Re:<E28> What made M5 Handle -incl. Tires

[Richard Nott <gis@xxxxxxxxxxxxxxxx>]

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 )
They installed Self-Levelling Rear Suspension, removing excessive
negative camber when heavy or lowered.
        ( Increasing the Tyre Contact Area & Rear Weight... improving
their notorious light back end.)
They used firmer springs, shocks and Swaybars.
        ( Making it handle better )
They installed 225/50/16 Tires all round on 7.5x16 Rims w- 20mm offset
and rolled the rear fenders.
        ( Giving it higher levels of adhesion )
Did they modify the rear wheel camber, less -, to improve rear tyre
contact, in addition to Self Levelling?.
        ( Giving it higher grip especially when cornering on off-camber
bends made worse by body roll?)
Who knows what else they did to suspension geometry and weight?.
        ( I'd REALLY love to know!  Anybody have a friend at M GmbH? )

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.
Very safe in
        the wet. See #1
2.  Get a Camber/Toe Correction (eccentric) Bush for Rear Susp.(BMW,
KMac) Removes
        excess negative camber. (I suspect this gives better adhesion on
off camber bends)
3.  Install Koni Top Adjustable Strut inserts with M-Tech or 535i
springs.  The springs are the
        same. See #2 below.
4.  Install Koni or cheaper Bilstein Comforts at the rear.  Comforts are
stiffer than Boge.
5.  Install thicker Swaybar for the front (from Metric Mechanic, KMac,
etc, 2-3 mm thicker)
6.  Keep the standard rear Swaybar as fitted to M535i, 535i. They are
the same.
7.  Keep the standard factory Front and Rear Springs (M535i, 535i are
the same).  Lower
        springs will bottom out all the time. See #3.
8.  Install Strut Brace.
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.

#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.
#2.  In stiffness, Koni is between Bilstein (harsh) and the standard
Boge (soft).   Bilsteins are
too rough and make the car unpleasant to drive around town.   They are
only good at speed! -
high enough to loose your licence. Just drive an M535i and 535i and tell
me which is better.
The only difference are the shocks.  The M535i has Bilsteins and every
bump on the road
jars the car.  Not a nice setup. The 535i uses Boge shocks - not sporty
enough for my tastes.
#3.  Not only do lower springs bottom out all the time and make your
BMW: "The Ultimate
Unpleasant Driving Machine",  but I am yet to find one that lasted 12
months before sagging!.
BMW Springs are almost impossible to drill a hole through, after market
"highest quality
hardened chromium grade steel" can be drilled through easily (don't ask
me how I know).
But this proves they are much softer than genuine springs.  Personally I
think their all crap
and inferior to Genuine BMW Parts, but if you know one that's good after
3 years...
let me know, Hell, let everyone know!.

#Note:  This setup is not for drivers who enter Track Events, but for
fast daily drivers on
normal roads (120-180 km/h), while still being pleasant to drive around
town.

I realise each person has an individual opinion regarding springs and
shocks.  My opinion is for
other E28 owners, who are interested in a proven daily driver setup that
works brilliantly. It's
been learned after the mistakes that only experience (building three
5'ers) can give you with
Lower Springs/Firmer Shocks, etc, for E28's only.

But the whole point here is to find out what made the E28 M5 such a good
handling car and
this is what it would be great to get some opinions on.  Does anyone
know what else they did
to improve the handling and chassis dynamics?.

I look forward to your comments - flame suit on  :)

Cheers,
Richard


74 3.0S (Since New!)
86 535i
This info and more can be found at:
Richard Nott's BMW Database:
http://www.gis.nsw.gov.au/staff/rnott/bmw/bmw.html

------------------------------