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I am going to be getting a set of 285/65 18 tires in the NEAR future and I am wondering..... when I change tire size with the predator, is it as easy as just inputting OLD tire size (245/75 16) then inputting NEW tire size? I thought I had heard a few people say that it doesn't work properly
 

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It is menu driven and very simple to change tire size.
 

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X-Treme-It's exactly like that. It works fine for most people, although some forget to put the stock size in first. The other reason some aren't getting an accurate speedo I think is due to differences in metric tire size. Mine is within 1 mph.
 

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I am going to be getting a set of 285/65 18 tires in the NEAR future and I am wondering..... when I change tire size with the predator, is it as easy as just inputting OLD tire size (245/75 16) then inputting NEW tire size? I thought I had heard a few people say that it doesn't work properly
Yes, it's as easy as inputting 285 - 65 - 18. It may still be off 1 mph or so.

On my stock tires, my speedo was reading 71 or so at 70 (Garmin GPS). I told my Pred that I was running 240 - 75 - 16 and the speedo is now agreeing with the GPS. FWIW.... Planning on 285's soon...
 

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I just went into modify tune and changed my tire size !! I think it's wrong though................with my Hypertech I was running about 2100 at 80 !!
With the Predator I run like 2400 at 80 mph !! And I redline at 105 mph ............a lot of these guys say I should be around 120 at redline !!

I need to re-check it !! What are you talking about by putting the stock size in first ????
 

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I screwed this up too..............

When you first change the tire size parameter it will first ask for the "factory tire size" then once you input and hit enter it will ask for the "actual tire size". If you don't get the factory tire size screen - try using the "reset all parameters" options and start over with modifying yur entire tune.

P.S. - if you don't get this correct - your shifting will also suffer.
 

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Thanks for the info Skoryaro2 !! I think originally I just put my 285 size in the first screen and loaded it !!

Anyway.........I cleared the parameters and reset it yesterday!! Thanks again !!
 

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I have never corrected my tire size with my predator, I just know I'm roughly 5mph off. Does anyone know what the metric size for my tires would be.
 

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Why not just run it 5 off. I've checked it with my GPS and you will actually put less miles on your truck. I've programmed 225-75-16 while running the actual tire size of 265-75-16's.;) I get almost 10miles less on the odometer per 100miles driven(all figures from the GPS plugged in). GARMIN of course. I've had NO ISSUES with the truck in more than 10,000 mi.
 

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^^Not real honest though is it?:rolleyes:
 

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devil they are a 305X???X20 you can put a tape measure on them and get really close the pred won't let you put a weird size on it.
 

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devil they are a 305X???X20 you can put a tape measure on them and get really close the pred won't let you put a weird size on it.
Thank you I will try that.
 

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When you program with the Predator to correct for a different tire size does the Predator correct/adjust the transmission shift points or just the speedometer only???
 

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the pred won't let you put a weird size on it
.

How about 343/48R20 Try this page http://www.dakota-truck.net/TIRECALC/tirecalc.html I knew dodge was good for something

I disagree, I ran mine at 295/70/r17 and it was off, I dont have no fancy GPS so after some tinkering I found that 293/70/R17 put it on as close as I can tell going by the state mile markers, luckly there are areas around me where every 1/10 of a mile is marked, puts me running right @2000 rpms @70mph. It will not calibrate correctly sometimes when I change tunes, and recently when I uploaded again after my update I had to load my tune twice, the first time the speedo wasnt right, reloaded tune and was ok, I dont pull any fuses when I upload so maybe that is why it didn't take the first time...dunno

Texasdeer the short answer is the speed and rpms and the shift points are all relitive so yes, Wait do you mean can you adjust the shift points (example Use the predator to program the truck to Shift from 1st to 2nd @3700 rpms etc.) than the answer is no, maybe with EFI live but I dont no, sorry
 

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I always hear how changing to larger tires, like 285s for example throw off your shift points with an automatic. I was just wondering if while using the predator to correct for a larger tire size does it affect the speedo only? I guess what I am asking is will the Transmission computer see the correct seedometer reading after it has been adjusted with the Predator?
 
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