nasaforums.com

Official Forums of the National Auto Sport Association
It is currently Wed Jan 17, 2018 3:49 pm

All times are UTC - 8 hours




Post new topic Reply to topic  [ 47 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
PostPosted: Fri Dec 01, 2017 3:15 am 
Offline
Postmeister in Chief
Postmeister in Chief

Joined: Sat Jul 17, 2004 9:37 pm
Posts: 4198
Location: Southern California & AZ
KY2K20 wrote:
What size tire, in regards to diameter, was being tested above? The Hoosier R7 has a 10" section width in a 15" diameter but it is 10.3" in 17" diameter.

245's were tested on 17's. 275's were tested on 17's and 18's. 205's and 225's were tested on 15's. 235's and 255's were tested on 17's, except the H 255 x 18.
Of course, we can't test every tire on every wheel, but we think we have a good formula for our most commonly used tires. The bottom line is that what matters is what the measurement is on each competitors wheel/tire choice, though.

_________________
Greg Greenbaum
National TT, PT, & ST Director
Nat. Medical Director
greg@nasa-tt.com


Top
 Profile  
 
PostPosted: Fri Dec 01, 2017 5:44 am 
Offline
Postmeister
Postmeister

Joined: Mon Feb 20, 2006 6:52 am
Posts: 1777
Location: Silver Spring, MD
Balroks wrote:
Do you have the base testing data available for those popular ones? Like 275 hoosier on 9.5 or 10 and bfg's on 9.5 or 10, etc? As in you know already what combos for sure aren't going to cut the mustard.


Vernon McClure did some measuring last night on 275s from BFG and Hoosier.

Both appear to work ok on a 9.5" wheel. On a 10" wheel BFGs are above 288mm, unsure on Hoosier.

-Eric Wong


Top
 Profile  
 
PostPosted: Fri Dec 01, 2017 11:52 am 
Offline
Forum Time Trialer
Forum Time Trialer

Joined: Sat Feb 11, 2012 10:22 pm
Posts: 261
Location: redwood city, california
Greg,
any chance to let cars 3000-3250 lbs used the bigger tire with a points penalty?
lets say give it zero points! Instead of the +0.3
I think this would give more flexibility for different models to run and not end up in no mans land. Plus would promote closer racing all around the track.

Thank you
Rafael
03 350z


Greg G. wrote:
KY2K20 wrote:
What size tire, in regards to diameter, was being tested above? The Hoosier R7 has a 10" section width in a 15" diameter but it is 10.3" in 17" diameter.

245's were tested on 17's. 275's were tested on 17's and 18's. 205's and 225's were tested on 15's. 235's and 255's were tested on 17's, except the H 255 x 18.
Of course, we can't test every tire on every wheel, but we think we have a good formula for our most commonly used tires. The bottom line is that what matters is what the measurement is on each competitors wheel/tire choice, though.


Top
 Profile  
 
PostPosted: Fri Dec 01, 2017 10:44 pm 
Offline
Postmeister in Chief
Postmeister in Chief

Joined: Sat Jul 17, 2004 9:37 pm
Posts: 4198
Location: Southern California & AZ
NASA Section Width templates were posted early today.
https://www.nasaproracing.com/rules

_________________
Greg Greenbaum
National TT, PT, & ST Director
Nat. Medical Director
greg@nasa-tt.com


Top
 Profile  
 
PostPosted: Mon Dec 04, 2017 9:27 am 
Offline
Postmeister
Postmeister
User avatar

Joined: Tue Aug 19, 2008 6:57 pm
Posts: 1376
Location: garage
When measuring a hoosier for example, and you're "excluding" the rather large rib they have, are you just squeezing it down or cutting a small piece out for said tool to "slide" ?

_________________
M'a't't
#463 TT3/TT2/ST2/ST3/WTH/BBQ Evo IX


Top
 Profile  
 
PostPosted: Mon Dec 04, 2017 1:47 pm 
Offline
Forum Time Trialer
Forum Time Trialer
User avatar

Joined: Tue Aug 17, 2010 11:25 am
Posts: 231
Location: Daniel Boone Country
Guess I'm not understanding the NASA Section Width fully. At what point does the NASA Section Width Rule/Tool come into play? 6.1.4 says, Tire and wheels size is unlimited for ST1, 2, 3. 6.5.2 says, NASA Section Width 267mm to 282mm (DOT- approved) Or any currently produced size 275, 245 or smaller = +0.3. I run the Hoosier R7's 275/35-18 on 9.5" wheels and take the +0.3 points. Do I need to have the NASA Section Width Rule/Tool applied or am I good with what rules 6.1.4 & 6.5.2 say?

6.1.4 Tire treatments and softeners are not permitted.
Tire and wheel size are unlimited in ST1, ST2, and ST3, but non-DOT
approved tires will be assessed via the “Adjusted Weight/Power Ratio”.

6.5.1 Definitions
4) “NASA Section Width” DOT tire width is determined by a measurement of the “NASA Section Width” of the largest tire (if staggered sizes) on the vehicle in post-competition impound/inspection, without changes to tire inflation (may be allowed to cool to pre-competition pressure). The tire may be measured while off or on the vehicle at any location not affected by ground contact sidewall deflection. A tire's NASA Section Width is the measurement of the tire's width from its inner sidewall to its outer sidewall using the NASA Section Width tire measurement tool(s) (excluding any protective ribs, decorations or raised letters) at the point 30mm deep to the tread surface on a new tire.

6.5.2 Modification Factors
Tire Size: NASA Section Width 266mm or smaller (DOT-approved)
Or any currently produced size 245 or smaller = +0.6
NASA Section Width 267mm to 282mm (DOT- approved)
Or any currently produced size 275, 245 or smaller = +0.3

Size 9.5” (241mm) or smaller (non-DOT approved) = +0.6
Size 10.5” (267mm) to 9.6” (244mm) (non-DOT approved) = +0.3


Top
 Profile  
 
PostPosted: Wed Dec 06, 2017 12:00 pm 
Offline
Postmeister in Chief
Postmeister in Chief

Joined: Sat Jul 17, 2004 9:37 pm
Posts: 4198
Location: Southern California & AZ
427R wrote:
Guess I'm not understanding the NASA Section Width fully. At what point does the NASA Section Width Rule/Tool come into play? 6.1.4 says, Tire and wheels size is unlimited for ST1, 2, 3. 6.5.2 says, NASA Section Width 267mm to 282mm (DOT- approved) Or any currently produced size 275, 245 or smaller = +0.3. I run the Hoosier R7's 275/35-18 on 9.5" wheels and take the +0.3 points. Do I need to have the NASA Section Width Rule/Tool applied or am I good with what rules 6.1.4 & 6.5.2 say?

6.1.4 Tire treatments and softeners are not permitted.
Tire and wheel size are unlimited in ST1, ST2, and ST3, but non-DOT
approved tires will be assessed via the “Adjusted Weight/Power Ratio”.

6.5.1 Definitions
4) “NASA Section Width” DOT tire width is determined by a measurement of the “NASA Section Width” of the largest tire (if staggered sizes) on the vehicle in post-competition impound/inspection, without changes to tire inflation (may be allowed to cool to pre-competition pressure). The tire may be measured while off or on the vehicle at any location not affected by ground contact sidewall deflection. A tire's NASA Section Width is the measurement of the tire's width from its inner sidewall to its outer sidewall using the NASA Section Width tire measurement tool(s) (excluding any protective ribs, decorations or raised letters) at the point 30mm deep to the tread surface on a new tire.

6.5.2 Modification Factors
Tire Size: NASA Section Width 266mm or smaller (DOT-approved)
Or any currently produced size 245 or smaller = +0.6
NASA Section Width 267mm to 282mm (DOT- approved)
Or any currently produced size 275, 245 or smaller = +0.3

Size 9.5” (241mm) or smaller (non-DOT approved) = +0.6
Size 10.5” (267mm) to 9.6” (244mm) (non-DOT approved) = +0.3

Since you drive in TT3, you are good to go at this time. And, if we end up deleting the tire sizes altogether in the next 6 months, and only use NASA Section Width to determine your tire Mod Factor (that's all it is for in your case in TT3, because you can choose any tire size you want), our research shows that your tire/wheel combination will have no problem fitting the 282mm size tool.

_________________
Greg Greenbaum
National TT, PT, & ST Director
Nat. Medical Director
greg@nasa-tt.com


Top
 Profile  
 
PostPosted: Wed Dec 06, 2017 1:50 pm 
Offline
Forum Time Trialer
Forum Time Trialer
User avatar

Joined: Tue Aug 17, 2010 11:25 am
Posts: 231
Location: Daniel Boone Country
Thanks Greg.


Top
 Profile  
 
PostPosted: Wed Dec 06, 2017 2:44 pm 
Offline
Forum Spectator
Forum Spectator

Joined: Sat Oct 11, 2014 12:28 pm
Posts: 16
Any reason why cars <3250 won't be allowed to run wider than 266mm with a power to weight penalty? Since we can't ballast up to 3250 quite a few of us are looking at either buying new wheels or new tires, which is a pretty big unexpected expense. It's just another barrier to entry for a class that had no TT participation at ECC this year.

_________________
James Cathers
TTB #129 - E36M


Top
 Profile  
 
PostPosted: Wed Dec 06, 2017 4:05 pm 
Offline
Forum Time Trialer
Forum Time Trialer

Joined: Sat Feb 11, 2012 10:22 pm
Posts: 261
Location: redwood city, california
Same here that rule will keep me from racing in ST4 next year with my 03 350z
I Just spent good $$ to get to 3050# and still under power
With some engine mods!
I have 3 new sets of 10 inch rims.
At this point the z is probably the wrong car so I am not buying new wheels just to see what goes down with this class plus pumping up my motor any more when this class should be a 12.0:1 class. Why do we give + points to something that is mandatory.
Cars up to 2900 should be on 245
Cars up to 3300 should be on 275
Cars over 3300 should be on even bigger tires
With no +points at 12.0:1 like the class states on the rules.
I will keep my car at 3050 With my 275s at real reliable 12.0:1 and and enter SU and have fun with whoever is out there.
Only cause I like the NASA bbq

quote="JCathers"]Any reason why cars <3250 won't be allowed to run wider than 266mm with a power to weight penalty? Since we can't ballast up to 3250 quite a few of us are looking at either buying new wheels or new tires, which is a pretty big unexpected expense. It's just another barrier to entry for a class that had no TT participation at ECC this year.[/quo


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 47 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 8 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group