Low-profile tires & ride quality

[Jon Tara <jtara@xxxxxxxxxxxxxx>]

"Thomas, Robert" <RThomas@domain.elided> wrote:

> The single item that will make the most immediate and long lasting
> effect on handleing are tires.  I know this sounds simplistic, but
> experience bears this out.  Going one inch wider and one inch less of
> sidewall will dramatically change handleing (for the better) but with an
> comensureate loss in ride quality (less civilized). 

My own experience bears out the most recent low-profile tire test in Car &
Driver. (Or was it Road & Track?) Advances in construction of low-profile
tires have made this MUCH less of an issue than in the past.

I recently upgraded by 95 325is from the factory 15" alloys to 18x8 front
and 18x9 rear (Kinesis K28) with Dunlop SP-8000 225/40 x 18's on the front 
and 245/35 x 18's on the rear. This is about as agressive as you can get
on a non-M3 E36 without bending sheet metal. And, yes, it looks damn
bad-ass (WHAT sidewalls?), though, of COURSE, that is NOT why I did it. :)

(These really are lovely 3-piece wheels - IMO the most elegant designs
around. HRE is nice. These are nicer. They set me back twice the cost of
the alternative I was considering - BBS RK's, which I do think are a great
value, and seem a practical choice if you just want to step up the size
and get a quality light-weight wheel at a reasonable price. I wouldn't
have spent this much money on a 95 325, except I'd already decided that my
next car will be another E36, verified that the offsets will be OK on the
newer model, and so these wheels will go with me to my next car...)

I'd also recently replaced the factory suspension with Bilstein Sport
shocks, Eibach springs, and Eibach anti-sway bars.

While the suspension made a big difference in handling, the wheels/tires
made a HUGE difference in handling - MUCH more so than the suspension.
Perhaps the handling is too good. I'm afraid I don't play on the edge on
freeway entrance ramps any more. The speed at the limit of adhesion is
imprudent for a public road. :) 

(I do think the suspension mods were necessary, though, as I doubt that
the factory suspension was up to keeping the new wheels/tires where they
belong, if for no other reason than the 70,000 miles it had on it...)

I have NOT noticed any significantly "less civilized" ride quality. (Er,
with the sole exception of speed bumps. The solution to this problem, of
course, is to outlaw speed bumps.) I was expecting a rough ride, and have
to admit that I was initially disappointed (somehow thinking that if the
ride wasn't uncivilized, then the performance wouldn't be up to snuff) and
ultimately pleased that I now have both good handling and a "boulevard
ride".
- -----------------------------
Jon Tara jtara@domain.elided
95 325is

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