Given that the E39 typically has a significantly optimistic speedometer,
going to 60 series would likely eliminate most of the error. Of course, if
you're accustomed to travelling @ 83 indicated in a 70 zone (75 indicated +
"8 over" for an actual 78 mph ... will often slip under law enforcement
radar), you're probably going to attract some attention.

The 60 series tire might right a bit better, corner a bit worse.

R / John

"Michael Low" > wrote in message
oups.com...
> The mechanic is wrong - he is mistakenly thinking of 15-inch rims. The
> standard tire size for 15-inch rims on a '97 528i is 225/60-15.
>
> For 16-inch rims, as you've already noted, the correct size is
> 255/55-16.
>
> If you use 225/60-16 tires on your 528i your speedometer will no longer
> be as "accurate" as it "should be". It will show a slower speed than
> otherwise intended by BMW. You may more readily get a speeding ticket
> and your on-board computer may go out of whack.
>
> 225/60-16 size tires may be more common but they are likely of lower
> performance characteristics. Many are probably grand touring tires.
>
> 16-inch rims are actually of a commonplace rim size but BMW chose the
> 225/55-16 tire size for performance reasons so that is why there are
> more tires available at a 60 aspect ratio vs a 55 aspect ratio.
>
> Remember that the standard rim size for a '97 528 was 15-inch. By
> definition, the tires on the 16-inch rim for the 528i is for
> performance and will be more rare on the road.
>