403portside

for some reason I'm having trouble visualizing this. If you have a tire that's 10mm wider, do you see all 10mm of the additional width when looking at the fender or only 5mm, because the other 5mm is on the inside?

jhbrennan

5mm

403portside

thank you sir.

Mumbles

I beleive that the 295's are a more commonly available tire, and better priced

user 72902

I have 305's on mine and can send you a pic if interested.

Jake951

Beware that advertised widths, like 305 or 295, are only approximate. Some makes are wider than others, event though they have the same specs. I've seen two tires from the same manufacturer that were supposed to be 20 mm different but measured exactly the same in width. Go figure.

dunlopnick

305's on Champion RG5 with 5mm spacers - and car is lowered.

Tires acquired thru Sports Car Tire in Wilmington DE - great deal, great people and also likes great cars .... Les's car at Deutsche Classic yesterday - Fleetwood PA

Chris from Cali

Please post a pic. I've got some HREs on order in a slightly different offset to obviate the need for spacers. From what I've been told I can put 305s on them with no problems.

user 72902

I have the 19" Sport Wheels (11.5 inches) hope this helps.

fontana302

PS2 295/30ZR19 11" Tread Width, 11.9" Section Width
PS2 295/30ZR19 11.5" Tread Width, 11.9" Section Width
Pilot Super Sports 305/30ZR19 12.1" Tread Width, 12.3" Section Width

From above you have between 1.1" & 0.6" difference in tread width with same brand depending on tire.

Suns_PSD

Realistically, if you increased your rim width 1/2", then you would get an additional 5mm protrusion (assume same brand and model tire). But w/ these low profile tires you would not get all of it. Probably closer to 3-4mm. The exception to this is if your old tire was stretched, in this scenario you might gain 6 or 7mm of width. I know I'm nitpicking here but I thought you might want to know.

The last thing I will point out, and look I've never been on track w/ a Porsche, is that cars need balance. You don't want too much traction at one end or the other. In a typical front mounted engine car, putting too large of tires in the rear really hurts rotation thru the turns and will lead to understeer. Now I've noticed that the 911 has more narrow wheels up front and wider wheels out back than my current track car so I can only assume that this is a factor related to the rear engine mount and the unique driving dynamics of the 911. Just be aware that wider and stickier is not always better for performance. And besides a little sideways action is really quite a bit of fun!