Weight of wheels-Impact on 1/4 mile times.

[rocket5979]

In my case, 15 pounds x 2 = 30 pounds rotational weight
30 x 8 = 240 lbs static weight
240 / 100 = 0.24 seconds ET reduction

That would've been nice, but I doubt I actually achieved that. I suppose it might have been a tenth or so. But I figure my worn suspension is costing me in the launch so much it possibly negates the theoretical weight savings.

You are right. There are other factors that come into play when swapping rim/tire combo's out. Stuff such as tire surface contact patch and traction come into play too, which though a car may net a little more MPH in the 1/4 due to faster acceleration it may not gain too much ET because of lack of traction off the launch. Analyzing time slips before and after the change will help a person diagnose what their achievement or problem was, and (better yet) why.

That was the case when I raced my Explorer last week. I had lighter rims and tires (with less contact surface) but I had to feather the launch soo much that I only ended up getting only .10 better when the weight diff was good for more than .25 seconds. In a situation, where the vehicle would be able to get sufficient traction in both the before and after scenario's, the rule of thumb stated above would be fairly accurate.

 

[02LSE96LSC91SE84TC]

Thanks for the imput. I did have a traction problem besides the weight thing so I guess its one of those have to make the change to see. Sounds like .2 is the average of the opinions, throw .2 for traction should I get it and I have what I guess the car can do as is. Also the run was hot. Thats what makes it a challenge right, the what ifs and don't knows. I only ran that car that 1 time, who would of thought my LSEs 1st time out would be better, at least in the final 1/4. I will be solving these questions with definate answers soon enough, with a little help from my friends.

 

[rocket5979]

Thanks for the imput. I did have a traction problem besides the weight thing so I guess its one of those have to make the change to see. Sounds like .2 is the average of the opinions, throw .2 for traction should I get it and I have what I guess the car can do as is. Also the run was hot. Thats what makes it a challenge right, the what ifs and don't knows. I only ran that car that 1 time, who would of thought my LSEs 1st time out would be better, at least in the final 1/4. I will be solving these questions with definate answers soon enough, with a little help from my friends.

Oh yeah. It is all about being methodical. That is the only way a person figures out what the variables were that could have caused the differences in results. I should have took track temp readings, tire psi, how bad I was spinning, what rpms shifting, how much gas, so on so forth and wrote them on the back of the slips. Oh well, we can settle down and get methodical this next time. I dont have to let the LS cool for nearly as long as the Explorer does!

You know what. We should just datalog our runs on both of my Xcal2's that I have, so that way we have a more accurate representation of shifting command vs actual and IAT's as well to name a few. If I can get the on-board datalogging feature to work correctly on these I might bring both out and give it a try. I would bring the laptop too but the screen took a sh1t.

 

[MediumD]

Driller, what size are those tires?

 

[driller]

Driller, what size are those tires?

26x9.50-16 Hoosier Quick Time Pro D.O.T. Drag Tires