High speed over long distance

Let's say you are on the autobahn and your averageing 150mph over 250 miles, how safe are low profile tyres (19") over a long distance in 90 deg + heat?

I would love to be able to find out

Carlos, you there? What's your take on this?

How low a profile do you mean. With 19's your gonna have a 30 profile, no? Not 25. For a fact there are a lor of cars with 19's and a 30 profile, especially German ones, and I would doubt there is any risk at all.

When they test the cars (in Germany) the test is done at top speed for 3 days (72 hours) staight! They illustrated this in the recent documentary on the science channel when then where testing out the 996 and 986. Of course, they were not on 19s, but I don't see that much of a difference.

Never consistently over 130MPH, a few dashes above ( wife along) but my 01 C4 did fine on the autobahn cruising for hours in May/June of 01, moderate temps. It will be on the track at Daytona the first weekend of Feb, but only for a few "slow" laps.

A typical Porsche design criteria is to design and build a car that will maintain Vmax for an entire tank of fuel, without anything melting, overheating or falling off. At least that was a criteria circa aircooled days. I am sure it still exists, although, profit is probably in there somewhere.

I couldnt imagine a 996 or any modern Porsche NOT being able to do that. It wouldn't make sense in any way. Even my 944 has it written in its literature. "150 is not JUST the maximum speed, its also the top cruising speed." Porsche has always made strived for long-term cruising ability at their top numbers. I would just make sure the air pressure is right and tire condition is pretty good.

Scouser I regularly do 150 for 2 - 3 hours in 30 + temperatures - no probs so far.

where?

I obviously live in the wrong place!

The reason I ask is that I am considering entering into the Cannonball 8000 2005 run. http://www.cannonball8000.com (I may not get a place as there are few left). This is a 48 hr sprint from London to Rome. About 1700 miles via autobahn. It will be held in September so high temps. I am more worried about my tyres than the car. Not for any particular reason just always worries me at high speed.....thinking of a blow out.

Scouser I regularly do 150 for 2 - 3 hours in 30 + temperatures - no probs so far. I would love to know the location of a highway that will allow you to cruise at 150 mph for 450 miles straight. I have travelled the world and there is none that I know of.

Porky must be from Montana.....

I thought the speed got limited again backthere

They have 75 mph signs posted! They're collecting the Federal Highway $'s but.....there's a lot of road.....

I think he's using the metric system. 150 km/h or 93.2 mph for 2-3 hours in 30+ degrees Celsius or 86+ Fahrenheit temperatures - no probs so far.

Sorry, I confused everyone. I meant 150mph at 90 deg F !! Got to do about 1700 miles in 48 hours (london to Rome) with nightly stop overs. But there will be some large stretches of Autobahn, I think 250 miles is the longest at any one stretch. I intend to give it plenty wherever I can. But with my so called "none standard" 19" wheels I am just a tad concerned.

Berny, I knew that was what you meant. That sounds awesome -- you should go for it! Do you know which route you're taking? Chunnel to France then down south to Cote d'Azur then the Italian Riviera and down to Rome? Or France to Germany to Austria then Italy? I drove both routes when I lived in Italy. You'll have a great time. Best of luck!

I lived in germany for 10yrs. and I cant remember it having a straight enough area to maintain those type of speeds.

I drove out from California to Arizona and was doing 125+ for 1hr+. I was actually getting worried that I did not see anyone for 1hr. Anyway...car was fine. This was in a GT3, but I dont see how it would matter.

Yeah sounds great but not certain I am in yet. There are only few places left and I haven't had confirmation. Here's hoping. The trip is via France (Calais), Germany (Nurmberg, Munich), Austria then Italy (modena, Rome). What's the roads like? Yeah P-Car944 I agree. Traffic near cities will slow things down. Forgot about that. It's an expensive run. About $7,500 just to enter! Then theres fuel and spends. If I don't get in on this I will be dissapointed but if not I will have the dosh for the EVO supercharger instead. Can't decide which is better

I don't see any problems running those speeds for long intervals. The car should be fine and in fact I think it will do it good :-) I have been driving fast for several days in out of germany with luckily not too much trafic ahead and so speed was rather constant. I got the impression that my tires worn much quicker than usual but I can't vouch for that as I did not mesure depth of thread before. Have fun if you get in.

I don't see any problems running those speeds for long intervals. The car should be fine and in fact I think it will do it good :-) I have been driving fast for several days in out of germany with luckily not too much trafic ahead and so speed was rather constant. I got the impression that my tires worn much quicker than usual but I can't vouch for that as I did not mesure depth of thread before Becasue of the negative camber on the rear wheels, you'll find that the faster you drive on the open road, the faster the inside of the tires will wear. Spritied driving where the back end is pushed down reduces the wear due to the camber becoming more neutral.

The German and Austrian Autobahns are, of course, excellent. It is very easy to drive fast and everyone knows to pass on the left and get back over to the right -- unlike here in the US where we have "left lane bandits." Traffic near the cities (i.e. Frankfurt, Nurnberg and Munich) is a growing problem. It is amazing after you enter the city limits how painfully slow 62 mph (or less) feels! Seeing the circle with diagonal lines (end of restrictions sign) once you leave the city limits is great! Driving through the mountains of the Austrian Alps between Munich and Italy is a lot of fun (although you may need to purchase a sticker for your windshield to drive on the Austrian Autobahn.) You will notice the quality of the road change once you cross the border into Italy -- they're just not as smooth as the Autobahns. However, the Italian Autostrade are still very fast roads -- don't be surprised to be passed by flying Fiat Cinque Centi! Italy has speed limits but I don't remember ever seeing the Policia pull anybody over. The A22 from Austria to Modena is nice especially through the mountains. The A1 from Firenze to Rome is beautiful and takes you through the Tuscan countryside. You'll really appreciate the cabriolet! On your way back to the UK I strongly recommended taking the A1 back to Firenze but instead of going north to Austria, take the A11 and go west to the Italian Riviera -- La Spezia and the Cinque Terre, Genova, San Remo -- and then cross over the border to Monte Carlo. I would spend a night in Monte Carlo and hit the Grand Casino. The Grand Corniche overlooking Monaco is a great drive. La Basse Corniche (the lower road) is the most scenic but also the most congested. The Corniche Moyenne (middle road) is a fun drive with a lot of hairpin turns. It is amazing how fast the locals take those turns but it is also a bit weird since Princess Grace's terrible accident on the Corniche Moyenne is always on the back of your mind. Anyway, drive further down the Cote d'Azur to Nice and Cannes then head north through Lyon to Paris and Calais. I hope you get a spot in the Cannonball. You'll have a blast!