<VV> Re: VirtualVairs Digest, Vol 3, Issue 62

[Kirby Smith]

The steering geometry and wheel offset are normally designed together to 
put the intersection of the axis of steering rotation at a particular 
point under the tire tread, for example at the point midway between the 
edges of the tire tread.  To maintain this geometry with larger width 
(but same diameter) tires, the mounting surface distance from the inner 
bead should increase by one inch for every two inches of overall tread 
width increase.  If the tire diameter (wheel diameter) also changes, 
some geometry homework is in order, although the effect may be slight.

IIRC, offset is positive if the wheel mounting surface is away from the 
middle of the car relative to the middle of the tire (halfway between 
the beads).  I don't have an OEM Corvair 13 x 5.5 wheel in my lap as I 
type, so I can't say what that offset is supposed to be.  (I think Finch 
commented on this, but I didn't see the remark when I looked for it.) 
But unless one has a particular reason for changing the steering 
geometry and resultant handling, the OEM offset should be maintained by 
selecting wheels of correct offset, or using spacers where appropriate.

kirby


virtualvairs-request at corvair.org wrote:

> Message: 8
> Date: Sun, 10 Apr 2005 10:55:41 EDT
> From: JVHRoberts at aol.com
> Subject: Re: <VV> 17" wheels
> To: jsconiers at mac.com, virtualvairs at skiblack.com
> Message-ID: <e6.678e391c.2f8a986d at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> Sure, if you use a spacer. There are plenty of manufacturers out there who 
> make them. That's a LOT of backside specing, and I doubt it'll clear everything. 
> There are also people who make measuring jigs to determine the best 
> backspacing. Sounds like an investment in one of those would be worthwhile.
> 
> John
> 
> In a message dated 4/10/2005 12:46:26 AM Eastern Standard Time, 
> jsconiers at mac.com writes:
> All,
> I would like to get some 17" wheels.  I've foud a set that is the 
> correct bolt pattern (17x8, 5x4.75) however the backside spaciinig is 
> 5.95in instead of 4in.  Will this work?
> JOHN
>