currently rolling on 215/40R17 Goodyear F1 GS-D3 and i've been toying around with the idea of EITHER upgrading to the new Goodyear F1 Assymetric in the same specs for regular & spirited use OR get a small wheel and tire combo exclusively for spirited use

option 1 (cheap): upgrade to Goodyear F1 Asymmetric 215/40R17
option 2 (expensive): buy 15" rims and Advan Neova 195/55r15 (no 205/50 available)

* according to tirerack, the F1 Asymmetric is closer to the dry performance level of the AD07 (0.34 on their scale of 1 to 10) compared to the GS-D3 but at the expense of a lower tread wear rating (GS-D3 280, Asy 240)

using the wheel calculator, i found out that the difference in overall diameter is 9mm with the 15" combo obviously being smaller but at the expense of having a sidewall that is 15mm taller.

the questions are:

1. will i notice a change in gearing with a 9mm difference in overall diameter?
2. will the higher sidewall of the Advan tire negate the improvement in grip?

 

1. Small difference. The tire size alone will be minimal difference but the tire grip due to change of tire itself will make more difference.

2. The higher sidewall if about 5% difference should not be enough to be negative so comparing 40 vs 50 series might start to make a difference but it depends which tires you are comparing. There are some soft sidewall 40 series tires and some stiff sidewall 50 series tires.

The biggest problem with your post is that at tirerack I do not see any of the sizes you posted for the tires you listed.

The smallest GY Asymmetric is 225/45-17 and the smallest AD07 is 175/55-16 or 225/45-17.

What are you using these tires for? Street only?

If so and you have lowered suspension and 17x7 wheels then I'd suggest
Dunlop Direzza Z1 Star Spec 215/40-17 ($126) or if you have stock suspension then 215/45-17 $133 each. Treadwear 200. A very good Extreme Summer tire at moderate cost.

The 215/40 will give better turn in response and a harsher ride but not too bad unless you have a stiff suspension and rough roads. The 215/45 will be more comfortable and still very good for street driving for handling because the rubber is soft and grippy but it is slightly tall at 24.6" tire diameter- not enough to make for slow acceleration (opposite of lowered gearing).

As far as gearing due to tire diamter goes. If it is within about 1/2" difference then it's close and not much to notice for street driving. However if you compare 215/45-17 which is slightly tall vs 195/50-15 which is very small at 22.7" then the difference is large enough to feel. But wheel gap is increased and load rating on the tire is marginal for street use.

Alteratively you can choose the new Bridgestone Potenza RE-11 Extreme Summer tire if you don't mind the faster wear- 180 treadwear and higher prices.
205/45-17 $166
215/45-17 $175

 

hi minihune. as usual, thanks for the detailed answers

i'm not in the U.S. btw but the AD07 is confirmed to be available here in 195/55R15 (as i've used them before). as for the Asymmetric in 215/40R17, i'm assuming that since they have size for the GS-D3 they should have the same size for the Asymmetric. still pending confirmation on that though.

i'll be using these tires on the street and the occasional trackday (maybe 4 max per year)

 

For street and track use either the Dunlop Direzza Z1 Star spec or RE-11 would work fine and come in sizes that will fit OK. Better price on the Z1 Star Spec but the RE-11 looks like the tire to have for this year.

GY F1 Asymmetric is a good tire but not in the sizes you can use- none in MINI sizes until 235/40-17 ($159 each) but that needs at least a 17x8 rim.
Just because GY GS-D3 comes in a size good for the MINI doesn't mean GY makes them for the Asymmetric.

The AD07 is definitely a good tire-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=107
But for the US doesn't come in 15" sizes- if you can get it then that would be an option however the prices are much higher vs the others.

If I had to pick-
1. RE-11 in 205/45-17 Less $ and 2 lbs lighter, stock size
2. Z1 Star Spec 215/40-17 at 23.8" is nearly the same tire diameter as 195/55-15. Will give effect of lowered gearing- faster to reach a given speed but lower top speed on the track.

On a budget? The Z1 Star Spec.