Nittos

[Taszar]

I recently installed a set of Nitto NT 555R 305/45/R18 Drag Radials. I know the tire is larger and I was wondering how much the speedo is thrown off or are there any other things I should consider. Is it that big of a deal?? Its not a daily driver. Just wanted to get info before I drive it too much. Thanks for the info.

[02BOLT]

I recently installed a set of Nitto NT 555R 305/45/R18 Drag Radials. I know the tire is larger and I was wondering how much the speedo is thrown off or are there any other things I should consider. Is it that big of a deal?? Its not a daily driver. Just wanted to get info before I drive it too much. Thanks for the info.
Your stock tires are 295/45/ZR18's while the Drag Radials are 305/40/VR18's. The first number...295 or 305 refers to the cross section(width) in millimeters, while the second number...45 or 40 refers to the aspect ratio of the sidewall of the tire which is a percentage of the cross section.

So, the 45 in a 295/45/ZR18 tire means, the height of the sidewall is 45% of the cross section(width). The Drag Radial while being wider at 305mm, has a shorter aspect ratio at 40% as opposed to the 45% of the stock tires, which more or less evens the heights of the sidewalls out.

To make a long story short, the difference in the speedo will be minmal at most. You do not need to be concerned. It's all good!:tu:

Later,
Rob

[L8 APEX]

Chill out Rob;) The DR's are 305 45 18. They may be a half inch taller if that. I don't think you will notice in the speedo. If so I can program it with the SCT.

[02BOLT]

My bad. I was thinking they were 40's for some reason. At any rate, you shouldn't need to calibrate anything. I ran them on my truck for 95% of the time I owned it, and never noticed a difference with the speedo.

[Tobbun]

Here is a great tool that shows you the exact difference between tires and the difference it will have on speed.

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

It shows that the tire change will affect the speedo by 3% too fast.

Just ignor the miata part... :)

http://www.svtgalleries.net/gallery/data/500/624TireComparrison-med.JPG

[Tobbun]

It shows that the tire change will affect the speedo by 3% too fast.




I put 40's in the equation instead of 45's.. with 45's it will affect the speed by 1.3% too slow.

[99WhiteBeast]

Your stock tires are 295/45/ZR18's while the Drag Radials are 305/40/VR18's. The first number...295 or 305 refers to the cross section(width) in millimeters, while the second number...45 or 40 refers to the aspect ratio of the sidewall of the tire which is a percentage of the cross section.

So, the 45 in a 295/45/ZR18 tire means, the height of the sidewall is 45% of the cross section(width). The Drag Radial while being wider at 305mm, has a shorter aspect ratio at 40% as opposed to the 45% of the stock tires, which more or less evens the heights of the sidewalls out.

To make a long story short, the difference in the speedo will be minmal at most. You do not need to be concerned. It's all good!:tu:

Later,
Rob
Check out the big brain on Rob..... he's a smart mutha scratcher:D

[FRDRCING]

Check out the big brain on Rob..... he's a smart mutha scratcher :rll:

I love that movie