Date: Sun, 6 Mar 2005 08:31:09 -0800
Reply-To: mark drillock <drillock@EARTHLINK.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mark drillock <drillock@EARTHLINK.NET>
Subject: Re: [syncro.org] Wheel offset
In-Reply-To: <20050306152116.64100.qmail@web60309.mail.yahoo.com>
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If you are right that a ET38 steel 14x 6" wide would only clear by 1/8"
then an alloy of that size would probably rub since they are thicker
metal. Your data shows that the rim clearance increases as the rim
diameter goes up but does not take into account the critical tire
clearance issue at the upper ball joint area. When VW used 15" rims they
made them 6.5" wide but did not change the offset from the 14x6 ET30 as
they still used 205 width tires. Since tire dimensions are so variable,
the only way to be certain for some tires is to try one.
Syncros have much less of a clearance issue and can use wider tires and
even rims with ET of 45.
Mark
TJ Hannink wrote:
>On Sat, 5 Mar 2005 15:12:25 -0800, mark drillock wrote:
>
>
>
>>VW did not make the 14x6 alloys with a different ET than the 14x5.5
>>steels to keep the rims from rubbing. They did it to keep the wider
>>tires from rubbing.
>>
>>
>
>I happened to be rotating the tires and checking the front-end alignment on Goldibox this morning and decided to do some checking. I bolted on a stock steel 14" wheel (less tire) 5.5" wide with 38mm of offset to the front right hub and measured the clearance between the inner edge of the wheel and the spindle and found 20/64" or 8mm of clearance.
>
>While a 14"x 6" wide ET38 wheel would (just) fit without rubbing, there would be less than 1/8" of clearance. I would guess that VW decreased the offset of the 6" wide alloy wheel in order to keep the same amount of clearance that the steel wheel had, and that having the proper amount of clearance was more important than having the 'correct' offset. AFAIK, they made no changes to the front suspension when they added the alloy wheel option so decreasing the ET by 8-mm must not have been a critical problem.
>
>While I was at it, I built a test jig and measured the clearances of wheel diameters up to 19" relative to the front spindle/control arm using the 5.5" ET-38 inside edge as a reference point.
>
>They are as follows:
>
>15" 53/64" 21mm
>16" 63/64" 25mm
>17" 66/64" 26mm
>18" 100/64" 38mm
>19" 168/64" 67mm
>
>An excel geek should be able to use these numbers and, by modifying wheel width and offset, calculate the amount of clearance a given wheel will have and the width of spacers required (if any) for the wheel to clear the 2wd front spindle/upper control arm.
>
>Remember that these numbers are for wheel clearance only and only for the front of the 2wd Vanagon; Use at your own risk!
>
>Thanks,
>
>
>
>
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