Re: <E28> What made M5 Handle

[SMILLER@xxxxxxxxxxxxxx]

Boy, Richard, trying to start a flame war while so many others are still
going on, that's brave!

>Date: Fri, 22 Jan 1999 22:04:54 +1100
>From: Richard Nott <gis@domain.elided>
>Subject: Re:<E28> What made M5 Handle -incl. Tires
>
>I hope this will encourage a lot of discussion and even disagreement.
>Maybe a die hard M5 fan knows the answers. Here goes...
>
>The E28 M5 had a reputation as a great handling car - WITHOUT the
>tendency for the back of the car to flick out with no warning in the wet
>- unlike the standard 535, 528, or the even worse 520.
>
>What did M GmbH do to make it handle so well?:
>They improved the 65/35 Front/Rear weight distribution by moving the
>battery into the boot.
>        ( reducing the tendency for the back to skip out )

NO BMW since at least the mid-'60s has had a 65/35 weight distribution,
that's more like what you'd find in a front wheel drive car.  The E28
chassis is very close to 50/50.

I had a 1988 535i with Dinan Stage 3 suspension, so it was lowered and
had more negative camber than the stock cars.  When the rear broke
loose, it did so gradually and controllably.  I did not find this to be a
problem.

<much selective snipping follows>

>What can you do to make your non-M5 'Touring Car' handle great?:
>1.  Fit F/R: 205/55/16, 225/50/16 Soft Compound Tyres as done by
>Alpina.

Larger rear tires will decrease oversteer and increase understeer.  If
understeer is how you define "great" handling, go ahead.

>3.  Install Koni Top Adjustable Strut inserts with M-Tech or 535i
>springs.  The springs are the
>        same. See #2 below.

The Konis I've seen (here in the U.S.) are pretty darn stiff, even when
adjusted to their softest setting.

>4.  Install Koni or cheaper Bilstein Comforts at the rear.  Comforts are
>stiffer than Boge.

I'm not familiar with Bilstein "Comforts".  I've seen 3 levels of Bilsteins: 
Street, Heavy Duty and Sport.  Sports are for lowered cars, and are
very stiff.  HDs offer much more control than the factory Boges, but are
not at all harsh.  It isn't clear whether your suggestion of Comforts would
be more like HDs or like Streets.

>5.  Install thicker Swaybar for the front (from Metric Mechanic, KMac,
>etc, 2-3 mm thicker)

This will also increase understeer when used with the stock rear bar.

>6.  Keep the standard rear Swaybar as fitted to M535i, 535i. They are
>the same.

>8.  Install Strut Brace.

This does very little on an E28 car.

>9.  Carry a bag of sand in the boot if your going on a fast country
>trip, especially if it's wet -
>        - These cars are light in the back.

With weight distribution nearly 50/50 (according to the factory published
materials), I don't feel they are THAT light in the back.  Sand bags for
snow and ice, maybe, but not for roads that are just wet.

>#1.  Fit 225/50/16 Front, 245/45/16 Rear if you like Track Events or
>Fast Mountain Roads.
>Personally I prefer F: 225/50/16, and softer compound 235/50/16 Rear
>to absorb bumps &
>keep rear end glued.  Rear 225 or 245 tyres above are actually shorter
>and hence affect
>speedo accuracy, even though they are the correct Plus 2/3 upgrade.

Again, more understeer.  (Plus 2/3 upgrade?  This needs clarification.  In
the U.S., most early E28s came with 14 inch wheels.  16 inch is a plus 2. 
17 inch would be a plus 3.  Most later E28s came with TRXs, size
200/60-390.  Converting from metric, this rim is about 15.4 inches in
diameter.  So going from 15.4   to 16 inches would be a Plus 0.6, close to
two thirds, is this what you meant by Plus 2/3?  Very creaative!)

>I look forward to your comments - flame suit on  :)
>
>Cheers,
>Richard
>
>
>74 3.0S (Since New!)
>86 535i

Well, if your definition of "good handling" is lots of understeer, you're on
the right track.  I guess your goal is for the rear end to never come
around at all.  Personally, I like my car's handling to be more neutral. 
Then I can induce a little oversteer or understeer by playing with the
throttle.  This way the balance can be enjoyed.  I highly recommend
changing both the front and rear sway bars with stiffer adjustable bars. 
The adjustments are used to fine-tune the balance.  Then you can set up
a little more understeer for the track, and a little more oversteer for
autocrosses.  Neutral for the streets.  A little understeer for snow and
ice.

So in keeping with your "flame war" theme, I think your ideas suck!  (Or in
more friendly language, your set-ups are not for me.)

Scott Miller
Golden Gate Chapter
BMW CCA #44977

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