dnwong

I have an original 1986 944 Turbo with factory m474 koni and updated Turbo S sway bars.

Over the years I went from phone dials to Italian Cup 1's and finally just installed 996TT hollow spokes. Granted the wheels are getting heavier. When I went from phone dials to Cup 1's, I could feel the weight of the new setup and lost of some responsiveness. Now, with the 18" Hollow spokes, the car just feels like a dog. Steering response is slow and car ride is feels soft.

Since I don't drive the car much (less than 1K per year), I am not sure if my expectation has changed or has the car's performance changed. During this time I got a 996 C4 upgraded with a track suspension (Bilstein coil-overs, H&R swaps, drop links and the like) to use as a street car.

So, my question: Did the 944 Turbo change that much with the new wheels or has owning a tuned 996 change my exceptions. BTW, the 996 steering is super crisp.

V2Rocket

If anything the heavier wheels on the same suspension should make the ride harder/worse...
What tires/pressure are you running? Same width rims/tires as before?

T&T Racing

The suspension response is affected by the sprung weight, which has not changed with the wheel changes and the unsprung weight which has changed. Changing wheels with different tires affects the spring rate because the tires have either the same, lower, or higher spring rate which additive to the spring rate of the front strut. Also, changing wheels affects chamber, steering angle, and toe.

So it is decision time....get an alignment to see if that makes improvements. Depending on the outcome, drop back to plan B, C, etc, performance and $ can be counterintuitive. Also, Google for suspension tuning to learn what happens when changes are made, better looking might turn out to be not the best choice.

mytrplseven

Is the power steering still operating? I had similar feedback until I looked under the car and found the adjusting strut had broken and the power steering wasn't working.

Humboldtgrin

How does it change the alignment when the tire diameter is near the same? I believe 285 30 18's are even a hair smaller if used in the rear over 245 45 16 tire.

Funn944

Changing wheel sizes doesn't change your caster or toe. I will change the ride feel for a lot of reasons.

catamount

Make no bones about it, if there is any slight against the 944 it's that the steering is "slow".

Humboldtgrin

Tire design has more to do with how a car would feel if everything else related to steering is in good mechanical condition and aligned properly. Usually people don't have all the tires matching in the tires manufacture and make on each different size rim they have, even then the tire may be wider and thinner on bigger diameter rims and handle different then the narrower taller tire of the same make on the smaller diameter rim. With bigger diameter rims that are wider the car tends to "track" the road more, meaning follow groves(usually brushed to the top surface of concrete freeways) and pulling to the low side of the crowned road. Sometimes a lot more depending on the tire designed used.

dnwong

285/30 rear and 225/40 fronts. Appx 30lbs. Wheels / Tires are wider.

dnwong

Power steering is working fine.

T&T Racing

The alignment on the car is for narrower tires. If the tires are wider, then the alignment, unless changed for the specific wide tires, influences how the car handles. The wider tire with the current alignment does not have a full contact patch with the road because the camber setting is for the narrower tire.

porscharu

The larger/wider wheels will have a higher moment of inertia and an increased scrub radius. Both of which will affect steering effort and response. The mass of the wheel will also negatively affect throttle response/acceleration and dampen strut bound and rebound rates. Do you really need the extra rubber or is it for looks?

DasSilberWedge

+1

T&T Racing

Stiffening of the front spring rate, existing front strut springs and larger/wider tires, increases the frequency and amplitude of the front suspension when going from bump (compression ) to rebound (extension ). Increase rebound setting in the front damper (shock) is required to compensate for the higher spring rate. If the front seems soft, it is because the front combo is responding like a baby carriage. If want to correct, more $$$, damper with adjustable rebound designed for your car.