275mm vs 305mm tires

[Shadow277]

Does anyone know what the difference would be between those tire sizes for track applications? Such as quarter mile and circuit. It is not my daily but I do like using it road trips. Specifically, it would be stock wheels vs the 20" Niche wheels that came on mine (I am the second owner). The only thing enticing is keeping the car entirely stock. Here in Arizona I wouldn't go cheap on tire quality so I'm okay with spending money on good tires. I mean, what could happen, snow?

Sponsored

 

[bluebeastsrt]

The difference is 30 millimeters.

 

[Fly2High]

Use the tire that delivers sufficient traction. Anything more is needless unsprung weight and will just slow you down.

Changing down to stock sized 19" wheels could reduce the weight of the wheel/tire combo and actually increase the speed of the car even if the outside diameter remains the same. Bigger heavier wheels/tires slow you down.

Also, if the outside tire diameter got larger, it will effectively reduce your gear ratio also slowing you down. It might also improve your gas mileage slightly and reduce tire wear.

Since the car does not change weight, the shape of the contact patch will change from a more forward long patch (275 mm tire) to a shorter and wider one(305 mm). This will improve lateral handling but could be at the expense of forward traction.


Sounds to me someone set the car up for looks and not performance based on this limited info.

 

[Norm Peterson]

Does anyone know what the difference would be between those tire sizes for track applications? Such as quarter mile and circuit.

Is this for all four tires or only the rear two?

Which stock wheel width(s)?


Norm

 

[Shadow277]

Use the tire that delivers sufficient traction. Anything more is needless unsprung weight and will just slow you down.

Changing down to stock sized 19" wheels could reduce the weight of the wheel/tire combo and actually increase the speed of the car even if the outside diameter remains the same. Bigger heavier wheels/tires slow you down.

Also, if the outside tire diameter got larger, it will effectively reduce your gear ratio also slowing you down. It might also improve your gas mileage slightly and reduce tire wear.

Since the car does not change weight, the shape of the contact patch will change from a more forward long patch (275 mm tire) to a shorter and wider one(305 mm). This will improve lateral handling but could be at the expense of forward traction.


Sounds to me someone set the car up for looks and not performance based on this limited info.

Probably. The black wheels look good with the metallic guard paint. I prefer circuit racing to quarter miles but I will do quarter miles to hone my shifting skills (I have the 6 speed). If the grip offsets forwards traction enough, then I would definitely keep the Niche wheels. That's why I'm here: trying to see if anyone has been in my position and knows what the answer is.

 

[Shadow277]

Is this for all four tires or only the rear two?

Which stock wheel width(s)?


Norm

255 in the front and 305 in the back, 19 inch diameter. I bet I could get away with 45 for the side wall, right? More tire life.

 

[Norm Peterson]

For running on a circuit, which I assume means road course, a 50 difference in tire section is way too much stagger.

Wheel width matters. A 305/35 tire needs to be mounted on wheels that are at least 10" wide, and preferably 11" or 11.5" for any road course use. Wheel widths depend on both tire section width and profile. More information is needed regarding both the wheels and the tires.


Norm

 

[Shadow277]

For running on a circuit, which I assume means road course, a 50 difference in tire section is way too much stagger.

Wheel width matters. A 305/35 tire needs to be mounted on wheels that are at least 10" wide, and preferably 11" or 11.5" for any road course use. Wheel widths depend on both tire section width and profile. More information is needed regarding both the wheels and the tires.


Norm

11 inches.

 

[jkstang78]

Here you go https://tiresize.com/calculator/

 

[Norm Peterson]

11 inches.

And the front wheels/tires?




like pulling teeth . . . sheesh


Norm

 

[Grintch]

Lot of variables. A sticky 275 will be way faster than some 305 all season tires.

What's you application?
Are you trying to stick with your stock/current wheels? If so what size are they?
Why aren't you considering a 285 or 295?
Budget?

 

[Shadow277]

And the front wheels/tires?




like pulling teeth . . . sheesh


Norm

You're right. They're 10.5

 

[Shadow277]

Lot of variables. A sticky 275 will be way faster than some 305 all season tires.

What's you application?
Are you trying to stick with your stock/current wheels? If so what size are they?
Why aren't you considering a 285 or 295?
Budget?

Circuit racing. Current wheels are 20 inch Niche and the tires are 255 in the front and 305 in the rear with a 35 profile. That seems a bit slim. Budget? Whatever.

 

[Norm Peterson]

Circuit racing. Current wheels are 20 inch Niche and the tires are 255 in the front and 305 in the rear with a 35 profile. That seems a bit slim. Budget? Whatever.

I wish we could

 

[Norm Peterson]

Circuit racing. Current wheels are 20 inch Niche and the tires are 255 in the front and 305 in the rear with a 35 profile. That seems a bit slim. Budget? Whatever.

get all of your

Sponsored