not really sure how to explain the question im asking but right now i run a BFgoodrich kdw-2 tire in 245-40-17.... i am soon about to need a new set of tires and i see a few guys talking about tire size and adding mph in the 1/4mile. since i am changing tires i want to also take advantage of this.

the tire im looking to use is a BFgoodrich T/A drag radial. the specs in the tire size i want ''225-45-17'' are here http://www.tirerack.com/tires/Spec.j...irePageLocQty=

now here are the specs for the tire i have now that im replacing..''245-40-17''
http://www.tirerack.com/tires/Spec.j...irePageLocQty=


so my question is should i stick with what i have or will the other tire im looking at add mph and help me run faster/quicker times???

sorry if i confused anyone its just i dont know how to explain what im looking for. thanks for your help

 

the diameters are not that much different from the ones you are looking at and are going to make not much if any difference.

Use this calc for reference http://www.discounttire.com/dtcs/infoTireMath.dos

The bf drag radial is a way better tire at the track, it will help you 60 foot better. I would run them rather then those kdw's

 

cool link.... but my issue is i dont know how to read tire size and what they do. meaning increase or decrease mph in a selected gear.

im confusing my self i think. haha.

 

hum. well i think i learned something from your link

i put the stock tire size in. and then used my current tire size.

if my speedo is reading 65mph im actually going ''with the tires i have now'' 63.43mph. so i lost mph in the 1/4 with these tires basically

but if i use the tire i have now to the ones im looking to get i gained .67 mph. now at 120mph it should be about 1.5 more mph.... am i thinking in the right direction??

 

Bump for more info

 

Shorter tires lower your gearing. Generally, you will accelerate faster with lower gearing unless you end up running out of gear and having to shift to 5th, or unless the gearing is so low that you can't get traction in 1st. For someone who is right on the edge of holding 4th, a taller tire can help because you avoid the 5th gear shift.

Your thinking in post #4 is not correct because the tire height affects acceleration. You can't gain MPH in the 1/4 simply by making your tires taller.

 

I don't think you'll see much if any difference in those diameters. However, the 245's wider footprint will help get more rubber to the ground and potentially better launch times.