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2019 NASA ST/TT discussion

 
Old Oct 23, 2018, 04:54 AM
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Originally Posted by Balrok View Post
Basically the way the Evo was meant to be built. Going into these "slower" classes is like putting a condom on king kong. It's trying too hard to be something it's not. In terms of safety it's way safer to have 500 hp on 295 R compounds then it is 255 "summer" tires.

My general beef with GL is they put SO much emphasis in spending the $ on the car and not the driver. There are about a dozen maybe less TT drivers in there that can strap into any car and push it just as hard without wrecking of the 100's participating.
I do agree, to a point with the first point. R comps are safer than summer tires but some don't let go very linearly so it's kinda tire dependent.

I do agree with the second one, there's no power limit in any class except stock because of their fuel limits. And with that said people tend to keep spending more and more for more power.

But with that said I still think Tut's car is set up much better for SM although I'd be glad to have him kick my *** in TM
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Old Oct 31, 2018, 08:48 PM
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Gridlife rules for street mod sucks. Its basically GTA street and enthusiast mixed together. You can run half gutted, 2 ways, fuel cell etc. I like what GTA did with Ethusiast class even though i dislike the name.
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Old Nov 1, 2018, 05:49 AM
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Agreed, some of it doesn't quite make sense like the 2 ways. I have the same gripe with track mod, most 3 way setups cost significantly more than 2 ways and the only guys who run 3 ways have suspension sponsorships 🙄
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Old Nov 1, 2018, 05:57 PM
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Yea, their 2016 rules made more sense. I think they changed to get more cars which is the end goal.
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Old Nov 2, 2018, 05:53 AM
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I have one ways and they work just fine.
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Old Nov 2, 2018, 11:17 AM
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Did anybody test fit 275/35x17, 275/35x18, Hoosier R7, to see if they fit inside 266mm box?

Tire Rack says thread width is 10.3", which x 25.4mm = 261.62mm - round it off at 262mm.

Thank you.

I am considering TT4/ST4, staying simple using NT03 + M 17x9.5 +38mm wheels with 275/35x17, to just fit I think within rule.

Next size down is 245/40x17 which is listed as 9.7" or 246.38mm.
Seems a lot to give up in thread width.

Its encouraging to learn that there are many TT4/ST4 cars in Norcal, makes it for enduring fun of the class.
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Old Nov 2, 2018, 11:43 AM
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I sort of found my answers:

Seems NASA tests section width, not thread width:

245/40x17 section width is 10.3" or 262mm.
275/35x17 section width is 11", way too big to fit.

Post from discussion on thread width on NASA forums:
Knowing that the Hoosier 245 is the most popular tire and size used in ST4, curious what measurements NASA has taken/recorded with various popular wheel sizes such as a 9" or 9.5" inch rim. In other words, would the expectation be that the 266mm/10.4in max section width only be possible using a 8.5 inch rim with the 245 Hoosier? Doing a quick check even with a 9" rim, it looks like 266mm is going to be tough using the Hoosier 245.
Our research showed that the 9" rim puts the tire at about 264mm, and definitely fits. We didn't have a 9.5" wheel for testing, but it certainly might fit as well. We would not expect a 10" to allow the tire to fit, but that is past the manufacturer's recommended size as well. The choice for 266mm NSW and not higher was that it was approaching the 275 tire size NSW
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Old Nov 2, 2018, 11:44 AM
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Old Nov 2, 2018, 01:56 PM
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Originally Posted by alpinaturbo View Post
I am considering TT4/ST4

Its encouraging to learn that there are many TT4/ST4 cars in Norcal, makes it for enduring fun of the class.

It would be nice to have another Evo out there in TT4, A lot of BMW's out in the NorCal Region.

I have confirmation that the 245/40/18 with a 9.5 rim will fit NSW fine.
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Old Nov 2, 2018, 02:59 PM
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Yes 245's on those BMW's has been the ticket this year. However don't plan on doing w2w on them at your weight. Even in TT you'll cord them pretty regularly as Tut found out.

275's fit the 282mm tool but not the 266 one. Remember tread width is not what this is going by, it's SECTION width. So if the tire is listed as 10.7" section width it'll likely clear. But if you get one that's 10.9 it likely won't on a 282mm tool. Which kinda stinks in my situation. For several years the trick was to have 10" wheels and run 275 tires netting you a 11 or so inch tire which allowed you to max out your A6/7's. However now it's a matter of deciding do you sell your 9.5's and get 12's and go ***** out on grip? Or do you sell your 10's and get another 9.5 to get some HP back. I'm in ST2 or 3 mind you.
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Old Nov 2, 2018, 04:22 PM
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GoodTimes,

Do you know any laptimes at local tracks that TT4 or ST4 "cars to beat" run?

Would be curious, I ca related to Laguna, THill, but don't know Evo laptimes at Sonoma recently: 10 years ago there were several active Evos locally, but nowadays I don't know any and things have moved on, tire technology alone has changed, not to mention Bmw's and Miata Turbos have been developed into formidable weapons.
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Old Nov 3, 2018, 09:16 PM
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Originally Posted by Balrok View Post
Yes 245's on those BMW's has been the ticket this year. However don't plan on doing w2w on them at your weight. Even in TT you'll cord them pretty regularly as Tut found out.

275's fit the 282mm tool but not the 266 one. Remember tread width is not what this is going by, it's SECTION width. So if the tire is listed as 10.7" section width it'll likely clear. But if you get one that's 10.9 it likely won't on a 282mm tool. Which kinda stinks in my situation. For several years the trick was to have 10" wheels and run 275 tires netting you a 11 or so inch tire which allowed you to max out your A6/7's. However now it's a matter of deciding do you sell your 9.5's and get 12's and go ***** out on grip? Or do you sell your 10's and get another 9.5 to get some HP back. I'm in ST2 or 3 mind you.
Got it. Right now I'm in the process of dropping down from 10.5 with 275 to 9.5 with 245 so I can get the most out of the Hp. Turbo cars have an advantage I think We can do some tricky things with "the curve" for the graph, mid range to top end. Trying to squeeze the most potential out of the car.

Originally Posted by alpinaturbo View Post
GoodTimes,

Do you know any laptimes at local tracks that TT4 or ST4 "cars to beat" run?

Would be curious, I ca related to Laguna, THill, but don't know Evo laptimes at Sonoma recently: 10 years ago there were several active Evos locally, but nowadays I don't know any and things have moved on, tire technology alone has changed, not to mention Bmw's and Miata Turbos have been developed into formidable weapons.
I have some data from Thill witch looks promising. I looked at past results. I have no data from Sonoma since I hate it there (wall) but I guess im going to have to get use to it since that's there main track lol

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Old Nov 6, 2018, 07:36 AM
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Also remember that Section Width is a property of wheel width and Tire Rack tells you what wheel size they measured the Section Width using. If you run a wider wheel than that, expect the Section Width to increase. If you are doing TT4 the 245/40/18 on a 18x9.5 or the 245/40/17 on a 17x9 are probably the right answer. If you are going ST4 then you will definitely want a 275 or the wide 255 18" Hoosier.
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Old Nov 6, 2018, 07:58 AM
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Originally Posted by King Tut View Post
Also remember that Section Width is a property of wheel width and Tire Rack tells you what wheel size they measured the Section Width using. If you run a wider wheel than that, expect the Section Width to increase. If you are doing TT4 the 245/40/18 on a 18x9.5 or the 245/40/17 on a 17x9 are probably the right answer. If you are going ST4 then you will definitely want a 275 or the wide 255 18" Hoosier.
Word of caution on the 255 hoosier, you WILL cord the outsides in 3 sessions or less. The sidewall is simply too short/soft to deal with the front weight of the car in low speed turns. We used to run that tire as a "cheater" back in the day when the rules went by points for mods, which included .1 for each 10mm of tire. Jumping to the 275 solved the problem instantly. Unless you're running ultra wide, the rule of thumb is to shoot for a 25.5" tire on an 18" wheel.
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Old Nov 6, 2018, 08:22 AM
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Originally Posted by Balrok
Word of caution on the 255 hoosier, you WILL cord the outsides in 3 sessions or less. The sidewall is simply too short/soft to deal with the front weight of the car in low speed turns. We used to run that tire as a "cheater" back in the day when the rules went by points for mods, which included .1 for each 10mm of tire. Jumping to the 275 solved the problem instantly. Unless you're running ultra wide, the rule of thumb is to shoot for a 25.5" tire on an 18" wheel.
I think I've read where you said the same thing about 275/35r17's. Good info
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