Why are the fronts always smaller on 911s?

[pwd72s]

I went to 7's all around back in the 1970's, the car was 6's all around stock. In some ways I wish I hadn't done it, because there were clearance issues....but even today, I think it looks okay, kind of cool...

[911-m5]

Ok an added question... Did all the ST's run smaller wheels in the front?

[911-m5]

Or I guess I should have said narrower.

[pwd72s]

I'm no expert, but I believe so....ST's were flared in the butt end...and the pics I've seen often show them running minilites in the rear, fuchs up front...so makes sense that the rears would be wide wheels than the fronts...

[911-m5]

I think they had 9" flares front and rear. I'm no expert either.

[pwd72s]

Let's hope an ST expert weighs in here. I'll confess to not researching them. I couldn't justify spending the $ the real deal would cost, and the over the top replicas running big bore air cooled engines aren't my style. So, to each his own, eh?

[Bill Verburg]

It' totaly for handling, as the cars became more and more powerfull they needed more rubber, at both ends, but the difference between front and rear grew at the same time while tire and suspension technology advanced at a very rapid pace

1973RS 210hp 6 & 7 x15 185/70 & 215/60
1976C3 200hp 7 & 8 x15 205/50 & 225/50
1995CRS 300hp 8 &10 x18 225/40 & 265/35
2007GT3 415hp 8.5 & 12 x19 235/35 &305/30

of course all sorts of other things were tried as well, everything from adj. sway bars asymetric and/or electrically controlled diffs, traction control to electric control of shocks etc.

[Miguel Antonett]

It is for traction.
The rear end carries more weight = oversteer, and power transfer to the road; those two issues are compensated with a bigger rubber patch on the rear.
If you pay attention to some of the high performance front wheel drive cars the bigger tires are up front = funky looking too!

[dd74]

Originally posted by Miguel Antonett

If you pay attention to some of the high performance front wheel drive cars the bigger tires are up front = funky looking too!

FWIW - not OEM equipped. Honda builds probably the ultimate in high performance FWD cars, and all four tires on all four corners, are the same size with each car.

The Integra R from about ten years ago, still stands as one of the fastest, best handling FWD cars produced. It used Bridgestone Potenzas IIRC, and they were the same size, front to rear.

So far, the only FWD car that has come close to the Integra (in the U.S.), is the Civic Si - which I think pulls about .98 on the skidpad. It uses same-sized tires and wheels on all four corners.

Of course, both cars have OEM-equipped LSD, which helps.

[ruf-porsche]

It just look cool with big tires in the back and small tires in the front, just like a real race car.

[john70t]

From an engineering standpoint, it's a bad design, along with the cooling airflow and some of the electrics(appologies to Herr Dr.).

A narrower front will want to roll more. Think of a triangle with the point towards the front. Assuming no limited-slip, the rear outer tire with the weight is pushing forward into space, wanting to break loose the chassis.
The front wil be nimbler, and big hp and tires can help any situation, but...

[pwd72s]

Originally posted by ruf-porsche
It just look cool with big tires in the back and small tires in the front, just like a real race car.

You mean like they do at the drags??? Grip at the drive wheels matters most there, since the race is in a straight line...