Bus Tire Pressures

[SuperBeetle]

Hi All,

I just realized today that the tire pressure sticker in my 1970 bus only gives the reccomended pressure for bias ply tires. Does anyone know the best pressure for radials?

Thanks

[redcorradoguy]

I always just use whatever is on the sidewall.

I think it was Click and Clack (the Cartalk guys) who said you should follow that instead of the car manufacturers recommendations cause the manufacturer doesn't know what kind of tires you have and the tire maker would know better what should be in it.

David

[redcorradoguy]

I always just use whatever is on the sidewall.

I think it was Click and Clack (the Cartalk guys) who said you should follow that instead of the car manufacturers recommendations cause the manufacturer doesn't know what kind of tires you have and the tire maker would know better what should be in it.

David

[Pillow]

Depends on the tires. If you get real load rated tires the inflation pressure is much higher and I doubt you want to run around at 50PSI on "d" loaders jarring your teeth out.

What I have come to like for a split is 28-30F and 32-35R. But the tires are not super load rated either, 35 Max PSI. I have an odd setup, so YMMV.

[Eaallred]

There is an actual formula to figure it out.

Hard part can be finding out how much weight is on each tire. Some state inspections will list this on thier printouts, which works for me.

On the sidewall, you will see a max weight rating, and a max psi rating. Remember, these are the maximum, and not the recommended. Also read the fine print on the sidewall, and the tires themselves will tell you to check with the owners manual. This means that the max psi rating is NOT the 'ideal' setting.

If the tire says it's max weight and pressure are 1500lbs and 44psi, and you have 750lbs on that tire, then 22psi is the optimal tire pressure (seems low, but it's not). Gas milage will not suffer, and the ride will be nice and smooth.

So if you know how much weight is on each tire, use this formula:

(actual weight on tire) / (max weight rating on tire) X (max tire pressure rating).

I like to add 2-3 lbs of air on each tire, to make up for anytime that I might be carrying extra gear, or extra passengers.

On my 64 13 window bus, I ended up with 28psi front and rear. I fill them to 30, and I'm good to go. For 4-5 months, I was driving back and forth from SLC to Las Vegas each weekend. I tried filling my tires to the max pressure rating (44psi), and running them at 30psi and the gas milage difference was nil. The overall ride quality was a whole lot better though with the 'correct' settings. Sidewinds didn't affect me as much, and the ride was nice and smooth as opposed to the max pressure setting that would throw me all over the road on a windy day and let me feel every little bump in the road. And when you're stuck in a bus driving 8 hours non-stop, driver comfort is a top priority to me.

With the 30psi setting, I was getting 25mpg while driving 65mph, and 28mpg while driving 60mph. I never checked what I got at 55mph, because that is just too damned slow for me to cruise at for 200 miles at a time.

[busman70]

Ever since Firestone this has become a subject full of air.

I have a 70 bus, the front tire are standard radials, I run 35 psi with no abnormal wear and get 45,000+ mikeage on the tires. The rears are also standard radials and I run 35 psi, normal wear pattern and get close to 50,000 miles. No the front and rear are not the same brands. They are not cheap tires either, just bought at different times.

On my 78 bus the fronts are standard radials with 35psi and the rears are 6ply reinforced (D), depending on the load I run 40 or 45 psi.

The tire today are not the tires of yesterday as far as what air pressure required. With standard radials 30 to 35 in the front, watch the wear pattern. The rear should get no less than 32 with a max of 37, the ass end of these critters is really heavy. Watch the wear pattern.

Oh yea, my 73 Westy non pop top is set up the same as the 70 bus except it gets the 37 psi in the rear.

The tire pressure listed on the side of a tire is "MAX", if you like a stiff ride and wearing out the center of your tire by all means fill-em-up.

busman78

[Eaallred]

One thing that Firestone thing reminded me of....

The Firestone tires that came stock on the Explorers were rated for a 35psi max. I managed a Jiffy Lube for 7 years, and NONE of the customers I ever had wanted thier tires set to the 26psi that was recommended by the manufacturer. They all wanted them set to the max psi.

I would be willing to bet that all those Explorers that flipped were running the tires at they're 'max' psi.

Then look at the Corvair. These cars were known for flipping or loosing control if the tire pressure was not set at what Chevrolet recommended. The tire pressure was recommended somewhere in the high teens if I remember right, but that just seems too low for most people, so they jack the pressure way up and create an unsafe situation.

Also, with my bus (a 64 delux), my weight on both the front and rear axle are the same (withing a few lbs). A perfect 50/50 weight ratio. I always thought they were heavier in the rear like a bug as well. Bay windows may be different, I don't know. I know my old 66 Westy was heavier in the rear than the front, about a 55/45 split.

[busman70]

Actiually, the findings showed that the majority of the failed tires were underinflated. Too much air is not good, but too little air causes excessive cord damage by flexing. Not a good thing. Also nothing like good old quality union labor building something with the instilled beleif that you can't be fired, your bosses accept absolutely no responsibility, unless there is a hefty profit, and now you have the ground work for everything but quality.

[Pillow]

Blame the process/management not the union. It is a recorded fact that Bridgestone (owner of Firestone) is horrible to employees and cuts costs as much as possible to make a buck at the expense of quality.

Everyone was focusing on Firestone when the real problem is Bridgestone in general.

Granted I have run some Bridgestone tires in the past and they have been quite good.

[Superbeetle]

Thanks guys I was going on a trip. I did some research on type2.com and came up with the general rec of 30 front 40 rear. 30 front was cool but thank the gods I checked the max pressure on the rear tires (32psi) before I went on my merry way at 40.
So I ran 30-30 for 260 miles with good ride and gas mileage.

And about the Union thing, at least they're still producing SOMETHING in the US, another few trade agreements and you won't find a tire that isnt made by a 12 year old indonesian girl.

Later

[amskeptic]

Tire pressure numbers take into account the fact that the manufacturers try to fine-tune handling with tire pressure.
The Corvair ran 18 psi front as a chicken-s**t attempt to incite understeer with a car GM knew damn well would oversteer wickedly.
Same with the Explorer fiasco. Ford knew these cars would roll over before they would slide. So they chicken-s**t reduced the inflation pressures to hopefully induce sliding before rolling over.
Tires hate underinflation, and their directional stability is a joke when the sidewalls are gushy mushy folding over.
The VW Bus, on the other hand, likes *slightly* lower front pressures not to hide diabolical handling, but to help prevent the centers of the treads from wearing before the shoulders. Most of the European rear wheel drive cars of that vintage were playing with massive caster angles that butchered the outside treads, they did benefit from maximum posted pressures. The Bus shows the best even tread wear at about 31-32 front and 35-6 in the rear for your usual passenger tires at normal loads. The LT truck tires available for the Bus prefer a bit more in the rear if you are hauling a camper package or other heavy trips, man. If the front is kept within 5 psi of the rears, you will have your normal Bus handling.
As for our Firestone Ford Friends, pick your suicide, either wreck your tires with ridiculous low pressures that separate the plies, blow out and launch you into a ditch upside down, or keep your pressures up and flip it over anyway when you avoid the little bunny.
Colin

[regis101]

I did some tire research. The most information that I have found was on the westfalia owners website. Anyway. I'm running Bridgestone 603's on our 78 Westy. I have the 185-14's. Load range D. Good for 1835 lbs' at 65 psi. I've been keeping them at 60 psi. Just did the first rotation at 15k miles. A little late, but nonetheless, They got rebalanced and rotated. The tread depth was even across the width of the tire on all four. The fronts had minor scalloping. Never had an alignment on this thing since I've owned it. It tracks nicely and does not wander even in crosswinds. Keeping the fronts pumped up helps with smooth steering. Never use passenger tires on the heavy busses/campers. These things need sidewall strength. I have tires on our 67 bus that have a rating of 1400 lbs at 44 psi. Good tires for the application. They came on the bus. I keep them at 40 with no problems. The point? As someone else stated, go with what the tire states. But more important is to have the right tire.

[amskeptic]

I did some tire research. I have the 185-14's. Load range D. Good for 1835 lbs' at 65 psi. I've been keeping them at 60 psi. Never use passenger tires on the heavy busses/campers. But more important is to have the right tire.

I have always been bemused by the continual references to
"the heavy bus." Mine weighs barely 3,200 lbs. That's less than a Taurus, a Pontiac Bonneville, a Mercedes 450, my BMW 5 Series weighs 3575 unladen, 4575 loaded to the gills. Put a pile of people in my Bus and you hit 4,200lbs. That's 1,050 lbs per tire, compensate for the weight bias and you are at 1,350 rears and 750 fronts, you are running rock hard 60 psi in the front????? Yikes, I feel sorry for those belts when they hit a pot hole.
I agree that you should know your weight and your tire specifications, and for those who like to load their Buses up to the gunwales, by all means weigh it and do the math with the tires.
I use Michelin LTX 195 x14s at 30-31 front because they have so little work to do, the rears at 36 give me an axle load of 2,900 and I have never exceeded that by a long shot. Tires are at 60,000 miles and are just now beginning to get near the wear bars. I like the performance safety of my Michelin passenger car tires on my passenger carrying conveyance.
Colin

[regis101]

The bridgestones 603's were originally designed for the toyota trucks that used a dual rear wheel set up. And they're made in Japan. Mmm, how convenient. Granted, their payload would probably exceed my westy's total weight. Calling the various tire stores to ask for a tire for the westy's of any year produces little results. I can get away with less air pressure. I am merely gathering data for my own bebefit and perhaps others. Here in sunny california, we have good roads. When the road surface does get bad, it usually constitutes slower speeds so it's no big. Our 67 has tires that max at 44 and have a 1400 lb rating. It is obviously lighter than the 78 westy. That application works. One thing that I've noticed about the 185-14's at 60 psi is the reduced rolling resistance most noticable when exiting the freeways. It just rolls on up to the stop sign. I'm getting just shy of 23 mpg's. The whole package works in this case. Kinda sweet. The 603's in a 195-75 have a load rating C which is about 1500 lbs, at 50 psi, if memory serves. I may try them next. Sure, the 1800 lb rating is on the high side for a Westy, but I had to try it, ya know. These tires are designed for the higher pressure.. It's not like I'm overinflating them. Lastly, the ride quality is smooth and quiet. It uses a highway type tread design. I do not think there is a right answer here. Ya makes yer choices and ya spends yer monies. Pass it on. Peace

[yesnomabyso]

just keep filling the tire when you hear a loud pop then you know you went to far