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-   -   Stock rims and tires question (http://www.wranglerforum.com/f274/stock-rims-and-tires-question-194220.html)

Posts On Percocet 10-19-2012 08:28 PM

Stock rims and tires question
 
Ok, so today is the first day every I've driven my '12 JKU on the factory tires and wheels (the cheep steal ones with the tiny tires). The dealer put on my rims and that's how I took it off the lot.

I have a couple of questions and observations. First off, the shake. My 17 inch Moto Metal rims and 285/70/17 Kelly TSR tires were smooth until about 65, 70 mph. Once you hit that speed, it was scary going any faster. Felt like they are totally unbalanced. The stock tire wheel combination allows me to hit 80, 85 smooth as silk. Is there any way I can get the bigger tires and rims to do that? They aren't balanced now with weights, they have the dyanbeads in them. Or is there no way to make them smooth at high speeds because of their size and aggressive tread pattern?

My observation is the gas mileage. Holy smokes. I'm not posting this to brag or anything, I'm simply flabbergasted. I've always gotten good mileage with my jeep. Usually 17.5 to 18.5 suburban/highway driving, and 20.5 to 21.5 highway only ( little to no hills). Now that the stock rim tire set up is on, I'm getting 22.5 to 23.5 mpg suburban/highway driving and 26.6 mpg highway only driving. I drive 55 and never do any sudden starts or stops, try not to pass and try not to down shift. But still, that seems just way to high.

I mean, I know you guys think I'm fooling around. I wouldn't believe it either. Tomorrow I'll take a video of the read out with my ipod and post it.

Do you guys think the mileage could vary from one engine to another that much, or is it mostly due to the fact that I don't go over 55, I don't drive in hilly areas, I don't take off fast, and I now have the small, smooth tires on it?

Jeff Loughlin 10-20-2012 07:26 PM

The gas mileage difference is partly because of the difference in tire size. Your odometer is calibrated for the stock tires, so you've been getting an inaccurate (lower) reading running the 33s because the computer thinks you've traveled less distance per gallon of gas (larger tire=fewer revolutions per mile, so your speedo/odo will read lower than true). Also the aggressive tread pattern does result in somewhat lower mpg, but not by that much.

As for the ride, I'd say you need a balancing. I know with my tires (BFG KM2 mud terrains) I have to get them balanced at least once every 10000 miles. I think it's just the nature of these kinds of tires (aggresive tread), that they wear unevenly and get out of balance frequently. I've never tried Dynabeads, so I can't comment on whether or not they work well.

WXman 10-20-2012 07:55 PM

The stock wheels/tires are LIGHT compared to your other setup. And, they are short, which effectively gives your engine more gearing. Those things combined mean that you will see huge increases in power, fuel economy, and braking ability with the stock wheels and tires on the Jeep. They drive SO much better without the aftermarket stuff.

Having said that, if you ever get a chance to see how thin the sidewalls are on the Goodyear ST tires, it'll scare you to death. I'm talking literally paper thin. I can't believe Chrysler uses them on SUVs.


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