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205 or 225 tire 16x7 wheel in H stock ?

Plainrt

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#1
I'm not sure what size tire to order for my 16x7s to run in h stock this year. To me a
I think a 225 is gonna be to wide for a 7 inch and maybe hurt performance. I'd think a 205 would fit better but i guess I'm just looking for what others are running for autocross.
 


RAAMaudio

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#2
What tires are available and what are others running that works well?

225 might rub if the wheel offset is not right.

Diameter can make a big difference in when you hit redline, usually better to have the ability to not hit the rev limiter in second gear.
Being able dig from lower RPM which will not be an issue with the stock turbo though if you have to run a stock tune you might hit the limiter causing you to have to lift, feather the throttle or shift up and down again more often, all of which will slow you down.

I like to run wider tires on wider wheels but I am mostly into road race track use, 225 on 9", 205 on 8" etc.....so I would probably go with a 205 on a 7" rim at the most.

But, autocross is different than what I mainly do I much prefer very precise feedback and control which can become an issue when the tires do not have enough sidewall support.

G-Force Rival is made in a 215/45/16 and is tested on a 7" rim, perhaps it was designed for class rules with that width rim and the sidewall is stiffer. It is just slighter lager in diameter thus might not be quite tall enough to not hit 60 in second, what autocrosses are supposed to be setup for(I have have been far faster than that, hundreds of runs:)

Star Spec II is available in 205/50 and 205/55 which might be better for gearing, I would see what you now hit sixty MPH at or before redline, etc....a taller tire has more contact patch than a shorter tire with the same tread width which helps a bit as well. Thier 225 is 24.9" tall which might be an issue and at 24lbs is a lot of weight to deal with.

Ventus RS-3 in 205/50 is 24.9 tall as well, 2lbs less weight than the 225 SSII above

Ecsta XS is getting a bit old so probably not the most competitive tire, 215/45/16 is 20 lbs which is great but 23.6" tall which again might be a gearing issue.

-----------------

If not done so yet I would get on the local and national solo forums and see what is the top tire and what people are using size wise, that would be the best bet.
 


RAAMaudio

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#4
You are most welcome:)

I have autocrossed on and off since the early 70's but rarely do so now and thus not up on the very best tire for your needs but the ones I listed are the cream of the crop for stock class tires.

Make sure the wear rating is 200, I forgot to check on that.
 


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#5
I ran a 225/45/16 ZII and the ZII star spec last year on a 16x7 wheel with a 42 offset.

I have had 0 issues with it rubbing....and the tire is a pretty good match to the car.

Assuming you are running H Street (pure topic) you have to stay with the 7 inch wheel.

The 205 is not enough tire and you will be very happy with the 225. It doesn't pinch badly either if that is a concern.

Some people have been going with a 235/40 on the stock wheels....those do rub in some instances.
 


RAAMaudio

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#6
That wide a tire on a 7" wheel is certainly not optimal but when you are stuck with the rules as they are then you have to run what works the best you are allowed, by all means do so!

What tire temps do you recommend for him?
 


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#7
That wide a tire on a 7" wheel is certainly not optimal but when you are stuck with the rules as they are then you have to run what works the best you are allowed, by all means do so!

What tire temps do you recommend for him?
Temps or pressures? I actually do I have a pyrometer and was getting temps around 115-118 degrees on the high side when it was ambient of 80. I didn't measure when we had three drivers at a 95 ambient temp or higher so we had to spray every run.

Pressures some people run REALLY high pressures, I was running a little lower pressures especially when I got the star specs. The side walls are really stiff and they look fine when mounted. They are only an inch wider tread wise when mounted over a 205/50/16.
 


RAAMaudio

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#8
I meant pressure, my bad, temps of course just look for consistent across the tread and not to hot or to cold though some tires grip better at specific temps.....:)

I use a pyro for the track or if in a hurry the palm of my hand, pretty accurate with it after all these years(no puns intended) for autocross I have had good luck just using the infrared units as the temps are more on the surface, unless co drivers where the heat has a chance to go deeper into the tire.

Stiff sidewalls help a huge amount, likely they were designed that way partly to help when on narrower wheels.

Ever see the Hoosier I believe 245 wide made for 7" wheels called cantilever tires? I have had them, they worked great though quite heavy.

I have also had 225 R and A6 tires that are at least a 245 wide tread but put them on wide wheels, 9" is best but can be run on 10's! I can fit them on the front on my 9" wide wheels but not on the rear though 225 Toyo fits great and they are a bit wider than most 225's.

Anyway, glad you are able to make the 225 SS work on 7's so well:)
 


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#9
I do know what you are talking about for the hoosier.

I ran the A6 and A7 on my Evo, both in a 245/40/17, I found that the A7 was actually more of a 255 then the older A6. They are both on a 17x9 wheel.

As for pressures I started the year at 38 front and 46 rear, then dropped the rear down depending on how bad it was tank slapping. I think in the cold October events I actually had the rears down to 34-36 and the fronts at 38.
 


OP
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Plainrt

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Thread Starter #10
Thanks much guys. I always enjoy as much info as I can.
 


k757

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#14
It might depend on wheel offset.

I have 16x7 Sparco Assetto Gara with 225/45-16 Dunlop Z2 SS. Great setup for this car
 




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