Front derailleur on V20

Discussion in 'Race Series (V1.x, V2.x, V20)' started by Max Id, Jun 14, 2017.

  1. trplay

    trplay Zen MBB Master

    The tape on the chain ring and the camera angle has me a bit confused as to the spacing on his bike. It looks very similar to all my cruzbikes. Just for giggles I measured the distance on all of my Cruzbikes and they were all +- 1.8 CM. Translation, I think this DR will work fine on my bikes. Based on the Cruz angle no way it drags the bottom of the cage. I suggest trying it before making a new mouse trap.
     
  2. Jeremy S

    Jeremy S Dude

    Are you shifted to the big chainring or the small chainring when you measure? (Except for Yaw, FD setup is initiated in the small chainring position since there is no cable tension.) Yes, I looked at my bike too.
     
  3. cranky cyclist

    cranky cyclist Well-Known Member

    Also you may want to check the placement of your Bottom bracket. Mine accidentally shifted left and I was unable to shift onto the large chainwheel when this happened. Even my bike shop didn't catch it.
     
  4. Brad R

    Brad R Well-Known Member

    According to this document there is something called a support bolt (page 8) that is supposed to be used to make the chain guide parallel to the big ring. If you adjust it, maybe it will push the chain guide down closer to the chainring.

    Good luck.
     
  5. super slim

    super slim Zen MBB Master

    from your side view of the chainring and the derailleur stalk, on my S30 the distance from the Crank centre Line to the bottom of the derailleur stalk bracket is 135 mm, and 133 mm for a Silvio V1.0 fixed to the boom stalk. What is your distance on a V20?
     
  6. Max Id

    Max Id Member

    I am not sure whether I am measuring the right thing, but here is what I have:
    IMG_20170618_160242.jpg

    I see that most people suggest to first try if the shifting works or not, but the thing is that I don't want to leave scratches and marks on the crankset, because I'll have to swap it with a bigger one if it doesn't work.
    There are no adjustments available to move the cage closer to the ring, and, according to Shimano, this might result in a poor performance.
     
  7. Max Id

    Max Id Member

    It is perfectly aligned, but even if it wasn't, this would not affect the distance between the cage and the chainring.
     
  8. Max Id

    Max Id Member

    Unfortunately they don't, apparently...
     
    Bruce B likes this.
  9. Max Id

    Max Id Member

    My understanding would be, provided the bracket is welded correctly, is that the V20 does not like compact double-ring chainsets.
    The second options is that it will shift just fine, despite what Shimano say.
     
  10. Jeremy S

    Jeremy S Dude

    Talk to an expert. If you haven't, email Cruzbike support (support@cruzbike.com). They might be busy with RAAM right now. You can also have your local bike shop look at it. They will typically blame the "weird" frame design, but sometimes they point out useful things.
     
  11. trplay

    trplay Zen MBB Master


    I've seen more compact chain sets on the V20 than standard (although not a 105). They have worked on ours for years with tens of thousands of miles. Put a chain on it and check it out, just don't scratch it.
     
    super slim likes this.
  12. Black Hawk Down

    Black Hawk Down Senior Rookie

    I'm having the same problem with my Shimano Di2 FD. It's at least 1.5 cm away from my Ultegra 6800 50 tooth chain ring. Here's what Robert at Cruzbikes told me:

    "It looks like it might possibly be able top move a bit closer in that
    pic, but the stalk is long and I run mine at a distance as well like
    in your picture. I have not encountered any issues with shifting. The
    mount is a bit on the short side for a 50 T ring for sure but it is
    usually OK."


    Here's the pic:

    [​IMG]

    I went ahead with the build but now find that I have trouble shifting in either the large or small chainring. It will shift if the chain is in specific gears on the freewheel. I have to move up and down the freewheel while I keep attemting to move the FD position. It's a real pain. Usually I fail to get into the smaller chainring just when I start up a hill. I wind up gutting up the hill in a higher gear-inchs than desired. I played with the derailier adjustments, front and back as much as I could stand. I can make it work while locked in the bike stand but on the road, it sucks. Any help is appreciated.
     
  13. Bill K

    Bill K Well-Known Member

    I also have a V20 with DI2 but with an Sram 52/36. I had the opposite problem: shifting to the big ring would sometimes throw the chain.
    It turned out that the 52 chainring is bent. There was about a 1mm wobble which is barely noticeable, but enough to cause poor shifting.
    This is unlikely to be your problem but it is worth checking out.
     
    super slim likes this.
  14. Jeremy S

    Jeremy S Dude

    What happens when it fails?
     
  15. Black Hawk Down

    Black Hawk Down Senior Rookie

    Nothing. It just doesn't shift. The derailleur moves but doesn't shift the chain to the other gear.
     
  16. Jeremy S

    Jeremy S Dude

    Well that's baffling to me. In my limited experience, sluggishness or failure shifting up = cable tension too low, and inability to shift down means cable tension too high. It's hard to imagine both at the same time o_O. Since it works sometimes I would doubt the problem is the limit screws, and I assume you used the manufacturer recommended technique for setting the chain length based on overlap. That said, on my older Silvio model I am able to set the derailleur height correctly (with 50T chainring) and I don't know what problems are expected when you can't achieve that. You might look into getting an extender that goes between the frame derailleur mount and the derailleur, I think I've seen such a thing before but not sure what it's called.

    For example check this out:

    http://www.artscyclery.com/descpage...Fj2CzJVQmeDgZ7o5iprJa-8VdV8zc51EaAomhEALw_wcB
     
    Black Hawk Down likes this.
  17. Black Hawk Down

    Black Hawk Down Senior Rookie

    I worked on it again today. I can get it working fine on my stand, then on the road, same issue. If I need to shift in a lower gear on the front, I have to be in a higher gear on the rear. If I need to shift into a higher gear in the front, I need to be in a lower gear on the rear.
    Perfect!! I've been looking for something but found nothing. I may be able to bolt this shim to the braze-on post using one of the holes, then attach the derailleur through the other hole. I was about to have a machinist friend make me something. I'll order the one in the link and see if I can make it work (just ordered, delivery tomorrow). Thanks!
     
    Don1 likes this.
  18. ratz

    ratz Wielder of the Rubber Mallet

    Check you chainstay, it sounds like you have your cup clamps biased a bit to the right or left placing you just out side the normal left and right adjustment of the derailleur. Also, check the programming of your Di2 to make sure the over shift trim is setup correctly, with the over shift as long as the limits screws are right she should shift like a dream. but you probably know that.

    To aid in tuned; put the front boom in a bike stand, and the rear wheel on a tall bucket so the bike is level when you tune the derailleur.
     
    super slim likes this.
  19. Black Hawk Down

    Black Hawk Down Senior Rookie

    I assume you're talking about the clamps on the bottom bracket cups. I do have a weird situation there. My cups are Ultegra and they are smaller than the clamps. I had to Macgyver them with some rubber shims They seem to be holding, but they could easily be shifted to one side or the other. I'll take a look after work tomorrow.

    Actually, I'm not sure what you mean by "over shift trim". I'm aware of the trim adjustment that is turned on by the Junction A button. You set that trim while the chain is in the middle of the freewheel. I had to set it so that the chain was a little offset to one side of the freewheel gear to make it shift smoothly. If I centered the chain on the gear, it would have trouble shifting into one of the gears. Can't remember which, maybe the third or forth from the smallest gear. The chain would not engage on that gear and would skip to the next one. All the other gears seemed to work.

    I used the two set screws to adjust the position of the FD while shifting through the rear cassette gears. I am having trouble with the front derailleur rattling when shifting through the rear gears. I can adjust the limit screws so that if the chain is on the large chainring, there's no rattling as I go through all the rear gears, but if the chain is on the small chainring, when going through the rear gears, at some point, the FD makes an adjustment to correct for the angle of the chain and the FD over corrects making the chain contact the side of the small chainring and rattles. After shifting a couple more times, another correction is made and the chain stops rattling. If I adjust the set screws while in the small chainring, I can make it so there is no rubbing by the FD on the chainring, but when I shift to the large chainring, it now has the same problem of the FD rubbing on the large ring when a correction adjustment happens. I go back and forth but can't find an adjustment that will work in both situations. It seems like the programing is off. I don't have the software to change the programming. Maybe I should get it.

    I admit my inexperience with this adjustment and would like to find a bike shop that can help me out, but I don't have a lot of faith in the ones around me, and besides, I would like to know how to deal with this on my own so I don't need to depend on anyone else when I have a problem. It's why I decided to do the bike build in the first place. It's my intention (now don't laugh..) in a couple of years to go touring with this bike and a trailer. I have some reservations about not getting the Silvio, but I really wanted the speed of the Vendetta. If in the end, it doesn't work out for touring, I'll sell it and buy the Silvio. But for the next two to three years, I'll enjoy riding the V20.
     
  20. 1happyreader

    1happyreader zen/child method

    ouch......ouch..... ouch.....
    all the time spent on shifting ,,, wasted because the bike frame was never securely assembled ??
    I am sorry ,, but you NEED a bottom bracket with a flat surface like they all used to have or a 2018 front end parts that no longer clamps in that manner.
     

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