Is 275 factor independent of non DOT factor??

[Red Tornado]

I will be running 275/40/17's on my car and wondered if the -.75 factor for non-dot was offset against the .4 for the smaller tires (for a net of -.35) or if it was a .4 only since it was the smaller tire??

 

IN otherwords fo I divide by 8.3 or 9.05 in my calculation for weight to get my max rwhp.

 

Thanks

[DriverGT5]

What tires are you running? Non-DOT are usually measured in inches.

 

That is an interesting point you bring up. I understood the rules a different way, but now that I look at them again, it seems you take -.75 for any non-DOT tire, then calculate size points after that. I'll have to change my program to calculate the points accurately.

[Greg G.]

If they are non-DOT, you subtract 0.75 from you calculated wt/power ratio. If they are also 10.5" to 9.5", you then add 0.4 to your calculated ratio. So, the net effect of having a non-DOT slick that is 10.5" wide, would be to subtract 0.35 from your calculated wt/power ratio.

[Red Tornado]

Thank you.

 

Now if I can only find a slick that is that much better than a R6 hoosier or kumho v710 to be worth giving up 35rwhp.

[Greg G.]

Chris, try calculating that out again (I think you will find it to be closer to 15-20 rwhp).

[rlogan]

Hmm, my Hoosier slicks are 305/18s I guess they must be DOT