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Unread 07-29-2013, 07:35 AM   #16
wilson1010
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Quote:
Originally Posted by WXman View Post
Why do you think Goodyear's new batch of offroad tires are the lightest in the market? Why do you think the new Toyo tires are specifically made with lighter weight materials? Why are these engineers specifically trying to reduce weight?
Quote:
Originally Posted by WXman View Post
It hurts the wallet because you're getting as much as 50 miles less per tank of gas. Weight kills.
Hahaha! 50 miles less per tank.

Let's see. Your rig probably gets, what, 15 mpg? So, 50 miles is 3.33 gallons. 20 gallons in the tank. That is a 16.66 increase in fuel economy, just from tire weight! I think you are on to something. Here is the phone number of the DOT so you can let them in on your discovery: 1-202-328-7448. And on behalf of all Americans, I want to thank you.

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Unread 07-29-2013, 08:50 AM   #17
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Additionally, the comparison to an MPG hit when towing is confounded by the fact that you don't drive the same way while towing, I hope.

I'd love to run a controlled experiment to verify or disprove my math (no, I didn't just read it online; I'm capable of doing my own math, thank-you). At this point at least,it's my math as well as others' math against your "nuh-uh!" I'm not saying that you can't be right and that I can't be wrong, but I can't take your current approach to discussing the matter seriously.

Look, the fact is that weight is a factor no matter what the inertial mass ratio is or what someone wants to believe it is, and given many other factors when tire shopping, yes, it's something to keep in mind but rarely something that makes or breaks a decision between different tires in my experience which is why I say that it's not worth fussing about usually.

I've got lots of different experiments and tests/comparisons that I'd love to perform with tires. If anyone wants to give me the time and resources to perform them, I'd happily share my findings with everyone, but I don't think it'll ever happen. Good science is t nearly as simple or easy as many people seem to think it is (some scientists included--not everyone is the greatest at their jobs). If someone has the time and resources of their own, I'd gladly supply them with a detailed methodology of my ideas.
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Unread 07-29-2013, 10:38 PM   #18
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Hey Wilson, wind your neck in.
If you wanna flame some one, go to GD or Pirate and lemme know how that works out for you. If you don't have any tech to add STFU and stop being signal noise others have to filter out to learn something. jackwads like you discourage people from posting because they don't want to get flamed because some self righteous idiot with a small "mass" wishes to impart his inertia to the discussion.

The OP's post was informative and helps to explain further to those new to the community why you should upgrade your brakes along with your tires with out the folklore of 10/1 ratio. Facts are facts learn some.
Sorry your dad took your pony away, didn't hug you and tell you how wonderful you are enough. FWIW, you are spechul.
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Unread 07-30-2013, 11:35 AM   #19
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I never gained or lost a mpg going from 31's to 35's that I have ran for years. If you build you're jeep correctly with gears to support the tire, You will have no problems. Brake wise, I never had problems then and don't now. To me its a hoax to waste high $$ on a 'black magic' kit that is nothing more than soft, Cheap 477 pad and rotors in a different box.

I built my jeep to DD, Drive from my location to SC to wheel and back with no problems. So far so good and if I followed all the bullchit on here, Id still be on 32's with metaljoke fenders from all the 'it wont stop' and 'you're steering will snap' BS.

Ill take the extra weight, Grip and tear resistant sidewalls over a a/t street tire any day.
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Unread 07-30-2013, 12:18 PM   #20
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Boy, there really are some dumb*sses in this thread. I wish all Jeeps were sprinkled with magic fairy dust like some of the ones in here.
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Unread 07-30-2013, 12:27 PM   #21
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Quote:
Originally Posted by wilson1010 View Post
Hahaha! 50 miles less per tank.

Let's see. Your rig probably gets, what, 15 mpg? So, 50 miles is 3.33 gallons. 20 gallons in the tank. That is a 16.66 increase in fuel economy, just from tire weight! I think you are on to something. Here is the phone number of the DOT so you can let them in on your discovery: 1-202-328-7448. And on behalf of all Americans, I want to thank you.

Actually...

We're going to go back to 3rd grade here for a sec, so hang with me, OK?

My 2011 JK was getting a solid 18.5 MPGs on my daily routine. I put heavy a$$ Falken tires on it in the 285/75-16 variety which is very mild compared to my other play toys. My MPGs went down to 16 or so.

That's a 2.5 MPG loss from heavier tires alone.

I drive about 1,500 miles per month. Gas is about 3.50/gallon. So, at 18.5 MPGs on stock tires I was using 81 gallons of fuel in a month. After the tires, I was using 94 gallons per month. At 3.50 a gallon, that's $45 bucks a month.

$45 bucks, per month, ONLY because of the weight of the tires.

Like I said in my first post, the guys with more money than brains won't give a crap about that. But the guys with family and budgets who are trying to enjoy this hobby and still buy groceries will definitely care about $45 bucks a month.

Oh... and I regeared to 4.88 to match the tires and spent a ton of cash and guess what? I didn't get that mileage back.... so then not only are you losing cash at the gas pump but you're losing it on that huge gear investment too.

Some of you guys are either A) stupid or B) ignorant. It's simple...you increase weight, you kill mileage, performance, and braking. I'm only trying to help you here. The 2:1 ratio is a joke. You should look for offroad tires that are the lightest ones you can get for what you will be using them for.
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Unread 07-30-2013, 01:51 PM   #22
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Some of you guys are either A) stupid or B) ignorant. It's simple...you increase weight, you kill mileage, performance, and braking. I'm only trying to help you here. The 2:1 ratio is a joke. You should look for offroad tires that are the lightest ones you can get for what you will be using them for.
Your personal insults do not improve your argument which no one believes other than the "stupid" or the "ignorant" to which you refer.

No intelligent person cares about getting lighter tires on a Jeep used on an off the road. You get what you pay for with tires. A heavier tire is a stronger, more durable, more damage resistant tire. Why don't you get a 10 pound motorcycle battery for your rig?

Your anecdote is BS. There, I called it. I called BS on your story of 50 miles more per tank solely from tire weight of comparable tires. BS. Nothing more to say but to take your story down to the tire store and try to sell it there.
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Unread 07-30-2013, 03:42 PM   #23
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He's demonstrated that he's closed his mind to this and that he's unwilling to be respectful. No one is going to change his mind or behavior, so just ignore it. We've read what he has to say, and lets just let him live with his beliefs.
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Unread 07-30-2013, 03:44 PM   #24
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All the bashing & anecdotal posturing is amusing to read, but I'd like to echo a few other posters and express my thanks to the OP.

I also believe the "rotating weight" issue is one of the most oft-miquoted values I've seen on this form & I have gone out of my way to correct it numerous times... but I never created a thread for it.
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Unread 07-30-2013, 06:31 PM   #25
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http://www.tirerack.com/wheels/tech/...jsp?techid=108

Wow. They lost 1.7 MPGs just by adding 7 lbs. to their wheel/tire package per corner. That's huge.
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Unread 07-31-2013, 05:19 AM   #26
mschi772
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Quote:
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http://www.tirerack.com/wheels/tech/...jsp?techid=108

Wow. They lost 1.7 MPGs just by adding 7 lbs. to their wheel/tire package per corner. That's huge.
No, they didin't "just add 7 lbs," they changed the tire model as well. They did one test in stock config and two tests with another tire and changed only the weight of the wheel. The MPG difference there was 0.4 MPG. The weight difference between these two was 10 lbs.

The stock config was heavier than the lightweight configuration, and it still got better MPG--a testament to the efficiency of those stock Michelins vs the Pirellis they used for the other two tests.

They also only calculated these numbers over 350 miles. That's really not all that much data to be drawing any concrete MPG conclusions from.
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Unread 07-31-2013, 07:36 AM   #27
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Quote:
Originally Posted by WXman View Post
http://www.tirerack.com/wheels/tech/...jsp?techid=108

Wow. They lost 1.7 MPGs just by adding 7 lbs. to their wheel/tire package per corner. That's huge.
That article is bad science... but perhaps good marketing. If they were really interested in empirical data, then they'd have made an effort to keep as many controls the same as possible. But they swapped tires.

I like Tirerack, but in this case I think they just want to sell some Pirelli's.

edit: oops. msch772 said the same thing, only better.
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Unread 07-31-2013, 07:53 AM   #28
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That article is bad science... but perhaps good marketing. If they were really interested in empirical data, then they'd have made an effort to keep as many controls the same as possible. But they swapped tires.

I like Tirerack, but in this case I think they just want to sell some Pirelli's.

edit: oops. msch772 said the same thing, only better.
They didn't swap tires. They swapped wheels/tires and used that to point out how the weight changes the game. Most Jeepers do the same thing..wheels and tires and add a bunch of weight.

Their findings agree with my findings over the past 20 years and the findings of most Jeep and truck enthusiasts. Adding weight makes the engine work harder to turn the weight. The engine working harder means more fuel is consumed. Additionally, the added weight means the brakes work harder to stop the rotating mass bolted to them.

Honestly, it's unbelievable to me that there are guys here who think weight doesn't matter. Like, I really can't wrap my brain around how you could think that adding 80 lbs. of rotating weight to your Jeep won't affect it.

But I'm going to step out of this thread now. You guys go ahead and suck that gas. The rest of us will buy tires wisely so that we can maximize our benefit and save money for other things.
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Unread 07-31-2013, 10:32 AM   #29
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It costs money to create kinetic energy stored in a rotating mass. True. Miniscule amounts of gasoline, but a cost nonetheless. But, that rotating mass (kinetic energy) does not disappear. It is stored in the rotating mass. None is lost. As the wheel and tire slows, the kinetic energy is transferred back to the vehicle, cashing in by moving the vehicle a little tiny bit further or faster down the road. This process of investing in kinetic energy and recovering kinetic energy continues, back and forth with no losses as the rig goes down the road, changing speed in tiny amounts. Not one bit of kinetic energy is lost until one puts on the brakes. When the brakes are applied, there is a loss of kinetic energy because it is converted to friction and heat instead of moving the rig. A heavier rotating mass suffers a larger loss to heat than a lighter mass. Tiny, miniscule amounts, but more just the same. In city driving this is more of a loss than on the highway. Either way, it is insignificant.
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Unread 07-31-2013, 10:58 AM   #30
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They are jeeps, Not Yugo's and if you want that mpg go buy one. The only stupid idiot, Is the one who bought a jeep, A block into the wind, For mpg and then *****es about it.
Guess in that '20 years' you didn't pick up too much if you willingly put a bigger size, More weight and not expect to loose any mpg, That was a thought out plan.
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