K75S Wheel bearings & spindle spacers

[pugsley]

I have a 1986 K75S.

I am in the process of fitting a pair of 3 spoke wheels instead of the snow flake wheels I have now to improve my tyre choice for radials. Can you use the same front wheel spindle and spacers from the snow flake wheel with the 3 spoke wheel or do I need the 3 spoke spindle and spacers? Part numbers are different for some parts.

On the same subject I notice BMW changed the front wheel bearings when they went from snow flake to 3 spoke. They changed only one of the pair of 6005 regular ball bearings for an angular contact radial ball bearing. I assume they decided the tension when the spindle nut was pulled up was loading the regular ball bearing with an unwanted axial load and this was causing problems, or is there another reason?

[Laitch]

I have a 1986 K75S.
Can you use the same front wheel spindle and spacers from the snow flake wheel with the 3 spoke wheel or do I need the 3 spoke spindle and spacers?

I'm guessing the you in that question means you, pugsley. Parts that have the same number in both wheels can be used if they're in good condition; parts with differing numbers must be swapped out for dedicated 3-spoke parts.

[rbm]

Any project involving the substitution of a later 3-spoke wheel for the standard Snowflake wheel will require substituting the entire front end of the motorcycle, including wheel, spindle, rotors, brakes, forks, triple tree, and master cylinder.  You can't fit the 3-spoke to the standard K75 forks AFAIK (at least I've never read of any success story).  The axle diameters are different, the wheel widths are different, the rotor sizes are different, the fork stanchion spacings are different.  Too many differences to accommodate with a 1:1 swap.

[Laitch]

Any project involving the substitution of a later 3-spoke wheel for the standard Snowflake wheel . . .

By later is meant the K1100 3-spoke, Robert?

[pugsley]

Thanks for the replies. I checked the rotor spacing and it is the same, these are 1992 K75S 3 spoke wheels. Bearing spindle diameter is 25mm for both. I was hoping someone had done it before and knew what fitted and what had to be changed.

[Laitch]

Thanks for the replies. I checked the rotor spacing and it is the same, these are 1992 K75S 3 spoke wheels. Bearing spindle diameter is 25mm for both. I was hoping someone had done it before and knew what fitted and what had to be changed.

Which radials do you think you'll be able to mount on these rims, Pugsley?

[rbm]

By later is meant the K1100 3-spoke, Robert?

Yes, Laitch.  By later I mean the K1100 3-spoke, 3.5 x 17 (36 31 2 311 272) which offers greater radial tire options, one of the OP's requirements.

Anton Largiader's wheel page is good reading for the OP.

[Motorhobo]

Any project involving the substitution of a later 3-spoke wheel for the standard Snowflake wheel will require substituting the entire front end of the motorcycle, including wheel, spindle, rotors, brakes, forks, triple tree, and master cylinder.  You can't fit the 3-spoke to the standard K75 forks AFAIK (at least I've never read of any success story).  The axle diameters are different, the wheel widths are different, the rotor sizes are different, the fork stanchion spacings are different.  Too many differences to accommodate with a 1:1 swap.

Before I was conscious enough to think about these things, I did just that -- just swapped out the 3-spoke wheels that shipped with one 95 K75 onto a 94 K75 and visa versa without any issues whatsoever, at least none I'm aware of after nearly 10 years later. So this whole issue just gets me confused. We're talking about the 3-spoke K1100 wheel, not the 3-spoke K75 wheel? Is the 3-spoke K75 wheel identical then to the snowflake K75 wheel, having the same radial limitations as same?

[pugsley]

Thanks Motorhobo,

To clarify the orginal question was relating to a donor wheels bike 1992 K75S 3 spoker and the receiver bike is a 1986 K75S snowflaker.

I know I had read somewhere something Frankenduck had written a while ago that it was fairly simple swap but I couldnt find it again. I wanted to make sure I had all in hand before I started.

I was also interested to know why they modified the type of wheel bearing when they went from snowflake to 3 spoke. It makes no odds to me as I'll replace them anyway. I was just intrigued why. Does anyone have an idea?