mitchlikesbikes

a couple of pounds can make a lot of difference if it's further away from the axis of rotation (like it is in this case). plus the added weight isn't the only issue. the larger tires gear down the transmission and put more of a load on the engine

Lowrange2

Weight isn't the only determining factor. The larger the tire the more leverage it takes to turn the tire. So, no. The 35 will still be way worse on stock gearing.

Eagle564

Oh ok. I figured there was more to it but weight seemed more a factor in my mind. Well ill go ahead and get the 33x12.50s. Thanks guys.

brdavis9

Its not all about the weight when it comes to "strenuous": it can be more about the forces that are exerted on the end of what engineers call "moment arms".

Think of a moment arm like you would a lever (and fulcrum).

If I need to lift something straight off the ground, I may be a weak-armed couch potato weenie, but I can get a long bar, put a fulcrum between me and that thing I want to lift, and "lever it" up: the longer the lever, the less force I have to exert. My weak arms and a suitable lever are going to trump your body-builder physique every time lol. (A lever is a force multiplier.)

So when something is wider, the forces that are exerted are somewhat akin to this (well, conceptually). Your wider wheels, even at the same weight, are going be "moment arms" - and force multipliers - like a lever would be.

ALL other things being equal, weight matters (ask any pro bicyclist: humans can only put out about a third horsepower continuous, so any reduction you can do to the wheel weight is a VERY good thing). Given two vehicles with the same suspension geometry, the same horsepower, and same rotational diameters, the lighter tire is going to allow faster acceleration (and in essence, at least, due to frictional losses, we're either accelerating - well, to some degree - or slowing down: there's nothing in between). Lighter tires and wheels "win".

But stresses that result in typical wear-and-tear, are more dependent upon forces (like moment arms). Given the stresses exerted by wheeling, narrower is better for stuff hanging out on the end of a moment arm, that exerts lever-like forces on suspension components.

Of course, being able to float through an obstacle with an aired-down big-butt tires can be very handy in some wheeling situations lol. So it's up to you to decide where you come down on that side of the "stresses" equation.

For looks-wise, who cares: utterly personal decision (I'm a "meh" type lol). For mpg on a dd, I dunno: for rotating weight, lighter is better, and you don't have to worry about wheeling type stresses so much though.

YMMV (pun very much intended, woot).

Eagle564

Well that is very informational lol. Im gonna save that info for future reference actually. I dunno what size im going to get, 10.50s or 12.50s is a tough choice.

Lowrange2

10.50's look better on a DD, IMO.

brdavis9

x2

Eagle564

Ya 10.50s would be fine until i get a 8.8 and regear. Bad thing is im gonna be at like 5.5"s of lift thanks to RE being so tall

Lowrange2

What difference will the 8.8 and gearing make between 10.5 and 12.5? Stock gearing is going to suck either way.

1976Mustang

10.5 would be the tire width, you'll be fine with any width on any axle.

Eagle564

I meant as in its fine with the stock gearing. And since its a dd.

And when i get an 8.8 it will be geared and all ill need is the front geared. I figure 10.50s will be nicer to the mpg and tranny then 12.50s

brdavis9

Thanks.

It sometimes isn't obvious to people, the bit about longer levers needing less force to do "stuff" ...all weight is NOT equal LOL.

If you put weight way out on the end of an axle, for example, the force applied at the outside edge at that point (i.e., the tip of the moment arm if you will) puts entirely disproportionate stress for the given weight you're talking about (think: weak-armed me at the end of a long lever).

So two pounds at the extreme end of an axle puts way more stress on the axle assembly than two pounds at the center of the axle assembly. Like a long lever would.

...but it's mostly when additional angular forces are also put on that end-of-axle component, that crap happens (sometimes, quite spectacularly lol). It's not the fault of the original engineer (and engineering design) that someone later decides to switch to a component (wider wheel and tire), that puts, say, 50% or more (whatever) moment-arm type stress on what was previously a perfectly adequate component, and it breaks.

...which doesn't even add Murphy to the mix LOLOL.

adarling

I am getting a banging around noise coming out of the front wheel area. The strange thing is that it starts happening after I make a really long drive or the time when I towed something heavy. Then after a week of so, it just diappears again. Now, it will only make this noise when you are going 30-35 and you are going straight and you let off the gas. Sometimes it will cause the wheel to bounce around a bit and cause vibration up into the steering wheel. I theorized that it could be a bad wheel bearing and that a bad bearing would jam up in there until you really put it under load or took a long trip. Replaced it, but it still makes the noise. Kind of like a shaft being loose and bouncing around inside a hub. So... I am wondering if it could be a half shaft gone bad (4WD) or maybe the shock or some part of the suspension (but why wouldn't it do it all the time???) Maybe even something going on in the trans axle, but I don't think it would cause as radical a vibration in the wheel area. Any suggestions???

pipeliner

hello. I have a 99 jeep grand cherokee with the full time 4x4 and there is a bad vibration in the front end almost like the front drive shaft is bent but only happens at 50mph or above. have checked the front axle cv joint and all the ujoints could it be the transfer case locking up.

salad

I would definitely crawl under there and start finding out what's loose or worn. Shocks, steering, and control arms are all suspect... at least I think WKs have those. This subforum is for the XJ Cherokee from 1984 - 2001, you will find people talking about your vehicle (WK Grand Cherokee) in this subforum: https://www.cherokeeforum.com/f5/