Tire widths on an RS

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

  1. chasbmw

    chasbmw Long timer

    Feb 19, 2006
    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.
  2. Darryl's bmw

    Darryl's bmw Darby

    Aug 2, 2012
    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.
  3. Wirespokes

    Wirespokes Beemerholics Anonymous

    Jul 26, 2002
    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.