Re: 195s to 215s - Hway Vibes

[raf40@oes.amdahl.com (Richard Funnell)]

I don't have specific experience with that upgrade, but you are increasing
the unsprung weight and should expect a rougher ride.  How much is hard to
say.  Stiffer shocks might help.

>Okay fellow listmembers, I need some wisdom! (Yeah, it's tire-related....)
>
>Here's the story:
>
>I recently got some new "sneakers" for my car (Pirelli P4000 SuperTourings),
>and decided to try upsizing from 195/65/15s on 6J x 15 inch rims, to
>215/60/15s. They fit fine, and in fact, it is an approved upgrade.
>
>These tires seem very nice (i.e. quiet, smooth, responsive, good ride, good
>handling) around town, and at low highway speeds (up to 45-55 mph?), but
>once I get up to cruising at 65, 70 or 80, I get a lot of
>vibration/feedback, mostly through the seat of the pants, and to some
>degree, in the wheel i.e. you can feel the car bouncing around over every
>little bump. The steering wheel does not vibrate back and forth, and it has
>recently been aligned, and all tires balanced and re-balanced.
>
>I was not having this problem with my worn Eagle GAs that were on there (and
>I thought they were horrible... these are "driving" me crazy somewhat... no
>pun intended). So, I don't really think the struts are bad. Unless these new
>tires somehow are exaggerating a problem that was unnoticeable with the Eagles?
>
>Am I just getting more road feel because of the tire size change somehow...
>or are the Pirellis that much stiffer than the Eagles?
>
>Someone mentioned before something about getting more "squirm" when
>upgrading like this. Is that what I am feeling?
>
>I welcome all comments, and if possible, please post to the list or e-mail
>me before Saturday morning, 'cuz I am seriously thinking of bringing them
>back on Saturday to NTW to get them swapped for something else (Comp T/As or
>Dunlops or something...). Should I try the Pirellis again, but at the 195
>size, or go with something else in the 215 size? Or should I get something
>else in the 195 size?
>
>Any and all thoughts are appreciated.
>
>TIA
>
>Jim
>
>
>
>
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>                      Jim Griffin
>             JGriff@ix.netcom.com
>  http://www.geocities.com/SunsetStrip/3010
>      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>                  Quattro List Info:
>                        '92 100S
>          Titanium Grey/Black Leather
>         A               U       D            I
>         ccelerate   ntil    eath is   mminent
>      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>    "Perception is often stronger than reality!"
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Richard Funnell,
San Jose, California
'83 urQ
'87 560 SL