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6.0L Performance Parts Discussion What has or has not worked for you?

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Old 10-12-2009, 10:41 AM
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Tires.

So I have a set of OEM rims and brand new 265/70/17's. When I put 2 of these on the rear end one time, and took the 35's off, the truck was ALOT quicker from 0-100.

My question, if I get an sct and have the 35's, does it tune the truck to run as good with large tires, as it would with smaller tires? Does it tune the transmission to run like I've got gears in the *** end?

Or would I still benefit from putting the smaller tires on the truck?
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Old 10-12-2009, 10:50 AM
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The bigger tires will always rob power. It wont run like there is gears in it unless you put some gears in it. But it will be more powerful so it should help. But all in all yes you will still benefit from putting smaller tires on the truck, as far as power and mpg goes.
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Old 10-12-2009, 10:50 AM
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I think the SCT has a tire setting that can be changed......
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Old 10-12-2009, 10:51 AM
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Im pretty sure that is to set the speedo to be corrected for the larger tires.
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Old 10-12-2009, 10:54 AM
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if you do a gear swap i believe you will have to change both front and rear gears at the same time
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Old 10-12-2009, 12:17 PM
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Quote:
Originally Posted by 01redcrew View Post
if you do a gear swap i believe you will have to change both front and rear gears at the same time
Well I know this, as well as the statement above, ofcourse to run like it has gears in it, you need to put gears in it.

What I am asking is, even with SCT custom tuning with tire size adjustment, will I still benefit at the track by putting the smaller tires on?
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Old 10-12-2009, 04:55 PM
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i emailed eric a longtime ago when i got my tunes...the tire size option or rev per mile, is for the tunning of transmission, and it doesn't affect he speedo,odometer, or abs, just a things for shifting is what i was told, as far as benis at the track with smaller tires....i would assume so as long as your not making enough power to break all 4 loose right? your 0-60 and 100ft times wouldbe up but would hurt top end speed even then unless your going over 140 or so would prob be benificial....hope im right and hope this helps....just my 2c
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Old 10-12-2009, 05:00 PM
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Correct, The SCT won't adjust your speedometer for tire size, the Revs/mile is all for transmission tuning and trying to get the shifts right. And yes tires ROB the hell out of power.
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Old 10-12-2009, 05:30 PM
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As was said..Yes smaller tires will be faster on the strip..you will lose top end, but you will never hit top end on a 1/8 or even a 1/4 for that matter, the best set up is to acutally hit your top end, as you finish in the 1/4, but that would be silly for a truck you drive on the street.. You will gain at LEAST a few 10ths with smaller tires if not more.. I could tell a huge difference just driveing home from work when i went from stock tires to 35s...

And yes, if your going to put gears in it YOU WILL need to do fronts and rears together,, unless you want a quick and easy way to destroy your driveline. Just for the heck of it..make a few passes on your 35s and make a few on your 265s you'll be surprized!
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