Carbonfiberboy 

I have a set of 2003 9-speed Shimano Ultegra brifters with a Flight Deck on our tandem. The last couple of rides, the Flight Deck has been doing a weird thing. When I downshift the cassette, the Flight Deck responds appropriately, but after a few seconds it slips to the next larger cog and of course starts displaying a slower cadence. If I downshift from that display, it shows a double downshift. I upshift one cog to get back to the gear I want, which it shows, but then it slips up a cog again.

I ride in the rain a lot, so I thought water might be a problem. I put silicone dielectric compound on the head unit contacts, dried the shifter contacts with a heat gun, and squirted them with WD-40. Didn't do anything. Anybody have an idea? Right shifter just worn? I know they don't last forever, but I think this shifter has less than 10,000 miles on it. It doesn't rattle like they do when they're shot.

bikeman715

Is it just the display acting up or is the drivetrain shifting on it own ? If it the drivetrain I would check the rear derailleur's housing loop and replace it and adjust the derailleur as needed . Also check the derailleur's pulleys and the derailleur it self for wear . It could be the shifter if all else fail if so try spraying it with something like WD-40 follow by a light oil when dry and see if it help ,if not then replace the shifter.

Carbonfiberboy 

Drive train is not shifting, and it's not just the display acting up. The shifters are telling the head that the drivetrain has shifted, when in fact it has not. Yet the shifters work perfectly, cabling and housing is new in the last few hundred miles, etc.

bikeman715

have you check the wiring from the shifters to the head ? there might be a short and it picking up magnet charge from something else ?

Carbonfiberboy 

Haven't put a VOM on them, but it all looks fine. I kind of hate to take the wiring harness apart because it's so delicate. I was hoping someone would know something about how the shifter communicated and would know what the problem might be.

bikeman715

yes it is very delicate and easy to break . other than trouble shooting it there no replacement parts , unless you know of a LBS than have some in a bin for parts , it best just to replace the shifter .

Kimmo

Actually, there are zillions of unused Flight Deck sensors. The problem is, they're buried inside other STIs... and that's not the worst of it.

I've overhauled quite a few sets of STIs, and 9s models are harder than 8s models... and 9s models that include the sensor are an epic PITA.

My uncle gave me a tired pair of ST-7700s with Flight Deck (I was like, wow, something to go with the sensors for once), and I'd love to get around to sorting them out, but (and this is hard for me to admit) I'm a bit daunted.

Andrew R Stewart 

The first thing I'd check after installing a fresh battery is the contacts between the wire's end plates and the receptacle contacts in the lever. The handful of little "fingers" that make the contact can be less forceful in their pressing against the lever's receiving points. In fact Shimano had a service notice years ago about this problem and offered a "tune up kit" with what was a tiny square of soft foam/rubber that was glued in place under the wire's plate's fingers, therefore increasing their pressure. I have just bent the fingers out with my finger nails when i didn't have the Shimano kit in stock.

I really don't think this the problem but as it was a know issue might as well eliminate it as a cause, being that it's so easy to do. I do suspect that the issue is internal to the lever. Sounds like the thingy that senses the lever's gear choice has come undone from the lever's index gear (to borrow a Campy term). Much like a cable which is under tensioned so the chain shifts between two cogs then settles back onto the smaller cog. Andy.

Carbonfiberboy 

I've already put in a makeshift kit for the end plates.

That makes sense. And being Shimano, no way to fix it I suppose. Frustrating, because all I watch is cadence and HR. At least it still shows me which chainring I'm in, which is a thing with a tandem.

GaIslander

CF-

I really appreciate the input you gave me on another subject. I have a Flight Deck system sitting on the self I took out of service when I went to the Edge 800 a year ago. If you need it, I'll sell it to you really cheap. I have the head, harness and mounts.

Hopslam

Have Ultrgra 9 biffers off 04 Lemond, triple & flight deck little use on it . Pm me if interested

Carbonfiberboy 

I "fixed" the problem with cadence by buying a Cateye GL50 computer which picks up the Garmin speed/cadence sensor on our tandem. Stoker has the Edge 800. The GL50 shows my HR, cadence, and speed on one display. The Flight Deck shows approximate cog and still shows the chainrings correctly, so that's OK for now.

Eventually I will upgrade the bike to 10-speed. I'll wait for a brifter to break to do that.