It could be several things, or that model may just be sensitive to tire pressures. Maybe the tires on the front and back or of different vintages? Snow tires are gummy, and after a few years, they lose a lot of that ( a lot sooner actually) stick, even if there is lots of tread left. You can check the manufacturing date by checking the code on the sidewall of the tires.
More pressure will stiffen the sidewall, and reduce the contact patch, somewhat. But the contact patch is quite small, and I think the added pressure would probably have more effect on the sidewall, especially an old style high profile tire. On high performance cars with a really low sidewall, it can be a bit trickier to feel the difference in tire pressures at times, or to my butt anyway. hee hee. Good reason to check pressures often. Another thing to check, is that the tires aren't "under inflated". If a tire is under inflated, once rolling at speed, the added friction generated from things like a "sloppy sidewall" etc, will cause the air inside the tire to heat and expand. Factors like speed, cornering forces, ambient temp, and the weight on them (engine, trunk full of cinder blocks..hee hee), and just how under inflated all play into it. So, check the tires before driving on them, to make sure the tires with more pressure, didn't get that way do to being under inflated, and then just expanded while driving. Just some thoughts I'm throwing out there. Still, seems like a big change in handling and performance, if 4 lbs of tire pressure was the only factor involved between front and rear tires. And hey, what are you doing driving a 240D at 75mph Curt ?? ;-) hee hee. You madman you!! ;-) Ed 300E On 24 January 2012 22:02, G Mann <g2ma...@gmail.com> wrote: > Could it be that the higher pressure changed the front wheels contact > pressure center which was reflected in steering geometry? > > ie. Older car, cumulative wear of all the steering components, which "in > effect" change the caster/camber of the front end, which translates to > "buttock feel" that the rear end was "loose"? > > Following that line of thinking, at 32 PSI the tire is harder, the contact > area is smaller, and steering becomes more "sensitive".... at 28 PSI the > tire is softer, the contact area is spread over a wider area, and the > softer tire "cushions" the worn component movement of the steering > assembly. Result, less "squirrel"... [engineering term, I'm sure]..... ;)) > > Grant... > AZ... > > On Tue, Jan 24, 2012 at 7:47 PM, E M <pokieba...@gmail.com> wrote: > > > After work, did you check the pressures "cold", or after your drive home? > > My backside is quite sensitive to differences in tire pressures. I can > > feel a 4 lb difference, but I'm a little surprised it would take your car > > from being really stable, to where the back end feels like it's walking > all > > over the place. I guess some cars are more sensitive to pressure changes > > than others. Wasn't the old 300SEL 6.3 really sensitive to tire > pressures, > > or they had something funky going on with the tires, that owners often > > complained about ?? > > > > Ed > > 300E > > > > On 24 January 2012 21:16, Curt Raymond <curtlud...@yahoo.com> wrote: > > > > > I put the snowtires from my '83 240D onto my '78 240D the other day. > They > > > were a little squirmy at first but I figured they just needed to get > > fully > > > warmed up with a good drive, they've been sitting over a year after > all. > > So > > > I aired them up good Sunday night for the drive to work Monday morning. > > > > > > On the way to work Monday when I hit 65mph the car suddenly got VERY > > > squirrelly. The rear end felt like it really wanted to wag. I slowed > down > > > and it was fine again, any time I was over 65mph though it would get > all > > > weird. > > > After work I took a look at tire pressure hoping one tire had gone low > > and > > > realized I had mistakenly put 32psi in the FRONT and 30psi in the > REAR. I > > > bled the fronts down to 28psi and on the way home powered up to 75mph > > with > > > no stability issues at all. > > > > > > In retrospect the feeling was almost exactly like when a trailer with > to > > > little tongue weight tries to wag the truck. It amazes me that tire > > > pressure can have that effect... > > > > > > -Curt > > > > > > _______________________________________ > > > http://www.okiebenz.com > > > For new and used parts go to www.okiebenz.com > > > To search list archives http://www.okiebenz.com/archive/ > > > > > > To Unsubscribe or change delivery options go to: > > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > > _______________________________________ > > http://www.okiebenz.com > > For new and used parts go to www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > > > To Unsubscribe or change delivery options go to: > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
