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Discussion Starter #1
I just got my RC 2" lift with Robby's spacers installed and am looking to get bigger tires. Which size should I go with. I would like something taller and wider but do not want any rubbing issues. Both of these sizes stated that they would not rub on the sticky. I am just looking to see what size you guys use and why?

thanks
 

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Both sizes are almost the same rolling diameter... 255/70/17 is 31.1" and 245/75/17 is 31.5". Obviously the 255 is about .4" wider than the 245. Note these dimensions are approximate. Either setup should be fine.

I lifted my XK with the RC 2" kit and switched to 245/75/17's. I am pleased... no rubbing. I didn't go wider in order to keep rolling friction down, but a wider tire does look nicer! I guess make sure you can get the tire you want in the sizes you are considereing.

You can see the pix in my garage (click in signature).

Chuck
 

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I think its worth bending over the pinch weld for 265 70 but then you need spacers and stuff. I would pick a tire. If it comes in both sizes go wider! More rolling resistance however larger contact patch means better traction!
 

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I think its worth bending over the pinch weld for 265 70 but then you need spacers and stuff. I would pick a tire. If it comes in both sizes go wider! More rolling resistance however larger contact patch means better traction!
Interesting thoughts.

Wider is not better for winter driving or fuel economy. It LOOKS tougher and is better for mudding, but unless you are mudding more that spending time commuting to work, I say get a setup primarily for street use and occasional off road capability.

Of course, you have to decide what you're using your XK for and what tires will suit your needs.
 

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I vote for 245/75's. Plenty wide enough, probably a bit more economical on the street. But either is fine. Might just want to go with what you can find for less money at the tire stores.
 

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I am nearing the same decision...

I would like to know from people with the setup some specifics that aren't quite answered or buried throughout threads:

On the RC and RR, does the difference in lift afford enough to increase tire size?

Without Spacers and trimming what rubs?

________RC_|_RR_
245/75 |____|____
255/70 |____|____
255/75 |____|____
265/70 |____|____

Without spacers with trimming?
With spacers without trimming?
With spacers with trimming?

not sure if all those charts could be completely mapped but man those are the details that would take the guess work out of my decisions...
 

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Discussion Starter #8

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I wasn't aware that there was much effective difference in those lifts. I have Rusty's 2inch lift. 255/75's with 1.5 inch spydertrax spacers. I had to pound down the pinch welds on the front and trim the plastic inner wells.

I don't know that you can exactly go by what the manufactures call their lift but if you had exact dimension of the parts you could identify if any real measurable difference.
 

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I did a 2.25 OME lift and went with 255/70/17. Yeah they look good, but next time I am going to go with a smaller size. When I take turns a little to fast, the tires will rub and it feels a little sketchy.

I tend to drive a little fast though. :banger:
 

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Looks good, I would like the tires to sit more flush with the fender flares, but I don't even think that 255's will???

What kind of mud flaps do you have? I need to get some.

Thanks! If you want the tires to line up with the fender flares you will need new rims or spacers. The mud flaps are stock molded jeep flaps.
 

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Discussion Starter #12
Thanks! If you want the tires to line up with the fender flares you will need new rims or spacers. The mud flaps are stock molded jeep flaps.

Thanks I need to get some mud flaps.
 

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Discussion Starter #13
I did a 2.25 OME lift and went with 255/70/17. Yeah they look good, but next time I am going to go with a smaller size. When I take turns a little to fast, the tires will rub and it feels a little sketchy.

I tend to drive a little fast though. :banger:
Do you have a leveling kit? I thought that 255/70's were not suppose to rub. If that is the case I will go with the 245/75's.
 

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somebody said wider is not better for winter? are you kidding me? make a fist. thats how much of your tire is touching the ground at a time. find someone with a bigger fist. that is wider tire with a larger contact patch. more rubber touching the road. wider is better. way better traction. better braking and better handling. but thanks for your opinion. only downfall. maybe fuel economy but i doubt you would notice. between a 245 and 255.
 

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How do you guys find the body roll with the 245/75 tire it seems like a lot of sidewall hight in relation to tire width. I would have thought it would have caused the car to roll pretty badly through corners at speed.
 

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Discussion Starter #16
How do you guys find the body roll with the 245/75 tire it seems like a lot of sidewall hight in relation to tire width. I would have thought it would have caused the car to roll pretty badly through corners at speed.

Good question, anyone notice any problems?
 

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somebody said wider is not better for winter? are you kidding me? make a fist. thats how much of your tire is touching the ground at a time. find someone with a bigger fist. that is wider tire with a larger contact patch. more rubber touching the road. wider is better. way better traction. better braking and better handling. but thanks for your opinion. only downfall. maybe fuel economy but i doubt you would notice. between a 245 and 255.
I was not kidding. That was me who stated wider is not better, so let me explain...

This is not an opinion. This is a fact. I am a mechanical engineer. What seems like common sense does not always work as you would think! In layman's terms, wider is better for dry, ideal conditions. Wider is better for mudding. Wider with extra siping is better for ice. Narrow is better for deep snow. For deep snow, you want a narrower tire so that the tread contact patch can easilly cut down to the pavement below.

So if you get more icy then snowy weather, wider may be better, but get a good A/T tire for severe winter duty. Mudders have no siping (slices in the tread blocks) to aid with gripping icy surfaces. For most of us, deep snow is better tracked with tall, narrow tires with a good, aggressive severe winter duty tread.

The approximate 1/2 inch difference in width between a 255 and 245 will not make for a drastic difference, but it will add rolling resistance... even if it is negligable.



Cheers,

Chuck
 

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Back to the question, does anyone have some feedback on the road handling of the 245/75, especially regarding body roll through high speed bends on road?
 

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Okay, back on topic for 08CRD...

I have no problem on typical high speed highway "bends". These are the same bends that semi's travel at speed.

I drove the truck in stock form and the current lifted form through the same twisty offramp part of my commute path. The 2" lifted 245/75/17 setup does add body roll. I definitely have to take some tight turns a little slower. Maybe as I get used to the higher center of gravity and "learn" how the truck behaves, I may be able to push it harder, but not yet. In comparison, my former ZR2 Blazer could handle this double apex better, but I tossed it through this area for 4 years every day... The XK has a narrower track and taller body, but a longer wheelbase. It definitely has more body roll in corners... but you should be fine if you do not drive it like a sports car. I can not "feel" any additional tire sidewall flex, but I am sure that is part of the change in handling.

The XK is a very capable, all weather / off road daily driver. Handling is as expected for a high stance 4WD.

If you want razor sharp handling, I suggest a Corvette. That is what I use for "spirited driving" :) .
 

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Sorry Chuck, but your still wrong about snow. In deep snow if your goal is to cut down to the pavement your going to bury your Jeep. In deep snow you want the widest possible tire. Then air down to maybe 10 psi and float on top of it. Im sorry your wrong. Maybe your definition of deep snow is only 3 inches or something and you want to reach pavement but my definition is a foot or more.
 
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