Balancing/end weights/swingarm stretch
Results 1 to 3 of 3
Like Tree6Likes
  • 5 Post By nihil
  • 1 Post By Fred

Thread: Balancing/end weights/swingarm stretch

  1. #1
    Senior Member nihil's Avatar
    Join Date
    Jan 2018

    Balancing/end weights/swingarm stretch

    One thing I've been pondering since I got the TW, and even more so since busting my ass last December, is the front to rear balance of this thing and how it kinda feels like my old air cooled VWs with being a bit ass-heavy and prone to the pendulum effect. So I did what any fan of overkill would do and bought myself a pair of ridiculously cheap 440lb capacity postal scales and weighed things.

    Static balance on the bike alone is pretty reasonable. With all the garbage I've bolted to it and about half a gallon of gas, mine comes in at 294.5lbs total. That's 165.1lbs at the rear and 129.4lbs front, giving it an approximate bias of 56% rear to 44% front. I'd approximate a similar difference in contact patch, so when it's sitting still with nobody on it and magically balanced on its own, it's very close to perfectly balanced.

    I measured about 52.5" from axle to axle, and while that will change due to the rake on the forks and the fact that they extend and compress, it's close enough for this exercise. This makes the center of mass on bike alone around 29.4" back from the front axle.

    Just out of curiosity, I also weighed it with the kickstand down, and the kickstand takes about 55% of the bikes weight (when you raise both wheels about 15mm).

    With my ~250lbs carcass astride the iron beast in my usual seating position, its balance changes to around 63% rear/37% front, which is a bit more rear biased than I'd like considering I sometimes stretch a bit farther back than that. Center of mass is around 33" back from front axle.

    Just for kicks, I also measured with me standing, and while I couldn't mimic my full standing while riding posture, it did shift the weight forward significantly at 57% rear/43% front, with center of mass back to around 29" from front axle.

    So, since I'd like to keep that fairly neutral balance while seated, a bit of a stretch on the swingarm should help pull that center of mass back to the sweet spot. I'm thinking around 2" to 3" worth of stretch should bring it back to 55/45 or so. The only off-the-shelf stretched swingarms I've seen for these things is from Webike, and that's 20cm/7.8" longer than stock. Does anyone make a shorter stretched swingarm for these or is it fabricobble time? If the latter, I'm probably going to try and source a spare swingarm.

  2. #2
    Senior Member ibdavid's Avatar
    Join Date
    Mar 2019
    Interesting project.
    2004 TW200

  3. #3
    Senior Member Fred's Avatar
    Join Date
    Dec 2011
    Turtle Wrangling the Sierras
    I was given a 2" extended swing arm that was homemade with professional grade welding by a fellow forum member. It works well, calms things a bit at speed yet the mild increase in turning radius is not objectionable. Increases suspension travel and changes shock stiffness slightly. A reasonable mod in my mind that doesn't also require other modifications to work other than lengthening chain & brake actuating rod.
    I'ld give his name but fear he would be inundated with requests for more from you fine folks.
    CJ7Pilot likes this.
    2003 TW200 "Betty Boop"
    2006 TW200 "Nibbler", a.k.a. “Mr.Gizmo"
    Hidden Content All Things Considered I’ld Rather Be Motorcycling

Sponosred Links

Posting Permissions

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