RE: Tire size on '90 325ic

["Ron Buchalski" <rbuchals@xxxxxxxxxxx>]

Larry,

I'll agree with Alex about using this 'Plus 0' upgrade on your car.  I have 
used several sets of 205/60HR14 Yoko A-509s on my E30 318i, and it provided 
a nice performance bump over the standard tire.

I'm not sure where you got the revs/mi number, but it's 874 for a Yoko AVS-I 
in 205/60VR14 (from http://www.yokohamatire.com/04b2e.html )

For my '85 318i, which came with 195/60HR14 tires, the 205/60HR14 tires were 
a bit more than 1.2% larger, but since the car went slightly FASTER than it 
did previously (874 revs/mi versus 891), the "optimistic" speedometer in my 
318i was now a little more accurate.

- -rb

>
>Date: Mon, 7 May 2001 14:04:43 -0400
>From: "Fadeev, Alex" <alex.fadeev@domain.elided>
>Subject: RE: Tire size on '90 325ic
>
>Larry Schwarcz [mailto:lrs@domain.elided] wrote:
>>
>>Well, it's time for me to buy some new front tires for my '90 325ic.
>>But, I've now been told by two different BMW places that I should
>>stick to the OEM size (195/65R14).  I now have 205/60R14s on the
>>rear since Yokahama didn't have the AVS Int in my size (yes, I really like 
>>those AVS Intermediates!).
>
>Larry,
>205/60 is what's known as a +0 upgrade over stock 195/65 tires. It's a 
>perfectly safe and reasonable move, particularly since AVSi's are available 
>only in 205/60 size.
>
>>Any thoughts on running a size that's not the OEM size?  I have a
>>program that shows differences between tires sizes that says:
>>
>>Specification  Sidewall  Radius  Circumference  Revs/Mile   Diff
>>195/65-14         127mm   305mm         1914mm      841     0.0%
>>205/60-14         123mm   301mm         1890mm      852    -1.2%
>>
>>This shows that there wouldn't be much speedo error (-1.2%) and the
>>new tire is 8mm (0.31") shorter and 10mm wider (0.39").
>
>Other than your speedometer indicating slightly (1.2%) higher than actual 
>speed, there are no negatives to going with 205/60/14 tires. Since BMW only 
>guarantees it's speedometers to display 0-10% higher than actual speed, you 
>would effectively we moving that margin of error window to 1.2%-11.2% over 
>actual.
>
>>So, it seems to me that the differences are very small in terms of
>>how the car would handle.  But, are BMWs more sensitive to tire size 
>>differences than other makes?
>
>Nope. I wore off two sets of 205/60 AVSi's on my E30 before retiring the 
>car into daily driver duty (SH30's from now on). AVSi's are the best dry 
>non-R tires you can put on stock E30 wheels!

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