Why does the steering feel so much heavier?

Deschodt · 07-31-2006, 11:32 AM

I recently traded my 73.5T for another CIS car, an 83SC...

Themost shocking thing is the weight of the steering on the SC compared to the T. Why is that ?

Bear in mind: same situation all around, new shocks, new alignment, same steering wheel on both cars (a Momo race), practically the same tire size (195 vs 205) - so why does the SC feel so much heavier to steer ?

Just curious ! I know the car itself is heavier but suspected the weight was mostly interior and engine, the nose part looks very similar in terms heavy stuff, could it be all it is ? Impact bumpers ? I though that on 2 cars w/o power steering, on similar tires, it should feel close ! The SC feels twice as heavy to steer ! Twice as solid too, mind you !

Engine wise, I really liked the 2.4 T with shorter gear ratios more in first and second gear - it was a rocket. But once in 3rd, the SC's torque is felt and the car feels more solid over 85 mph !
I think it's the gearing that did it, the Sc feels like it has a way longer 1st gear - maybe too long !

Flyer88 · 07-31-2006, 11:35 AM

Strut tower brace and turbo tie rods will make a world of difference.

Deschodt · 07-31-2006, 11:37 AM

Got the TT-rods already, and it's lowered a bit, I should have said...
You are saying a strut brace will make the front end feel lighter ?

450knotOffice · 450knotOffice's Garage

Caster setting has an effect on the "weight" of the steering. The less caster, the less steering "weight", IIRC. More caster gives you better stability at speed but resists steering inputs more. Less caster gives a lighter feel but less high speed stability. I'm not sure of the stock caster settings on the two cars but I suspect it might be less positive on the older car than the newer car.

And yes, tire size will have an effect, as will the weight of the front bumpers and any junk in the trunk, tank capacity, etc.

Jastx · Jastx's Garage

wider wheels and tires, no?

cbeers · 07-31-2006, 01:41 PM

Greg, don't you have a car that is really two halves spliced together?

Could have something to do with it.

I would bank on the combo of what has been said:

wheel/tire set up
alignment set up
added weight in the front of the SC, even if most of the added weight is in the rear.

-Chris

blackbear bob · 07-31-2006, 01:44 PM

greg,
you have lost(sold) that lovin feelin
early cars have it and sc's dont.
cheers
bob

Miguel Antonett · 07-31-2006, 01:49 PM

IMO caster, toe and wheel/tire combination... I re-aligned mine last week and came back "TOO LIGHT"; re-adjusted the caster and the feeling came back.

911pcars · 07-31-2006, 01:58 PM

Both cars are basically 40-60 frt/rear. The SC is heavier, thus more weight in the front as well.

If you like the lightweight feeling, put more air in the front tires or put the SC on a diet.

Sherwood

Flyer88 · 07-31-2006, 02:10 PM

Quote:

Originally posted by Deschodt
Got the TT-rods already, and it's lowered a bit, I should have said...
You are saying a strut brace will make the front end feel lighter ?

I had both done at the same time so hard to say - my guess is mainly tie rods. I was night and day though and my front end is at 24" (since).

Early_S_Man · 07-31-2006, 02:42 PM

The 205/55ZR-16 tires have a wider tread and larger footprint than 195/65ZR-15 or 195/60VR-15 tires ... also, the scrub radius is longer, requiring higher steering effort with the same steerring wheel.

Jack Olsen · 07-31-2006, 03:51 PM

There are lots of unknown in the equation, from tires to alignment settings to the condition of the steering racks.

Chuck Moreland · 07-31-2006, 04:18 PM

Tire size, tire pressure, wheel offset, caster, camber, and vehicle weight - all affect steering "weight".

Paulporsche · 08-01-2006, 05:02 AM

Were both cars set up the same WRT front/rear ride heights? If not, the car w/ a lower front ht relative to rear will have more weight distributed to the front, which will create heavier steering.

lateapex911 · 08-01-2006, 08:40 AM

911s have the most sensitive steering in the world, nearly. Anything becomes magnified, Chuck hit the big ones. 1 degree more caster can make a big difference in feel. And air pressure is huge too.

rlh930 · 08-01-2006, 08:58 AM

I have a similar difference between my '73 911T and '87 930. The Turbo's steering is much heavier. This in spite of the fact that the '73 has Turbo flares and is running 245's on the front vs. 205's on the 930.

Part of the difference in steering effort is probably weight (2900 for the 930 vs. 2400 lbs for the 911), but it is also true that, per the Porsche spec book, the '73's caster is 5.5 deg. vs. 6.5 for the Turbo. Caster is also 6.5 for the SC, so my guess is that more caster is the real difference.

450knotOffice · 450knotOffice's Garage

I noticed the same thing after my alignment guru re-aligned my car last year after I'd rebuilt the suspension. I think he pulled the caster back to at least 6.5 degrees and the steering became noticably heavier than it had been before (which previously had the lightest steering of all the Carreras I'd driven).

Caster seems to be the main culpit here.

72doug2,2S · 72doug2,2S's Garage

I have to agree on the setup. I bought my 72 after driving a very heavy steering SC. I thought this is just how they were, until a few weeks ago when I got to drive a friends 82 and BoxsterS. That 82 was really sweet. I never thought a 915 could shift that crisp and the steering felt just right.

lateapex911 · 08-01-2006, 12:16 PM

Honestly, I find caster to be (within a reasonable range) a matter of personal taste. I think that if you like light steering, go for a bit less. Or if more force as you turn is your thing, then add some caster.

In racing, i like a bit more caster, so that I can feel the forces load, and more importantly, unload through the wheel. It helps me get a better idea of whats going on at the interface point of road and rubber.