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Discussion Starter #1
Hello all.
I know this topic has been discussed before but not exactly to my situation. I'm having a really hard time deciding between 285/70r17 or 315/70r17 for my JKU. It's a 2008 with 265/70r17 currently and has the crap 3.8L...it's already a nightmare going up hills and merging on the highway, etc. I found an absolute steal of a deal on the 35's and would love to get them. I've read a lot that this will make the jeep even weaker and even less fun to drive on the highway. I don't do much off-roading- basically just some light trail riding on hiking trips so offroad performance is NO concern to me at all. I want to know how my highway driving and every day driving will actually be affected. I plan to purchase a tuner. The 35s are falken Rocky Mountain tires and I believe I have 3.73 gearing. I also have a 2.5" TF BB. What should I do?
 

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Gunnery Sergeant USMC (ret)
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Did you try the search function here? Why not post in the welcome room first and introduce yourself?

Maybe you could have googled jeep jk gearing chart. Oh wait let me do that for you.

 

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Discussion Starter #5
Sorry for the quick post but I have to make my decision tomorrow morning so I needed quick advice!
So what is your decision?
Well...I was hoping to get some advice here. I see the chart says I shouldn't even be running the tires I am now. I'd say the chart is a little modest. I was just looking for testimonials from people with the same setup as myself. I would like the 35's, but not at the total cost of daily driving performance.
 

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I have a 3.6 manual with 3.21s with 35s. I need an incredible amount of throttle input to get going. I never stalled a vehicle so much in my life. And my jeep is lighter than yours and more "powerful" so you might be alright with your 3.73s. but I personally wouldn't go over 33s with your current set up.
 

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Gunnery Sergeant USMC (ret)
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I have a 3.6 manual with 3.21s with 35s. I need an incredible amount of throttle input to get going. I never stalled a vehicle so much in my life. And my jeep is lighter than yours and more "powerful" so you might be alright with your 3.73s. but I personally wouldn't go over 33s with your current set up.
I was running 37's with 4.10 gears for over a year.
 

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We put in 4.88s on a Jeep (3.6L auto) with 35s and it's awesome on the trail (Rubicon transfer case) but rev's a little high on the freeway. I have ran 35s and 37s on 4.10s and finally installed 5.38 and love it (3.8L, auto).

If you think you will get larger tires in the future always go lower than expected. IF you think you will be running more street than trail you can be modest on your gear selection...say 4.56s.
 

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Hello all.
I know this topic has been discussed before but not exactly to my situation. I'm having a really hard time deciding between 285/70r17 or 315/70r17 for my JKU. It's a 2008 with 265/70r17 currently and has the crap 3.8L...it's already a nightmare going up hills and merging on the highway, etc. I found an absolute steal of a deal on the 35's and would love to get them. I've read a lot that this will make the jeep even weaker and even less fun to drive on the highway. I don't do much off-roading- basically just some light trail riding on hiking trips so offroad performance is NO concern to me at all. I want to know how my highway driving and every day driving will actually be affected. I plan to purchase a tuner. The 35s are falken Rocky Mountain tires and I believe I have 3.73 gearing. I also have a 2.5" TF BB. What should I do?
If you're not happy with it now, you'll want to park it with 35's.

I drove my buddies 2010 auto, 3.73, on 35's and didn't feel it was unbearable. BUT, I WANTED to like it. I was having a great time driving a "Jeep." So much so, that I went out and bought one for my self. Granted I bought a '14 Rubicon with 4.10's, I knew I was going straight to 35's.....

Is it really a "nightmare" or is it a "Jeep?" They're not built to be an autobahn cruiser. Everything on them is a compromise. Price we pay to have folks glaring enviously at us when the weathers nice and the top and doors are off.
 

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Sorry I should have been more clear in the original post- I don't want to regear, ever.


If you don't want to regear then expect quite a bit of drop in power when you go to the 35's. On my old '07 JK I had 35's w/ 4.10 for 3 or so years and it wasn't a nightmare to drive but I wasn't winning any races. However if your not happy with your power now, then you really wont be happy with the power after you go to 35's.

There are small things you can do to retrieve some of the lost power, but in the end re-gearing is your best bet. You can do the programmer, cold air system, exhaust system, throttle body spacer.

Or....
Go ahead and do the tires you want and save up to regear. I'm not sure what you have against regearing, but that will be the best way to give it the pep you want. I had 5.13's with 37's in my '07 when I sold it and it wasn't too bad. If your scared that re-gearing will screw up your jeep, just make sure you do your homework and find a good reputable shop that stands behind their work.
 

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Discussion Starter #13
Hello all.
I know this topic has been discussed before but not exactly to my situation. I'm having a really hard time deciding between 285/70r17 or 315/70r17 for my JKU. It's a 2008 with 265/70r17 currently and has the crap 3.8L...it's already a nightmare going up hills and merging on the highway, etc. I found an absolute steal of a deal on the 35's and would love to get them. I've read a lot that this will make the jeep even weaker and even less fun to drive on the highway. I don't do much off-roading- basically just some light trail riding on hiking trips so offroad performance is NO concern to me at all. I want to know how my highway driving and every day driving will actually be affected. I plan to purchase a tuner. The 35s are falken Rocky Mountain tires and I believe I have 3.73 gearing. I also have a 2.5" TF BB. What should I do?
If you're not happy with it now, you'll want to park it with 35's.

I drove my buddies 2010 auto, 3.73, on 35's and didn't feel it was unbearable. BUT, I WANTED to like it. I was having a great time driving a "Jeep." So much so, that I went out and bought one for my self. Granted I bought a '14 Rubicon with 4.10's, I knew I was going straight to 35's.....

Is it really a "nightmare" or is it a "Jeep?" They're not built to be an autobahn cruiser. Everything on them is a compromise. Price we pay to have folks glaring enviously at us when the weathers nice and the top and doors are off.
It is my opinion that it is indeed a nightmare as it is now. When I can barely reach 60mph to merge on to the highway or pass someone without having to slam on the gas and watch the RPMs skyrocket, I'm not that happy. I had a grand Cherokee v8 for 5 years previously and that thing was a powerhouse. Don't get me wrong, my jeep is the love of my life, but I'm not trying to make it not enjoyable to drive. I want to find that balance of performance and looking BA :) (without having to regear because it's just not in the budget any time soon and the jeep is 8 years old with 161k miles on it already)
 

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In reality you should be looking into going down to a 30" tire not up. I ran 33's on 3.21 in my 07 JK with the 6 speed and it sucked. Thats when I was in Champaign and the biggest hill was a bridge overpass. No way would I run 35's and off road will be just as bad as on road.
 

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If you don't want to re-gear and hate the way it drives with the tires you have, you certainly shouldn't be considering bigger tires. At this point, you have two alternatives: buy smaller tires (and have your Jeep look like a scared cat with the 2.5" BB) or buy bigger tires and re-gear.

If you want 35s, get 35s. Just understand your Jeep will be a gutless wonder around town and will be constantly shifting in and out of OD on any highway with the slightest grade. Drive it for a while, roll your pennies, and re-gear later.

Or, buy the 285/70R17s, which are only slightly taller than the 265/75R17s you have, drive it for a while, roll your pennies, and re-gear later.
 
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