Tire widths on an RS

Discussion in 'Airheads' started by headtube, Nov 18, 2012.

  1. chasbmw

    chasbmw Long timer

    Joined:
    Feb 19, 2006
    Oddometer:
    2,700
    Location:
    Bath Uk
    Both my airheads were greatly improved when I fitted a pair of the new Michelin pilot series tyres that are properly sized to be 3.25 and 4.00. Handling was much quicker AND more stable that the original BT45s. This is a good combination, in the wet or dry.

    I found that my nominal 4.00 BT45 was in actually 118mm in width, so nearly a 120.

    On your bike a 120 should fit with a bit of grunt in fitting it, if it rubs on the swinging arm there used to be a spacer that could be fitted to the hub to move the wheel away from the swinging arm.
    #21
  2. Darryl's bmw

    Darryl's bmw Darby

    Joined:
    Aug 2, 2012
    Oddometer:
    330
    There is a spacer you can get that moves the rear wheel over about 3/16 over to the left to have the tire clear the swingarm..

    Back in the racing days they ran much wider tires with a very large offset.

    They even compensated with an offset for the swingarm in the frame but it could be hard on the u-joint.
    #22
  3. Wirespokes

    Wirespokes Beemerholics Anonymous

    Joined:
    Jul 26, 2002
    Oddometer:
    8,724
    Location:
    Jackson's Bottom Oregon
    I doubt the small offset to the side would make any difference to the ujoint! They're made to handle offsets, up and down, so what difference would a little to the side make? They, in fact, don't do well with no movement; it's the extremes you want to avoid.
    #23