final drive gear ratio.

Discussion in 'GS Boxers' started by blues_bleu, Dec 6, 2012.

  1. blues_bleu

    blues_bleu Been here awhile

    Apr 12, 2004
    Hi guys, wanna check if anyone have done and final drive swooping on a R1100gs? mine is a 96". lately my crowngear seem to have worn-out. so looking to replace one.
    but i have seen in the forum that some people are swooping final drive from RT , RS to GS.

    Actually for my case, i am not doing much offroad now as this GS will be my main transportation bike. looking to travel about 120km daily. i have already installed a big touratech tank and now looking to get the best mileage out of this bike. i would like to cruise around 90m/hr.
    see what is the best option i can get.

    thank you very much!!!!!!
  2. Twilight Error

    Twilight Error Going nowhere slowly

    May 18, 2002
    The Submarine Mines
    I know the FD from an 1150GS will fit an 1100GS, the 1150 uses a slightly higher ratio.

    If you've got ABS, the sensor position may need a shim adjustment to get the proper gap.
  3. AntonLargiader

    AntonLargiader Long timer

    Aug 28, 2003
    Charlottesville, VA
    I have a bunch of info on my website that should give you an idea of what's available and what your resulting speed/RPM should be.

    Swapping gears within an existing FD housing requires a lot of careful work. If you can just buy the FD you want at an acceptable price, that's the way to go. Otherwise you have to totally disassemble two of them and reassemble (and reshim) at least one. That's a lot of work.

    If you just want the GS fender mount on a different FD, you can change the cover pretty easily. I have never seen cover dimensions change by more than 0.01mm (they are all either 13.50 or 13.51mm deep), so there's no shimming issue. But the R11RS and K12RS use a housing without the standard ABS sensor hole, so you can't just buy any FD. I should probably add a section on housings and covers to my web page.
  4. Paul Young

    Paul Young Low Flying GS Pilot

    Jul 8, 2001
    Preston, England
    Anton, you have my thanks for that information/site.

    It was what I referred to when I was contemplating this same scenario. The reason for my investigations was that I was finding 5th gear a tad too low - regularly hitting the rev limiter in 5th is a PITA when 6th is too tall for the roads I was riding. Gearing it up seemed the best option (I know it's contrary to popular opinion) so I used your gearing tool & decided to fit an R1100S FD, which I picked up for peanuts. What a difference... Ultra low cruising revs on the motorway but great spacing & ratios for the twisty stuff. Like the ideal combo of an R1150GS 6th & an R1100GS 1st-5th...