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  #1  
Old 03-01-2016, 07:15 PM
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Changing to bigger tires

Hello everyone,

I was wondering, if I get 265/70R17 tires in place of 245/65R17 tires...do I need to change my gears also?

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  #2  
Old 03-01-2016, 07:31 PM
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Re: Changing to bigger tires

No to the gear change, but your odometer will be off and you'll get a little worse mileage. If you get a bigger tire, try to keep the diameter within ~1/2 in. (preferably less than that though) of the stock tire diameter. Same is true if you do a "stagger" fit like some of us do.

There is a little over a 2 in. diameter difference in the two sizes you listed.
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Old 03-02-2016, 01:16 PM
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Re: Changing to bigger tires

That's why I was wondering about changing gears...wouldn't that take care of that?
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Old 03-02-2016, 07:00 PM
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Re: Changing to bigger tires

If you selected the correct gear ratio, yes it would. That's a pretty expensive way to go about it though, plus the gear ratio selections are quite limited. The problem is that the PCM/TCM is programmed for the current stock ratio (3.73:1) and you'll get DTC's and error messages and the vehicle will also go into limp mode because it will detect the different ratio. The only way you'd then be able to fix it is to purchase a tuner that will allow you reprogram the ratio into the PCM/TCM, or have it done at the stealer, if they can do it.
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05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
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Old 03-02-2016, 10:15 PM
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Re: Changing to bigger tires

so should i just get a tuner and that's it? is there one you would recommend?
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Old 03-03-2016, 04:16 PM
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Re: Changing to bigger tires

I have both a Superchips and a Diablosport (Predator) for both my Hemi vehicles. IMO, the best one for the Jeep is the Superchips, solely because it allows me to totally control the up/down shift schedules and torque management settings on the transmission. This, along with a Sonnax Line Pressure Booster and Transgo Shift Kit, makes the transmission about as good as it can get. I am sure you have discovered the lousy (slip and slide) shifts and the oozy WOT upshifts.

The Diablosport Tuner will only give you control over the 1-2 and 2-3 up/downshifts, but no additional control (other than what's built into the canned tunes) over the torque management. Otherwise both tuners are somewhat similar in their features, and both will allow you to adjust tire sizes. The DS Tuner also allows you to adjust both timing and fuel mixture but, IMO, neither is important unless you have a highly modified engine. I will continue to run the SC Tuner (91 Tune) on the Jeep, but I run the Diablosport on my Hemi LX, along with the Mopar Performance Transmission Contol Module. On it I run the 93 CAI Tune unmodified, except for tire size (I have larger tires on it) rev/top speed limits and WOT shift points.

Additionally, IMO, because of the lousy Positive Crankcase Ventilation (PCV) Sytem, a catch can is a must on ANY 5.7.....sooner rather than later. This will eliminate most of the combustion tract contamination that adversely affects performance/economy
caused by detonation and the associated knock retard that accompanies it.

So, IMO, bottom line for the Jeep top mods.......Superchips Tuner with the Advanced Transmission Tuning Application and some sort of catch can. After that, pretty much your choice. On your 05, especially if you have the original spark plug wires on it, a set of Taylor Shorty wires might be a good next choice.
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05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
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Old 03-03-2016, 07:27 PM
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Are the tuners hard to install? I really have no clue about them at all. Any inside is greatly appreciated. Do you set them once and forget it or is this something you have to mess with alot?

I've had this jeep for almost 5 years. I've changed spark plugs but nothing else. So I'll look into the wires you suggested.
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  #8  
Old 03-03-2016, 10:35 PM
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Re: Changing to bigger tires

Quote:
Originally Posted by jsherv View Post
Are the tuners hard to install? I really have no clue about them at all. Any inside is greatly appreciated. Do you set them once and forget it or is this something you have to mess with alot?

I've had this jeep for almost 5 years. I've changed spark plugs but nothing else. So I'll look into the wires you suggested.
The tuners are easy to install.....just plug into the OBDII port, it'll start up and you select your tune and follow instructions. You don't have to continually mess with it unless you want to try different tune and other settings. Some folks try them all to see which works the best for them. Also, if you have problems or questions about loading and set up, there are lots of folks here that have them and will help you.

How many miles on your rig? Are the spark plug wires the originals? How does it run and what kind of fuel economy do you get? Have you serviced the transmission, transfer case and differentials?
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05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
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  #9  
Old 03-03-2016, 10:44 PM
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Quote:
Originally Posted by jeepgcoman View Post

The tuners are easy to install.....just plug into the OBDII port, it'll start up and you select your tune and follow instructions. You don't have to continually mess with it unless you want to try different tune and other settings. Some folks try them all to see which works the best for them. Also, if you have problems or questions about loading and set up, there are lots of folks here that have them and will help you.

How many miles on your rig? Are the spark plug wires the originals? How does it run and what kind of fuel economy do you get? Have you serviced the transmission, transfer case and differentials?
I have had a tune up and got new spark plugs so whatever goes along with that. I've serviced differentials and the transfer case, but not the transmission. I usually get 14.5ish mpg. I have 125k.
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  #10  
Old 03-03-2016, 10:45 PM
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I haven't really paid much attention to it though since the lift. I'll have to look tomorrow and see what it says.
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  #11  
Old 03-05-2016, 09:37 AM
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Quote:
Originally Posted by jeepgcoman View Post
I have both a Superchips and a Diablosport (Predator) for both my Hemi vehicles. IMO, the best one for the Jeep is the Superchips, solely because it allows me to totally control the up/down shift schedules and torque management settings on the transmission. This, along with a Sonnax Line Pressure Booster and Transgo Shift Kit, makes the transmission about as good as it can get. I am sure you have discovered the lousy (slip and slide) shifts and the oozy WOT upshifts.

The Diablosport Tuner will only give you control over the 1-2 and 2-3 up/downshifts, but no additional control (other than what's built into the canned tunes) over the torque management. Otherwise both tuners are somewhat similar in their features, and both will allow you to adjust tire sizes. The DS Tuner also allows you to adjust both timing and fuel mixture but, IMO, neither is important unless you have a highly modified engine. I will continue to run the SC Tuner (91 Tune) on the Jeep, but I run the Diablosport on my Hemi LX, along with the Mopar Performance Transmission Contol Module. On it I run the 93 CAI Tune unmodified, except for tire size (I have larger tires on it) rev/top speed limits and WOT shift points.

Additionally, IMO, because of the lousy Positive Crankcase Ventilation (PCV) Sytem, a catch can is a must on ANY 5.7.....sooner rather than later. This will eliminate most of the combustion tract contamination that adversely affects performance/economy
caused by detonation and the associated knock retard that accompanies it.

So, IMO, bottom line for the Jeep top mods.......Superchips Tuner with the Advanced Transmission Tuning Application and some sort of catch can. After that, pretty much your choice. On your 05, especially if you have the original spark plug wires on it, a set of Taylor Shorty wires might be a good next choice.
What size spark plug wires do I need? Should I get the heat insulation boots also?
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  #12  
Old 03-05-2016, 12:10 PM
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Re: Changing to bigger tires

The 8.2 mm wires are fine. Just type, "Hemi Taylor Shorty Wires" into your search engine and hunt for the best price. The wires come ready to install, and the install should take maybe 10-15 minutes at most.

Here's a pix of my home made originals when they first came out back in about 2006. i wanted to see how they worked.....no difference at all, except it gets rid of the mess over the top of the engine and there is less wire to fail now. I have since changed my entire system on my 05 over to the 06 and later system....coil over both plugs.
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05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
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