I dont really know much about tires, so I thought I would ask those of you who are total tire freaks to chime in.

Regarding tire profiles: The stock tire for the steel 16in rim is 235/70 R16 (I think theres a 215 also). What would it do for handling and load rating (thinking of safety) if you were to replace that tire with a lower aspect ratio tire, like say a 235/65 or 235/60 or even move to a wider size and lower aspect ratio like 245/60 or 245/50? The loss of ratio obviously means less sidewall flex, but also means better handling because of reduced tire squat. Is it dangerous to reduce the aspect ratio for weight handling reasons? Is it okay though to get a wider tire to allow a reduced aspect ratio?

Also, if reducing the aspect ratio is a safe possibility, how does that translate to how mileage is calculated if the overall tire diameter is less than the stock tire overall diameter. I've heard those of you with huge mudding/wheeling tires lose torque since the overall tire diameter is much larger, so would you gain some torque if your overall tire diameter was smaller?

And in regards to those "bling bling" SUVs with the HUGE chrome rims and super low 30 and 40 profile tires, is that safe for weight distribution and handling? I'm worried about certain driving scenarios on the freeways around here which are not so much bumpy, but really undulous and cause the springs to bottom out from absorbing the up and down momentum of the road. I know stiff shocks will help a bit in this scenario, but I'm thinking it might have a lot to do with tire flex also, and how reducing the added rebound from high profile tires might help with handling.

I saw an Infiniti FX35 the other day, and if I'm not mistaken those come with 18 or 19 inch rims stock. The guy driving it looked like he had some 16s with really low profile tires. The result of this combo was that the vehicle looked like it was lowered, although I'm pretty sure that the overall tire diameter was drastically reduced, and so less of the wheels filled up the wheel well. Isn't this sort of thing dangerous at high speeds, or could you actually utilize the speed ratings of lower profile tires by switching out your high profile SUV tires?

I saw what looked like a lowered KJ that had deep dish chrome rims on the same day, and same concept, because it looked like it had either 17 or 18 inch rims, but had a much lower profile tire and therefore much smaller overall tire diameter. We were all stuck in traffic on the Bay Bridge, and I was close enough to ask the passenger of the KJ if he lowered his Liberty or if it was just the rims that made it look low. He said rims. I complimented his chrome rims and said it looked nice, but I was really just thinking in the back of my mind what a nasty combo it was on a renegade with the Mopar light bar up top and and cargo rack.

I'm not exactly following convention either when I say this, but if I were to get rims for the KJ, I'd probably go with forged and/or multipiece wheels in either a matte black or gunmetal finish. I'd want to get some 18s or 19s and combine it with a low profile tire that would still match the overall tire diameter, but I dont want to do anything unsafe for the load rating expected from the tires. I'm really not into bling bling, and although wheeling and Moab looks really fun, I dont realistically have the budget to get all the offroad equipment necessary. I drive in a very urban environment and ocassionally go up twisty roads, so I'm going for a more crisp handling approach with less body roll, tire squat, and lower center of gravity.


I know its another mouthful from me again, but any input is greatly appreciated.

_________________
"It's not what you drive, but how you drive it."

02 Sport in Stone White
-AEM CAI, Borla XS muffler
-Duralast Premium rotors and PFC pads in front (rotors are cool but the pads suck); Satisfied pads in back drums
-6k HID mains, Hella 500 high beams
-Yokohama Geolandar HTS 235/70 R16
-smoke corners with silver turn signal bulbs

First off, I take offense to tire freak... more appropriate would be tyre whore

By putting large wheels and tires, you change several performance characteristics on your vehicle. Your concern re: aspect ratio is valid and keep in mind the wt rating for the tire before you buy. There are tons of wheel/tire sites to check out.

Plus Sizing

Plus sizing your wheel & tire combination was designed to enhance vehicle performance and looks by allowing fitment of larger diameter rims and lower profile tires. The theory is that while making these changes, you keep the overall tire diameter within 3% of the original equipment tires. This is important because larger variances can cause problems with transmission shift points which can decrease fuel mileage. It can also confuse braking system computers which can even lead to brake failure.

Here's the rule of thumb for "plus sizing":

Plus 1:
Increase section width by 10mm
Decrease aspect ratio by 10 points
Increase rim diameter by 1 inch

Plus 2:
Increase section width by 20mm
Decrease aspect ratio by 20 points
Increase rim diameter by 2 inches.

This is not exact, but it will usually get you in the right ballpark. We always recommend consulting with the people you are purchasing the wheels and tires from to ensure fitment.

If your sidewall is too low or too big of a wheel ie > 17", you risk easily damaging the rim curbing or deep potholes as commonly seen on sport cars low profile tires. Also you won't be able to climb curbs/medians etc.

Cost will also be a big factor, larger 'performance' tires cost more the bigger you go. If you want to make your KJ more stiff in ride, just get LT tires IMO. By going bigger than 17" you negate some of the benefits of having a 4x4 ie airing down if needed. For tires/wheels, go function before form. Big wheel/tires may look great but if you bend or rash your big rims hitting a curb, you may regret it. Perf low profile tires wear faster typically and will require more frequent replacement and offer no mileage warranty.

I like yourself drive 95% on highways/city and the odd gravel road once a quarter and follow religiously tire reviews paying heavy attention to braking and wet traction due to my local. Cons Rep compares them objectively side by side. My preference is 16" size as I have sets with several different tires... keeps in spec per above and only upsize slightly to due OAD. I have some 17" with GY Fortera tires as well.

Cost of tires for me is not an issue as I crashed a KJ in the past w/ the crappy GY stockers.

Other consideration is liability and warranty, if you go big beyond the 3% of spec, DC may decline warranty work and insurance may 'blame' the mod. That is why places like Costco will not install bigger tires on your spec wheel. Lots of specialty tire shops sell 'bling' wheels but check for reputable source.

_________________
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Hare on my Chest

Thanks for the tips!

I know that some KJs are equipped with 17's instead of 16's. Does the plus-2 sizing apply to that also, meaning a 19x8 inch rim is possible with a 255/60 R19 tire?

_________________
"It's not what you drive, but how you drive it."

02 Sport in Stone White
-AEM CAI, Borla XS muffler
-Duralast Premium rotors and PFC pads in front (rotors are cool but the pads suck); Satisfied pads in back drums
-6k HID mains, Hella 500 high beams
-Yokohama Geolandar HTS 235/70 R16
-smoke corners with silver turn signal bulbs

The 17 and 16" both should have a OAD of 29.1" plus or minus.

Are you going to lift your KJ?

If you go 19 and no lift, you will obviously need to to keep the OAD under 29.5" and also be mindful of the wheel offset and width of the tire and may need to pound the pinch weld too.

Use some tire websites and manufacturers site to review OAD.

What are you trying to obtain? More responsive handling? Go w/ a stiffer street SUV tire... like the GY Fortera tripletred... I have these... the passenger version was rated No 1 last year but see my post re: Consumer Report review or even a stiff AT offroad tire but they will be noisier.

Mich have 'softer' sidewalls where they often look like your tires are low on air. Typically, Japanese tires are more rigid than North American brands.

Look at your door jam to see the spec'd tire size (where they tell you the PSI for each tire) and then look up the GY website for that tire to get the OAD. You go from there as to bigger wheels/lower profile rubber etc but my advice is to stay below 29.5" OAD.

_________________
[_|_, [""""""]
l--- L---ollllllo-
( )_)-( )_)-o-)_) Liberator

....o_o_o_o
../| ,[_____],
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()_)¯ ()_) ¯¯¯ )_)

(\__/)
(='.'=) <]{
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Hare on my Chest

I know someone who spent an insane amount of $$$$ and tried this type of thing on a Blazer, was not happy with the results. It royally screwed the ride quality and performance. I wouldn't use more than a 17 inch wheel on a KJ. Liberator is on the mark with this, check the OAD carefully along with a rev/mile chart. You will need to stay in the low 700's rev/mile to fit under a stock suspension.

_________________
2005 Liberty Sport CRD, Lt Khaki, sunroof

Thankful to now be an EX-CRD owner.

By stiffer tire do you mean a stiffer sidewall? I'm running Yokohama Geolandars right now with the 051 tread pattern. Its still a much better tire than the stock Goodyears, but in terms of grip and responsiveness, I liked the Dueler H/Ts I had before this. The yokos are formulated to last longer and so have a harder rubber compound which sacrifices grip for durability. The Bridgestones I had lasted well, but once I got to the tread depth where it changes compound, the tire began wearing a lot faster. Still, the yokos chirp too much, which means less traction, but the bridgestones barely chirped.

If I do the bigger rim thing, I'm looking to find a size that Falken makes tires for. They're a lot cheaper than their Japanese counterparts, and they provide really good grip.

The only decent Michelin tires for SUVs are the Pilot Sports for X5s. All of their other SUV offerings are total garbage. Their Pilot Sport series which is standard equipment on some exotics, and many high end european saloon cars are very great though.

I would really love to have a set of Advan tires for the KJ though. But the treadwear rating and overall cost is out of the question.

_________________
"It's not what you drive, but how you drive it."

02 Sport in Stone White
-AEM CAI, Borla XS muffler
-Duralast Premium rotors and PFC pads in front (rotors are cool but the pads suck); Satisfied pads in back drums
-6k HID mains, Hella 500 high beams
-Yokohama Geolandar HTS 235/70 R16
-smoke corners with silver turn signal bulbs

Street

I concur on several points. I have a set of Mich Artic Ice snows for the KJ and prefer my GY Forteras HL and Tripletreds. The Mich's albeit snows were nothing exceptional... noisy and still hydroplanes.

I have on my sedan a set of Cons Report top rated (at the time) Mich MXV4 Energy plus H rated all seasons and they always sat w/ a bulge softer sidewalls. These now rate 6th for V rated tires. My stock Dunlops were better but as you say Falkens rated really well in CS and would be decent if you go bigger than 17". Still not cheap and they will wear fast.

The Falcon Ziex ZE512 rated No 3 after Mich Pilot Exalto A/S (No 2) with Dunlop SP Sport 5000 as No 1 for H rated performance A/S. Oddly enough I spoke to somebody this month who is trying to sell 20" wheels he used on his KJ... no takers. Look at pricing for rubber at 20"

I currently have 2 sets of Bridgestone HLs and find them capable but they are new (less than 8000miles) on my crossover AWD SUV. Tires perform best not when new but after a moderate 'break-in' ie. that is why racers 'burn' their tires when newly installed before the race. My backup tire for winter for this vehicle is the GY Fortera Tripletred too as there are not many good 17" SUV snow tires.

The Geolanders only rated moderate in CS SUV review.

Dunlops were better but as you say Falkens rated really well and would be work if you go bigger than 17".

With over 26 crossover vehicles on the market now... you will see the tire companies offer more of a street oriented P or LT tires in larger sizes. However IMO, SUV w/ bling wheels and low profile tires may look cool but they negate the benefits of having a SUV in the first place. As I said, you can't even climb the curb to drop off your Home Depot load That FX35 can't drive over the curb and really was not marketed to...

_________________
[_|_, [""""""]
l--- L---ollllllo-
( )_)-( )_)-o-)_) Liberator

....o_o_o_o
../| ,[_____],
|¯¯¯L--↨|||||||↨
()_)¯ ()_) ¯¯¯ )_)

(\__/)
(='.'=) <]{
(")_(")

( . )( . )

Hare on my Chest