Audi 18inch Wheels for R8

[desperado]

The local dealer brought in a set of the 18" Audi wheels for me. I'm interested in your opinion on their weight and appearance!

I was thinking of using these for a track wheel. I'll be mounting Toyo R888 DOT Competition Radials on them.

The available widths are 8.5" front and 10.5" rear. I was surprised that the pattern is different than the usual 19" five twin-spoke; instead it is has six single-spokes. I don't remember ever seeing a picture of a R8 fitted with these. If you know of one online, I'd appreciate getting a link to it.

I believe they are the same pattern as the "winter wheel" that some of you have may have on your cars (toecutter?). Here is a picture of the wheel:


They felt "heavy", so I weighed one of the rear wheels on my bath scale at 28.5# (only shows to nearest 1/2 pound). TireRack.com shows three OZ racing wheels for the R8 that weigh 28.0, 29.0 and 33.0 lbs each (rear). Does anyone know what the (NA Std) 19" wheels weigh?

[Because I know you will ask: I believe the Audi retail is USD$855 each (front or rear); the USA standard 19" wheels list for $954 each. My dealer was having a 10% off promotion on wheels for March, so the net was about $770 each. The OZs on tirerack.com retail from $950 to $1003 each (rear). None of these prices include the TPMS sensor assembly which is an additional $120 per wheel.]

[harrison]

Great winter wheels!!

[MotherTucker]

The stock 19" wheels weigh 23.5 lbs. They are actually pretty light, and are forged from what I've read. So fellow track rats, the right thing to do is buy a 2nd set of wheels for your pretty street tires, and use the stock wheels for track tires

[harrison]

No TPMS bolt on my wheels.MAYBE this is an indication it is forged? '08 R8

[desperado]

The stock 19" wheels weigh 23.5 lbs.

Wow, five pounds lighter! It appears I'll need to rethink my plan!

[desperado]

No TPMS bolt on my wheels.

Sorry for the mixup. It's my fault for using misleading slang for the TPMS sensor mounted inside the tire.

The Tire Pressure Monitoring System (TPMS) sensor and its mounting is not visible when the tire is mounted on the wheel. The valve stem is metal, and the end inside the wheel has an internal thread. The TPMS sensor is a little box which is fastened to the inside end of the valve stem using a small hollow steel bolt. There is a recess cast into the rim of these wheels to provide clearance for the TPMS sensor. You can see detailed drawings of all this on pages 10 and 11 of self study program book SSP219 (see excerpts attached).

[R84ME]

Desperado - as I understand it,TPMS just sends pressure readings to one of your car's electronic control units and this ECU it is calibrated to generate a low tire pressure warning at a programmed pressure setting. If you're using different diameter wheels (18?) and different sizes tires - with different pressures- you might have false warning light - or no warning- unless you reprogram the ECU. Much like programming ABS for different size tires/rolling diameter. Maybe some of the racers can chime in?

While we're on the subject, I was quite disappointed to learn that TPMS does not display the individual pressures. The Pontiac G? I rented even had that, you could cycle through the pressures, front and rear, at any time. Nice feature!

[MotherTucker]

Yes, that's how it works as far as I know. The sensors have a specific pressure below which they raise an error. Audi uses Beru brand transmitters, they are all at 433 mhz frequency. Each sensor has a unique number, and the ECU must be programmed to accept those numbers, otherwise you would read your neighbor's tire pressure when your car is near other Audis like when sitting in traffic. When I bought my 2nd set of wheels at Tire Rack, I had them install Beru TPMS sensors, and then I had to take the car to the dealer to get them to tweak the ECU to accept them. The technician had trouble getting the car to accept the new sensors, he said he had to redo it several times before it took. But now I can swap between the 2 sets with no problems. It doesn't matter which locations on the car where the wheels are mounted, apparently there's a single antenna for all 4 wheels.

[R84ME]

The GM sensors report "RF32:LF34/RR:32:LR:33" so the sensors must be "aware" of which wheel it is monitoring. I wonder how that works rotating tires - when RF becomes RR and LF becomes LR? I guess there are tpms and there are TPMS!

[harrison]

When R.f. signal is reading rt.fr. leading to P.M.S.!!The Pontiac "G" spot is nice though