# Tire Size

Grant Lenahan glenahan at vfemail.net
Sat Feb 14 14:36:10 PST 2015

```If you take a good look at the space between the tire and the upright, on a loaded wheel, you can gauge how much clearance you will have.

Grant
On Feb 14, 2015, at 5:20 PM, Vincent Gelinas <vrgelinas at gmail.com> wrote:

> Thanks for correcting my math. I should have known that it was just a radius difference and not diameter. It's been a while since my last math course.
>
> I suppose the worst that can happen is that they don't fit and I sell them and buy the right size.
>
> Thanks,
>
> V
>
> Sent from my iPhone
>
>> On Feb 14, 2015, at 17:11, Grant Lenahan <glenahan at vfemail.net> wrote:
>>
>> According to my math the diameter difference is 1.7” and therefore the radius delta is -+0.85” - a LOT. This also translates into a 9% gearing difference, also a LOT. I can’t say if it will fit, but its very, very big.
>>
>> I run 225/55-16 winters (=2.8%, ~ +.25”R) out of choice, and they look, well, full.
>>
>> To gt the delta you need to, for the radius, multiply the width  delta by the section % (215 x .65 - 215 x .55) = 215 x .1 = 21.5mm increased sidewall - and that is not he top and bottom (only one interferes, but it also increases ride height by nearly an inch.
>>
>> Yuk.
>>
>> Grant
>>> On Feb 14, 2015, at 4:59 PM, Vincent Gelinas <vrgelinas at gmail.com> wrote:
>>>
>>> Hi, all.
>>>
>>> To update, it seems like I had a bad tire. I put the spare on and it all went away. I need four new tires now and I got them for free (almost new Goodyear Extra Grip Ice) but they're 215/65/16 instead of 215/55/16. That's less than an inch difference in  diameter if my math is right (10% of 215 mm is 21.5mm... 21.5mm is around 0.84 inches).
>>>
>>> I know this will cause my speedometer and odometer to read a little slow, but I'm wondering if it will fit under a stock suspension on a 2004 A6qA. C5 chassis. My research points to yes, but I would like the group's opinion.
>>>
>>> I would get the correct size, but beggars can't be choosers.
>>>
>>>
>>> Vinney
>>>
>>> Sent from my iPhone
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>>
>

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