes. And batteries last about a year or so. I think I have an old Avocet 40 laying around here too...

Geez, it is hardly polite to describe someone's sending unit as ugly! I do hope you aren't so candid with your with your descriptions on Pictures of happy tandem couples.


http://farm5.static.flickr.com/4085/...456f7df9_m.jpg

I didn't mean to offend I'm sure, you all may commence to admonish me for having ugly wires all over my frame! I have the preliminary fitting done, I just need to solder the speed sensor wires together, and then I have some stainless zipties to pretty it up once I'm done...

Captains View

http://img.photobucket.com/albums/v3...a/DSCF4434.jpg

Stokers View

http://img.photobucket.com/albums/v3...a/DSCF4433.jpg

Speed Sensor

http://img.photobucket.com/albums/v3...a/DSCF4429.jpg

Cadence Sensor

http://img.photobucket.com/albums/v3...a/DSCF4435.jpg

My wife and I run with two wireless VDO C2DS computers both linked to one wheel sensor mounted on the front forks. We have been very happy with this setup.

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