[David]

To figure your Bus’s proper inflation pressures, You really should go by your actual axle weight. Your Steers maybe seem a little low?

[Archived]

Just had cat scale weight done

[George]

Steer should be around 110 (or better).

Drive around 100

Tag 85-90

[Dick]

Tire size would help, 365 or 315.

[Archived]

Me and George have been talking about this,I tried to explain it to him and I thought I knew the answer but I realized I’ve forget. A couple of years ago I did the same as George and weighed our XL 40 . Our 40 ft weight with full tanks was Steer 13,680 lbs- Drive 16,900lbs- Tag 10,140 lbs total 40,740 lbs, So at that time I lowered front from 120psi to 100psi and drives 100psi tag 95psi and that was still over what I thought it should be. I talked to a friend that has a truck shop and he said 1st thing, what is your tires rated at? I’m running Toyo tires all 315’s and steer tires are rated @ 10,000 lbs @ 130 psi drive tires 9090lbs@ 130 psi tags 10,000 @ 130 psi, so that means if the front was 20,000 lbs tires should be 130psi but front is 13,680lbs well under 20k, Looking @ Michelin chart front psi (single) should be 85psi ?? and drives @ 9090lb tires @(Dual) 16,900 Psi should be under 85lbs ??? tags @ 10,000 lbs tires should be under 85??? I’m confused, Is there a simple answer ?

[Archived]

Coach has 315 all positions

Using inflation formula

Steer 13,340/2=6670 / max weight 9090 =.73 x 130 max pressure = 95.3 lbs

Drive 18460 /2 = 9230 / 18180 =.51 x 130 = 66 lbs

Tag 11120/2 = 5560 /9090 = 61 lbs

All the tire charts have 85 as lowest air pressure for 315 tires

[Art]

I am not one to disagree with Michelin they are very good at manufacturing a great product.

I still remember about 45 years ago when they came out with truck radials and guys were having major issues with the inflation pressures they wanted you to run. The tires were getting zipper tears in the sidewalls and people were getting hurt. This has stuck with me for life.

The Beru system on new Prevost buses is out of touch with what guideline’s Michelin says to run your tire pressure. I have spoken at length with Prevost reps about this and they agree but it’s like a big secret.

I can talk tire wear until the cows come home from experience with cross country trucks but I won’t go there.

A couple things inexperienced people say, the ride is better. I say BS, if you think you can tell the difference between a tire with 15 to 20 more lbs of air you can go to the time out corner right now. You have an air ride seat and air ride suspension but your that good?

The other fantasy is if you run more pressure and the tire builds heat and pressure it will blow, negative. If you have capabilities to watch tire temperature on a hot desert road the blacktop is about 145 degrees and watch a tire that had 95 lbs of air to a tire that has 120 lbs of air heat up. The 120 tire will run much cooler than the less inflated tires. Tires running at 155 deg is normal. Sensors start going off at 165.

There are cushions we don;t know about. My new bus was the 1st converter X with the electric fan drive and Prevost wanted to see HP ratings and performance so they flew out to Eugene ,OR and we went to the Dyno. They ran my coach for 2 hours on the wheel and my tires heated up to 207 degrees. You would think they would blow but nothing. Lucky I guess.

So what does all this mean? Do you think Michelin pulls into 50 campgrounds and makes a tight turn into a spot with 85 lbs of air in a tag tire and watches it buckle and accounts for extra wear?

When they want you to run these low pressures I ask WHY?

When you turn a corner and the bus leans left or right you think you still have 8000 lbs on one side. If you drive in the SE you can get away with lower pressure but if you get in the NW Mountains you won’t.

So I get asked a couple times a month what pressure should I run. My safe answer is on 365’s and 315’s, 115 Steer 110 drive and 105 tag.It’s a good number for all positions. On a bus with 315’s the same numbers won’t hurt you. It’s about averages, if you create a small leak you won’t ruin a tire. Their numbers are to close to failure.

I actually run more pressure then what I posted and these are my opinions only. Let common sense be your guide.

I forgot a question from a friend riding with me about 7 or 8 years ago up Indio hill going out of the Desert on I 10. He has had 3 buses and he said to me how come when we go over those expansion joints on the little bridges I don’t feel them? I told him because I put air in my tires.

Later

bv

[Larry]

I know more air less rolling resistance and less heat, but when I 1st bought bus 5 years ago, steer he was running 120 psi, max 130 psi 10,000lb rated tire, steer 13,700lb you could feel every pebble or crack in the road, At 100 psi much better, My tire monitor did not change temp between the 2 psi’s, I’m still 15 lb’s higher then what the chart say’s,

[Tim]

Hard to find fault with Bernie’s logic, low pressure on 365’s on the tag (under 100 lbs) is a recipe for problems.

[Andre & Kathy]

I’m with Bernie on this one. I too was long haul trucking when radials came in and those zipper failures are unforgettable. As life evolved and I went through mechanical engineering school, I was fascinated by lessons about materials and how they fail. Sidewall flex is a killer on tires sooner or later. I run 125 all around in my 315s and my aging tender rear end can’t tell much difference in the well suspended Prevost. And I sleep better. Mike

[George]

Does the XL2 buses run all 315’s or are they like the H’s and run 365’s on steer and tag, and what is your weights on the XL2 buses?

[Rudy]

Around 2004 XLII went 365’s.

My XLII 2 slide 2006 chassis 07 Marathon build weighed 54,000 lbs.

18,000 ish

22,000 ish

14,000 ish

Later

bv

[Bill]

When I installed a Continental Pressure Pro system oon my Royale, they weighed it and said my pressure should be at:

100- front

90- drives

80- tags

My tires wear well, the ride is smooth and the last set of tires i just replaced were 10 years old with the blessing of a Michelin dealer that had inspected them at 8 years and said they were in excellent condition.

Btw, the tires were 3 years old when I put the pressure system on the bus.

[Joe]

Andre, I thought you sold your Royale and picked up an H model

[Mike]

Different Andre’