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Re: wheel spacers, please don't...

To: Ofarrell.Fergus@hitco.com, datsun-roadsters@autox.team.net
Subject: Re: wheel spacers, please don't...
From: "Ian Miller" <ianmiller07@hotmail.com>
Date: Wed, 13 Aug 2003 15:29:20 -0400
I have removed the dust cap to try and fit the center cap, just for fitment 
purposes, and it was a no go.  I took some quick measurements and my new 
wheels actually move the wheel centerline in approximately 3/8-5/16 of an 
inch.  That means by spacing the wheels back out I am placing the load back 
in its original position.  Now its also true that the new wheels and tires 
will provide mor grip increasing the loads while cornering.  So I'm not too 
worried about wheel bearing failure.  Now you brought up the bending moment 
induced in the studs from the wheel spacer.  This made me think, and now I 
thave thought myself in a circle!

Consider the simple case, without a spacer.  Cornering forces would not 
generate a verticle load on the studs, so no bending.   Brake and bump 
forces do generate a verticle load.  It would be equal to the spring force 
at whatever maximum displacement, then it would go infinite as the spring 
bottoms out.  So That force is what causes the bending moment on the studs.  
With out a wheel spacer the force acts at the face of the wheel/hub surface, 
essentially putting the stud in shear.  When I add a 1/4" spacer I am moving 
that force out 1/4" on the stud and now I am putting threads in bending.  I 
know how bad this is, it was one of Carrol Smiths pet peeves.

Ok so now what can be done about it.  I have never had the rotors off my 
car, but I assume then act as a wheel spacer in themselves.  Do they sit on 
the shoulder of the stud?  Could I drill through my wheel spacers and tap 
the rotors so the rotor/spacer assembly would be 1 piece.  Would that help.

You refer tot he good kind.....what are they?  what do they do differently?

Thanks
Ian



>From: "O'Farrell,  Fergus" <Ofarrell.Fergus@hitco.com>
>To: "'ianmiller07@hotmail.com'" <ianmiller07@hotmail.com>
>Subject: wheel spacers, please don't...
>Date: Tue, 12 Aug 2003 13:41:31 -0700
>
>Ian,
>90% of the wheel spacers you will find are very dangerous, they are just
>glorified washers which load the studs in bending rather than tension.
>Lots of wheels are based on the rim inner circle locating on a ring on the
>hub.  while roadsters are not that way (they center using tapered lug 
>nuts),
>wheel spacers are verboten issue when talking of safety.  (and we all take
>enough risks with the 10+ foot SUV's roving around)
>
>What Bill Kenyon describes as wheel centers are "the good kind", which is
>also "the rare kind" and "the pricey kind".
>
>the bearing dust cap is just that, a dust cap.
>whack the end with a dead blow hammer until the center cap fits, you'll
>sleep better in those high-speed turns.  (ooh, bad analogy there eh?)
>
>Fergus O in CA
>
>
>Date: Tue, 12 Aug 2003 15:55:13 -0400
>From: "Ian Miller" <ianmiller07@hotmail.com>
>Subject: wheel spacers
>
>Does anyone know of a source for wheel spacers.  I need to space my front
>wheels anout 3/16" to fit my center caps over the bearing dust caps.  I
>guess I will also need to install new wheel studs.
>
>Thanks for the info!
>Ian

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