250 narrowcase rear axle orientation info needed

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JimF
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250 narrowcase rear axle orientation info needed

Postby JimF » Fri Jun 08, 2018 12:34 am

I know, horizontal....

But I did not pay attention when I took the old bearings out.

I am getting ready to put in a new bearing on the brake drum side of the rear hub.

Between the bearings the axle which is shouldered becomes captive.

I just realized that the axle is about 9mm longer (0.325 inches) on one side of its collared shaft than the other. I suspect the longer side of the axle goes through the cush drive/sprocket flange side given the added depth of that assembly, but my suspicions and sound logic are only right about half the time.

Would someone advise me if the longer side of the axle goes towards the sprocket flange or the brake assembly.

Thanks.

Jim

Bevel bob
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Location: Bromley Kent UK.

Re: 250 narrowcase rear axle orientation info needed

Postby Bevel bob » Fri Jun 08, 2018 4:09 am

Hi Jim, I had my rear hub to bits recently (can't remember which way the axle went! dont think mine has a shoulder at all) but had some interesting information from Nigel Lacey on hubs ,it would be usefull for you to look up the posts(28.3 2018). I initially thought my spacer too short (which would allow the bearings to jam under the axial loading of the axle being tightened), I then found the spacer was long and did not allow the bearings to fully seat in the housing, Getting it perfect was beyond me ,so I left it long. the lesser of 2 evils?. One of the bearings was a bit loose in the housing and was fitted with locktite, have to keep an eye on that.Just remembered ,my spacer just a plain bit of tube!.Look out for fine cracks in the alloy housing around bearing, not acceptable.

Paul W.
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Joined: Mon May 20, 2019 11:14 am
Location: NYC/NJ

Re: 250 narrowcase rear axle orientation info needed

Postby Paul W. » Mon May 04, 2020 9:18 pm

Hmm, the answer to this question has never been posted. Were you right, Jim? Does the longer end of the captive rear axle belong on the drive side?

Duccout
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Location: Essex UK

Re: 250 narrowcase rear axle orientation info needed

Postby Duccout » Tue May 05, 2020 6:22 am

Is your spacer original? I thought all the hub bearing spacers were just simple lengths of tubing? Could yours have been modified?

Jon Pegler
Posts: 459
Joined: Sun May 16, 2010 6:19 pm

Re: 250 narrowcase rear axle orientation info needed

Postby Jon Pegler » Tue May 05, 2020 7:54 am

The early rear wheel spacer was integral with the axle shaft itself, not a separate length of tube between the bearings.
One end of the shaft was 70mm long and the other end 78mm long, either side of the stepped spacer.
From memory, I think the long end was on the LHS.
If fitted the wrong way around it is impossible to fit the wheel into the swinging arm.
The early rear axle with the stepped shaft was also common on many Spanish Ducati singles long after the plain axle shaft had been adopted by Bologna.

Jon
Last edited by Jon Pegler on Tue May 05, 2020 3:29 pm, edited 1 time in total.

DBDBrian
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Re: 250 narrowcase rear axle orientation info needed

Postby DBDBrian » Tue May 05, 2020 11:12 am

Long end of shouldered spindle towards brake plate.

P1070725.JPG
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Brian
Made in England

Paul W.
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Location: NYC/NJ

Re: 250 narrowcase rear axle orientation info needed

Postby Paul W. » Tue May 05, 2020 2:28 pm

Thanks Brian. It's a little counterintuitive, as Jim and Jon will note. My brakeplate and cushdrive are elsewhere, but I deduced the orientation after my post. I'm glad for confirmation. A mnemonic: Long End Left.

Commodore
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Re: 250 narrowcase rear axle orientation info needed (Front, too!)

Postby Commodore » Sun May 10, 2020 7:39 pm

Sorry to tag along on this subject, but it is axle related, only front. My front axle is so short that the axle bolt only has about half of its depth engaged in axle threads. Now, I'm not sure why.

I have rebuilt my entire front wheel, following good advice found elsewhere here on the forum. I believe I have shims in the correct spots. The wheel is centered between the fork legs. I believe I have the axle engaged correctly in the right fork leg.

So, were there different length axles? When I bought my '66 Monza it was in baskets, there were two sets of hubs and one set of wheels. The previous owner(s) tried converting this into a chopper. And some of the parts seemed to have been from a scrambler. Therefore my question about axle lengths.

Hope to post more pictures in the near future, as one benefit of self isolation is much more garage time. Thanks for your help once again, and keep well.
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Jon Pegler
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Re: 250 narrowcase rear axle orientation info needed

Postby Jon Pegler » Sun May 10, 2020 8:21 pm

It's not the axle lengths that are different, it's the speedo drive plates.
There are speedo drive plates with narrower bosses in the centre that allow the axle to pass further through the RH fork leg.
When the nut on the LHS is tightened, it pulls the whole wheel assembly to the left.
With a thinner speedo drive plate boss this allows the spindle to go further, exposing the full thread for the nut on the LHS to fix to.

Jon

tobydmv
Posts: 88
Joined: Wed Apr 16, 2014 4:59 am

Re: 250 narrowcase rear axle orientation info needed

Postby tobydmv » Mon May 11, 2020 1:21 pm

Talk about wheel candy, man those are some nice wheels. What brand and size are you guys using for rims?


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