Best Tire Pressures?

[desperado]

The factory recommended tire pressures are 39 psi front and 36 psi rear. I 'm running the stock summer performance tires.

The car feels slightly 'nervous' at SoCal freeway speeds (still not broken in completely, so don't know about higher speeds yet). The dealer had the tires set at about 36 psi all around, and it may have felt better at that setting.

My question for the R8 owners out there is, has anyone determined their personal favorite tire pressures to run on the street? I'd appreciate your insight!

[SFR8]

My dealer sets my front tire pressure at 38 and rear at 35 (1 pound less than factor recommendation). I just got mine last Tuesday and have been cruising around 70 to 80 mph with occasional burst up to 110. The car feels VERY stable at 110. 60 and 90 mph feel about the same. No nervous feeling at all. Try my setting and see how it works out for you.

[hmp10]

The car feels slightly 'nervous' at SoCal freeway speeds (still not broken in completely, so don't know about higher speeds yet).

I keep my tires set at exactly the factory spec and have no problem. Are you sure you're not experiencing tramlining from the very wide rear tires on freeways that have developed slight longitudinal grooves?

[Rob A]

Since I'm based in Europe -close to Germany- I likely reach higher speed than the average North America-based R8 owner, but I have found no need to use other pressures than those Audi recommends.

[desperado]

Thank you all for responding.

Tramlining is a good word! Yes, the freeways here are mostly concrete and are intentionally longitudinally grooved (with saws) for our occasional wet weather. That could be what's going on, however the TT is extremely stable and well balanced on the same roads and under the same conditions, such that 100 mph speeds are a total non-event.

Since the R8 has even wider and lower profile (stiffer) tires, it could just be that difference. The car isn't bad, but it is not as confidence inspiring.

I've driven in Germany, Switzerland and Italy recently, and it's true that the Autobahn and Autostrada are in generally better condition than our USA freeways for high speed work. Unfortunately our interstate freeway system, which was the best in the world and is still the most extensive, is showing its age. Traffic levels are certainly way up from the time of its inception, and deferred maintenance is becoming quite noticable. Seems the national priority has shifted away from infrastructure (which benefits all) and toward wealth re-distribution.

Not to mention the fact that European drivers are better trained and do NOT sit in the fast lane and 'toodle along'. What a breath of fresh air! Rob, you are a lucky man!

I guess the first thing is to verify the pressure gauge I'm using. If that's OK then it's possible that the alignment is slightly out from the factory.

[imclueless]

Not to mention the fact that European drivers are better trained and do NOT sit in the fast lane and 'toodle along'..

The Uk still suffers with these fools I'm afraid

[desperado]

Ummm, that's because the UK sits apart from Europe, right?

[imclueless]

Some may like to think so, but we are European I'm afraid

[desperado]

UPDATE: I had the alignment checked by the dealer two weeks ago. I had the tech drive it first, and he didn't feel anything amiss. But when he put it on the rack, the front and rear toe was off. When he corrrected the rear, then the front came into specification. The camber on one was slightly out, too.

I think the car feels better. Nothing dramatic, but it's not as unpredictable. I haven't taken any long drives, which is where I really noticed the nervousness before. When I get back from a long trip, I'll update this thread.

[Rob A]

... but it's not as unpredictable...

My R8 is the most predictable car I've ever driven (I'm 53 btw, and I've probably driven thousands of different cars by now), so if your R8 is unpredictable something is definitely wrong.