Go/No-Go Gauge?

[rxryanm]

Hey all,

Had been watching some videos on YouTube about Hot Rod's Drag Week and decided it sounded and looked like a blast, so I tossed my hat into the ring this year. Certainly won't be competitive, but it should be a fun week.
I've not ever sent my car down a strip, but will be trying to get a lot of trips in this summer leading up to it. So my n00b self has some questions. The first and biggest one right now is what is a go/no-go gauge? I'm going to have to run radials or slicks that are 11.5" or less at the tread, so I'm thinking 305/45r17 ET Street Rs since MT's website says they're 10.5" at tread. But I'm just curious as to this measurement device as I can't find anything about it/would like to know how it measures to make sure I'm good to go.
Car is mostly stock right now performance-wise, minus some Steeda braces, alignment kit, and a Borla catback, but going to have Wengerd tune it for me and may put some GT350 half shafts on since there's concern for breaking the stockers. Will be on RideTech's air ride in the upcoming month-ish since this is my "daily" and I'm into looks too.

Any and all help/advice is appreciated!

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[NGOT8R]

I have MT 305/45/17 ET Street Rs on my car. They are a 28” tall tire. Not sure exactly what measurements you need, but I’m on factory springs and I can fit two fingers between the fender/wheel well and top of the tire.

 

[Coyote Chase]

Aren't 305/45-17 tires 305mm wide and is the 45 for the measurement of the sidewall, or 45% of 305mm?

 

[NGOT8R]

Yes, 305 = width and 45 = sidewall measurement.

 

[rxryanm]

I have MT 305/45/17 ET Street Rs on my car. They are a 28” tall tire. Not sure exactly what measurements you need, but I’m on factory springs and I can fit two fingers between the wheel well and top of the tire.

Here's a paste of the rules -
Modified cars must use tires on the dragstrip that are no greater than 11.5 inches wide at the tread, as measured with a go/no-go gauge with the tire carrying the vehicle’s weight and at 20 psi of tire pressure. Tire edges may not be shaved or cut to meet the 11.5-inch maximum.

So I guess that's what I'm trying to make sure a 305/45r17 will fit into. And what the heck a go/no-go gauge is for my curiosity lol.

 

[Proshop]

A go/ no -go gauge is just an instrument used to make sure items are within certain tolerances. In your case they are going to use a device to measure your tire to make sure it fits with in the tolerances that you posted above and make sure you are within specifications/ tolerances of the class ( no more than 11.5”s wide when tire is at 20psi).

 

[Proshop]

I’m currently running an MT ET street 305/35 /19 @25 psi and when I do a quick measurement they are wider than the 11.5 that are allowed per the rules. A 305/ 45 /17 may have less width when at a lower psi but I can’t speak to that since I am not running that size.

 

[NGOT8R]

It just so happens that I took the rear tires off today to check balancing accuracy. Here’s what I have for a measurement with the tire off of the car at 26 psi of air pressure. I think you’ll be in compliance with the rules, as the 305/45/17 is a commonly used radial tire for drag racing.

 

[Proshop]

@NGOT8R I wonder what they would measure with weight on them? Probably still be with in the tolerances but you do have to factor that into it all along with them being at 20psi.

 

[NGOT8R]

@NGOT8R I wonder what they would measure with weight on them? Probably still be with in the tolerances but you do have to factor that into it all along with them being at 20psi.

For the greater good of the Mustang community, I’ll take another measurement with weight on the car at 20 psi, once I take it off of the jack stands.

 

[Coyote Chase]

According to Wallace Racing's calculator; The tire is 12.01" in width...
My recommendation,is to run the 275/50R-17 rear tire, plus at set of skinnies on 18" wheels up front.
PS: With which gear ratio is your car equiped?

 

[rxryanm]

A go/ no -go gauge is just an instrument used to make sure items are within certain tolerances. In your case they are going to use a device to measure your tire to make sure it fits with in the tolerances that you posted above and make sure you are within specifications/ tolerances of the class ( no more than 11.5”s wide when tire is at 20psi).

Well dadgum, I looked all over for that and wasn't able to find anything like it. I appreciate you locating it! Easy to see how they measure now.

It just so happens that I took the rear tires off today to check balancing accuracy. Here’s what I have for a measurement with the tire off of the car at 26 psi of air pressure. I think you’ll be in compliance with the rules, as the 305/45/17 is a commonly used radial tire for drag racing.

For the greater good of the Mustang community, I’ll take another measurement with weight on the car at 20 psi, once I take it off of the jack stands.

You are a gentleman and a scholar and I don't care what anyone else says about you, Adrian. (Jokes, but much appreciated!)

According to Wallace Racing's calculator; The tire is 12.01" in width...
My recommendation,is to run the 275/50R-17 rear tire, plus at set of skinnies on 18" wheels up front.
PS: With which gear ratio is your car equiped?

19 with PP1, so should be a 3.55. And you're right, may have to step down in width a bit.

 

[rabid_josh]

Here's a paste of the rules -
Modified cars must use tires on the dragstrip that are no greater than 11.5 inches wide at the tread, as measured with a go/no-go gauge with the tire carrying the vehicle’s weight and at 20 psi of tire pressure. Tire edges may not be shaved or cut to meet the 11.5-inch maximum.

So I guess that's what I'm trying to make sure a 305/45r17 will fit into. And what the heck a go/no-go gauge is for my curiosity lol.

the event staff would have the so called '' go/no go gauge'' ... that tire should be fine. my 20 gt looks the same as the above one. the treadwidth is only about 10.5inches . typically with it being a 17in wheel vs a typical 15in wheel they let it slide. (less sidewall advantage). Your best bet is to reach out to the Drag Week Event staff... I am also shocked you got in. Typically drag week is full within minutes.

 

[rxryanm]

the event staff would have the so called '' go/no go gauge'' ... that tire should be fine. my 20 gt looks the same as the above one. the treadwidth is only about 10.5inches . typically with it being a 17in wheel vs a typical 15in wheel they let it slide. (less sidewall advantage). Your best bet is to reach out to the Drag Week Event staff... I am also shocked you got in. Typically drag week is full within minutes.

You and me both, brother. I had it on my calendar and it wasn't live at 9am sharp like I assumed, so I putzed around for a bit and blew through the registration whenever it finally opened.
I've got an email out to them right now, so I'll tack that on when I get a response. Appreciate ya!

 

[NGOT8R]

Here are the measurements on my ET Street 305/45/17 Rs folks. The car is back on the ground and both rear tires have been deflated to 20 psi.

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