Did bigger tires make my truck slower?

[Gorske]

Recently I went from Falken Wildpeak AT3 265/65/18 to Cooper Discoverer ATP 275/65/18. Tonight I went to the track to test it out to see if the truck got slower. Weather conditions were very similar which worked out perfect. I was surprised with the results.

 

Previous time slips with the Falkens.

 

Time Slips from tonight with the Coopers

First pass versus a V6 Impala.

 

Second pass versus a mystery UTE. Worst traction of the night.

 

Final Pass versus a 2012 Vette 6.2 with a Vortec supercharger.

 

In the end very similar times, made my fastest pass and if you notice the big change in the trap speed. Truck was right around 1 mph faster. Very happy it did not hurt my times.

[Rolling Thunder]

Gorske,

 

With the tire size change, and if your default rear axle gearing is 3.42, you changed that ratio to 3.37 rears, negligible and it's probably not noticeable unless you are in a real even and tight race.  Bigger doesn't help.

 

I love your videos! 

 

[Gorske]

3 minutes ago, Rolling Thunder said:

Gorske,

 

With the tire size change, and if your default rear axle gearing is 3.42, you changed that ratio to 3.37 rears, negligible and it's probably not noticeable unless you are in a real even and tight race.  Bigger doesn't help.

 

I love your videos! 

 

I was hoping to see if my theory was going to be right about the gearing change and I would see a little higher mph which I did. However I thought I would see a slightly slower time. Yes general rule of thumb is bigger tires means slower. I made a pretty minor tire size change but was cool to test.

 

Glad you liked them. I am hoping to make some more videos at the other local track soon.

[Rolling Thunder]

Had you considered spare GM 17" wheels with default 17" tire size for them just for the track?  

 

The calculator says 265x65x17 gives you 3.53 rears on a default 3.42 OEM, not a whole lot but you will come up against a real tight race one day.......  I also noticed on some of your earlier dash board videos that your RPM's never go below 5000 during shifts.  Is that from a tune?

[Gorske]

20 minutes ago, Rolling Thunder said:

Had you considered spare GM 17" wheels with default 17" tire size for them just for the track?  

 

The calculator says 265x65x17 gives you 3.53 rears on a default 3.42 OEM, not a whole lot but you will come up against a real tight race one day.......  I also noticed on some of your earlier dash board videos that your RPM's never go below 5000 during shifts.  Is that from a tune?

I will probably stick with my daily wheel/tire setup for now. If I went with a track wheel tire combo I'd go with a lighter 17" wheel with drag radials. The wheels I have now are actually pretty light. they are 25lbs each and the stock Z71 wheels are 32lbs each ;)

Now as far as maintaining the higher RPMs that is from the Circle D stall I have. That is another benefit to having an aftermarket converter is you maintain a higher RPM after the shift. I'll post a video to compare the RPMs before and after the stall.

 

Stock converter.

 

With the stall

 

[Rolling Thunder]

Yep, they are the videos I saw previously.

[hizzo3]

I'd argue they made you faster... You just accelerate slower

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[Gorske]

15 hours ago, Rolling Thunder said:

Yep, they are the videos I saw previously.

It is funny that is the first time I have watched those two videos side by side and wow talk about night and day. With the ProCharger and the stall the truck goes from 0-130 20 seconds faster lol.

[L86 All Terrain]

That's a hot 5.3L, though it was a RCSB until I read your signature. It would smoke my 6.2L with 305/55 E loads, that is for sure. Wish I had the balls to buy a D1SC kit but I think I am holding out for a C6Z or 1SS to play with instead. Seems like a lot more potential yet in your truck. Are you carrying your spare tire at the track? 

[Gorske]

51 minutes ago, 10SierraA.T. said:

That's a hot 5.3L, though it was a RCSB until I read your signature. It would smoke my 6.2L with 305/55 E loads, that is for sure. Wish I had the balls to buy a D1SC kit but I think I am holding out for a C6Z or 1SS to play with instead. Seems like a lot more potential yet in your truck. Are you carrying your spare tire at the track? 

Thanks. Before moding my truck I was debating getting a project car. Then I thought I'd just make a fast daily truck and skip having two insurance and car payments lol. Truck is at its peak for the current mods expect for weight reduction. All my times have been full street weight with a spare. Was going to try at the track removing various items like the spare, tailgate, and back seat and see how they effect the times and see which is most beneficial.

[2tallromero]

Thanks. Before moding my truck I was debating getting a project car. Then I thought I'd just make a fast daily truck and skip having two insurance and car payments lol. Truck is at its peak for the current mods expect for weight reduction. All my times have been full street weight with a spare. Was going to try at the track removing various items like the spare, tailgate, and back seat and see how they effect the times and see which is most beneficial.

****ing awesome bro


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[swathdiver]

The spare will likely aid your short time, worth testing with and without though.

[Pearl2017]

the spare may be helping with traction...

[L86 All Terrain]

^^ thought that too, but if launching in AWD or 4 HI it shouldn't matter. Not sure if that is his method, or if he has radials? 

[SILVER SLED]

As usual, good to see that truck in action.  One of these days Ill get mine to the track and see if I can break into the 13's.