How much friction in a Crystallite Hub? Overtightened?

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DrInnovation   100 W

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How much friction in a Crystallite Hub? Overtightened?

Post by DrInnovation » Sep 24 2016 9:25pm

How much friction should there be in a hub? I know direct drive has more inherent friction, but I think my hub now has more than normal.

Contact: I bough a used Crystallite 4012/4009 hub and build a bike around it. My original build thread has pic.. https://endless-sphere.com/forums/viewt ... =3&t=80874 The hub was woven in a 24" hub and given my climb on 10% hills I decided to keep it on that. I hack an extension to the bikes caliper brakes, which has worked for about 3 months but the fatigue of daily hard braking on it is taking its toll on the hack so I decided to put on the disc brakes.

When I bought it, the seller included a cover that support a 160mm rotor, so today I put that on. It did not have bearings so I took those from the old cover. When I reassembled I replaced the various plastic washers (one slides into the bearings and the second has a notch for the cable to come out the side. As far as I can tell it was assembled the same as it was before I took it apart.

When I remounted it it spun reasonably well, until I tightened the bolts at which point it was hard to spin and the washers were squeaking a bit so I added some grease, and it will make about 1 or 1.5 rotations from a hard spin. I had never really noted how easily or hard it was to spin before, so I don't know what is normal. But to me it seems something is a miss. if it was a normal hub I would presume I over tightened the cones.. but I don't think this even has cones.. correct?

Is it normal or did I somehow mess something up?
Any ideas what I might have done wrong or how to debug it?
Owner of a Crystalyte 4012/409 with 10aH 16s Headway on a old huffy frame. Its not fast but it climbs my daily commute up 8% and 10% grades nicely. Washout frame with a "e-bike" front-drive hub with a home-built 18650-based 20ah-36v. My bigger "E-ride" is a chevy volt.

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dogman dan   100 GW

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Re: How much friction in a Crystallite Hub? Overtightened?

Post by dogman dan » Sep 25 2016 6:13am

The axle should be supporting on the shoulder of the axle, bearing on the frame. I think for some reason you have the cover rubbing the frame.

But look at one thing first,, if the motor is unplugged, and the big wires can touch each other, then the motor will resist like crazy. It might be that.

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DrInnovation   100 W

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Re: How much friction in a Crystallite Hub? Overtightened?

Post by DrInnovation » Sep 25 2016 5:47pm

Thanks dan.. the axel on the gear side has a nice shoulder and it is sitting nicely. On the side where the wires come out of the motor there is no shoulder, there the threaded axle with washers.

I took it all apart and reassembled it again today. Here is the original ordering
Image
It has two plastic washer element (one notched so the power cable can be laid though it) then two metal washers. The inner plastic washer it an L shape and part goes into the bearing. It seems to rotate with wheel. (does that suggest the bearings are not working properly, or is that normal? The notched one does not rotate.

To be sure it was not a rubbing issue Iadded another washer (which required spreading the frame more) to ensure the disc rotor cannot hit the frame. Still about the same. Clearly spins better if I don't tighten it. Did take it for a ride and it seems reasonable while riding, though hard to tell for sure if its a problem.

I was thinking maybe rather than a the now 3 metal washers I have on the inside, I could get a thin nut to put inside which would allow me to tighten the two nuts onto the frame and allow the bearings to be less tight. Is that reasonable or somehow unsafe?
Owner of a Crystalyte 4012/409 with 10aH 16s Headway on a old huffy frame. Its not fast but it climbs my daily commute up 8% and 10% grades nicely. Washout frame with a "e-bike" front-drive hub with a home-built 18650-based 20ah-36v. My bigger "E-ride" is a chevy volt.

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Re: How much friction in a Crystallite Hub? Overtightened?

Post by amberwolf » Sep 25 2016 11:46pm

If you put the old cover back on, does it still have the problem?

If so, then something is wrong with the way the "new" cover is made, or spaced, vs where and how bearings/etc all sit on the axle/etc.

You might have to add an internal spacer to prevent the cover rubbing on whatever it is rubbing on there, if it's inside the motor.


If it's outside the motor (so that the cover is sticking out past the axle's shoulder), you might need spacer tube with OD no bigger than the inner race of the bearing, and ID no smaller than the axle, to go between dropout and bearing.

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Re: How much friction in a Crystallite Hub? Overtightened?

Post by DrInnovation » Sep 27 2016 11:42am

amberwolf wrote:If you put the old cover back on, does it still have the problem?

If so, then something is wrong with the way the "new" cover is made, or spaced, vs where and how bearings/etc all sit on the axle/etc.

You might have to add an internal spacer to prevent the cover rubbing on whatever it is rubbing on there, if it's inside the motor.


If it's outside the motor (so that the cover is sticking out past the axle's shoulder), you might need spacer tube with OD no bigger than the inner race of the bearing, and ID no smaller than the axle, to go between dropout and bearing.
Thanks.. going back would be a good bit of work and I'll then have no brakes, so I've been trying to avoid that.

Not sure what you refer to as the axel shoulder.

Here a pic of the inside of the old cover, where the bearings went.
Image

In the old cover the bearings were close enough to the front that the plastic insert would go inside. As you can see in the photo above, there is a small gap between the metal of the hub and the plastic of the first washer.

The new cover with the disk brakes is thicker with the offset for the brake rotor and the plastic washer does not reach it and is instead flush against the hub and the washer spins somewhat with the wheel or slips but then there is friction between it and the next washer. I've looked online but so far could not find any of the T-shaped washer.

My idea was to add a jam nut (like http://www.lowes.com/pd/The-Hillman-Gro ... ts/3012489 on the inside of the fork (removing the washers) and then when I tighten the outside nut it will not increase the pressure on the hub motor. Does that sound like a reasonable solution? is there some safety factor I'm not seeing?
Owner of a Crystalyte 4012/409 with 10aH 16s Headway on a old huffy frame. Its not fast but it climbs my daily commute up 8% and 10% grades nicely. Washout frame with a "e-bike" front-drive hub with a home-built 18650-based 20ah-36v. My bigger "E-ride" is a chevy volt.

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Re: How much friction in a Crystallite Hub? Overtightened?

Post by MadRhino » Sep 27 2016 4:50pm

You need to make C-washers to extend the axle shoulder long enough to clear the disc cover that is thicker. The open part of the C-washers matching the axle channel, and the outer small enough to clear the cover so you won't have any rubbing. the plastic wire cover becomes useless, but you still can cut it and use it if you want to.
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Re: How much friction in a Crystallite Hub? Overtightened?

Post by amberwolf » Sep 27 2016 5:05pm

[quote="DrInnovation"]Not sure what you refer to as the axel shoulder.
The axle has a point at which it becomes narrower after exiting the side cover. This is to rest on the dropouts.

If this narrowing point (shoulder) is not outside the cover (and disc brake rotor and bolts!) then those will press against the dropout instead, and the wheel can't turn properly.

Your rotor-capable cover is wider than the original, so the axle shoulder has to be wide enough to work with both--it probably is not, and this is probably causing your problem.


I cannot see your image; it just comes up as a circle with a dash in it for me. If you upload the image to the forum like you did your previous ones, I will be able to see it.


The jamnut idea might work, but is not necessary.

All you need is a spacer tube (or stack of washers) that has an inside diameter big enough that the threaded part of the axle *just* fits thru it, rests on the axle shoulder but small enough diameter so that it does not touch the motor cover, and is just long enough to force a gap between cover, rotor, rotor bolts, and dropouts/frame.

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