PAS sensor on Shimano ISIS Cranks.

[StuartsProjects]

I had anticipated that fitting a PAS to my bikes Hollowtech cranks might not be straight forward.

I have a PAS disc with a sufficently large hole in it to go over the crank axle. I have fitted the PAS sensor as shown in the picture.

The magnet disk is too thick, I will need to remove the raised edge. I have dremel tools (a Proxxon actually) and a belt sander in my shed, so thinning the disk ought to be straight forward. I should also be able to drill some small holes in the 22T cog, I have a pillar drill also, but dont yet know how hard the cog will be. That would allow the magenet disk to be tie wrapped in place.

Or maybe semi circular cutouts in the magnet disk where the 4 nuts securing the 22T cog in place are, then the magnet disk would be completly flush on the 22T cog. Then maybe just stick the magnet disk in place.

If the gap between the magnet disk and sensor is still tight, is in in order to fit spacing washers on the bottom bracket fixings to move the chainwheels out maybe 1-2mm ?

 

[Scorpio]

Hi, I'm using a temporary solution for now on my hollowtech axle, I'm expecting a parts delivery today with the bits I need to make it permenant.

Some background & suggestions on this thread https://www.pedelecs.co.uk/forum/threads/advice-on-choosing-the-right-kit-please.41155/

Hope it helps, other folk may be along shortly with more ideas for you

 

[Nealh]

Your BB isn't a Hollowtech but an ISIS with internal bearings.
It matters not what it is though as yes machine the rim/lip on the mag disc down.

What you can do is bolt the mag disc direct on to the granny ring by using the tapped holes in use, you will need to source some longer chain ring bolts and carefully drill in between the magnets to align the holes.

 

[StuartsProjects]

Your BB isn't a Hollowtech but an ISIS with internal bearings.
It matters not what it is though as yes machine the rim/lip on the mag disc down.

Oh thanks, easily confused I am.

I am sure I have a end mill drill somewhere, with that in my pillar drill it ought to be easy enough to cut away the rim.

 

[StuartsProjects]

I made up a test disk to represent what the thinned modified magnet disk would be like (yes out of cardboard) and assembled the cranks - not enough space.

I had a 2mm bottom bracket spacer and after checking that the sleeve on the bottom bracket bearing would still engage fully with the left screw in fixing, I added the spacer. Together with a little bend on the sensor it looks like the modified disk should fit.

I drilled 4 x 3mm holes in the 22T cog for tie wraps. A HSS drill just polished the surface, a titanium coated one did drill the holes but was blunt after doing the four, I used a pillar drill on 2500rpm.