Drag radials on V-6 rims?

[BlackBadGT]

I have a set of V-6 rims off a 1999 sitting in my basement. I was gonig to use them for snow wheels, but i never got around to buying snow tires for them. SO i think i'll use them for track wheels instead. I assume they're lighter than the 17's that are on the car now. But my question is how large of a tire can i fit? They are 15x 6 i want to say... maybe 15x7. Could i fit a 275 BFG drag radial on them? I'd like to keep the stock tire height... for speedo purposes.

 

[nickthegenius]

I think the 275's are what most people are running with the V6-wheel/DR combo.

 

[StangYellow]

275's will fit on a 7" wide rim.....barely. But if you want to keep your stock tire diameter, you are losing 2 inches off your stock wheel. Then however many millimeters of sidewall you lost. So in order to keep the accuracy of your speedo, you are going to need a pretty tall sidwall, which i doubt you will find with drag radials. I may be wrong, but I think you are better off finding a tall sidewall with regular drag slicks. Try looking for Mickey Thompson drag radials. They might offer some awkward size tires. good luck.

 

[JonJon]

275's will fit on a 7" wide rim.....barely. But if you want to keep your stock tire diameter, you are losing 2 inches off your stock wheel. Then however many millimeters of sidewall you lost. So in order to keep the accuracy of your speedo, you are going to need a pretty tall sidwall, which i doubt you will find with drag radials. I may be wrong, but I think you are better off finding a tall sidewall with regular drag slicks. Try looking for Mickey Thompson drag radials. They might offer some awkward size tires. good luck.

The speedo thing doesn't really matter, they're drag tires and he's a speed 5.

 

[StangYellow]

If you decrease the tire diamater, you increase the speed of the drivetrain. While your speedometer and tachometer will still operate in the same way, they will actually read higher that what they should be doing.

For example, if you run through the traps at the top of 4th gear, and you decrease the tire diameter by an inch or more, chances are your tachometer will redline early and you either let off, or bang 5th. Thats why it is an issue to retain the correct tire diameter.

 

[nickthegenius]

http://www.miata.net/garage/tirecalc.html

Plug the numbers in and you will find out that a 275/50R15 is within 1/10th of an inch from our stock 245/45R17 tires.

Math....what a concept.

 

[JonJon]

If you decrease the tire diamater, you increase the speed of the drivetrain. While your speedometer and tachometer will still operate in the same way, they will actually read higher that what they should be doing.

For example, if you run through the traps at the top of 4th gear, and you decrease the tire diameter by an inch or more, chances are your tachometer will redline early and you either let off, or bang 5th. Thats why it is an issue to retain the correct tire diameter.

Why would the tach be affected?

 

[nickthegenius]

Why would the tach be affected?

Ah, come on! You didn't know that the tach readings are based off of axle speed? Geez

 

[JonJon]

Ah, come on! You didn't know that the tach readings are based off of axle speed? Geez

 

[StngStr]

The tach isn't affected, but the engine RPM's are. A smaller diameter tire is like going to a higher numerical gear ratio. On a stock GT with 3.27's you should be at the top of 3rd gear when going through the traps. With a smaller diameter tire, you will probably need to shift into 4th before the end of the 1/4.

On the original note, I think 275 is WAY too wide for a 7 inch wide rim. A 275 is 10.8 inches wide. With a 7 inch rim you'll have almost 4 inches of rubber overhanging the rim (2 inches on each side) and it will either cup or be really sloppy. The contact patch won't be as good as it would be with a 245 (9.6 iches wide).

 

[StangYellow]

Why would the tach be affected?

The tachometer itself isnt affected. Its the engine speed, which you read on the tach. If you put smaller tires on the back of the car, the ratio of axle revolutions to 1 tire rotation is altered. If the tire is smaller, your drivetrain will have to rotate quicker to maintain a certain MPH then it would with a taller tire.

Picture peddling a bike with a 3 foot tall tire, then replacing it with a 1 foot tall tire. And your goal is to get that rear tire to maintain 30mph. Imagine how fast your feet have to be kicking to get the bike going 30mph with a 1foot tall tire.

 

[nickthegenius]

I just took a look at the BF Goodrich site and they recommend at least a 7.5" rim width for the 275's.

http://www.bfgoodrichtires.com/assets/pdf/comp_ta_drag_radial.pdf

 

[JonJon]

The tach isn't affected, but the engine RPM's are. A smaller diameter tire is like going to a higher numerical gear ratio. On a stock GT with 3.27's you should be at the top of 3rd gear when going through the traps. With a smaller diameter tire, you will probably need to shift into 4th before the end of the 1/4.

Gotcha. I didn't think of it in 1/4 mile terms, like going through the traps but having to shift again.

 

[Jackie Chan]

get some 26x10.5x16 mickey thompson sportsman pros

 

[StngStr]

get some 26x10.5x16 mickey thompson sportsman pros

Hey Nissan man...I don't think those will fit on his 15 inch rims.

You going to OSW on Friday john?

 

[BlackBadGT]

I was of the thinknig that the v-6 rims were 15x6 They are the type with 6 spokes in a triangular pattern. not the newer 5 spokes.

 

[downsouthman1]

I know this has already been stated but a 275s not a good idea on a 7 inch wide rim. I have a 9 inch wide rim & am only running a 285. You'd never get wide enough rubber on that rim for a performance increase. Will it fit? Yes. Will it help? No.