stradadoc

Can anyone tell me if dropping down from a 305 30 19 rear to a 295 30 19 would have any negative effect on the operation of my car (08 Targa 4S)? In particular, traction control or other drive train issues or associated electronics?
Reason: It opens up a whole realm of tire choices.

Thanks for any input.

GentlemanRacer

295/30/19 and 305/30/19 should for intent and purpose be the same. No negative effects, no TC issues. In fact 295/30 is the winter tire recommendation for cars with standard size 305 tires.

mdrums

Nope no effect you will ever notice on the street or light track duty.

alexb76

Not much, they went to 305 on 4S due to wider rear-end. You tires would be stretched a bit on the wider wheels, and you MAY curb them easier as the curb lip would be stretched out.

Edgy01

All of the AWD Porsches (save Turbos) came with 305s in the rear. My C2S came with 305s because I opted for the XRR wheels (11.5x19 rear). The majority of 997s come with 295s (because the wheels back there are 11x19). There is little difference between the two.

2K7TTMIA

there is a minute difference. 305's will have less revolutions per mile than a 295.
As Dan mentioned above, 295's will stretch a bit much on an 11.5 inch wide wheel; on an 11inch wheel, it's not as drastic. Likewise, I went up from a 295 to a 305 on an 11 wheel and sidewall height went up a few tenths of an inch, if that. I also opted to go from a 235/35/ to a 245/35 front tire size; no rubbing issues at all. ( stock suspension and ride height; C2 Cab, much different than yours)
For AWD cars, you must pay attention to the Front/Rear diameters; best to stay within manufacturers specs.