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Low profile tires?

Shawn L. Larsen asked
>Does anyone know how low profile tires effect the handling of a '87
>325is?  If it improves performance or if it doesn't effect it at all,
>then could you suggest some good quality low profile tires.

Any change in tires will affect performance.. 

Tires are sized using 3 main variables:
width, sidewall height, and wheel size.

E30's use 195/60/14" which means
width of tire is 195 mm
sidewall height is 60% of 195mm or 117mm
wheel size of 14" diamater

If you want to change sizes without affecting gearing and speedometer,
you must make sure that the final circumference of your tire is the
same as stock (or pretty close).

You can use the same wheel, buy wider tires with a lower sidewall
ratio such as 205/60/14" ( a popular upgrade ).
width of tire is 205mm
sidewall height is 60% of 205mm or 123mm. <-- pretty close to stock
wheel is same size 14" diameter.

You can buy new wheels (+1 or +2 inch diameter like 15" or 16" or
more) and then buy tires with the same width but lower sidewall height
or even more width and even lower sidewall ratio.

In most cases on dry pavement (not snow or gravel or dirt or..)
wider tires = more cornering grip
lower sidewall = less tire deformation in cornering = more grip

but also with higher performance you have higher discomfort - wider
tires tend to follow ruts in the road more, lower sidewalls mean less
shock absorption and more bumps can be felt in the car, lower
sidewalls mean easier to get flat tires when hitting bad potholes,
etc.

Also, just changing brands of tires can improve performance by a huge
amount. Summer tires and winter tires make a huge difference over all
season tires.

It all depends on what you want. As most things you tend to get what
you pay for. And remember, cheapo discount tires *work* but you *will*
lose much of the performance of your BMW.

Don't let people talk you into more than you want. Buy what you need.

I personally bought some winter tires for the winter ( some used
Michelin snow tires stock size on steel OEM 14" wheels ) and bought
some decent performance Yokahama A509's for the summer in a slightly
wider width ( 205/60/14 ).

Now I'm starting to think about some track tires and another set of
wheels. Sigh. I need a garage :)

chris pawlowicz
'89 325i