Yes htis may sound a little funky, but I'm in between new pairs of
tires..

Today I just got 225/55/16"s (Dunlop SP sport 5000's) put on the rear wheels of my 90 LS..

The fronts are a little different - 225/60/16"s (old worn out dunlops)

The problem I'm having is while on the freeway. The car feels extremely floaty and the rear end moves from side to side alot, like it's doing a bunch of 'mini-fishtails.'

Should this go away as the tires set it? There' maybe 50 miles on these so far. Could it be becuase the front are a higher profile than the back?

 

No answers?

The back end is really floaty on the freeway. I can move the steering wheel left and right at about 65mph very little and after I stop the back end still floats a bit.

 

What you're seeing is normal. New tires have thick threads which tend to be squirmy. Old tires which have balding threads provide a much better steering response. This is the reason autocrossers "shave" their new tire threads in order to get the positive response bald tires provide.

In your case, you put the new tires in the back and so what you're feeling is quite normal. Wait till the new tires settle a bit and you should be ok.

 

K. Thanks for the input.

Basically the guys at the tire shop said the same thing.

COmbination of new tires and bald tires in the fonrt have an effect on new tires in the back. Will get new ones this week.

 

I know it's premature, but the wheels are still floaty and feel like they are grabbing and letting go of the road instantaneously.

I just got the front tires installed yesterday and the float is reduced a little..but it's still there around 60 mph. They have about 40 miles on the front and 300 or so on the back.

At 90+ it's stable, and at 110 the wheels are shaking.

??!!

 

Have you tried switching them front to back to see if there is any difference? Also, since these tires are directional, do you know if they are mounted and rotated in the correct direction at each corner?

 

I thought about the directional thing, but gave the tire shop the benfit of the doubt. I'll check the tire markings today.

Thanks for the input.

 

hmmm. what are your tires inflated to?? you can borrow my gauge