30 or 31's for a daily driver?
#1
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30 or 31's for a daily driver?
I just ordered a set of 30" BFG AT's from discount tire, not sure if I did the right thing or I should of gotten 31's. They have not been mounted yet so I can switch if I want.
I looked at many posts here on tires but it seems too many details are left out to get accurate info for comparison so I'll lay out what I have and what I'm looking to get out of it.
As of now my 96 Cherokee is stock height but a 2" budget boost from Rocky Road is on the way and will be installed by the end of next week. I plan on using the stock steel wheels. I drive a ton of freeway miles as well as light off roading. I'm working on a project developing 1700 acres of farm land so I need to be able to get through it with no problems. I also live close to the Western Carolina mountains so the occasional trip on the unimproved roads is in the forcast.
Ok so here are my concerns:
How do the 30's vs 31's affect fuel mileage over the stock size tires? Less rpm at freeway speeds should be good but how about turning the extra weight?
How about power delivery? I don't plan on re-gearing; it's an auto with 3.55's. Is the difference significant? For reference I had a 82 toyota with a 22r, 5spd, 33's and stock gears and it was less than ideal, couldn't use fith gear unless going down hill with a tail wind.
What about tire rub during articulation? I plan on leaving the sway bars connected so is this an issue? What if front sway bar is disconnected?
What about tire rub during steering? I think this will be a greater issue with the 31's. I have tire spacers ranging from 1/16 to 1/4 I can use if a little more backspacing will help.
How much back spacing is necesarry to keep 31's from rubbing during full lock steering?
I also plan on up grading to Old Man Emu 2" springs front and rear before the end of the year so I could go to 4" of lift but I'd rather keep it as low as possible for street manners. Are there stiffer sway bars available for the XJ? Maybe fat bars for the street with disconnects?
I have to act quick, tires are waiting....
Thanks for any insight.
I looked at many posts here on tires but it seems too many details are left out to get accurate info for comparison so I'll lay out what I have and what I'm looking to get out of it.
As of now my 96 Cherokee is stock height but a 2" budget boost from Rocky Road is on the way and will be installed by the end of next week. I plan on using the stock steel wheels. I drive a ton of freeway miles as well as light off roading. I'm working on a project developing 1700 acres of farm land so I need to be able to get through it with no problems. I also live close to the Western Carolina mountains so the occasional trip on the unimproved roads is in the forcast.
Ok so here are my concerns:
How do the 30's vs 31's affect fuel mileage over the stock size tires? Less rpm at freeway speeds should be good but how about turning the extra weight?
How about power delivery? I don't plan on re-gearing; it's an auto with 3.55's. Is the difference significant? For reference I had a 82 toyota with a 22r, 5spd, 33's and stock gears and it was less than ideal, couldn't use fith gear unless going down hill with a tail wind.
What about tire rub during articulation? I plan on leaving the sway bars connected so is this an issue? What if front sway bar is disconnected?
What about tire rub during steering? I think this will be a greater issue with the 31's. I have tire spacers ranging from 1/16 to 1/4 I can use if a little more backspacing will help.
How much back spacing is necesarry to keep 31's from rubbing during full lock steering?
I also plan on up grading to Old Man Emu 2" springs front and rear before the end of the year so I could go to 4" of lift but I'd rather keep it as low as possible for street manners. Are there stiffer sway bars available for the XJ? Maybe fat bars for the street with disconnects?
I have to act quick, tires are waiting....
Thanks for any insight.
#2
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Year: 1995
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Engine: 4.0 high otuput
i have 30x9.50 with a three inch lift and i have no clearance or rubbing problems what so ever so if you do stay with the 30's you shouldn't have any rubbing or clearance problems
#3
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My girlfriends stock 96 has 235/75s on it (about 29"). The speedometer is still accurate and she gets pretty good mpg on the highway (about 21-22mpg).
About 2050 rpm going 65, about 2100-2200 going 70 on the highway.
Same specs as yours, 4.0/auto/3.55s.
OTOH my 89 isnt on the road yet, but it has a 3" lift and 31s. I dont know what the mileage is gonna be like, I hope its not too bad. I dont think another 2 inches over the 29s will be too much of a difference (comparing to my girlfriends mileage)...
About 2050 rpm going 65, about 2100-2200 going 70 on the highway.
Same specs as yours, 4.0/auto/3.55s.
OTOH my 89 isnt on the road yet, but it has a 3" lift and 31s. I dont know what the mileage is gonna be like, I hope its not too bad. I dont think another 2 inches over the 29s will be too much of a difference (comparing to my girlfriends mileage)...
#4
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Year: 1994
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1.) No noticeable difference between 30's and 31's when it comes to milage or highway performance.
2.) I'm running an auto with 3.55's and 31's at the moment and it performs great. No need to regear.
3.) 31's will rub when turned to the steering lock, not sure about articulation, as I have my sway bar connected, but with only a 2" lift, it will rub when stuffed. I'd say a 1/4" of back spacing should stop them from rubbing when turned to the lock.
Honestly, I would go with the 4.5" lift now, versus waiting and having to compromise on things. With a 4.5" it will still have decent street manners. You can always just get discos for the front bar for when you really need the articulation.
2.) I'm running an auto with 3.55's and 31's at the moment and it performs great. No need to regear.
3.) 31's will rub when turned to the steering lock, not sure about articulation, as I have my sway bar connected, but with only a 2" lift, it will rub when stuffed. I'd say a 1/4" of back spacing should stop them from rubbing when turned to the lock.
Honestly, I would go with the 4.5" lift now, versus waiting and having to compromise on things. With a 4.5" it will still have decent street manners. You can always just get discos for the front bar for when you really need the articulation.
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How much rub and where? The rubber piece that joins the fender flares and inner fender are already rubbed through in the rear on the lower rear quaters and top where someone had larger tires on it before me. It was probably 30's with no lift. By how rusted tight all the suspension bolts are I doubt it has ever been lifted.
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Just found your pics, it does look good.
Last edited by BC61; 11-24-2009 at 10:52 AM.
#7
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Year: 1994
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How much rub and where? The rubber piece that joins the fender flares and inner fender are already rubbed through in the rear on the lower rear quaters and top where someone had larger tires on it before me. It was probably 30's with no lift. By how rusted tight all the suspension bolts are I doubt it has ever been lifted.
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#9
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Year: 1995
Model: Cherokee
Engine: 4.0 high otuput
i think that it looks good. it would look better with 31x10.50's on 15x8's for a more aggressive look but im pleased for now. they are procomp m/t's and as far as grip goes i havent had any problems yet. they are mean tires tho they tear up anything thats not rock solid. the spot in my backyard where i park has turned into a mud hole from my tread rippin up the ground lol
#11
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Year: 1994
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I agree. You will always want to go bigger. You will think you're fine with 30's, then six months down the road... lol I was certain I would be ok with just 31's, and now I want 33's or 35's.
#12
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Year: 1992
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x2. I've got 30" A/T's and I wish I had 31" M/T's. It's only about a 3% difference in size so you wouldn't notice a diff in power or milage on the street, but I think you'ed notice a diff off road.
#13
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Year: 1996
Model: Grand Cherokee
Engine: 5.2L V-8
For a daily driver you arent gonna notice the difference between a 30" and a 31" but when it come to accually off-roading thats when you will notice that extra 1". My philosophy is " GO BIG OR GO HOME" so i would get the 31".
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Year: 1991
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What's wrong with bringing up an old thread? I clicked on it wanting to see what people said on this topic, found it worth reading, the fact that it's two years old didn't make it any less useful...