Hello all, I decided to upgrade my 96 Heritage after many many years of service. I bought new wheels, tires, exhaust the works. But I managed to overlook one thing or was so excited about the upgrades that I failed to realize that my stock rear wheel is a 16x3 riding on a MT90B16 Dunlap tire.
I bought a Ultima Fat Spoke 16x3.5 wheel, a Avon MT90B16 and added a Super Spoke pulley/rotor set(with 1/2 inch spacer) boy was I excited when I got them back with the tires mounted and bolted on the rotor and pulley. I quickly noticed that my belt rubs against the tire. The setup is too wide with the 1/2 inch spacer and wont fit the swing arm but rubs when I remove it. I was thinking of replacing the 1/2 in spacer with a 1/4 inch, but I am not sure if I will have to replace the axle spacers with larger/smaller ones. Ideas?

 

Put the wheel back on with NO pulley spacer and bolts loose. Don't put the belt around the pulley.

How's the wheel/rotor/tire look in relation to centering/caliper/fender?

If it looks good, start loosening pulley bolts and moving it outward until the belt will clear the tire (you'll be holding the back of belt in the pulley "groove". If you can make all that happen satisfactorily, then measure the gap between the pulley and wheel. That's your spacer width needed.

If right off the bat you can't make the wheel work before even getting to the belt issue then spacer sizes will need to be addressed



If all else fails, put the wheel on without any spacers at all to see what's possible
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Hey Multihdrdr,
I appreciate the advise, I went home last night and with a clear head did something very similar and figured out I need different axle spacers in order to center the wheel. But before I go that route, I will try the method you described above to ensure the 1/2 inch spacer I currently have is not too much. Any idea how much space should be between the tire and belt? as I have it now, it has about 1/4 of an inch between them.

 

I could definitely live with a 1/4" (or less if I HAD to)

 

Also keep in mind that you're working with "Timkens" with a SEPARATE grease seal. So you should keep your existing most inward spacers (seal rides on those) and use a longer "2nd" spacer on the left and trim the "only one" on the right. You can only trim the right side if the rotor to caliper relationship is NOT correct (there's a little "Fudge" there). If the rotor to caliper relationship IS CORRECT, then you need to trim the right side of the caliper bracket "IF" you can. That is, assuming you are trying to move the wheel to the "Right"

If you do get new spacers the most inward need to be the same OD as the originals.
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great info... I really appreciate it. I will let you know how it turns out.

 

Another way to check what you have is as follows. With the wheel out of the bike and the pulley installed (no spacers) simply look down the side of the tyre, so the top and bottom edges of the tread are in line, as per my photo. What you can see on my wheel is the thickness of the inner edge of the pulley. In fact there is a very slight sliver of light between pulley and tyre, but it doesn't show. This gave me 3/16" clearance, the thickness of the pulley flange. If you cannot see the full width of the pulley teeth, then the belt will not clear the tyre.

That is where Multi's technique comes in. I suggest around 3/16" clearance between tyre and belt. Do your installation without the belt guard, then trim that to fit if necessary.

On your wider rim the tyre may spread a little wider than on a stock width rim. When using the same tyre on my '90 Glide I removed part of the inner rubber part of the guard.