harpoonflyby

I upgraded to a set of SSR 16x7.5 from my stock WRX 16x7s. I stuck with the same stock tire size (205/55-16) for the new wider wheel, and i'm not sure i did the right thing. To me, the driving characteristics of the car have changed substantially but i am not sure if it has to do with the wheel being too wide / less than ideal for the tire, or if it's just the way these new tires feel. The car seems to "wander" more at speed than previously, and i feel i have less steering response, despite the better grip from upgrading to Michelin PSC.

So what is the ideal tire size for a 16x7.5 wheel? 215 perhaps?

EsoterikWRX

What is a Michelin PSC? PS2 maybe? At any rate, you would be well served with wider tires, ie 225/50, 235/50, maybe even 245/45s

harpoonflyby

PSC=Pilot Sport Cup. Yeah i figured 215 or 225 would have been a better choice. However, i am not looking to do anything else beyond exhaust and cold air filter perhaps. Considering that i'd like to find a balance between traction and the stock power output.

Is there any reason to put a 205 on a 7.5" wheel? Tirerack seems to make this as their "suggested" tire for this 16" wheel, when it clearly doesn't make any sense to anybody except them.

harpoonflyby

just to follow up - i calculated there is a 2 pound per wheel weight savings between 205 and 225 with this tire. So i am saving quite a bit of unsprung weight, in exchange for a slight increase in grip i would have had by adding 7/10" with the 225s. The suspension feels much more responsive with the lower weight wheel/tire combo. I can feel there is less feedback between wheel and motor in 1st gear, in parking lots for example there is less lurching at slow speed than with stock wheels. The 245s would have been way more weight than i needed with my near stock setup.

I did an alignment and took the camber to -.88 deg (which i believe is max negative camber with the stock bolts), then went out to Thunderhill on Sunday. I think it was a good choice. I could beat more powerful cars on the corners, while still able to hold my own on the relatively short straightaways. I think many of us forget that more tire on the road also increases rolling resistance, so you have to consider this and take advantage of that AWD.

Kevin M

iTrader: (12)

Don't worry about the weight- given a choice, I will always take the heavier tire, because 90% of that extra weight is in the sidewall, making it stiffer, which has a profound effect on steering transition and "feel". Anyways, a 7.5" wheel needs a 215-235 tire. I'd recommend going with 225/50R16, there are several great tires in that size, particularly Bridgestone So3s. With the weight savings from the wheels (~4.5 pounds each) you're not gonna lose anything going to slightly heavier tires.

WillysPU

If you plan to do a few track days each year you may want to mount some 225/50ZR16 toyo -ra1's on your stock wheels and keep the PSC's for daily driving. If you like the psc's in the corners you would love the ra1's.

harpoonflyby

Just checking in since my last post. I am not totally happy with the new tiresize on my 16x7.5 SSRs. I can feel the sidewall is not as stiff, which makes the car a little softer laterally in corners despite the grip from the added tread. They're good all season tires, so i am not too upset. The 205s I had originally were competition tires of course and may have been a stretch for that wheel (didn't look so cool either) - but sidewall stiffness is definitely all gone now. For me, the Tirerack recommendation was a good one that i should have stuck with. Also, the 225-50s look silly on a 16x7.5 wheel.

WillysPU

[QUOTE=
Also, the 225-50s look silly on a 16x7.5 wheel.[/QUOTE]

Explain "silly".

harpoonflyby

[QUOTE=WillysPU][QUOTE=
Explain "silly".[/QUOTE]

Silly, as in the tire bulges out over the rim greatly. Looks great if you like pickup trucks.

215/50 might look a tad better, behave stiffer somewhat, however Michelin didn't make em in 50 profile.

I may go back to 205/55s in the next day or so when my dealer gets them in stock.

breeze04wrx

[QUOTE=harpoonflyby]not . They're good all season tires, so i am not too upset.


All season tires REALLY suck for dry pavement; they are generally average in dry, wet and snow. Have you ever tried increasing your tire pressures? Each tire's optimal PSI is different.

WillysPU

[QUOTE=harpoonflyby]Silly, as in the tire bulges out over the rim greatly. Looks great if you like pickup trucks.

QUOTE]

Ok, I know what you mean, I use the oem wheel for track days and the toyo ra-1 only comes in 225/50. It kind of reminds me of the old school muscle cars with bulging BFG's but then I probably have a few years on you.

Do you think the 8in wheel would have worked out better?

harpoonflyby

[QUOTE=breeze04wrx]the PS A/S appear to give as good traction as many performance summer tires do. I live in a rainy area, and occasionally make trips in the snow. Thanks for the tip on tire pressure - i already have everything pressured up as specified (not sure what that has to do with sizing tho)

harpoonflyby

[QUOTE=WillysPU]Yep that's what i mean. 8" wheel? I am not changing wheels again, but sure, 8" would probably be better for that tire. Do they even make 16x8 for these cars?

Imprezer

iTrader: (9)

What is the offset of your new 16x7.5 rim?

Kevin M

iTrader: (12)

Wait, were you comparing Pilot Sport Cups to Pilot Sport all-Seasons, and complaining about sidewall stiffness? :rotfl: