Originally Posted by BobR
well, good point. I assumed they were not since they do not have the R designation in the description (just the Z designator). Do you have a K100 with radials? My concern is that I read somewhere that some of the early K bikes had rims that were a little narrow for a radial tire, which I understand does not have the same sizing requirements as a conventional tire, even though the sizes may be the same (i.e. - both 120/70 for example)
Well I happened to have a -90 K100RS for many years. Used Metzler Z4, and it felt right.
BMW changed the wheels and suspension when they introduced the 16V K100 engine in -89. This may be what you have in mind.
Anyway, radials are great on this bike. If you like the Metzler, the Z8 will be great, but surely Michelins and Bridgestone are great tires too.
Take good care of your bike. The -91 was the last year when the brick was a light bike. By the K1100 it started to gain weight before it evolved into the even heavier "Bundestank"- K1200RS.
(And history has repeated itself, as we now see the new K1200 ending up in the K1600, that weights in like a Harley)