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Larger tires...slower times

linda

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linda Enthusiast

linda

Posted
Posted

I am very much interested in jumping to a 285 tire on my HD, but im worried about the loss in low end performance. I am very happy with my performance right now, and worry that the larger tires wont get me off of the line quick enough. I dont have the $ right now to throw 4.56's in the rear just yet, but im dying to get some bigger rubber under this thing. I just dont want to sacrifice performance. Whats your opinions? How much will i lose, and will it be a noticable difference?

03GMC2500HD Enthusiast

03GMC2500HD

Posted
Posted

Honestly the 285's won't make that much difference at all. It will be slightly noticable but very slightly (really minimal). Spend a couple bucks and get a HPIII and correct it with a little perf. to boot if you think it is too sluggish. Unless your putting a clock on it down the strip you won't notice much.

Chevyfreek Enthusiast

Chevyfreek

Posted
Posted

Well according to your sig you already have a Westers tune, so if you do go with the larger tires just get the Westers PCM reburned for them and you should be good to go. Your shift point will be off quite a bit going up to a 285 tire. With the 8.1 I don't think you will notice to much of a power loss. I just put a set of 265 Nitto's on my 2500HD, upgraded to a 93 Octane Hot Tune and I have still gained performance over the 87 octane tune with the factory 245's.

tbyrne Senior Enthusiast

tbyrne

Posted
Posted

You probably won't notice any performance decrease by going with a set of 285. The bigger tires really start to cut down the gear ration plus they are heavier to move around.

 

Tom

 

Silverado2004sidesm.jpg02suburban22sm.jpg

 

2002 8.1 Silverado HD - Full Throttle lift, 37" tires, Comp Cam, TOG headers, Volant induction plus more!

2002 8.1 Suburban -Intercooled Whipple supercharger, 22" wheels/tires + more - 407hp/558 ft-lb torque at the rear wheels - 14.0 @ 96.59 MPH

 

www.tbyrnemotorsports.com

linda Enthusiast

linda

Posted
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Posted

you confused me a little Tom (not hard to do). You say it wont have an effect on performance, but will greatly reduce the gear ratio. Well, a reduced gear ratio means slower off the line, which i equate to less performance. So did you mean that 285's wouldnt make that much of a difference compared to the big tires (like yours)? Or are you saying that 285's are big, and WILL make a noticable difference in my truck? Im also concerned about my trany shift points now that someone brought that up. Any comment on that, and what are talking about exactly here as far as differences? If its shifting at 4500 now, it will shift at what......3800,4000 or something?

2001 HD Enthusiast

2001 HD

Posted
Posted

Linda-I went from 245 to 265 to 285 and I have noticed a slight loss of low end due to the over all effective gear ratio( 4.10 to 3.81) and about 1 mpg loss in gas milage (corrected for tire size). I have no programming yet! But like chevy freek said, get your Westers reflashed and shift points and speedometer/odometer should be fine. And with the 8.1, you probably won't notice the low end or loss of gas milage very much. Might even get better.

I need a programmer but I don't want to risk dealer warranty rejection due to programming. I know the diablo doesn't give you the gains that wester does, but at least you can revert back to the stock program before dealer service. And like computers, every time you turn around, there is something newer and better coming out (Tunercat)

 

Do you drag race with a camper shell?

 

:thumbs:

 

:eek:

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