Tech on wheel distance collars/ spacers

Related:
Create New Tag

1/6/2018 12:45 PM

I have a set of rare hubs from a former 97-99 era MXGP Honda team for my CR250 build. They came without bearings, distance collars, sealers or spacers and I have been trying to figure out what it needs by trial and error. The front hub was easy and too many of the orginal Honda CR parts, but not the case for the rear bub which uses much bigger bearings and seals than OEM.

The OEM distance collar was too long to allow the bearing to set on the inner bearing seat (lip), so I had to shorten it. However, when I tighten down the axle nut, there is some noticable drag even though all inner bearings turn freely. It is not hitting the anything, nether the chain guard or the caliper (pads still have plently of play when piston is pushed back).

My Question:.. My beleif is that the distance collars were not supposed to prevent the bearings from seating on the lip, but just long enough for them to sit on the inside of the lip and not fall into the wheel. To ensure this, I have a very slight amount of lateral play in the distance spacer.. probably less than 0.5mm. Is this OK?

I read elsewhere that the distance spacer was supposed to preload the inner race of the wheel bearings. I am not sure how this helps and it would be very tricky to cut the exact perfect length for a custom distance collar such that it just kisses the bearing, but doesnt prevent the bearing from sittting on the seat of the hub bore. It would have to be within 0.1mm, I would guess which is a challenging tolerence for a home garage situation.

Please educate me on what the correct length is for wheel distance collars and if a very slightly too short collar would cause binding or not.

thanks,
mike

|

1/6/2018 1:53 PM

Did you put in the inner hub earing spacer?

Paw Paw

|

1/6/2018 2:08 PM

Paw Paw 271 wrote:

Did you put in the inner hub earing spacer?

Paw Paw

Yes and this is my whole question, Paw Paw.. it is about the length of the space I put in

|

1/7/2018 8:41 PM

Guess I will have to answer this myself.. did more internet research and from the quote below, it seems the distance spacer must be dead balls on to preload the inner races of the bearings. This makes it tricky to cut the perfect length for a custom spacer for a first timer and has becoem a trial and error exericse for me trying to get just the perfect length to get just enough proload while still allowing the bearing to seat.

"I'm a bearing engineer - for real, so I will give you the low down. When you clamp through the axle the load travel through the inner races.the spacer between the bearings ensure that the clamp load goes directly the the inner racesand never through the balls and into the outer races. Without the spacer between the inner races. you can actually Brinell (dent) the outer or inner races during clamping up the bearing, and/or create an excessive axial pre-load through the bearings which will significantly lower the bearings life. Without the spacer you will take up the C3 or whatever manufactured internal clearance is built into the bearings."

|