Sealed wheel bearing axle tension

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flybikedave
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Sealed wheel bearing axle tension

Post by flybikedave » Wed Aug 22, 2018 1:10 pm

2010 Solo ST with sealed wheel bearings and disc brakes. I just installed new tires and am now having great difficulty getting proper tension on front axle & nut. When spinning the front wheel, in order to eliminate any resistance/whining noise, I Must loosen both the axle and/or the nut to a point where the dust cover and spacer can both be rotated by hand. If I tightened it up just enough to put tension on the dust cover and spacer, resistance/whining noise reappeared. I am getting conflicting info on the forums and hoping to find some help from you guys who have been. Would greatly appreciate any tips so that I don’t destroy the bearings. Thanks

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Snakeoil
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Re: Sealed wheel bearing axle tension

Post by Snakeoil » Wed Aug 22, 2018 8:15 pm

Not personally familiar with the disc brake front wheel on a Ural. I assume these are ball bearings rather than tapered rollers. This means that the spacer between the bearings has to be correct or you force the inner races against the outer races. I suspect that your spacer is either too short or missing.

Here is an exploded view. The spacer I'm talking about is #14.

The other possibility is the bearings are not driven home in the hub.
Regards,
Rob
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Lokiboy
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Re: Sealed wheel bearing axle tension

Post by Lokiboy » Wed Aug 22, 2018 8:29 pm

My dust covers (front (disk) and back drum)) all can be rotated by hand. I don’t think your jeopardizing safety by loosening the play.
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Obo Scribe
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Re: Sealed wheel bearing axle tension

Post by Obo Scribe » Thu Aug 23, 2018 1:31 am

As long as there is no lateral movement along the axle, then they're fine. I'm with Lokiboy on this one.
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VWK75S
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Re: Sealed wheel bearing axle tension

Post by VWK75S » Thu Aug 23, 2018 4:44 am

Lokiboy wrote:
Wed Aug 22, 2018 8:29 pm
My dust covers (front (disk) and back drum)) all can be rotated by hand..
You may want to check that, on the inside of the dust cover is a tack welded spacer.
John
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Re: Sealed wheel bearing axle tension

Post by Crawford Sales Co. » Thu Aug 23, 2018 7:28 am

The rubber dust cover on one side of the wheel needs a shot of WD 40. Jack up the bike, spin the wheel, shoot it and the noise will stop.
Terry Crawford
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flybikedave
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Re: Sealed wheel bearing axle tension

Post by flybikedave » Thu Aug 23, 2018 9:07 am

Thanks so much guys. Got it right on the edge of “No lateral movement” and no squeak. Good to go! Greatly appreciate the help.

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Snakeoil
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Re: Sealed wheel bearing axle tension

Post by Snakeoil » Thu Aug 23, 2018 10:19 am

Crawford Sales Co. wrote:
Thu Aug 23, 2018 7:28 am
The rubber dust cover on one side of the wheel needs a shot of WD 40. Jack up the bike, spin the wheel, shoot it and the noise will stop.
Terry, what is the factory procedure for tightening that axle? Is it a finger tight and tighten the clamp thing?

I noticed in the diagram that there is a outer spacer and a thrust washer as well. That leads me to believe that there is one step machined in the hub against which the thrust washer is placed and the bearings and spacers are then loaded in from one side and the retaining nut installed. From that I have to assume that the outer and inner spacers are precision machined (Ural, go figure) so that tightening the axle does not put a side load on the ball bearings. If that is the case, then the nut can be tightened as much as necessary and the bearings will stay centered as long at the outer spacer is the same length as the inner.
Regards,
Rob
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Re: Sealed wheel bearing axle tension

Post by Albuquralque » Thu Aug 23, 2018 1:13 pm

Crawford Sales Co. wrote:
Thu Aug 23, 2018 7:28 am
The rubber dust cover on one side of the wheel needs a shot of WD 40. Jack up the bike, spin the wheel, shoot it and the noise will stop.

+1
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Re: Sealed wheel bearing axle tension

Post by Obo Scribe » Thu Aug 23, 2018 6:18 pm

I buggered the wheel bearings on a GS500e Suzuki years ago by overtightening the axle, beacuase of the 'tight is good, tighter is better, and tightest is best' principle. I now know that is not correct. So as long as nothing moves more than it should, it's as tight as it needs to be. I would sooner have a tiny bit of play than a tiny bit of overtight-ness as I can keep a check on the amount of play but overtight definitely wears things in a way they shouldn't be worn.
As a postscript - I'm not an engineer and never have been, but a long time maintaining my own bikes causes me to draw some conclusions. At the end of the day it's a Ural, and WWID...
2003 750 Dalesman, 1975 CB400/4, '93 CBR900RR, 2012 DL650, 91 Ducati 750SS . Twenty eight bikes in the last six years, my missus thinks I have a bike problem. :boogie: ..
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Re: Sealed wheel bearing axle tension

Post by Crawford Sales Co. » Fri Aug 24, 2018 11:46 am

Shown below is a picture of the sealed wheel bearing set up for wheels from 2007 to 2013 as shown on my web site
The parts below the axle are the parts that have to be replaced on the earlier wheels with tapered roller bearings.

The whole idea of this set up is to load everything into a straight empty hole in the hub and have just the center inner race of the bearings and the end distance bushings to rotate that in turn will rotate the axle. Everything else is locked down and can not rotate once the big nut in tight.. There are 15 surfaces that have to be flat and parallel to each other to make this happen. The only surfaces that depend on size are the two distance spacers between the bearings. The smaller one of the two that hits the surfaces of the inner race of the bearings has to be .002 (inch) with a tolerance of +.001 for a total of .003. This lets the inner race move using the built in tolerance of the bearing which is not much. You have to have some free play to make up for all of the 15 surfaces that might not be flat and parallel. How tight you lock down the axle is not that important as you think except to over tighten it a little to square up those 15 surfaces to each other and then loosen it up a little before mounting the wheel on the bike with the dust cover in place. Using a wheel axle will help to load up and get all of the parts square with each other. Just a normal feel is fine because you are locking the axle with the pinch bolt. If the dust cover is tight you are good. The dust cover usually tightens up more when you lock the axle down because it throws surfaces out of square with each other.

The parts coming from the Factory are not machined as accurate as they could be. The kits I sell on my web site are reworked to the above tolerance.
That is about it. Thanks for listening.
Last edited by Crawford Sales Co. on Sun Aug 26, 2018 7:05 pm, edited 1 time in total.
Terry Crawford
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Re: Sealed wheel bearing axle tension

Post by Crawford Sales Co. » Fri Aug 24, 2018 11:50 am

Sorry
The picture did not load up but it is on my web site listed under the - Performance & Upgrades Page.
Thank you
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Re: Sealed wheel bearing axle tension

Post by Snakeoil » Sat Aug 25, 2018 8:19 pm

Thanks Terry. Good description. I tend to think that a lot of riders don't really understand bearings and bearing set-ups.

Knowledge is king!!
Regards,
Rob
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Re: Sealed wheel bearing axle tension

Post by n3303j » Tue Sep 11, 2018 12:17 pm

A properly set up bearing stack in a wheel (or final drive) works quite well at 25 ft/lb axle nut torque. The spindle system is designed that the axle assembly holds all components in rigid alignment. The only movement should be that allowed by the internal clearances (C-3) of the bearings.
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