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Old 06-24-2017, 02:23 PM   #1
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Wheels list 65 max PSI

Hello All,
I have some 16" American Racing rims on my rig. I just had one of my older BFGs blowout. I was considering powder coating the rims and upgrading the rubber to the KO2s. When I checked the inside of the rim it said the max PSI is 65.
Is this something to worry about with the new KO2s at 80 PSI? Should I just bite the bullet and get new 17" rims?
Any thoughts would be appreciated.
Matt
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Old 06-24-2017, 04:28 PM   #2
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Just because the cold pressure rating on the new tires is 80 psi, as it is on most e-rated tires, that doesn't mean you want to run them at that. The ride will be punishing, trust me. I learned this the hard way. I was having all kinds of handling issues on my first van as well as the gut busting ride. I dropped it to about 60 and everything got MUCH better. There have been lots of threads on this but the consensus is this: Adjust your PSI for load or for offroading, don't just run the maximum cold PSI listed on the tire. In most of my vans I run 50-55 up front and 60-65 in the rear, the higher if loaded.

If you want to really study your tires at different PSIs other than just by feel get an IR thermometer, one of these:

https://www.amazon.com/Etekcity-Lase...ir+thermometer

Keep it in your door pocket and check your tire temp on hot days or when loaded and on long trips. You'll find some averages there and this will tell you in an instant if you have a low tire. It will be a LOT hotter. I generally see temps from 110-150 or so on a loaded rig, if I remember right. I drive too many vans and trucks. If they aren't hot to the touch you're ok.

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Old 06-24-2017, 05:53 PM   #3
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Quote:
Originally Posted by 86Scotty View Post
Just because the cold pressure rating on the new tires is 80 psi, as it is on most e-rated tires, that doesn't mean you want to run them at that. The ride will be punishing, trust me.
There is no doubt that lower pressure will make for a much softer ride, but depending on a lot of variables, low pressure may not be the best idea. I'm running Duratrac's that have very soft sidewalls. On one hand, this can contribute to great traction because the tread is able to conform better to the ground, but those weak sidewalls also cause some problems. First, they are prone to punctures, more so than stronger sidewalls. Secondly, they allow the tires to squirm around a lot on the pavement when run at a more comfortable ride pressure. Unless I'm running at least 65 to 70psi, the van wanders around quite a bit, while running them at the max 80psi results in much better directional stability, but at the cost of a much harsher ride. Lastly, the maximum carrying capacity of any tire will be at it's maximum inflation pressure, so if you van is loading the tires near the max tire capacity, you will want to run your pressure near the max, but if your rims have a lower maximum recomended pressure, you could exceede the designed safety factor of that rim. If your van is lighter than the max tire capacity, you will probably be fine at a lower, better riding pressure that doesn't exceede the rim max psi.
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Old 06-24-2017, 08:42 PM   #4
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Quote:
Originally Posted by 86Scotty View Post
Just because the cold pressure rating on the new tires is 80 psi, as it is on most e-rated tires, that doesn't mean you want to run them at that. The ride will be punishing, trust me. I learned this the hard way. I was having all kinds of handling issues on my first van as well as the gut busting ride. I dropped it to about 60 and everything got MUCH better. There have been lots of threads on this but the consensus is this: Adjust your PSI for load or for offroading, don't just run the maximum cold PSI listed on the tire. In most of my vans I run 50-55 up front and 60-65 in the rear, the higher if loaded.
Absolutely agree. Depending on how much your rig weighs, and whether you're mostly on pavement, no need for the maximum pressures. My rig is lighter than most and I run Toyo Open Country MT tires in the LT285/70R17 size which have an extremely stiff sidewall; I run 45 psi in the front and 50 in the rear. But then most of the roads my van sees are dirt.

By the way, I used to run the BFG KOs also. Loved them for how quiet they were and the traction in snow. But after rock breaking several (no sidewall damage, rocks coming right through the tread) I went to the Toyos. A bit noisier but not one rock break in 3 years.
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Old 06-25-2017, 05:45 AM   #5
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I think the OP's concern is running on rims that are limited to 65 psi, so even agreeing that we probably won't set the cold psi at 80, would you not have some concerns of running on 65 psi limited rims? I think I would seize the moment and buy new rims.

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Old 06-25-2017, 07:34 AM   #6
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Exactly which American Racing rim is it and what is the load rating?

Wheels on our heavy rigs should have a load rating of 3000lb+ and handle E rated tires at 80 psi. If not, then get new rims. Safety first is safety at last.
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Old 06-25-2017, 11:22 AM   #7
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Yeah, I'm also wondering what the wheel (rim) is rated for? Anyway a quick call to the manufacture usually gets you the right answer. I had one crack and they were very proactive with that at least.
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Old 06-25-2017, 12:26 PM   #8
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Quote:
Originally Posted by Scalf77 View Post
I think the OP's concern is running on rims that are limited to 65 psi, so even agreeing that we probably won't set the cold psi at 80, would you not have some concerns of running on 65 psi limited rims? I think I would seize the moment and buy new rims.

-greg
I agree, and with you too, Joe. I really didn't even think of that before but a rim with a limit of 65 psi probably isn't strong enough for one of these heavy vans.

I'm a big believer in stock Ford rims for this reason. Cheap and strong.
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Old 06-25-2017, 01:04 PM   #9
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Gonna add one more unsolicited opinion, lol:

>> 100% agree that checking the spec'd load racing for the wheels themselves first is truly the place to start, no question.

After that ---
Has there been any talk of running the OP's van over a set of scales to determine the actual weight of the van, and the specifics front/rear weight over each axle? With that data in hand, and armed with the tire model and size, you can usually call the tire manufacturer and they'll tell you what the ideal PSI setting is. It's a good place to start, anyway.

For sure, it really seems that the stickers that SMB on the driver door sill with recommended tire pressures are often inked with numbers that are WAY too high. My 7000 pound RB had an SMB-installed door sticker that requested 60 pounds front, 80 pounds rear. So, dutiful new SMB owner that I was (trying to be, anyway...), I aired up to the indicated specs....and oh man. Like 86Scotty said -- it rode like a punishing stone-wheeled flintstone car. Even the mildest pavement irregularity felt like a hammer was hitting the suspension.

When I replaced the tires, I called the manufacturer (Cooper) and they told me I should be closer to 40 pounds for the weight of my rig! So air down I did. And holy ****, what a difference.

Again to 86Scotty's recommendation -- I think I might have to pick up an infrared tire thermometer! That said, after a lifetime of owning and working on plenty of not-very-new cars/trucks....I've long grown into the habit of checking (by hand) the heat of my tires at every rest stop. (And also the warmth of the hubs/wheels, to be sure bearings and/or brakes are running cool....)

Depending what weight the OP's rig is, I'm going to hazard that it's quite possible his 65-max-psi-rated wheels are indeed spec'd with very adequate capability.

Get the weight....and then start with the specs!
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Old 06-25-2017, 05:16 PM   #10
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I hope that tidbit helps you and others Mike. It's an incredibly useful tool in your traveling vehicle. It can save you from burning yourself in a quick roadside fix of any sort and it helpful around camp for lots of things. I bought one for myself, Dad and brother after about 8 friends had trailer tires blow. Heat is the enemy of tires!
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