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Discussion Starter #1
Greetings all - I'm new here.

I am having 3" spindles put on my truck (as I type). I would like to put 285/75-16 tires on after it is lifted. I have 255s right now. I've can't find anywhere to reprogram the computer for the bigger tires. I called three dealerships in the area - 2 aren't sure if they can do it, 1 will only reprogram if I put 265 or 275s on, anything bigger they won't touch.

My question is does anyone have a similar setup and did you notice any major change in speedometer/odometer? Is it a small enough change not to worry about? Would it just be worth it to get a Hypertech programmer and reprogram myself? Or just put the 265 or 275s on and let the dealer reprogram.

2004 - 2wd - Silverado Ext Cab

Thanks for any help and sorry for so many questions, I just don't want to screw my truck up to bad.
Brad
 

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I wouldnt worry about it. It's not going to be that far off. If you plan on putting a power programmer or getting your truck tuned, just do it then.
 

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you wont be off anymore than like 3 mph at the most. i went from 235/75/16 to 265/75/16 and it was only 3mph. not very noticeable at all
 

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Discussion Starter #4
Thanks for the replies.

I got the truck back from having the spindles put on. I talked with the mechanics and they said if I went to 285s (from 255s) it would be about a 10% difference on the speedometer and that there would be a noticeable difference accelerating with the bigger tires. They said if I put 285s to get a programmer - problem is the extra money won't get the wife's ok. I'm thinking I'll just put 265s on it. Of course I'm tempted to take a chance and put 285s and not worry about reprogramming.

Any thoughts?

Thanks
 

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They're 10% bigger in diameter, but your mileage will only be off by 5% (If I'm thinking correctly).

So...
At 25 mph you'll be going 26.25 mph.
At 50 mph you'll be going 52.5 mph.
At 65 mph you'll be going 68.25 mph.

It's not a huge difference at all. Yes, acceleration will be a tad slower and your mileage will be like 1-3 mph off.... BIG DEAL!!! You don't need a programmer.
 

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Discussion Starter #7
I'm starting to lean towards the 285s - that is what I'd rather have. Besides I figure if I need the programmer - it would make a nice birthday present!

klemmentine - I'm a bit confused, I thought that bigger tires would result in a faster speedometer reading...
At 25 mph you'll be going 23.75mph.
At 50 mph you'll be going 47.5 mph.
At 65 mph you'll be going 61.75mph

Do I have that backwards?

Thanks
 
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