Practical lift/tire upgrade - JeepForum.com

 
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post #1 of 8 Old 02-21-2016, 01:01 PM Thread Starter
mreff555
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Practical lift/tire upgrade

I am putting money aside to do a tire + suspension upgrade on my 2015 rubicon when my stick tires get a little closer to their end of life.
I know this is a popular topic but I haven been able to answer all my questions. This is a daily driver, frequently on the highway, however I would really like to get my ground clearance to 12".

Here are my questions.

1. What size tires can I get to without sacrificing driveline performance. (4:10 gears)

2. I'm currently thinking 33s would be about right. What is the minimum suspension lift i need to avoid unwanted contact while wheeling?

3. What else do I need to do this right? I would like to keep a similar caster angle.

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post #2 of 8 Old 02-21-2016, 01:24 PM
larcin
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I am interested in getting more info on this as well. I have 2015 JKU with the Hardrock package.

I have been looking at the Mopar 2" lift so it is covered in my warranty. Need to think tires next.

Any thoughts?
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post #3 of 8 Old 02-21-2016, 01:37 PM Thread Starter
mreff555
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I just did a bit of research and in my case, my stock tires are 255/75 17 (32's) I'm thinking that only going to 33's wouldn't be worth the effort. 35's is starting to sound more reasonable.

As for gear ratio, I found this table.

http://www.morris4x4center.com/jeep-...atio-chart.htm

According to this I'm currently at 2805rpm at 65 mph. That seems about right. I'm thinking it would probably make sense to go to 4.27:1 for my rear end.
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post #4 of 8 Old 02-21-2016, 01:40 PM
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Today, with the quality from Mopar, warranty etc... I'd only go Mopar on a new JK. We are planning to do my sons JKU this summer.

Mopar responds to the market and just like building a Rubi in '03... they are now offering lifts. I think their factory lifts will workout just like the original Rubi did. Fully engineered, well thought out and easy to install.
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post #5 of 8 Old 02-21-2016, 03:37 PM
Lawrence
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Quote:
Originally Posted by mreff555 View Post
This is a daily driver, frequently on the highway, however I would really like to get my ground clearance to 12".
Here are my questions.
1. What size tires can I get to without sacrificing driveline performance. (4:10 gears)
2. I'm currently thinking 33s would be about right. What is the minimum suspension lift i need to avoid unwanted contact while wheeling?
3. What else do I need to do this right? I would like to keep a similar caster angle.
1) It depends on what your threshold is. If you plan on staying with the 4.10s, 33s or 35s will be ok.
2) Proper bumpstops > amount of lift
3) It depends on your choices, but in general if you stay with 35s max, you don't need much.

Quote:
Originally Posted by mreff555 View Post
I just did a bit of research and in my case, my stock tires are 255/75 17 (32's) I'm thinking that only going to 33's wouldn't be worth the effort. 35's is starting to sound more reasonable.
As for gear ratio, I found this table.
http://www.morris4x4center.com/jeep-...atio-chart.htm
According to this I'm currently at 2805rpm at 65 mph. That seems about right. I'm thinking it would probably make sense to go to 4.27:1 for my rear end.
You won't find 4.27 gears, it'll be either 4.56 or 4.88. If you have 4.10, it makes no sense going to 4.56 given the small gain compared to the big cost. So, if you plan on 35s, 1) stick with the 4.10s and it'll be fine or 2) go with 4.88 gears which will give you more performance. Proper chart here.

Quote:
Originally Posted by billiebob View Post
Today, with the quality from Mopar, warranty etc... I'd only go Mopar on a new JK. We are planning to do my sons JKU this summer.
Mopar responds to the market and just like building a Rubi in '03... they are now offering lifts. I think their factory lifts will workout just like the original Rubi did. Fully engineered, well thought out and easy to install.
Not saying it's a bad thing but most Mopar stuff is just rebranded aftermarket parts. There is no secret sauce there.
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post #6 of 8 Old 02-22-2016, 07:52 AM
propped1
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Quote:
Originally Posted by mreff555 View Post
I am putting money aside to do a tire + suspension upgrade on my 2015 rubicon when my stick tires get a little closer to their end of life.
I know this is a popular topic but I haven been able to answer all my questions. This is a daily driver, frequently on the highway, however I would really like to get my ground clearance to 12".

Here are my questions.
What do you mean by 12"? The bottom of the pumpkin is just under 9" from the ground on a stock rubi. These are 32" tires. You cant change that with suspension, only tire. Since you need 3.2 inches, the OD of your tire must be 6.4" bigger than your stock set up. 38.5" should do.

If you are talking frame rail to ground, that is already over 12 from factory. 15.4". So please clarify.

Quote:
Originally Posted by mreff555 View Post
1. What size tires can I get to without sacrificing driveline performance. (4:10 gears)
Any tire heavier than what you have will hurt driveline performance. Going bigger, they get heavier. You can get 33s on without doing anything to the suspension. 2.5" lift will get you 35s.

Quote:
Originally Posted by mreff555 View Post
2. I'm currently thinking 33s would be about right. What is the minimum suspension lift i need to avoid unwanted contact while wheeling?
Dont need one at all. Depending on the width of the tire you will either want wheels with less back space or (not recommending) a spacer.

Quote:
Originally Posted by mreff555 View Post
3. What else do I need to do this right? I would like to keep a similar caster angle.
Then get 33s and dont lift it. Or get lower control arms with the front on whatever kit you decide on. There are a bunch of these types of threads since there are 9 years of guys with JKs asking the same questions. Keep searching. The answer to everything is "It depends".

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post #7 of 8 Old 02-22-2016, 07:59 AM
propped1
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Quote:
Originally Posted by billiebob View Post
Today, with the quality from Mopar, warranty etc... I'd only go Mopar on a new JK. We are planning to do my sons JKU this summer.

Mopar responds to the market and just like building a Rubi in '03... they are now offering lifts. I think their factory lifts will workout just like the original Rubi did. Fully engineered, well thought out and easy to install.
Theyve been offering lifts. Not a new thing... And they just contract with aftermarket suppliers to do a Mopar branded kit. They dont design, they just markup someone else's design and charge dealer labor prices.

If you want to spend $2 for every $1 you should be spending on a lift, by all means, take it to the dealer. Otherwise there are better options. Both in engineering and price.

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-OlllllllO]
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post #8 of 8 Old 02-22-2016, 12:12 PM
mcgyvrZJ
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I run 33 x 12.5 x 15 on stock suspension with spidertrax spacers and wheels with 4.5" backspacing.. No rubbing/no trimming/no clearance issues at all.

But you ain't gonna get the 12" clearance you want with 33s.. or 35s or 37s.. As stated above stock is like 32" tires already.. And its gonna take much more than just tires to get what you want..
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