Flight Deck 6502 Gear Display Problem


New Member
Mar 31, 2013
There are various threads about the Flight Deck 6502, but none quite speaks to my problem.

My 6502 only shows my granny gear in its display and calculates RPM using the granny gear count. This is annoying on our tandem, where I rely on the read out to tell me which ring I am in. It worked well for many years. When the front read out stopped working, I cleaned the pickups in the shift lever. Then I replaced the shift lever. Then I replaced the cables and holder. Now I have replaced the head unit itself, but the result is still the same: I can see the rear cluster, but the front cluster only shows the granny gear. Any suggestions?

its odd because you did everything already, i was going to suggest to take the batteries out, reset and re-enter the gears and re-configurate, but since you bought a new head unit and still get the same problem,
Yeah, it's a mystery. I guess I'll start over and see if some combination of the pieces work together. Meanwhile the rear derailleur readout continues to work admirably.
Originally Posted by EVSwanson .

Yeah, it's a mystery. I guess I'll start over and see if some combination of the pieces work together. Meanwhile the rear derailleur readout continues to work admirably.
FWIW. When in doubt, find SOMEONE with ANOTHER BIKE which has a functioning Shimano Flight Deck computer setup ...

Swap computer heads & see if the problem persists, or not!

  • to state the obvious, if your FD computer head works on the other bike & their FD computer head exhibits the same problem on your bike, then it is your harness What did you mean when you said that you "replaced the cables & holder"? Does that mean you replaced the harness?.
[*] if your computer head does not work on the OTHER bike, then contact Shimano for a replacement.

The OTHER option is to buy a set of 10-speed (v2) CAMPAGNOLO SHIFTERS + a CAMPAGNOLO ErgoBrain computer ...


  • Yes, you can mate Campagnolo shifters with Shimano drivetrains ...
  • if in doubt, check SANTANA for confirmation that it has been an accepted option by Tandem riders for over a decade.

FYI. Here is Chris Juden's 'matrix' which shows the compatibility ...

The RAMPING on the cogs of most Shimano & SRAM cassettes means that the realized compatibility is greater than suggested ...

[COLOR= rgb(24, 24, 24)]I ([/COLOR]so, you, too![COLOR= rgb(24, 24, 24)]) can downshift UNDER LOAD with Campagnolo shifters + Shimano Cassette [/COLOR]without[COLOR= rgb(24, 24, 24)] [/COLOR]unloading[COLOR= rgb(24, 24, 24)] the drivetrain -- [/COLOR]a good thing!

  • the description of the shifting of Di2 & EPS shifting echoes what I have experienced with the mechanical Campagnolo shifters + Shimano Cassettes
  • regardless of the load on the drivetrain, the only time a shift was not executed was when I was already on my bailout Cog!
  • front shifting is better, too; and (after direct experimentation), I found that shifting with Campagnolo shifters is BETTER with unramped chainrings (I wanted to test a moderately extreme shift between 39t & 53t chainrings) than Shimano shifters with ramped & pinned chainrings ... obviously, Campagnolo shifting is even better when using ramped & pinned chainrings than unramped chainrings ... so, the front derailleur's outer stop can be set up with greater precision and eliminate the possibility of throwing the chain ...
  • while I have found that shifting can be executed when the mixed drivetrain is under load there may be people who can botch the shifting
[*] you may-or-may-not want to continue to use a chain catcher for the Granny depending on how inboard the largest Cog is & how it affects the chainline just in case you ever dump onto the Granny when the chain is already on the largest Cog -- THAT is one possible problem which I know can be encountered (probably, with any shifters & shifting down to a Granny)

Non-Campagnolo shifters typically require the front derailleur & chain to be MATCHED to the shifters, and vice versa -- 9-speed Shimano Road with 9-speed Shimano Road, 8-speed Shimano Road with 8-speed Shimano Road, etc.

On the other hand, Campagnolo shifters will mate to almost any front derailleur & chain combination.

I have found that a 9-speed SHIMANO chain not only works well with a 9-speed Shimano drivetrain, but it also works with a 10-speed CAMPAGNOLO Cassette ...

If you are using a 10-speed drivetrain, then a 10-speed SRAM derailleur will index with a 10-speed CAMPAGNOLO shifter & yield 10-speed Shimano indexing.

  • recently, I tested a 10-speed Shimano Cassette with the 9-speed Shimano chain, and it seemed to work 'okay' in the workstand, but (as they say) your-results-may-vary (as may mine when I try it on the road!)
  • the MISMATCH of a 9-speed Shimano chain with the 10-speed Shimano front derailleur would probably precluded this from being a realistic combination when using Shimano shifters

In case you have reservations about using a(ny) SRAM rear derailleur (or, product!), I believe that Campagnolo's 11-speed indexing wheel can be retrofitted into a V2 Campagnolo shifter ...

  • the pre-2009 CAMPAGNOLO CENTAUR shifters are all alloy (i.e., more robust)

Due to residual Lance-effect pricing, you can probably sell your Shimano shifters on eBay for more than the pre-2009 Centaur shifters will cost if you buy them on eBay -- another good thing!