Can it hurt the truck if the tires/wheels are unbalanced?

Sorry that you're going through this. It could be really annoying shaking down an issue like this. I have non-LT 285/70R17s on mine that I keep around 30-32psi. They are balanced , but I get shaking around that same speed. I read somewhere in this forum that it could be from lifting the 4Runner. Had I known this, I probably would have bought another vehicle to avoid this issue.

You get shaking at different speeds depending on the harmonics of the tire and how well that meshes with the road surface you're driving on. In a sense, your tires and road are "harmonizing" with one another to keep you from feeling any vibrations, but if one goes out of sync, you feel a vibration. Depending on the tire construction and road surface, you can feel vibrations at different speeds. That is what a Road Force machine measures in your tire and wheel assemblies when being balanced.

Running a LT tire instead of a P-rated (metric) tire on a vehicle that doesn't need a LT tire will definitely allow you to feel the road a lot more, like bumps and dips.

 

Also, if you are running the LT275/70R17 WildPeak A/T3W, you should be running 44psi in your tires, according to my math.

I know it sounds high, but LT tires run on a different inflation chart than P metric or Extra load tires. The only problem is, you're going to feel even more of the road now, but at least you won't be underinflated.

 

I run Falken 285/70/17 M/Ts and by the chalk test i am at 44psi. in the front, and 35 psi. in the rear.

 

Are you running 35psi in the rear when your 4Runner is loaded with gear?

If not, I'd make sure to bump up the pressure in the rear when hauling rear passengers and/or trail gear, camping gear, etc.

 

I adjust according to my use, as i hope most are doing.

 

I'd hope so too, but you'd be surprised. That's why I always have to ask just to make sure.

 

Thanks for the info/tip. However, and not to necessarily argue with you, are you sure you'd go that high for a C rated LT tire? I ask because now that you've pointed this out I went and checked Falken.com, and I noticed that the MAX pressure for this C rated tire is 50, which is basically the same as with the P rated tire, whereas the max pressure for the E rated tire is listed at 80 which is of course significantly higher. I'm no expert, and am learning a lot here, but from what I can tell so far, C rated tires are very different than E rated tires. Not a lot of info out there on exactly what the differences are, however they seem to weigh more yet be less durable which I find odd. I can only speculate that the rubber compounds used to get a stronger (than P rated) tire while maintaining sidewall flex for both comfort and sufficient aired-down traction must weigh more than what is used in both P and E rated tires.

I suppose a chalk test is the best method, but jeeze I hope they shouldn't be at 44 psi, or I'm afraid I've already damaged the tires after a week of driving. @SlvrSlug , are your M/T's E or C rated? Guess I need to get out there and do a chalk test ASAP, regardless...

 

Yes, I'm sure. I'm not trying to toot my own horn here, but I've been in the automotive tire industry for over 12 years. While some will say that they know best and have been doing this for x number of years, I have actually been trained by some of the best in the industry and have been certified by the Tire Industry Association (TIA) and Standard Testing Labs (STL) among others.

SlvrSlug's tires are E rated, but it's about the difference in the load index, not the ply rating, which is why your pressures are similar. Your tires have a lower load index, which is why they take more psi to support the same weight. SlvrSlug should actually be able to get away with running his tires at 40psi, if he wanted to.

 

They are E rated.

 

Well now I'm just confused. What is the point of a C rated tire? They weigh more and require more pressure, while not being able to support as much weight..

My thoughts prior were that a C rated tire fell in between a P and E, but these things you're saying (and the figures I'm finding in the spec sheets) do not support that..

 

Your C rated tires weigh a little less and will ride a tad smoother than E rated tires.

 

Except the odd thing is that they don't (weigh less). I agree, everyone says that is usually the case, but if you look at this specific model of tire...
I'm gonna use the 285 as an example because they make that size in all load ranges. The 275 seems to follow suit in that the C 275 weighs a little less than the C 285, as one would expect.

Falken Wildpeak A/T3W:

P 285/70/R17 - SL - 51 lbs - 2830 max load (117) - 51 max PSI
LT 285/70/R17 - C - 64 lbs - 2750 max load (116) - 50 max PSI
LT 285/70/R17 - E - 59 lbs - 3200 max load (121) - 80 max PSI

So even though everyone would say (and assume) that the C rated tire should be stronger, and be able to support more weight than the P rated tire, that is apparently false. All while weighing a butt-load more, too. So what's the point then? Stronger sidewall for puncture resistance? Who knows...

 

For the record, this argument is not personal but rather to learn.. so I hope you take no offense regardless of how I may come across. I sincerely appreciate your help.

I thought load index and ply rating were basically the same, or at least went together in the same direction. Everything I read said that a higher load *range* meant the same as a higher ply rating, and that a higher ply rating or load range meant that the tire could support more weight and more pressure. But then along comes these Falken Wildpeaks where the higher load range supports less? Granted, technically we are starting to compare a Passenger tire with Light Truck tires, but where do they get off making this so confusing when no damn passenger *CAR* takes a 285/70/R17 tire. So am I to accept that there is no way to compare a P rated tire to a C tire because the industry doesn't want me to, or what??

So regarding correct tire pressure, if I compare my C rated tire to the P rated (SL) tire and the E rated tire, I believe the load index is much closer to the P rated tire (basically the same) than it is to the E rated tire, which is what leads me to second-guess your advice. My bet is that you aren't necessarily wrong in your assumptions, but that you may be assuming that these C rated Falkens are normal while maybe they quite odd indeed..?

 

The C rated LT285/70R17 is an OE tire for the Jeep Gladiator Rubicon. OE manufacturers often have certain/different specifications for their vehicles' tires, so that's where any pattern or rhythm you see gets thrown out the window. Also, anything on Falken's site, where the item # starts with "59" means it's for an OE application.

I was stating in my previous post that your C rated LT275/70R17 All Terrains weigh less than SlvrSlug's LT285/70R17 Mud Terrains, but that your tires also have a lower load index than his.

 

Haha. No offense taken here. I'm just trying my best to point you in the right direction.

It can get confusing with ply ratings and load indexes. That's why people trust professionals in the tire industry to make sure they get the correct tires for their vehicle.

My air pressure math is correct though.

Also, I have P metric 285/70R17s on my 4Runner because they ride smoother and I get to keep the same 32psi in my tires. I see a lot of other Yotas, Nissans, and Jeeps with them as well.

The LT tire may be able to handle an impact better than a P metric tire in the same size on the trail when rock crawling, but it's so marginal that I'd rather have a smoother ride when I'm on pavement 99% of the time. So, if you see a P metric and a LT tire in the same size for a half ton or lighter vehicle I'd personally go with the P metric all day long.

I had LT315/70R17s on my 2017 Wrangler and they felt like I was driving on Flintstone wheels made of solid rock, lol.

 

Curious, what do you speculate was "thrown out the window" regarding the OE spec'd 285's on the Gladiator? I speculate that my 275's are simply a sized down version of the exact same tire, so I'm trying to figure out what the heck these are aimed at lmao. I suppose the Jeep Gladiator Rubicon is a quite capable truck, and is aimed at basically the things I like to do with my truck, so I suppose this is a good omen!

 

I'm not 100% sure. OE has very strict standards, so it could have something to do with the vehicle's required specifications that makes it a heavier tire than the tires that you and I can buy from a tire store.

 

Hey guys I wanted to report that I went back to Discount Tire to have them attempt to re-balance the new LT275 tires. This was their second attempt at this set of tires after they failed to balance the first set of tires twice. I am super happy to report, though, that they managed to get it this time! I'm not sure if they actually "road force" balanced the tires this final time or not, but they're definitely balanced and feel much better than they did before. I would definitely call them "buttery smooth" as far as heavy truck tires go. I put about a thousand miles on them last week on a camping road trip in the mountains and they handled very well on the twisty paved roads as well as interstates. I also did some trail riding but it was very mild / gravel and didn't even bother airing down yet. I have no doubts that they'll perform well off-road though as my last set in a smaller size did. Thanks for the help! Cheers

BTW, the shop shift-manager did try to give me the ol' "oh well you're just not used to A/T tires yet and that's just how they are" spiel, but I was having none of it. The moral of the story is to keep trying. I guess these Wildpeaks (or maybe most A/T tires) are just a PITA to balance so it takes some effort and patience on everyone's part. But yeah, happy to report that they are smooth and I'm happy to keep them because they look pretty sick. Now to figure out correct tire pressures and trim for rubbing.