Advertise on Bikeforums.net



User Tag List

Results 1 to 12 of 12
  1. #1
    Senior Member zonatandem's Avatar
    Join Date
    Dec 2003
    Location
    Tucson, AZ
    My Bikes
    ariZona carbon fiber tandem & single
    Posts
    9,968
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Update: Test Dummies . . . Again?!

    Updating on testing of Di-2 with NMH battery in stoker seatpost.
    Asides from a couple minor issues listed in our previous post, at just over 1,000-mile mark, had to fine tune rear shifting a tad.
    At 1,325 miles, the green little LED light by handlebars started flashing every so often when shifting, indicating battery life was going down.
    At mile 1,360 our front derailleur ceased working, but rear worked fine; indicating it's time to re-charge pretty quick!
    According to the manual a red blinking LED light was supposed to activate before that, but that did not happen.
    Guess that's why we refer those those little LEDs as 'idiot' lights!
    Hooked up charge unit to the little 'tail' under stoker's saddle for 3.5 hours.
    Checked battery with voltage meter and decided to keep trickle charge going for another 3.5 hours tAttachment 277781o top off the battery.
    So far so good . . . and we are still very pleased with the performance of the Di-2 unit.
    Pedal on TWOgether!
    Rudy and Kay/zonatandem

  2. #2
    Senior Member colotandem's Avatar
    Join Date
    Oct 2007
    Location
    Golden, CO
    Posts
    226
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Rudyy,

    I have a couple of questions regarding your test. How often have you had to charge the system?

    Prior to using the Di-2, you were using a triple front deraileur, correct? Regarding the change to a double chainring, do you find that you require a lot more frequent shifts of the front chainrings? Maybe with the smooth shifting, this is not much of a problem?

    Thanks!

  3. #3
    Senior Member
    Join Date
    Oct 2009
    Posts
    905
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    What is the rear derailleur? Di-2 with a long cage added? How is it made to clear a wide range cassette as I would of thought anything bigger than a 30t low gear would hit the top pulley?

  4. #4
    Senior Member zonatandem's Avatar
    Join Date
    Dec 2003
    Location
    Tucson, AZ
    My Bikes
    ariZona carbon fiber tandem & single
    Posts
    9,968
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    colo tandem:
    Recharged battery only once, at 1,360 miles.
    No big adjustment for us going from triple to double chainring.
    With the double (48/32) and 10 speed cog (11/34 cassette), we have 19 very usable gear combinations.
    With the old triple/9speed cassette had about 22 usable gear combos. Our highest gear used to be 130 now is 120. At our age we no longer 'bomb' down the hils so if we spin out 120-inch gear, we coast!
    Our granny gear is still mid-20s.
    We spend most of the time on big chainring and the 32T is used for steeper/longer ascents.

    Dean V:
    Our builder, Bob Davis, installed a Yumea long cage on the Di-2 Dura Ace rear derailleur.
    Works fine.
    So far these test dummies are enjoying the ride TWOgether!
    Pedal on!
    Rudy and Kay/zonatandem

  5. #5
    rebmeM roineS JanMM's Avatar
    Join Date
    Jan 2006
    Location
    Indiana
    My Bikes
    RANS V3, RANS V-Rex, RANS Screamer
    Posts
    11,546
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Wasn't aware till recently that the battery for those systems lasts for such a very long time. Would be a deal-killer if frequent battery charge/change were required.
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  6. #6
    Senior Member zonatandem's Avatar
    Join Date
    Dec 2003
    Location
    Tucson, AZ
    My Bikes
    ariZona carbon fiber tandem & single
    Posts
    9,968
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    The other advantage of the battery system is that it is located ^inside^ stoker Kay's seatpost and is not the same battery used by Shimano.
    Pedal on!
    Rudy and Kay/zonatandem

  7. #7
    Gear Combo Guru Chris_W's Avatar
    Join Date
    May 2007
    Location
    Switzerland
    My Bikes
    Spec' Tarmac (road), Spec' Secteur Disc (commuter & tourer), Salsa Mamasita (MTB), CoMo Speedster (tandem), Surly Big Dummy (cargo), Airnimal (folder), a train pass, and NO car :)
    Posts
    2,046
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by JanMM View Post
    Wasn't aware till recently that the battery for those systems lasts for such a very long time. Would be a deal-killer if frequent battery charge/change were required.
    I believe the standard Shimano battery is offically rated for 1000 miles (1600 km) per charge, but I've heard of people getting up to 3000 miles (5000 km) per charge! Charging frequency mainly depends on shifting style and air temperature.

    In fact, the capacity is so good that there are several weight weenies who would like Shimano to release a race-day battery that is less than half the weight, but only has the capacity for a couple hundred miles or so.

  8. #8
    West Coast Weenie Esteban58's Avatar
    Join Date
    Sep 2012
    Location
    Sunnyvale, CA.
    My Bikes
    2013 Caletti, Trek 7500 fx
    Posts
    639
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Newbie-ish question here:

    The one thing that concerns me about electronic shifting is dealing with failures 'in the sticks'... Aside from the battery dying, where the obvious solution is to carry a spare, if the circuitry itself fails, are you stuck? How would you deal with that?

    I suppose that's not much different then some catastrophic cable failure on a mechanical system, but I'd like to hear how people plan for this (if they do...).

    thanks!
    there is no signature.

  9. #9
    Senior Member waynesulak's Avatar
    Join Date
    Jan 2008
    Location
    Ft Worth, TX
    My Bikes
    650B tandem converted from Santana Arriva, Santana Noventa, Boulder Bicycle 700C, Gunnar Sport, Trek TX700,
    Posts
    1,693
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Esteban58 View Post
    Newbie-ish question here:

    The one thing that concerns me about electronic shifting is dealing with failures 'in the sticks'... Aside from the battery dying, where the obvious solution is to carry a spare, if the circuitry itself fails, are you stuck? How would you deal with that?

    I suppose that's not much different then some catastrophic cable failure on a mechanical system, but I'd like to hear how people plan for this (if they do...).

    thanks!
    I deal with it by carrying one spare derailleur cable and one brake cable. I suppose for Di2 I should be a spare wiring harness? battery? Our tandem has no following car, sometimes goes where there is no cell service, and there is no one at home to call anyway (she is on the back of the tandem). Of course there are friends and relatives, only a few of which have an appropriate vehicle, but I have an aversion to making them take hours out of their day to bail us out of a bike maintenance issue.

  10. #10
    Senior Member zonatandem's Avatar
    Join Date
    Dec 2003
    Location
    Tucson, AZ
    My Bikes
    ariZona carbon fiber tandem & single
    Posts
    9,968
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Failures of any type of component can be a hassle and usually not expected!
    Have had a chain jam/bend at the north rim of the Grand Canyon; nearest bike shop 300 miles away. Took me about a half hour of to fix it with mini-pliers and small screw driver.
    Have broken front der. on 100 mile ride and then rear cable snapped later in the ride; yup, managed to finish.
    Have ripped out half dozen rear spokes with unexplained overshift. Fortunately were within driving distance from home. Hitched hiked a ride home while stoker stayed with tandem. Got our car and picked up stoker/tandem.
    For the Di-2 setup we carry no spares; keep tabs on battery by doing a voltage check before each ride with voltage meter.
    If Di-2 fails totally (like no power/broken circuitry), you are stuck in the last gear you selected.
    However you do get a warning/flashing light to tell you if battery is 'low.' If you don't pay attention to that, then front der. quits functioning but back is still good for a few dozen shifts.
    Battery strength/life is dependent on how many shifts and even temperature.
    Tested our battery up to 140 degrees Fahrenheit and still functioned; that was parked in the sun at mid-day/ summer in Phoenix for several hours.
    Don 't know how well it holds up in freezing temps and no plan to test that!
    We tend not to overworry about failures . . . deal with things as they happen.
    On multi-day tours we used to carry spare brake/der. cable + folding tire + 2 spare tubes.
    Oh, we don't carry a cellphone . . .
    After 37+ years of tandeming we have survived all sorts of minor-to-major dilemmas.
    Just our experience.
    Pedal on TWOgether!
    Rudy and Kay/zonatandem

  11. #11
    Senior Member Team Fab's Avatar
    Join Date
    Jan 2012
    Location
    Vancouver BC
    My Bikes
    Comotion Supremo, Trek T1000, Comotion Supremo Triple
    Posts
    211
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have had the local battery specialty store make battery packs for my riding lights, why have racers not had similar done for race day battery packs. Also, could you build a solar charger that was less weight and use an even smaller battery?

  12. #12
    West Coast Weenie Esteban58's Avatar
    Join Date
    Sep 2012
    Location
    Sunnyvale, CA.
    My Bikes
    2013 Caletti, Trek 7500 fx
    Posts
    639
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Team Fab View Post
    I have had the local battery specialty store make battery packs for my riding lights, why have racers not had similar done for race day battery packs. Also, could you build a solar charger that was less weight and use an even smaller battery?
    I'm sure you could do this, but you'd have to check the charge generated vs. weight trade off. Solar panels are certainly getting better / lighter - you could probably get something that mounted over the top of panniers or a rack (but would you have a rack if you were worried about weight)?

    Then some circuitry to feed the generated electricity to the battery - on a sunny enough day you might be able to get away with a ridiculously light battery.

    Di2 battery weight is 70 g, so that's not much to begin with.

    Also, thanks all for the replies to my question. This isn't an issue with our current tandem ('80 peugeot), just a consideration for the future.
    Last edited by Esteban58; 10-31-12 at 08:37 PM.
    there is no signature.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •