This is topic Slicks vs. street tires with MPH? in forum Tech Talk at Northern California Ford Owners  .


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Posted by Black94 5.0 (Member # 655) on :
 
Does anyone have any theories on why generally your 1/4 mile MPH is faster with street radials and slower with slicks?..Given the fact that the tire is the same overall diameter....

For example:
Street tires=13.6 @102mph
vs.
Slicks=13.4 @ 101mph

[ March 26, 2003, 04:58 PM: Message edited by: Black94 5.0 ]
 

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Posted by street_illegal_stang (Member # 1554) on :
 
maybe the drive has somthing to do with it
 

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Posted by Chico Stang (Member # 801) on :
 
Not sure why exactly, but maybe because a street tires has less rubber touching the ground. Meaning once the tire cathes, there is less drag allowing you to go faster. Kinda the same way why real races use skinnies up front. Allows for less rubber toucing the ground, for less drag. Just a thought.

Josh
 

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Posted by 98slowhoe (Member # 895) on :
 
This is what I think it is. When you run slicks it allows your car to run the most efficent(no tire spin) run it can make. When you have Street tires you tend to spin the tires a lot more and that gives you more time on the current run so with more time there is more MPH since they are directly related it can only make sense.
 

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Posted by 5.0Brian (Member # 262) on :
 
Slicks also balloon at speed. Mine even touch my bumper cover when I'm making a pass, but not when it's parked.
 

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Posted by shade-tree (Member # 298) on :
 
gearing makes the main difference (aka tire size)

my best mph always comes from my ET Streets, but I hear others who say their best mph comes from some nice tiny radials, I dunno.
 

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Posted by Chris M. (Member # 1708) on :
 
i dont understand the tire spin = more mph theory. i think mph is direcly related to distance. you have more time on the track while spinning tire but that is waisted time not accelerating.
 

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Posted by Chico Stang (Member # 801) on :
 

quote:

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Originally posted by 98slowhoe:
This is what I think it is. When you run slicks it allows your car to run the most efficent(no tire spin) run it can make. When you have Street tires you tend to spin the tires a lot more and that gives you more time on the current run so with more time there is more MPH since they are directly related it can only make sense.

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So according to this theroy. Taking this is the exact same car, only difference is tires.

The car on slicks runs an 11 sec 1/4 mile at 120mph, and has a 1.50 60 foot time.

Then you put street tires on it, and the 60 foot time is now 3.0, so becuase his run is going to take longer (more time) and he should have a speed of almost twice as fast. Cause 3.0 is double the 1.50 time that was done on slicks.

The mph should be translated to the distance.

Another example, a honda civic runs a 10 second 1/8 mile at 50mph, while a mustang drives a 10 second 1/4 mile at 140mph.

Now the Honda should end up being much faster then the mustang because he has more time to finish his 1/4 mile, correct?

I think 5.0Brain and myself have the best theories yet. His with tire ballooing, mine with drag resistence.

Josh
 

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Posted by The Nick (Member # 2244) on :
 
It could also have something to do with just the plain old diameter and not the ballooning. If you run a 245/50/16 like I do, that translates to 25.65" of tire when at recommended psi. Then when you mount a slick, since they don't make 25.65" slicks, you must get a 26" tire and this will create a slower rotating mass, which I guess could translate into a decrease in trap speed.

Damn, I should have paid more attention in high school physics.
 

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