5.5" rear wheel conversion

[MrFeldman]

I know this subject has been covered, but I got a little problem I could use some input on. The 5.5" rear wheel I bought is apparently for the abs bike,..my R1100s is an I-abs bike,..meaning I'm gonna need to replace the stock " I-abs" stamped steel sensor ring w/ an "abs"cast aluminum sensor ring to fill the 5mm gap,..the problem is the notches on the cast ring measure out slightly different than the slots on the stamped steel ring,..rendering my rear integral abs unreliable or inop. That wouldn't be so bad as long as my rear brakes behave like normal non abs brakes,..and I'm unclear as to whether I should remove the spacer inside the hub of the final drive or leave it in to achieve correct offset.

[brentw1]

several have used the non iabs rings on a iabs bike,
the abs system should account for any differences in ring slot counts.
it has to deal with other variations such as wheel diameter etc.
your speedo could be off though,
what is the difference?
you should still need the spacer. check the rotor centers on the brake caliper and the sensor clearance.

[MrFeldman]

Brent, maybe I'm over thinking this but, my mech. tells me if the slots (stamped ring) & the notches(cast ring) don't measure out the same,..I'll have a abs fail code, and the abs light will blink continually while riding,...I've got a great machinist near by that could make me some spacers out of billet aluminum w/ the correct diameter to match the rotor towers on my wheel as long as I have the right measurement in mm to match the difference ,..how many millimeters of spacer will I need "exactly". ?
Then everything will operate correctly. Also, advise me on where to acquire the 8x25 mm bolts as apposed to the stock 8x20mm.

[PFFOG]

I had a friend make aluminum spacers, just make sure you get the LONGER bolts for the early ABS, the shorter will only engage a few threads.

My sense is the ABS calibrates itself, so the difference would not make the ABS not work, but I do not have any body verify this.

[brentw1]

search this forum several people have done it
and as I said the abs must adapt to different rates anyway.
the abs does calibrate itself which is why it will work.
or you can do lots of work for no reason,
the abs looks at the rate of change difference between the front and rear.
the pulse rates are different between the front and rear as designed
the tires are not the same diameter.

[brentw1]

and it is easy just to try it anyway.

[MrFeldman]

Originally Posted by PFFOG

I had a friend make aluminum spacers, just make sure you get the LONGER bolts for the early ABS, the shorter will only engage a few threads.

My sense is the ABS calibrates itself, so the difference would not make the ABS not work, but I do not have any body verify this.

I'm having trouble finding a BMW dealer that has longer bolts. Their parts list only has 8x20mm available.
Any suggestions?

[PFFOG]

Originally Posted by MrFeldman

I'm having trouble finding a BMW dealer that has longer bolts. Their parts list only has 8x20mm available.
Any suggestions?

The bolts for the early cast abs ring ARE the long ones. I want to say 8x25

[MrFeldman]

That's what I thought,. 8x25,...again I've called 1/2 dozen BMW parts dept. & none of them even list anything but 8x20mm.

[MrFeldman]

FYI ,...found bmw stainless steel 8x25 ,..you just use the bolts for front wheel.

[PFFOG]

Originally Posted by MrFeldman

FYI ,...found bmw stainless steel 8x25 ,..you just use the bolts for front wheel.

Anywhere you use a cast ring or spacers, on the front would only be L side