205s and 245s

[GeorgeM]

Anyone running 205/55/16 front with 245/45/16 rears?

I can't get the 225/50/16s to fit up front with my 7 in Fuchs and I just bought a set for the track. I have 7s in front and 8s in the rear.

Is there any issue with that much difference between front and back?

I assume there's not that much difference in the 245 and the 225 on the back either. More is not always necessarily better (?).

I seem to remember this topic covered in the past, but can't seem to locate the thread.

Thanks.

[Bill Verburg]

The 245/45 is a better rear tire than the 225/50 for several reasons

• 245 is shorter for better gearing
• sidewall is shorter/stiffer for better handling
• less oversteer

The 205 is fine in combination with either of the above rear tires. The 205 will promote understeer a bit more, 225 will allow better utilization of your bigger brakes though and promote more oversteer.

Other factors such as swaybars and tire air pressures can be used to fine tune over/under steer so it's the least significant factor mentioned.

[Jack Olsen]

I ran that combo for a long time, and was happy with it. I also couldn't fit 225's with stock 7's. Every car's a little bit different.

[GeorgeM]

Thanks guys.

My last set of A-032s were those sizes, and it seemed to be okay to me.

I just remembered someone making a comment about too much difference between the 205/245.

Just got a set of AVS Intermediates for the track when we move to Germany. Apparently, the PCA there doesn't allow track tires (treadwear rating less than 100) for their competitive slalom series. Since the TUV doesn't allow the locals to use them on the street, it would be an unfair advantage for us military folk (those rules don't apply to us I guess). So the PCA leadership voted track tires out for competitive events.

[Joeaksa]

George,

Are you PCS'ing to Germany? I lived there ten years ago and at this time we did not have to abide by TUV rules with regards to our licensing and inspection of the cars. Have not heard that its changed since this time.

They have their own on-base inspectors and licensing and its a lot easier than going on "the economy" especially with regards to cars. One important aspect is that if the factory has not approved 245's on the rear of your 911 for that model year, then TUV will not allow you to use them, period, end of discussion. The American inspectors are not bound by this restriction and should allow you to use these tires and other parts on the street that a local national cannot even think of using.

Joe

[PeteBrown]

I'm currently running 205/55 with 245/45s on my car with Todd Serota's alignment specs which are -1/16 toe in front and back, 1.0 neg camber in front, 1.3 neg camber in back and 5.5 deg of caster. The tires are some sort of Dunlop DP5000 I think that came with my 7&9x16s I bought from a Turbo owner.

Compared to m 6&7s which had 205/225s on a stock alignment, the 245s really plant the rear end. The car exibits understeer when accelerating out of a turn but this can be managed into slight oversteer using the throttle. The rear end breaks away in a much slower, and more manageable rate than with the 225 which were crappy BFG all season tires. I would like to put 225s up front to reduce the understeer but that will have to wait.

Next year I will buy some new tires.

Pete Brown
'87 Coupe

[Milu]

I'm running the following Fuchs combinations on 88 Carreras:

6 & 8s with 205/55 & 245/45 (Pirelli assim)

6 & 8s with 205/55 & 225/50 (winter tyres, Pirelli)

7 & 9s with 205/55 & 245/45 (Goodyear Eagle)

Both cars are at Euro sport ride heights. No clearance problems.

I think that the inset of the 9s is different and consequently a narrower track. If it's a consideration one can always add a spacer. The 7 & 9s "spread" the tyre more and the car just feels more sure footed in spirited driving.

In 1988 and 89 the 7 & 9s with 205/55 and 245/45 were available as an option in the UK and I believe in Germany so they are ipso facto approved by Porsche.

German Pelicans can probably expand or correct me on the TUV process but it is my understanding that if one departs from original manufacturer spec it is relatively easy to have the new spec tested and approved. In Italy where changing to a non approved tyre combination is an administrative mightmare one of the ways around it is to re register the vehicle in Germany, take it through the TUV process and then re-register it in Italy with the TUV certification which is accepted. I believe TUV have now opened an office in Italy for motorcycles to expedite the process!