Fleetwood Bounder Ride/Tires PSI

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majicchuck

majicchuck

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Joined
Aug 3, 2017
Posts
127
Location
Buffalo NY
Hi folks-

I have a 93 Fleetwood Bounder 31k with 454 (that I purchased six months ago). This my first motorhome. Thus far have put over 6,000 miles on it. Primary use is weekend camping trips and vacations. I have had a lot of work done to the coach. New shocks, springs, airbags with compressor, tires, tie rod ends, ball joints, and addition of the safety-t plus. From the beginning the engine has run like a champ. Great on the highway. Plan on keeping for maybe a year before I move up to a newer coach.

Even with new tires (Kelly Armorsteel) I noticed that the coach seems to ride rougher over non-smooth roads. Not expecting a diesel ride. However, the older tires seemed to have less harsh responses to every dip in the road. I lowered the air pressure from 90 to 75 and did notice the ride was less harsh. The coach driver side interior wall suggests 65PSI (Cold). Should I come down to 65?

Thanks,
Chuck
 
Hi Chuck
The 1st thing to do is weigh the rig, if possible corner by corner. But axle by axle is good enough.
Once the weight is known refer to the tire manufacturers recommendation for air pressure.
I would suggest when weighing the rig have it loaded as you would when traveling with it, full load of fuel & fluids, and propane, etc.

I had a Bounder '97 34H that I removed the air bags and replaced them with coils that were designed to carry that kind of weight. That alone changed how the unit went down the road, made all the difference in the world.

Corky
 
majicchuck said:
Hi folks-

I have a 93 Fleetwood Bounder 31k with 454 (that I purchased six months ago). This my first motorhome. Thus far have put over 6,000 miles on it. Primary use is weekend camping trips and vacations. I have had a lot of work done to the coach. New shocks, springs, airbags with compressor, tires, tie rod ends, ball joints, and addition of the safety-t plus. From the beginning the engine has run like a champ. Great on the highway. Plan on keeping for maybe a year before I move up to a newer coach.

Even with new tires (Kelly Armorsteel) I noticed that the coach seems to ride rougher over non-smooth roads. Not expecting a diesel ride. However, the older tires seemed to have less harsh responses to every dip in the road. I lowered the air pressure from 90 to 75 and did notice the ride was less harsh. The coach driver side interior wall suggests 65PSI (Cold). Should I come down to 65?

Thanks,
Chuck

I certainly would check the tires and make sure they are fresh (no older than 7/8 years). We had a 34J and ran the tires around 75 and felt the ride was actually good, but the tires were new. They can harden with age.
Click to expand...
 

How can I delete my idiotic response LOL...certainly didn't read the part where new tires were bought!!

I think I need a nap.
 
If the tires are the same size as shown on the tire placard, then definitely drop the pressure to the 65 psi it shows. That is normally the psi needed for a full load (coach is at GVWR weight). Don't go any lower than that without getting it weighed on a scale. I recommend the weigh-in regardless, though, because you really should have at least the axle weights and total (gross) weight.

If you have changed tire size, all bets are off and you need both scaled weight and a tire load/inflation guide to determine the right pressure.

You also need to check and possibly adjust the pressure in the front air bags, which are part of the coil spring suspension on that coach. If they've never been replaced, they may be holed or cracked and deflated, or the pressure may have bled off over time, or maybe a former owner fiddled with it. The correct pressure depends on the front axle weight rating, but somewhere in the 50-70 psi range is probably good. You go harder for firmer handling or softer for a smoother ride. The max is about 90 psi, and the smallest GAWR axle can go as low as 40-50 psi.
 
Corky-

Thanks. Good point. I definitely need to check the weight. Thought about going away from airbags but decided to replace with new ones.

Chuck
 
Gary-

You just reminded me of something. I did switch from 8R 19.5 to 225/70/19.5. The 225's are slightly shorter tire. There is a 3-4 mph difference in the speedometer reading compared to the GPS.

Okay I will definitely need to find truck stop to weigh coach.

There are new airbags installed. However, I find that the pressure drops mostly in the front. I typically do try to keep them at 40-60 PSI. I thought the airbags had more to do with ride height than smooth/harsh ride.

Thanks,
Chuck
 
No, the air bags in the Chevy P-series chassis are part of the suspension, i.e. air springs.  The front axle weight rating is the combined capacity of the coil springs and air bags inside them. Insufficient air in the bags lets the suspension bottom out more easily, while high pressure can make the suspension very stiff.

You need a load inflation table for that size of tire. Each manufacturer has one, but not all make them easily available to the public. However, since the Tire & Rubber Mfgrs Association has well-establish tire construction standards, you can pretty much use any manufacturers inflation table for that size & type of tire. Here are Michelin's and Goodyears:

https://www.michelinb2b.com/wps/b2bcontent/PDF/RV_Tires_Brochure.pdf
http://www.goodyearrvtires.com/tire-inflation-loading.aspx
 
To expand on Gary's explanation, my air bags both had slow leaks. In the intermediate to lower air pressure zones my rig would porpoise (sp?). The nose would move quite a bit up and down over even the slightest of bumps. Almost like the shocks weren't working. The coils changed all of that behavior and made 4, 6, 10+ hours trips enjoyable.
I hope that all you have to do is make an air pressure adjustment in either or both tires and bags.

Also if my memory serves the bag pressure should be close to 90psi, but I could be wrong due to memory being overfilled with gobblygook.

Corky
 
Gary, thanks for the additional info. That makes sense. I just checked the tire inflation table. Very helpful.

Corky yeah definitely hoping that air adjustment makes the difference.

Thanks again for the feedback!

Chuck
 
90 psi is used on the heaviest of the old Chevy P30 front ends, the 5500 lb version. Later Workhorse P30 had an improved suspension and up to 6000 lb GAWR, and 90 psi was recommended for the 5500 and 6000 lb models. 110 psi was the max.

Lower GAWR Workhorse front ends used pressures from 60 to 70 psi, adjustable up or down for personal preferences in ride and handling. 50 psi was the minimum for those later model years. I think the minimum was 40 on the older Chevy versions.

Here's a Chevy vintage P30 Service Manual:
http://www.gmcmi.com/wp-content/uploads/2014/05/P30-Chassis-Manual.pdf
 
Don't know if this is pertinent to your situation or not, but since you mentioned that you changed tire sizes to a tire that is slightly shorter then OEM, is there any possibility that rear duals are rubbing together. A "shorter" tire may have a wider cross section than the OEM tires and if they (OEM) were close to start, you could have some intereference. Was this possibility considered when changing tire sizes? Just asking.
 
2kGeorgieBoy said:
Don't know if this is pertinent to your situation or not, but since you mentioned that you changed tire sizes to a tire that is slightly shorter then OEM, is there any possibility that rear duals are rubbing together. A "shorter" tire may have a wider cross section than the OEM tires and if they (OEM) were close to start, you could have some intereference. Was this possibility considered when changing tire sizes? Just asking.
Click to expand...

I agree, when I replaced the tires on my Challenger I wanted to go to a wider tire. The dealer that I bought the tires from refused to install the 225/70/19.5 on my wheels. He said the wheels weren't wide enough and they would be too close together. I stayed with 8R and ran 50 psi in the front bags. New shocks made a world of difference in my Challenger, I went with Gabriel shocks and steering damper. 
 
Changing tire size is not something to be done casually on these rigs. Some critical factors are steer tire clearance in the wheel well, dually spacing, wheel width vs tire width, and reassessment of the tire pressure based on scaled weights.  Some folks want to change to wider, lower, or larger tires, maybe because car guys have traditionally done so to make their vehicles look cool. Not a good idea without solid research into the effects and then a very careful selection of the new size.
 
Gary RV_Wizard said:
Changing tire size is not something to be done casually on these rigs. Some critical factors are steer tire clearance in the wheel well, dually spacing, wheel width vs tire width, and reassessment of the tire pressure based on scaled weights.  Some folks want to change to wider, lower, or larger tires, maybe because car guys have traditionally done so to make their vehicles look cool. Not a good idea without solid research into the effects and then a very careful selection of the new size.
Click to expand...

Gary and Charlie you bring up good points. I did my homework before switching from 8R tires (which were common in older motorhomes) to the 225/70/19.5's. However, it is not uncommon to make this switch. Also, it is a lot easier to find 225s. Some motorhomes require narrower rim size to make this switch. The tire dealer mentioned that I had enough spacing on the dually's to replace with 225s.

On another note, I checked my airbags and they were pretty low (all but the right rear below 40).  I forgot that the dash compressor only fills the rear tires. I have to manually fill the fronts not a big deal). The front passenger air bag had almost no air. So this is likely the culprit of my recent suspension/handling issues. However I still need to get the coach weighed.

I'm in the early stages of looking for newer coach (2005 and up). Would definitely prefer diesel pusher with air suspension in the 34-38' range. Want to be able to talk in normal voice while driving. But overall, the Bounder has been good to us. Got into this to see if we deed indeed like camping/vacationing in a motorhome (which I knew we would); now it may be time to make the jump. Thanks again for the feedback.

Chuck
 
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