2002 C4 Cabriolet, with ROW M030.
Currently on 18" Carrera wheels with Pirelli P-Zero Rossos 225/40 front 285/30 rear.
Need advice re 19" HRE 542s:

a- What is the difference between 542 & 542R?
b- What tires should I get with those to maintain the overall tire diameter? (don't want to re-calibrate speedometer, also different diameter might mess up All Wheel Drive system)

TIA

 

for 19s, i'd stick to 235/35/19 F and 265/30/19 R to keep diameters close, but then the rear wheel is skinnier than stock. Our usual advice is to keep the diamteters close to each other, and go with a 245/35/19 F and 285/30/19 R. This will result in some speedometer error, but the handling will still be good.

R series have the flat lip, ever since these were made available, we have not sold even one set of the standards for Porsches.

I would recommend wheels in 19x8.5 for the front and 19x10.5 for the rear....in case you need a price quote, feel free to give us a try.

 

Lee, according to the tire size calculator, the front and rear wheels will be turning at slightly different rates. Doesn't that cause mechanical problems in all wheel drive cars?
Should I PM you for a quote? (or you PM me)

 

Hi, for a quote, please email me at peter@wheelexperts.com with the year and model of your car, and the style, size and finish of the wheel deisred. Thanks!

the tires sizes are within spec - even Porsche's OE tires are slightly different. also, tire wear plays a part - when tires are new, they will obviously have less revs per miles than tires with 5000 miles on them.

 

Love the 542R's considering getting them myself!

 

How off will the Speedometer be? I was looking into getting 19's also.

Thanks

 

Try this site:
http://www.miata.net/garage/tirecalc.html

You put your current and desired sizes and find out how messed up the speedo will be.